Abstracts-Senior Seminar- 5/1/99

Abstracts in italics have not been updated to the final version
Anderson, Angela

A Comparison of the Economic and Biological responses of Cottonwood and Loblolly Pine to increased atmospheric levels of CO2

With the intent purpose of extrapolating the economic and bological response of increased levels CO2 for the foresty industry, photosynthesis measurements were taken on Cottonwood cuttings, Populua deltodies. The paper consists of two data sets. Upon planting of the cloned Populus deltodies intial increased CO2 measurements were taken, and after the completion of a full growth term the tree were cut and complete above ground carbon intake was measured. To determine how increased atmospheric CO2 will affect the physiology of cottonwood trees, cuttings of the cloned Populus deltodies [cottonwood] were grown in open-top chambers containing ambient or elevated CO2 concentration. The control treatment was maintained at ambient Biosphere 2 atmospheric CO2 (c. 450 +/- 505l l-1), and elevated CO2 treatment was maintained at approximately double ambient Biosphere 2 atmospheric CO2 (c. 1000 +/- 505l l-1). The effects of elevated CO2 on leaf photosynthesis, and stomatal conductance were measured. The cottonwoods exposed to CO2 enrichment showed no significant indication of photosynthetic down-regulation. There was no significant difference in the maximum assimilation rate between the treatment and the control (P< 0.24). The CO2 enriched treatment showed a decreased stomatal conductance of 15% (P< 0.03). The elevated CO2 concentrated atmosphere had an effect on the respiration rates of the plants; the compensation point of the treatment was on average 13% higher than the control (P< 0.01). (Second Data Set in collection)


Babbitt, Courtney

Phylogeny of the Opiliones (Arachnida): Maximum Likelihood, Miximum

The phylogenetic relationships within the Order Opiliones were examined using both morphological and molecular (18S ribosomal RNA) data for 33 members of the Order and multiple outgroups within the Class Chelicerata.  Phylogenetic analysis was then explored using both parsimony and maximum likelihood criteria, as well as different alignment schemes. The focus of this study was to untangle the relationships between the four main groups of Opiliones (Cyphophthalmi, Laniatores, Eupnoi, and Dyspnoi), as well as between problematic taxa within those groups.
        The variety of results obtained from all of the different methods of analysis for this data set implies that a plurality of methods does not necessarily converge on one "truth."  Instead, it is suggested that philosophical and methodological continuity are more important in defending the results of any phylogenetic analysis. For this data set, it is argued that direct optimization alignment with parsimony as the optimality criterion provides the best tree as evaluated by character congruence.  Therefore, one of the parsimony analyses, created by direct optimization alignment, and with the gap cost set at unity, is defended on those grounds.  The resulting topology is (Cyphophthalmi(Laniatores (Eupnoi+Dyspnoi))).  The alternative topology that was well supported was (Cyphophthalmi(Eupnoi(Dyspnoi+ Laniatores))) , but character congruence was higher when the Palpatores (Eupnoi+Dyspnoi) are a monophyletic group.

Biase, Blaire

Assessment of Recruitment to Casitas by Juvenile and Adult Panulirus argus on the Caicos Bank, Turks and Caicos Islands, British West Indies.

The Caribbean spiny lobster, Panulirus argus, is an essential resource to the South Caicos fishery. The current lobster stocks are potentially being harvested at unsustainable rates. In an effort to increase future lobster stocks, artificial shelters known as casitas have been used. THis study examined the success of mini and large casitas in the recruitment of P. argus to the areas on the Caicos bank. Three new sites were chosen for deployment of both mini and large casitas. Two sites, waters around Admiral's Aquarium and Mangrove Island, had an abundance of Laurencia spp. averaging 10% of the benthic cover of the area measured. One site at the south end of Long Cay had an abundance of Thalassia testudinum with 75% cover. From the initial introduction of casitas until December 1, 1998, no recruitment into the casitas had been recorded at the three new sites. Continued monitoring of previously deployed casitas at the Bell SOund Nature Reserve revealed 10 lobsters inhabiting sponges, 2 in mini-casitas, and one was found in an overturned conch shell. Since December of 1998, monitoring has continued and revealed recruitment into the Laurencia spp. abundant habitats.

Some potential reasons why no lobsters initially recruited into casitas are 1)The main larval pulse was missed since it occured during the new moon in July, 2) The tail end of El Nino brought in two main hurricanes to the West Indies that may have altered larval recruitment, 3) The time constraints of this project did not allow for sufficient soak time for the casitas. Recommendations for future research include continued monitoring , identification of additional sites, and large scale deployment of casitas in the preferred habitats.

Bickford, Slaten

Volcanoes as Hazards

Data were taken from three recent well-documented eruptions, Mt. Pinatubo in the Philippines, El Chichon in Mexico, and Mt. St. Helens in Washington state. The data encompass all aspects of the volcano as a hazard, specifically geared to the effects of a volcanic eruption on human activities and structures. Warning systems for an eruption were examined to determine their extent and level of preparedness for a volcanic event. Their response to an eruption was then judged with respect to the extent of their preparations to determine the effectiveness of different levels and types of preparations. The effects of each eruption both locally and globally were analyzed for their extent and severity. Local events examined include any lava produced, pyroclastic flows down the sides of the mountain, lahars flowing along its valleys, and ashfall in the immediate vicinity of the volcano. Secondary effects such as landslides, seismic activity or fires were also examined. Global results studied include the ash cloud, its extent, and the chemicals it contains, and the long term effects of the eruption on the atmosphere.

Based on the data collected, a set of guidelines have been established. The guidelines serve as a ground level from which volcanoes can be examined and eruptions compared in terms of their hazard to man. With the guidelines created from these three volcanoes, other previous eruptions can be assessed, adding their results and refining the system to account for a wider variety of eruptions and aftermaths. Active volcanoes can be examined to determine the potential hazards they pose to the regions around them and the rest of the world.

Britt, Lisette

Can recycled materials such as glass be used in construction materials like concrete?

As America deindustrializes and depletes its natural resources, it must figure out a way to use its accumulated wastes and search for other resources. During this past century, we have created an ever-increasing amount of waste, like glass, which landfills can no longer support. Our mining quarries are depleted. One cement company has started research and development to incorporate glass into its cement mix. It has streamlined the process of including recycled material in industrial processes that favor raw materials due to the depletion and cost of natural raw materials. A major hindrance to using waste glass in concrete is the alkali-silica reaction (ASR). This alkali-aggregate reaction occurs in concrete that contains traditional types of aggregate (i.e. gravel) but increases with the use of glass as the aggregate. The ASR produces an expansion in concrete which contains high-alkali cement (Ramachandran,1981). This expansion and subsequent deterioration take place over months and years. Glass based concrete usually has low strength due to the expansion (Ramachandran, 1981). However, a newly developed admixture has solved the ASR problem thereby increasing strength of concrete with glass as aggregate (Shimanovich, 1998). We use different colored glasses which have different levels of ASR. Because green glass most noticeably suppresses the reaction, it has aided in the use of waste glass as aggregate. Chromium oxide is a heavy metal that makes the glass appear green. It is still not known why glass containing chromium oxide suppresses the ASR in concrete. However, adding chromium oxide to concrete with other colors of glass (clear, amber, cobalt) does not suppress the ASR (Bob Nelson, 1996). Crushed glass is being tested and developed to be used as aggregate. The use of this recycled material requires several tests of its properties. The study of mechanical properties will help determine if the material is suitable for construction or even comparable to most traditional forms of aggregate. Traditional forms of aggregate include gravel, limestone, sand, sediment, stone, and pebbles. Among the technical difficulties related to the use of glass as aggregate in concrete, low strength in glass-based concrete is a concern. After getting beyond the ASR problem, strength was able to come to the forefront to be considered. An introduction to strength and the properties of concrete that influence it will be useful to understand the strength of glass-based concrete. Flow (static and dynamic) and compressive strength, are the two mechanical processes will be studied in this paper. Static flow, dynamic flow, and compressive strength will be studied as they relate to water/cement ratios and four different admixture types.


Chae, Young

Biodiversity of vagile arthropods and forest succession

Previous studies of forest succession have demonstrated that the diversity of plants and less mobile animals gradually increase through successional time, reach a maximum, and decline to a less diverse but stable climax community.  In this study, we explored the applicability of this trend to very vagile arthropods, whose home ranges likely exceeded the size of the treated area. Vagile arthropods were collected in early June 1998 at Black Rock Forest, a temperate mixed  hardwood forest in New York.  Two replicate plots in each age class of 11, 41, 65, and 87 years since a clear-cutting event were sampled.  Arthropods were sampled using pan traps and sorted to morphospecies.  Species richness and individual abundance at each plot were assessed through raw numbers , Shannon and Simpson Diversity Indices and an evenness index.  Chi-square tests were conducted to assess significant differences among all samples and samples within the same age classes, forest area, and taxonomic orders.
       Results indicated that overall species diversity and abundance were high early after a clear-cut (11 years) and peaked at mid-succession (65 years).  Diversity and abundance were low in the sites of the 41 year class, and they also declined at the oldest forest sites.  Different processes may be responsible for the two peaks.  Colonist and open-habitat
specialists with great dispersal abilities and large cruising ranges likely accounted for the early peak, whereas the later peak was probably due to the actual increase in community diversity through the persistence of early forest succession species.  Overall trends in succession reflect the changes in the diversity and abundance of specific taxa.
        While certain taxa did show no significant change in diversity and abundance through successional time, other vagile taxa sampled in large quantities seemed to follow natural community successional processes characterized by a peak in mid-succession.  These patterns suggest that certain vagile arthropod taxa may be used as bioindicators of the successional status of forest ecosystem.  However, factors other than successional age alone likely affected vagile arthropod distribution.

Chau, Nguyet

Categorization of ENSO and Its Relation to Precipitation in  the Murray/Darling River Basin

A brief review is given on the fundamentals of weather and climate in order to analyze the effects of ENSO (El Nino Southern Oscillation) on Australia.  The relationship between the relative variability of annual rainfall, the long-term mean annual rainfall, and the correlation between annual rainfall and the Southern Oscillation Index/Sea Surface Temperature are examined using precipitation data from the Murray/Darling River Basin for the period 1913 to 1990.  These variables are highly statistically correlated with the annual rainfall of this region of Australia.

Furthermore, ENSO events are categorized using Trenberth's methodology applied to the Nino 3.4 region (5°N-5°S, 120°-170°W), which appears to be a key component in the coupled atmospheric-ocean interactions of ENSO.  An El Nino is defined as occurring if 5-month running means of sea surface temperature anomalies exceed 0.4°C for 6 months or more in the Nino 3.4 region.  Alternatively, periods in which SST anomalies are less than -0.4°C  can be categorized as a La Nina event.  With this definition, El Ninos occur 29% of the time and La Ninas occur 25% of the time.

Mean smoothed sea surface temperatures have also increased since the 1950s, with the post-1979 period showing a large deviation from the overall SST anomaly value of the entire period of 1856-1998.  The base period climatology of 1950-1979, which is chosen as representative of the record this century, is dominated by average sea surface emperatures, whereas the period after 1979 has been biased towards warm conditions and dominated by El Nino conditions.  The tendency for more frequent El Nino events and fewer La Nina events since the late 1970's has been linked to decadal changes in climate throughout the Pacific.

Cherry, Jessie

Impacts of Climate Variability on the Energy Sector: climate and energy around the North Atlantic basin with a Norwegian case study

Abstract: Climate, the mean temperature and precipitation conditions on which all life depends, is known to have several large-scale mechanisms of variation which shift phases over a period of twelve months to several years. Three examples of these mechanisms, which are temporally defined here as medium-term, and which influence much of the world's climate, are El Nino-Southern Oscillation (ENSO), the Pacific-North American (PNA) pattern, and the North Atlantic Oscillation (NAO). There is now evidence from climate records and global observation systems that the intensity and frequency of these modes are changing in our current era. While government and industry have a strong interest in studying the source of climate variation and the cost-effectiveness of mitigation, sectors like the energy industry have already been affected by recent changes in mean temperature and precipitation. This study examines impacts of climate variability on the energy sector in countries around the North Atlantic basin, in addition to examining how the structure of those energy markets shapes climate impacts. Shocks to Norway's hydropower supply are discussed as an example. This study also suggests that if atmospherically forced changes in the intensity and frequency of large-scale climate mechanisms are the way in which longer-term climate change (the 'greenhouse effect') has its greatest affect on the energy sector, an even stronger argument exists for the inclusion of climate variability mechanisms in energy forecasting models. It is concluded that supply and demand for particular energy products in some countries near the North Atlantic are significantly correlated with these large-scale climate mechanisms. For example, heating oil consumption in Finland is highly correlated with the NAO index, even more so than is heating oil consumption with temperature. In Norway, hydropower production is strongly influenced by the NAO which, in turn, affects the price customers pay for electric utilities. In Suriname, hydropower production is correlated with both the NAO and the PNA pattern. Turkey's electricity consumption in the residential sector is highly correlated with ENSO. Other results are inconclusive. States on the Atlantic seaboard of the United States which have climates strongly controlled by the modes of the NAO, have no significant correlation to the NAO in their consumption of heating products. Aspects of climate variability examined here include the impact of the NAO, the PNA pattern, and ENSO on the supply and demand of energy commodities. This study endeavors to contribute to an integrated (scientific-economic) assessment of the interactions between climate and energy commodities.


Chin, Mona

How does Energy Cycle Through the Food Web in Black Rock Forest?

The purpose of this study was to quantify the amount of usable energy available to plants in Black Rock Forest and to use these results to estimate other quantities suchas the amount of energy consumed by animals in teh forest and higher level consumers. We want to see how solar energy is being cycled in the forest ecosystem and from here, to compare these calculations to typical human energy uses, such as how much energy an apartment building in Manhattan uses over a similar period.

Two data streams were taken from the "Data Harvester" for a closer examination at http://ingrid.ldgo.columbia.edu/SOURCES/.BRF/.Weather The PAR (amount of radiation that plants can use) and Net Global (total solar radiation ) for the year 1998 was used. The PAR measured the amount of enrgy which supports the biomass production and the Net Global calculated the total incoming amount of energy. Using these two data streams will allow me to see how much of the incoming solar energy is utilized by primary producers to create biomass and to quantify the energy available to support consumers at the various trophic levels.


Cohn, Alicia

Climate Variability and Peruvian Small Pelagic Fish Catch: Possibilities for Prediction

Peruvians have long known that a decline in fish stock tends to follow a warming of the water off their coast.  In the last one hundred years understanding of this phenomenon has become more sophisticated.  We now know that this localized warming is part of a global climatic fluctuation, the El Niño-Southern Oscillation.  This interannual variability is marked by slackening trade winds which reduce upwelling and drive fish deeper and further south in search of cold, nutrient rich water.  The catch data and sea surface temperature record display a strong negative correlation.  Using an El Niño model which forecasts sea surface temperature, we are able to forecast the catch.
    This study found a significant correlation (r=- 0.54) between yearly catch (1952-1992) values with a five year running mean subtracted, to remove long-term variability, and sea surface temperature anomaly (SSTA) in the NINO 1+2 index region.  Because the greatest drop in catch does not immediately follow a warm event, this correlation appears when SSTA leads catch by 10 months.  Fish catch correlates as well with the model forecast of SSTA as the observed SSTA.  A six month forecast averaging the SSTA in the  NINO 1+2, NINO 3, or NINO coast (defined as 80-90 W, 10N-15S) of "cold" predicts a 50-60% probability of the next year's catch falling within the highest tercile; a forecast of "warm" predicts a 50-60% probability of next year's catch falling within the lowest tercile.

Cox, Susannah

Salamanders of New York City: Evidence of Local Extinctions due to Urbanization

Data collected by various researchers on salamander presences in New York City were compiled and organized into a Geographical Information System. Information includes data from 1880 to 1940 that the Museum of New York State released in a book and data collected by the New York City Department of Parks and Recreation Natural Resources Group (NRG) from 1994 to 1999.  From comparisons of these data and references to other research on salamanders, it can be concluded that five species of salamanders have gone extinct in the New York City area in the 1900s. Loss of habitat is presumably the primary cause of these extinctions. This particular study will not be completed to my satisfaction until late autumn of 1999, the end of the salamanders' active season.  Significant conclusions can be drawn, however, that salamander extinctions have occurred and may continue to occur without adequate habitat management. In the event that reintroductions take place, this research should be referred to as the GIS shows where appropriate habitat areas and salamander populations currently exist.

Gillette, Felix

A Time Series Analysis of Land Cover Change in Gifford Pinchot National Forest from 1972 to 1992 Using Landsat MSS Digital Satellite Imagery

Debates over forestry management in the Pacific Northwest have initiated a number of scientific studies which use digital satellite imagery to investigate the spacial and temporal alteration of forest land cover associated with anthropogenic causes: specifically, those related to timber harvesting activities. A simple and relatively inexpensive technique which has been demonstrated to be an effective method of monitoring changes in forest dynamics in the Eastern United States, was
applied for the first time to an area in the Pacific Northwest, which approximates the boundaries of Gifford Pinchot National Forest.  The choice of study sight allowed for a preliminary test of the underlying hypothesis which posits that variation in ground vegetation can be accurately quantified, by applying a modified parallelepiped classification to the observed spectral variation in a NDVI-RGB image.
        The explosion of Mount Saint Helens in 1980 provided a natural test of this hypothesis.  Three Landsat MSS images from 1972, 1985, and 1992 were transformed to a single band of information called the Normalized Difference Vegetation Index (NDVI) which has been demonstrated to have a high correlation with green biomass.  The 1972, 1985 and 1992 NDVI values were then assigned to Blue, Red and Green respectively in a composite multi-temporal NDVI-GRB image.  Areas with high biomass in 1972, low biomass in 1985 and low biomass in 1992 were hypothezised to appear with a distinctinve blue hue in the NDVI-RGB image.  The explosion of Mount Saint Helens in 1980 replaced the forests to its north with dense lava flows incapable of supporting rapid succession to a high biomass
biome.  Therefore, according to the hypothesis used to define classes of change/no change, this region should appear blue in the NDVI-RGB image; and it does.  Although more research is needed, this finding suggests that the RGB-NDVI technique is a feasible method for supporting future inventories of forest dynamics in the Pacific Northwest.

Goldberg, Irit

Emerging Evidence Questions the Toxicity of Mercury Amalgams

The widespread public concern over possible neuropsychological effects from mercry amalgams necessitated a large research project. Becuase potentially harmful mercury vapors may escape from the amalgams as a result of chewing or grinding the teeth, the safety of dental amalgams is in question. Data was collected from 295 Columbia University ersonnel, aged 30-49 years, who were randomly selected to participate in this cross-sectional epidemiological study. The hour and a half study visit for each subject included a non-invasive dental exam, a blood test, and a series of neurological, neuropsychological, and mood tests.
        Mean values for the neurological, neuropsychological, and mood tests were significantly similar to the normal standards. Mean urinary mercury levels for the subjects (1.88 +/- 1.99 ug Hg/g creatinine) were within the range of 1 ug Hg/ g creatinine, the reference urine level in nonexposed adults (Magos, 1991). The results seemed to suggest that inorganic mercury vapors from dental amalgams may not be as harmful as expected. The conclusion of this ongoing project will eventually yield data from approximately 600 subjects in total. The statistical correlation between urinary mercury and neuropsychological effects will then be assessed.

Grossman, Xena

Monitoring Monitoring Water Quality in Costa Rica and New York  - Water Quality analysis of the Protected Santa Elena Biological Reserve Watershed: Costa Rica, the Unprotected Rio Chiquito: Costa Rica, the Croton Reservoir: New York, and the Harlem Meer Watershed in Central Park: New York.

Water Quality in the Santa Elena Biological Reserve, Costa Rica In 1989, the Santa Elena Biological Reserve in Costa Rica was founded as a multipurpose area of conservation.  Located in the cloud forest, the reserve and the Arenal protected Area to its north, serve to protect the watershed of the town of Santa Elena. Residents and visitors to the local town of Santa Elena rely on the watershed for potable drinking water.  The purpose of my research is to determine the effect the biological reserve has on the quality of the drinking water.  My working hypothesis is that the water quality within the Reserve and protected area deems the water potable.  The alternate hypothesis is that the biological reserve does not ensure that the water is potable.  In order to determine the quality of the water, standard methods of drinking water quality were applied as outlined by the World Health Organization.  The following parameters were tested: nitrate, hardness, pH, chloride, fecal and total coliform, temperature, dissolved oxygen, and conductivity.  Samples were taken from rivers in the Santa Elena Biological Reserve, outside of the reserve but still in the Arenal Protected Area, and in rivers without any management.
        The only parameters in which both the protected and unprotected samples in Costa Rica did not all pass WHO standards were pH and fecal coliforms.  Many of the water samples were too acid and fecal coliform was present in many of the samples.  Likewise, I do not feel confident that with my data alone, decisions about where to draw potable water can be determined.  This paper also compares the rural, tropical water system of Santa Elena, Costa Rica, with the urban, temperate water system found in New York. Like in Costa Rica, water samples were collected in both a protected and unprotected watershed.  The protected water was from the Croton Reservoir, New York.  This water is monitored and treated by the NYCDEP to ensure potable water.  The unprotected water was sampled from the Harlem Meer, a water body in the high-use Central Park, New York City.   Water from Croton flows via the Croton aqueduct to inlet pipes at the Harlem Meer. Additional water enters the Harlem Meer from watershed runoff.  The same parameters were tested and the following hypothesis tested: Water quality in the unprotected Central Park will exhibit lower water quality in comparison to it's protected water in Croton, than will the unprotected water in Costa Rica when compared to the protected reserve.  Comparing this data to the Costa Rica it is interesting to note that the values for
the parameters were not that different.  However, the effect of the unprotected watershed on the water quality was more noticeable in New York than in Costa Rica.

Harry, Nandy

Forest Migration and Climate of Coastal Alaska - Macrofossil Stratigraphy of Ragged South, Alaska

Vegetational history is interpreted using stratigraphic analysis of samples obtained from a core taken from Ragged South, Alaska. The oldest segment of this core dates to approximately 10780 + 140 years B.P.  40 samples were studied to establish the vegetational and climatic history of Ragged South. Contents of the core were identified using modern reference materials collected from other sites along the coast of Alaska. The Ragged South region experiences high levels of precipitation and high humidity. Areas along the coast exhibiting similar climatic conditions have a  high occurrence of conifers. The Pacific Coastal forest is the major representative of vegetation along the southern coast of Alaska. Studies done on neighboring regions to the east and west of the site suggest that conifers may have entered the Ragged South region between 6000 yr B.P. and 2680 yr B.P.
    While pollen results indicate that conifers may have entered the Ragged South area around 3,000 years ago, there is no evidence in the form of macrofossils, namely seeds, needles or twigs found in the core to support this. Reasons for the absence of macrofossils can be attributed to climatic patterns, soil content and proximity of the site to the shore. The substantial presence of a various mosses and plants and the continuously changing lithology of the core indicate that the environment was constantly changing over time. This study indicates that the conifers may not have traveled along the coast as believed, but further sampling and studying of areas neighboring Ragged South need to be performed before
a conclusive tree migration pattern can be reached.

Hasan, Fatima

Reconstructing Past Environmental Conditions From Diatom Abundance in Lake Sediments at Black Rock Forest, Orange County, New York

This study used surface sediments from five Black Rock Forest ponds to establish a correlation between environmental parameters and diatom assemblages.  Efforts to reconstruct the environmental history of the ponds were attepmpted.  The present study addressed two main questions concerning Black Rock Forest ponds: (1) Are there detectable changes in diatom assemblages among the five ponds.  (2) Do the diatom assemblages correlate with environmental parameters?
        The environmental parameters are pH, conductivity, ammonium, nitrate, phosphorous, silicate, and calcium.  The results of this study suggest that there is a correlation between environmental variables and some diatom assemblages (p= 0.05). The detectable changes found among the five ponds are as follows.  Tabellaria fenestrata is highly abundant in
acidic environments of Tamarack, Sutherland, and Jim's Pond.  Tabellaria flocculosa is abundant in all five ponds.  Eunotia sudetica is abundant in acidic ponds (Tamarack, Sutherland, and Jim's Ponds) and absent in alkaline environment.  Frustulia rhomboides is significantly abundant in Tamarack Pond (greater than 20%).  Surirella ovalis is most abundant in Aleck Meadow R. 1. Nitzschia sp. A is most abundant in Upper Reservoir. Neidium affine var. affine is most abundant in Jim's Pond.  This information is interesting and will form the guideline for future investigation.

Karimi, Shaheena

Urban Toxic Exposures of High School Students in New York City: An Analysis of Questionnaire Data

Studies have been performed in the past that deal with toxic exposures to those residing in urban America.  However, the data available is very minimal.  The effects of Volatile Organic Compounds (VOC), Aldehydes, Particulate Matter less than 2.5 microns in diameter, and metals, on the human body is not well understood.  Using high school students, and their homes, this study will attempt to asses the contributions of a range of source categories to personal, outdoor, and/or indoor exposures collecting data on individual VOC's, Aldehydes, and metals.
        Student Survey questionnaires were administered to 575 high school, and to date 19 students have participated in the investigation.  The remaining 11 students will have completed the study by the end of the school year.  It was important to determine whether or not the students chosen to participate in the investigation were representative of the 575 students asked to complete the questionnaire.
        Using percentages to determine representation, all sub-categories were represented within a reasonable margin except for gender and students that had been diagnosed with asthma.

Kim, Grace

Posisoned Homes

Background:  Moderate to low levels of lead exposure cause permanent behavioral changes and learning disabilities in young children. Residential paint used before 1950 contained up to 50% lead by weight and currently 26 million families live in pre-1950 housing.  New York City hosts 63.5% of the nation's possible problematic housing and houses a population of approximately 7,230,479 people.  Children under the age of six comprise 8.48% of this population and about 78% of these children live in housing in which lead paint is likely to be present.  The objective of this case-control study was to assess the association between children's (ages £ 5 years) elevated blood lead levels (BLLs), hand-to-mouth activity and renovation or repair of homes built before 1950. Methods:  In 1998, parents of case and control children living in middle class New York City neighborhoods were interviewed.  Odds ratios were generated to determine statistically significant variables that affect lead levels in children.
Results:  Case children (N=106) were only slightly more likely than the controls (N=159) to have had renovation (N=70) within their homes (OR=1.61, 95%CI=0.93-2.80).  Location of the home (borough) also had a significant relationship with case status (OR=2.21, 95%CI=1.34-3.65). Race, although not directly linked to case status, was associated with
renovation activities (OR=1.24, 95%CI=0.76-2.03) and with hand-to-mouth behavior (OR=1.15, 95%CI=0.69-1.93).
Conclusion:   As hypothesized, renovation within pre-1950 housing and hand-to-mouth activity were associated with increased risk of childhood lead poisoning.  However, the location of the home (borough) and the race of the child were also important factors associated with the hypothesized variables and further explain the model.


Kotowicz, Dawn

Factors Determining Salt Front Location in the Hudson River Estuary Under Current and Future Climates

The Hudson River estuary is an ecosystem in which salinity, flow rates, suspended matter, temperature and other hydraulic processes vary cyclically in response to changing tides and seasons.  The salt front is the interface in the shape of a wedge between the more dense, saline water traveling upstream from the ocean and the less dense freshwater flowing downstream.  This investigation examines several types of data in relation to salinity values in the Hudson River.  Data types include conductivity, suspended matter, river elevation, and precipitation data over various time periods at several locations along the Hudson River to determine the influence of these factors on the salt front.
    Climate change and sea level rise pose a threat to estuaries because an increase in sea level is likely to increase salt intrusion and push the salt wedge upstream. This would change the range of conditions affecting a given area of an estuarine system.  All the data types investigated, influence the location of the salt front, however, precipitation appears to show the most significant correlation with conductivity.  Increased precipitation increases freshwater flow downstream directly and indirectly, as runoff.  An increase in freshwater flow causes a relative decrease in the influence of saline water on the Hudson River estuary because the salt front is pushed downstream.
    Considering the effects of the factors investigated, if all other factors remain unchanged, a rise in sea level should increase salt intrusion in the Hudson River.  In the specific case of the Hudson River estuary, water quality may be effected by an increase in sea level rise, as the Hudson serves as a drinking water source (NYS DEC, 1998).

Lapidus, Sivia

The Prospective Neuroepidemiology of Adult Lead Exposure

The main objective in this study is to determine whether there is a longitudinal association between the low-level lead exposure experienced by construction workers and decrements in their nervous system function.  We performed intake examinations on a population of 91 ironworker apprentices.  Examinations consisted of interviews investigating the individual's work history, medical history, and symptoms. In addition, nerve conduction velocity, grip and pinch strength, grooved pegboard, vibrotactile threshold, and  omputerized neurobehavioral tests determined the subject's neurological functions.  K-X-Ray Fluorescence (a non-invasive method of measuring cumulative lead exposure) and Atomic Absorption Spectrophotometry (for measuring lead in whole blood) were used to assess long-term and short-term lead exposure respectively.  The follow-up examinations, which took place one to three years after the intake examinations, were similar to the intake examinations in that neurobehavioral tests, bone lead measurements, and questionnaire administration occurred on both occasions.
       The data from these examinations revealed subclinical  peripheral neurological dammage in the subjects after one to three years of lead exposure.  The nerve conduction velocity test results whose decreases were significant included ulnar motor conduction velocity and median sensory nerve conduction velocity with respective significance values of .006 and .005.  An increase in years of  ironwork was predictive of the slowing of the median sensory, ulnar motor, and sural sensory conduction velocities.  The model variance explained was, however, low.  In addition, blood lead level at the intake examination was predictive for the changes in sural sensory conduction velocity, but was not predictive for the changes in the ulnar motor and median sensory conduction velocities.  These results reveal that blood lead is not predictive for all subclinical symptoms resulting from cumulative lead exposure.  Although bone lead level was not predictive of slowing nerve conduction velocities and was not significantly altered between the intake and follow-up examinations. The increase in bone lead suggests that with an extended time span, bone lead may indeed predict changes in nerve conduction velocity. The implications fo these results are that the Occupational Standard Health Administration should elucidate their standards by requiring employers to assess lead exposure through years of iron-work, bone lead measurements, and tests for subclinical symptoms of lead exposure in addition to measuring blood lead levels.

Liu, Darice

Use and Effect of the 1997/98 El Niño Forecast:  Assessing Zimbabwe and Mozambique's Food and Agriculture Security

Today, long term climate forecasts draw considerable attention worldwide.  Interest in such forecasts is based on the belief that, if one could predict the emergence of a seasonal event by identifying and focusing on its precursors, intervention could be taken early enough if need be (example: preparation for possible drought).  Forecasts are based
on statistical and probability climate models.  Due to increased monitoring and analysis of data combined with technology and worldwide resources, the percent value of error for forecasts is relatively small. But what happens when forecasts turn out to be incorrect?  What are the negative effects of erroneous information given to countries that  mold
their lifestyles to compliment forecasts?
       In my project, I review warning reports of official 1997/98 El Niño forecasts related to food and agriculture security, the impact of those advisories, and the recorded precipitation and crop yield.  Using the case scenario method, this study assesses the use of ENSO information during 1997/98 in Mozambique and Zimbabwe.  Forecasts for the southern African region called for low precipitation and a strong probability of drought were the likely effects of the El Nino episode.  Having experienced the devastation of the 1991/92 ENSO event, these two southern African countries prepared for the event with water conservation, decreased crop planting, maintaining a high capacity of dams, and other
means to mitigate any possible results of El Nino.  In the end, instead of below-normal rainfall, heavy rain fell on the lands.  Flooding and reduced planting resulted in lower than average crop production.  An investigation is made on the value of forecasts using ENSO warnings and the impacts of inaccurate warnings is made.
        In the final chapter, I note that lessons were learned from the 1997/98 El Nino forecasts in Zimbabwe and Mozambique.  Forecasts influence many aspects of human life, including food security.  Erronerous forecasts can lead to false warnings that could have an adverse effect on food security.  Nevertheless, the value of forecasts should not be based on the success or failure of any single forecast.

McClelland, Mandalyn

Geophysics and Hydrological Modeling: Studying Subsurface Flow

Current trends in the exploitation of groundwater resources require that hydrogeologists and water resouce managers monitor and mitigate against contamination of rural and municipal water supplies.  Recent advances with geophysical imaging methods such as ground penetrating radar (GPR) indicate that this technology may be a cost effective way to image the subsurface and track paths of preferential fluid flow.  However, before it can be fully incorporated into mainstream use, the limitations of the technology must be tested further.  To this end, the environmental and engineering geophysics group at Columbia University has created a unique laboratory facility that will use physical models to research and develop imaging techniques.  This paper concentrates on the process of developing these physical models through the use of numerical model (MODFLOW) simulations.
        The physical properties of the chosen transport medium (sand) were classified and used as inputs within the numerical model.  MODFLOW was used to design experimental scenarios which would create a recognizeable change in the surface of the water table over time.  This includes the specification of inflow and outflow systems that are both cost effective and easy to implement within the physical models.  Three types of model scenarios were attempted:  the creation of a hydraulic head gradient, rising water table, and falling water table.
        While successful simulations of a hydraulic head gradient and a rising water table were created, the falling water table was not acheived. In addition, complications arose with both of the other two simulations. Although a relatively stable gradient was created within the model, it required a the use of a pumping system that would not be easily implemented in the physical models.  The falling water table simulations were not uniformly successful, as only one of three simulations maintained its integrity after the introduction of the physical porosity data.  The cause of the first is presumed to be the high hydraulic conductivity of the sand that is used in the experiments, the second  is most likely due to the modeler's lack of expertise.   Further work on the simulations will be necessary before an adequate assessment of their ability to accurately predict the  outcome of the physical models can be made.

McCreary, Leone

Carbon dioxide dynamics in a coral reef ecosystem: Hog reef flat, Bermuda

Recent studies suggest that coral reef ecosystems are net sources of carbon dioxide to the atmosphere, thereby serving as positive feedbacks to the current trend of increasing atmospheric carbon dioxide concentrations (Lashof, 1990). This paper investigates the role of reefs in air-sea carbon dioxide fluxes at Hog reef flat, Bermuda from October 12th to November 4th, 1998. The partial pressure of carbon dioxide (pCO2) in the surface waters of the terrace reef was measured at one hour intervals for a twenty-four day study period. Measurements were made by an autonomous pCO2 meter, CARIOCA. PCO2 ranged from 340-474 microatm with an average daily variation of ~40 microatm. Data shw that pCO2 in reef surface waters follow a regular diurnal cycle with pCO2 peaks in the early morning hours and pCO2 miniums during the late afternoon. In addition, normalization of the data for temperature has little effect on pCO2 values on a dirunal time scale. Therefore, the biological processes of photosynthesis and calcification, not temperature as has been found to be the case in other non-reef regions (Bates, 1998), are the dominant driving forces controlling pCO2 in reef surface waters. During the study period, average sea surface pCO2 (398 microatm) was higher than atmospheric pCO2 (~360 microatm), indicating a net efflux of CO2 from the ocean to the atmosphere.


Poulshock, Helene

Impacts of Climate Change on Agriculture in Arizona: Validation and Application of a Crop-Yield Model

        Agriculture is imperative in meeting human food needs and may be currently threatened by climate change.  Climate models are often one of the critical tols for analysis of such impacts; e extent that we place faith in these models should reflect how well they represent actual physical processes.  In this study, a crop-yield model, CERES-Wheat, is explored and its simulations tested against observed agricultural data collected in the arid environment of Maricopa, Arizona.  The observed field data provide both plots of spring wheat grown under ambient CO2 conditions and those grown under elevated CO2 conditions.  This allowed testing of CERES-Wheat as a climate-vegetation interaction model.  This model was then used to consider possible impacts on agriculture in Arizona under plausible future GCM climate change scenarios. The study found that CERES-Wheat accounts reasonably well for CO2 and water interactions, despite its rather simplified form.  Simulatons of growth have high statistical correlations to observations (r2 is between 0.96 and 0.99), though biomass is slightly overestimated and yield slightly underestimated.  Sensitivity analysis reveals that the model is able to reproduce the bio-physical relatonships between CO2, watr, and vegetation that are observed in arid environments.
       When GCM predictions are used to generate weather data for this agricultural region of Arizona (which are utilized as data sets in the CERES-WHeat model), the model can be used to examine the local effects of climate change on agriculture.  Yields were found to decrease from present day simulations when simulated both with and without the physiological effects of CO2, but this exercise also points to the possibility that increasing CO2 will make these yield decreases less drastic relative to present day.  These results suggest theshifting face of agriculture in light of predicted climate change.

Salzer, Sarah

The use of carbon and nitrogen isotopic ratios to trace food web interactions

In this experiment, the isotopic ratios of 13C/12C and 15N/14n in organic matter will be used to trace the feeding dynamics in aquatic systems. Isotopic fractionation occurs in most chemical reactions and favors the lighter isotope. Thus, the isotopic composition of organic matter as it is transferred from one trophic level to the next may indicate the source of the material and the number of transfers. Experiments were conducted on simple communities of Protozoa and prey under well defined laboratory conditions. Stentor coeruleus, a relatively large protozoan was used. the Stentors will be fed a homogenous diet and grown in a temperature and light controlled cabinet. Using a mass spectrometer, the isotopic ratios of the food and protozoa will be measured. The relationship between the isotopic ratio of the food and the isotopic ratio of the protozoa will be determined. Using multiple protozoa and prey types we hope to assemble an overall picture of the changes in isotopic ratios from trophic level to trophic level. The relationship of the prey isotopic ratios to the organism's isotopic ratios observed in the laboratory can then be applied to field measurements.


Schrein, Caitlin Maureen

Paradolichopithecus arvernensis: A European fossil monkey and its morphological affinities with macaques and baboons.

Qualitative and quantitative analyses were performed on two casts of the European fossil monkey, Paradolichopithecus arvernensis,  from the American Museum of Natural History to determine the morphological affinities of this type species with extant macaques and baboons.  Because phylogenetic relationships between these taxa have been subject to debate, this author persued the study with the goal of classifying the species into either the subtribe Macacina or Papionina, both of the subfamily Cercopithecinae.  This species was represented by the type female specimen from Seneze, France, and a male specimen from Graunceanu, Romania. Quantitative analyses established that characteristics of the male muzzle exhibit similarities with baboons and that statistical analyses were required to differentiate taxa.  Based on t-test results, and grpahical analysis, it is possible to say that the Seneze specimen greatly reembles macaques in one feature that distinguishes baboons and macaques, and that the Romania specimen more closel resembles members of Papio.  Results of multivariate analyses demonstrate that certain characteristics of both fossil specimens are fairly intermediate between the two extant genera, the Romanian specimen more closely resembling baboons and the specimen
from France more often sharing traits with macaques.  Thus, it is of the author's opinion that there is enough evidence to show that the ROmanian male may be placed within the subtribe Papionina and that the SEneze female amy be placed within the subtribe Macacina.  Results pertaining to the assignment of this species to a subtribe are thereofore  nconclusive. Further anlyses should be done on biogeography and craniometrics to clarify the strength of those affinities and to explain the evolution of  the unique characteristics of this species' morphology, in particular, the evidence of low sexual dimorphism.

Scdoris, Amanda

An Educational CO2 Measurement Kit: Teaching the Carbon Cycle

The presence of carbon dioxide in the atmosphere and the carbon cycle in the biosphere are often as hard to visualize as they are to understand.  This thesis hypothesizes that hands-on, real life examples of the features of the carbon cycle -- namely photosynthesis, respiration, and gas exchange -- will help to bridge the gap between confusion and comprehension.  The goal of the project was to create a simple, affordable carbon dioxide measurement kit, with which the aforementioned metaphorical bridge may be built.
        The experiments involved measuring the carbon dioxide content in a closed cylinder, into which was placed a collection of leaves, which were manipulated in order to produce a quantifiable change in the concentrations of CO2 present.  This was achieved by controlling the amount of incident sunlight.
        My role in the project involved designing and testing the experiments, as well as researching both the carbon cycle and Environmental Education.  The goal was to develop an educational tool that will prove useful to both teachers and students.  Taking the recommendations into account, the goal is well on its way to being reached.

Sem, Shruti

The Relative Contributions of Population, Technological Innovation, and Affluence on Groundwater Contamination: A Global Model

This study focuses on the causes of groundwater contamination. Population growth, technological innovation, and affluence are the independent variables of this study.  The dependent variable, groundwater contamination, is defined in two ways, the Percentage of Population with Access to Sanitation and the Percentage of Population with Access to Safe
Drinking Water by Country.  These particular proxies are used with the understanding that the higher the impact of the independent variables on groundwater contamination, the lower the percentages.  The IPAT model, Impact equals the multiplication of Population, Affluence, and Technology analyzes the causes of these three independent variables.  Thus, the measure of impact will equal the two proxies for the measure of groundwater contamination listed above.   Two models are generated from this data by graphing each independent variable against the dependent  variable, impact.  After the plotting this data, two models will be constructed from the generated linear trend lines.  There are two main objectives for this experiment.  The first is to judge whether the models are good global indicators of groundwater contamination.  The regression analyses will provide a method to judge the two models. The second objective of this experiment is to consider if either model is a good fit for India.    Inserting India as a data point into these equations will test the generated models.  If India's data fits, the model will be a good predictor for India's future.  It was concluded that Impact model #2 was the better fit for India's data, while Impact model #1 was a better global model.

Stamler, Dina

Los Frailes mine spill & effects of As

This project is designed to determine the amount of arsenic that was released in the Los Frailes mine spill in Southern Spain, and the effects of that release on the natural ecosystem.  The Guadiamar River is connected to the Guadalquivir River and to Donana National Park.  it is usually protected from the acid tailings that are produced by the mining at Los Frailes by a large basin within which all of the acid sludge is stored after the zinc is removed from the ore.  In an accident on April 25, 1998, approximately 5x106 m3 of acid sludge was released into the water of the Guadiamar River.  Research has already been done on zinc, cadmium, copper, and lead in order to determine their behavior immediately after the spill.  This project entails analyzing water and sediment samples that were collected from the site one week after the accident.  Through this analysis, it was determined that the highest concentration of arsenic can be found in the sediment samples and that the concentration of arsenic in the water samples decreased rapidly downstream.  Some long term goals of this research include, learning how to effectively deal with such accidents in the future, and having scientific evidence with which to promote the enforcement of laws pertaining to mining.  Other goals include assessing the damage to the  urrounding areas and generating strategies for the treatment of that damage.

Tawil, Sophia

Persistent Organic Pollutants: International Prioritization

In June, the United Nations organized the first formal negotiations on establishing global controls on Persistent Organic Pollutants (POPs), a class of chemicals that includes pesticides such as DDT, industrial chemicals and by-products such as PCBs and dioxins, as well as other long-lived, bioaccumulating, toxic compounds.  Twelve specific chemicals, known as the "Dirty Dozen" are currently being discussed within the international negotiations.  This paper attempts to prioritize which of the nine pesticides should be regulated first.  The investigation consists of three analyses.  The first compares the probable effects these chemicals will have on humans and the environment based on their different chemical properties.  The second analysis attempts to compare the costs and benefits of regulating these chemicals.  Data for this analysis was limited due to minimal economic comparisons of these chemicals within the available literature.  The third analysis discusses probable political factors which will play a strong role in the negotiations process.  While the political and scientific analyses (the economic analysis was inconclusive due to lack of available information) revealed that Aldrin and Dieldrin should be prioritized in the negotiations, further comparison of the results showed that the priority lists differed greatly.  A discussion of the economic options for managing and regulating these chemicals presented that a system of tradeable permits would be the most cost-efficient and environmentally effective.  It would also allow for a more equitable distribution of cost between developed and developing countries.

Thomas, Jessy

Projecting Impacts of Climate Change on Jamaica  Bay Wetland Habitats Using Aerial Photography and Global   Climate Models

Sea level rise, as a result of climate change, is posing a threat to the wetlands of Jamaica Bay (41º North, 74º West).  With more frequent storm events under projected climate change scenarios, saltmarshes become vulnerable to erosion damage.  Coupled with continuing sea level rise, the severity of erosion increases, thereby threatening the loss of valuable
wetland habitats.  In order to avoid complete loss of the marsh, the dominant saltmarsh vegetation Spartina alterniflora will have to perpetuate itself at a rate greater than or equal to the rate of current sea level rise (2.73 mm/yr in New York City; 2.5 mm/yr in Jamaica Bay). The rate at which a marsh perpetuates itself is referred to as the rate of
accretion, and is relative to the rate of subsidence. Because of its unique characteristics and responsiveness to sea level rise and tidal cycles, S. alterniflora is a prime indicator of habitat vulnerability to climate change.  The objective of this thesis is to develop vulnerability assessments for protected wetlands by projecting the impacts of climate change on wetland habitats of Jamaica Bay.
Direct anthropogenic impacts on the loss of wetlands were documented by examining a series of historical NOAA navigation maps from 1926, 1948, 1970, and calculating the acreage of wetlands, uplands, and open water through time using the design program AutoCAD R 14.  Between 1926 and 1970, there is a cumulative 5% loss of wetlands in the Broad Channel area (includes Little Egg marsh and Giant Bar marsh), a 25% loss in wetlands in the Edgmere landfill site, and a 42% loss in wetlands at the John F. Kennedy International Airport site.  These changes are attributed to dredging, filling, and other development activities within the bay. Aerial photographs of several marshes of Jamaica Bay from 1959, 1976, 1991, and 1998 were used to assess the evidence and extent of erosion on selected study areas.  Several federally protected marshes, such as Yellow Bar Hassock, Black Wall marsh, and Big Egg marsh, were used to demonstrate possible impacts of climate change.  Visible evidence in acreage loss was quantified on aerial photographs using a transparent grid (16 boxes per square inch).  Results indicated a net 13% decrease in marsh acreage in Yellow Bar Hassock, a net 7% loss in Black Wall marsh, and a net 15% loss in Big Egg marsh--losses that are attributed to sea level rise and other influences.  Applying several Global Climate Models (GCMs) and scenarios, sea level rise was projected into the twenty-first century and estimated for the Jamaica Bay region.  Current sea level rise is estimated at 2.7 mm/yr in New York City and 2.5 mm/yr in Jamaica Bay.  The projections for sea level rise range from 2.5-15.5 mm/yr. The quantified erosion of the protected marshes implies that they are not keeping up with the current rate of sea level rise.  Drawing upon the results of this study, severe marsh erosion in Jamaica Bay in the future will prove detrimental to both
the wildlife community as well as the residential communities relying on the saltmarshes for the innumerable benefits they have to offer.  Jamaica Bay Wildlife Refuge will see a decline in the number of migratory "stopover" species as well as the indigenous wildlife.  Moreover, the residential communities will experience poor water quality, as well as increased property damage from storms and tidal surges. 

Ujiki, Amy

Ethnobotany in the Urban Environment:  Traditional Chinese Medicine & Women's Health - A Comparative Study of Herbal Formula Compositions

This thesis attempts to determine relationships between textbook formulas of traditional Chinese medicine (TCM) and Chinese practitioners' formulas. I performed data entry and data analysis based on literature research and data from fieldwork completed by other researchers working on the project. Data derived from interviews with TCM practitioners and literature reviews.  It appears that certain herbs may be specific to a condition; however, I found that many herbs are used in formulas across various conditions.  This may be due to the fact that TCM formulas rely on a particular group of primary herbs.  Because TCM is a complex field of study, more research is required.  My research took place at the Center for Complementary & Alternative Medicine Research in Women's Health and at the Pacific Institute for Oriental Medicine.


Vaughan, Trinke

Forest Fires of northeastern Mexico and their Effects on the Breeding Biology of the Maroon-Fronted Parrot

The Maroon-Fronted Parrot Project in northeastern Mexico observed some notable changes in the breeding schedule of the Maroon-Fronted parrots for the 1998 season.  Since the project began in 1994, it has been observed that birds arrive to the breeding and nesting areas by late May. However, in 1998 the parrots did not come until late June, and they arrived in much lower numbers as compared to the previous years of study. In May of 1998 forest fires swept through Mexico and into the breeding ranges of the Maroon-Fronted Parrots.  These fires destroyed a large portion of pine forests located around the nest sites.  The parrots consume pine seeds as a staple diet and depend on the pine forests as their principle food source during breeding season.  This study focuses on the potential correlation between the forest fires in the breeding area and the altered breeding biology of the Maroon-Fronted parrot population.
       Through comparative studies of the observation data for 4 seasons, as well as an understanding of the effects of the forest fires that occurred in northeastern Mexico, it is concluded that there was only a possible correlation between changes in some of the breeding behaviors and the fires.  Furthermore, these correlations indicate that the fires had a
negative effect on the status of the parrot population by hindering normal breeding behavior, specifically chick production and nest selection.  It is inconclusive as to how the changes in breeding behavior for the 1998 season will affect the population in the future.  The continuation of intensive observations of the parrots in the future will be necessary to assess any long-term effects the fires may have on the parrot population.


Vidor, Carla

A winter severity index for deer at Black Rock Forest

The severity of the winter season as it affects the health and vitality of the deer herd at Black Rock Forest, can be estimated on a relative account, by data collected during the winter months at the Ridge Top station.  Winter severity parameters, such as temperature, wind speed, snow fall, and humidity, will allow for a more complete understanding of the health of the deer population as they emerge from the winter season. Since herd reproductive rates are entirely dependent on the physical condition of the female deer, estimates on herd health, made according winter severity, should be able to predict the future reproductive rates of the deer herd.  With this information, the deer harvest quota for hunting season, determined according to predicted reproductive rates, can be adjusted to suit both the needs of the forest and the herd by ensuring that the relationship between forest resources and deer population numbers is maintained in equilibrium.
    Winters are a critical time for the herd as overall body mass is ultimately threatened by low temperatures and high wind speeds that hasten body heat loss to the environment.  In addition to the increase in the rate of body mass depletion, deer are forced to trample through soft and deep snows to search for adequate shelter and nutrition, creating greater demands for energy during a time when nutritive availability and value of deer forage are at their lowest.  The available data offer two climatic variables that contribute most to herd health deterioration and will be included in the index.  These are the wind chill equivalent temperature, a measure of temperature and wind speeds, and snow fall.  The effects of cooling from low temperatures and high wind speeds, and the hindrance of movement experienced as a result of increased snow depth and decreased support from soft snow, are the main environmental threats that force the herd into critical condition.  By calculating the departure from the monthly average wind chill equivalent temperature and snow fall parameters for each winter month, a relative index of winter severity can be determined.  The index is simply a sum of the degree of departure from the average monthly wind chill and snow pack conditions for each winter  month.
    Unfortunately, data from the Ridge Top station only dates back until 1995, making the calculated averages quite insufficient to represent the "normal" and tolerable winter conditions at the forest.  However, the results do show relative severity in terms of the three winters.  The 1995-1996 winter was the most severe, with all the monthly indices at extremely negative values.  In contrast, the 1997-1998 winter was the mildest, with monthly index values over one thousand.  Clearly the enormous range of the indices is the result of the poorly averaged wind chill equivalent temperature and snowfall data.  The extremely short environmental data series prevents the estimation of a critical minimum winter severity index value which would determine the whether or not herd health will decline, stabilize, or improve.  In addition, the chill factor needs  to be adjusted for deer, and snow pack data, (which include snow depth and hardness), are necessary.   Before both parameters can be successfully integrated into a winter severity index, better and more climatic data are essential.

Wilson, Erica

The Saturation State of Calcium Carbonate and its Effect on the Coral Calcification Rate

Formation of coral reefs occurs in shallow tropical waters where there is a high supersaturation of the calcium carbonate mineral aragonite. Oceans constitute a substantial resevoir for anthropogenic CO2. Presently atmospheric CO2 levels are rapidly increasing and as a result calcium carbonate levels are dropping. A doubling of fossil fuel CO2 will reduce carbonate saturation levels by one third of its present day value. Previously, changes in the aragonite supersaturation were not thought to affect calcification rates of marine organisms. However, based on the results performed in the Biosphere 2 coral reef mesocosm the concentration of calcium carbonate greatly influences the rate of reef calcification. We show, linearly, that the reef calcification rates decrease with the concentration levels of calcium carbonate, with reference to aragonite saturation-states. If the level of atmoshperic CO2 continues to rise by 0.5% per year the atmospheric CO2 will double by the year 2080. As a result of this, and if the Biosphere 2 coral reef mesocosm is an accurate model of a natural reef system, the rate of calcification of the planet's reefs will decrease by approximately 30%.


Williamson, Alexandra

Analyses of Dissolved Organic Nitrogen in Forested and Estuarine Ecosystems: Black Rock Forest and Hudson River

Nitrogen is considered a limiting nutrient for primary production in both forested and marine ecosystems, and estimates of primary production can be based on nitrogen budgets.  Often in these past studies, dissolved organic nitrogen (DON) has been ignored.  However, DON has proven to be a significant component of the fixed nitrogen cycle in both forested and marine environments.  This thesis seeks to investigate the concentration and the chemical composition of DON in two non-marine environments in an attempt to more accurately describe the nitrogen budgets of these ecosystems.  Two different environments were studied. The first study compared the concentration of dissolved organic nitrogen and the characteristic dissolved proteins released from two watersheds in Black Rock Forest.  Cascade Brook watershed was characterized by a wetland and by primarily deciduous vegetation; Black Rock Brook watershed had a distinctive stand of coniferous hemlocks.   The second study examined the concentration of dissolved organic nitrogen and characterized the proteinaceous component of DON from Hudson River water collected at Erie Pier. Data for both studies were collected from 2/12/99- 3/27/99.
       Dissolved organic nitrogen was a significant component of the total dissolved nitrogen in both the forest and the estuary.  In Black Rock Forest, DON accounted for between 45% to 55% of total dissolved nitrogen.  Cascade Brook Watershed had a lower concentration of DON (1.2-1.7mM) than Black Rock Brook Watershed (3.7-4.1mM).  Samples collected after the Cascade Brook wetland had an increased concentration of DON.  The watersheds had similar characteristic proteins.  Cascade Brook had proteins of 62kDa, 66kDa, and 150kDa.  Black Rock Brook had proteins of 118kDa, 64kDa, and 62kDa.  Water that passed through the Cascade Brook wetland had a higher molecular weight protein (150kDa) than water that had not passed through the wetland; this suggests DON production in the wetland.  Water that passed through the hemlock stand had no distinct protein bands; this suggests protein degradation.  The Hudson River samples had DON concentrations of 3-20mM; these values represented between 5% to 50% of total dissolved nitrogen.  The Hudson River samples had some proteins in common with the Black Rock Forest samples (116kDa, 65kDa, 62kDa, 118kDa).  These samples also had some unique proteins (85kDa, 29kDa, 17kDa, 10kDa). The quantitative information about the DON contribution to total dissolved nitrogen indicate that DON should be considered in nitrogen budget calculations.  The qualitative information about DON provides insight into the biogeochemistry of ecosystems that can be useful in constructing nitrogen cycles and nitrogen budgets.

Wong, Jennifer

Environmental History of Piermont Marsh, Hudson River, NY

Although wetlands of the Hudson River have long attracted the interest of naturalists and scientists, Piermont Marsh has not been studied as extensively as others along the Hudson estuary.  The purpose of this study is to provide a broad overview of the paleoenvironment of Piermont Marsh, particularly changes in vegetation and fluctuations in sea level.
An 11.15 m core was retrieved from the site and sampled for macrofossil, loss-on-ignition, and pollen and spore analysis.  The lithology of the core is comprised of peats and clays that vary in color and texture.  Several short reversals between peat and clay sediments were found between the 6 m and 7 m depths.  AMS carbon-14 analyses revealed the marsh is approximately 4190 years old and the rate of deposition in the marsh is about 0.26 cm/yr.  Loss-on-ignition (LOI) of the sediments ranges from 1% to 85% and indicates the marsh has undergone changes in organic content due to deposition of different sediment types.  Plant macrofossils indicate the core site included sedges throughout much of the history of the marsh.  An increase in the pollen percentages for Gramineae in the younger sediment at 0 m, 0.3 m, 2 m, and 3 m suggests human influence in facilitating the prevalence of this family of plants.  Pollen influx values for Gramineae do not mirror the values for other local marsh species in the uppermost sediments.  Deviations in the pollen data from the regional signature indicates a change in regional climate not previously recorded in other cores from the Northeastern U.S.A.  The Tsuga pollen influx value is as much as three orders of magnitude higher at 4190 carbon-14 years, and about two orders of magnitude more Pinus grains are found between 3000 and 4190 carbon-14 years.  Foraminifera macrofossils reveal marine transgression at the core site, and record a history of oscillations between low marsh and high marsh environments.  The absence of foraminifera specimens at certain depths is a possible indicator of stream influence, salt pannes, or dilution due to rapid deposition.  Charcoal particles peak at 3 m, 7 m, and 11.15 m depths in the core, which is evidence for a change in fire frequency due to climatic change or from anthropogenic influence.

Yaraghi, Katayoun

A Study on DDE and Leptin and their effects on the risk of breast cancer

Analysis of the association of DDE and leptin concentrations with obesity and its effects on Breast Cancer development in three different ethnic groups.
                Earlier studies conducted on benign breast disease (BBD) did not emphasize the relationship between leptin and breast cancer or the relationship between DDE and benign breast disease within three ethnic groups.  This study, however, proposes to use previously obtained baseline data from a Breast Cancer (BC) study to investigate potential io-markers for obesity, such as the leptin protein and DDE.  Subsequently, the relationship between the concentration of leptin and DDE in the blood and the development of Breast Cancer and/or Breast Disease within three ethnic groups will be analyzed.  Furthermore, this study proposes to find an association between DDE, leptin and the risk for benign breast disease and breast cancer.   In order to adjust for possible confounders in the study, other factors such as body mass index, diet, age, physical activity, socio-economic status, alcohol consumption, age at menopause, oralcontraceptive use, and smoking will be examined.  Analysis of the risk factors that have previously been established as relevant to this esearch will be carried out.  Any variables that have not been shown to have statistically significant associations will not be examined.
       The three ethnic groups in this study represent very diverse dietary and behavioral habits.  This contributes to a varying risk of breast cancer and benign breast disease within these groups.  I have made two separate hypotheses regarding leptin and DDE.  My first hypothesis is that leptin is higher in and positively associated with obesity and minority status.  My second speculation is that DDE may be protective for Benign Breast Disease among the three different ethnic groups in this study.  Circumstances have only permitted testing of the later hypothesis which regards the analysis of DDE blood plasma concentration among the three ethnic groups.
        In order to reach conclusions and find the relationships between the variables in proposed leptin study, plasma concentrations of leptin will be analyzed using an Enzyme-Linked Immunosorbant Assay (ELISA). Furthermore, previously calculated results of the body mass index (BMI) will be used to examine the obesity levels within the three ethnic groups. For the leptin study, my mentor has made available to me biological samples, baseline information and dietary questionnaires from approximately eight hundred control patients in an on-going case controlstudy of breast cancer since 1996.   Of these eight hundred, 180 women have been randomly selected who have benign breast disease, breast cancer, and no breast disease.  In this group, one third were African American, one third Caucasians, and one third Hispanic, all with a similar age distribution.  Future research will yield the results of the leptin analysis.  Because the leptin study was temporarily suspended, I was given already obtained DDE data in order to analyze the relationship between DDE and benign breast disease (BBD).   Data regarding the concentration of DDE  in the blood plasma were determined by measuring the lipid plasma concentrations of the blood samples.
        The samples used to analyze the DDE concentration in the blood were taken from a case control study of women who were enrolled at the Mount Sinai Medical Center (New York) between September 1994 and February 1996.  The blood samples that were used to analyze the lipid concentrations were taken from female patients, corresponding to the three ethnic groups, at the Mt. Sinai clinic after a twenty four hour fast.  A control subject who had not reported a diagnosis of cancer was matchedwith each patient.  After all the data was organized, the DDE levels were compared among African Americans, Hispanics, and Caucasians.
         In addition to promoting future research on the leptin protein, the purpose of this study is to increase our understanding of DDE and to determine the relationship between DDE and BBD in order to prevent future incidence of disease.  The sample in the DDE study were matched on age, race and diagnosis.  Health history and dietary data were obtained through questionnaires.  This study includes 356 women (African Americans, Hispanics and Whites), but not all of these women provided blood samples or complete questionnaires.  Analysis of the blood plasma  concentrations illustrated that DDE is not protective for BBD in this study, and BMI, the accepted protective factor for BBD, is not protective for BBD at BMI values between 25-29.
        My part in this study is to formulate a hypothesis, gather and analyze data,  prepare blood samples into batches for testing, research background, analyze dietary and health questionnaires, draw graphs, combine data, and conclude.

Yeung, Laura

Valuation of Non-Timber Forest Resources: Examples from A Belizean Medicinal Reserve

The tropics harbor some of the most pristine and unique forest ecosystems.  However, economic pressures and growing populations result in the clearing of large areas of forest for agriculture and timber.  These practices, unfortunately,  are often unsustainable and their short-term economic gains are usually outweighed by the long-term environmental egradation caused by forest loss.  For these reasons, it is important that we develop a system to determine the economic value of a forest, not for one-time or short-term extraction practices like clearcutting, but for sustainable, long-term use.  While there have been many attempts to value forests,  these studies have traditionally been for the purpose of unsustainable logging.  In recent years, there has been a movement towards examining the value of a forest under a sustainable extraction regime, but because of the more complex nature of the question, these estimations of forest value are highly variable.
       My study focuses on the sustainable harvest of three naturally-occurring tree species whose bark is used for medicine Ð Bursera simaruba (gumbo limbo), Sweetia panamensis (billy web), and Simaruba glauca (negrito).  My goal was to determine regression equations which predict the volume of harvestable bark based on the diameter.  In the future, these equations can be used to determine sustainable harvest when combined with inventory data and studies of the maximum harvest intensity which the trees can sustain.  The estimate of sustainable harvest along with the price per unit volume of bark will allow us to quantify the value of the forest in terms of its medicinal resources.
        My part in the project was the development of equations which would estimate bark volume given the diameter of the trunk.  I compared these estimations with ones made with a more meticulous and accurate method of stripping and weighing pieces of bark from each sample tree.  By comparing the two methods, we can then determine the accuracy of our equations.  Because of some problems with methodology, our equations did not accurately predict bark volume.  However, knowing the problems associated with this and other studies, we can develop a better design for future attempts to value forests.

Young, Devorah

PCBs in the Hudson: Evaluating the Scientific Arguments of Policy Opponents

General Electric used  PCBs in capacitor plants located at Fort Edward and Hudson Falls, New York between 1947 and 1977 and thus introduced hundreds of thousands of pounds of PCBs into the Hudson River.  Polychlorinated biphenyls (PCBs) are a group of 209 distinct compounds.  Each PCB molecule is composed of two six carbon benzene rings with varying numbers of chlorine atoms attached.  PCBs have been used in a variety of capacities since 1929, especially as non-flammable dielectrics  in transformers and capacitors.  Since PCBs are persistent contaminants, they have not degraded appreciably.  Although they are no longer being used to manufacture capacitors, PCBs already present within the Hudson could continue to pose a significant risk to humans, animals, and the Hudson River ecosystem.    Environmental activists and  General Electric disagree with regard to the human health risks of PCBs, and the appropriate course of action.  This thesis poses three main questions: (1) What are the policy arguments presented by General Electric (GE), the environmental community, the New York State Department of Environmental Conservation (NYSDEC), and the United States Environmental Protection Agency (USEPA)? (2) Is science used
in the formulation of these arguments? (3) Is the science underlying the policy claims used responsibly, or is it being distorted?  In order to answer these questions, I first trace the history of PCB use and production, and examine the Hudson River environment.  The thesis then presents major policy claims regarding health and environmental impacts of
PCBs in the Hudson River made by each party.  The arguments are then critiqued and analyzed in terms of their scientific assumptions.  Possible plans for remediation are similarly presented and discussed.   Finally, the above questions provide the context for  a commentary on the interplay between scientific evidence and public policy.