Biology & Paleo Environment Events

Current BPE seminar organizing committee: Daniel BishopThomas WeissJonathan LambertJan-Erik Tesdal

Time and Location: Mondays at 1 pm, Comer Seminar Room

 

Next seminar:


04/23/18: Trevor Porter, U of T

"A 50,000 year record of relict ice, precipitation isotopes and climate in Eastern Beringia"

Abstract: 

Precipitation-derived stable isotope ratios of hydrogen (δD) and oxygen (δ18O) from ice layers in ice cores are widely recognised as a gold standard temperature proxy in paleoclimate studies, and have revealed more about Late Quaternary climate transitions than perhaps any other land-based proxy. However, long ice core records are mostly restricted to ice cap locales, which leaves large spatial gaps in knowledge of precipitation isotopes and climate in the pan-Arctic. In this talk, I will discuss recent efforts to close gaps in the paleo-water isoscape by employing an unconventional water isotope archive – relict ice in syngenetic permafrost. Syngenetic permafrost is permafrost that forms simultaneously with an aggrading surface. In rapidly aggrading systems, syngenetic permafrost has great potential to stratigraphically preserve ancient meteoric waters as sediment pore ice. This talk demonstrates this potential using long records of pore ice δD and δ18O from two different types of aggrading systems in central Yukon, Eastern Beringia: (1) a soligenic peatland near Engineer Creek on the Dempster Highway which aggraded continuously over the last ~13 ka; and (2) a composite record of valley-loess deposits from the Klondike Goldfields spanning the last ~50 ka. Critical attention is paid to uncertainties regarding the formation of these deposits, which has a major influence over the seasonality of precipitation integrated and preserved as ground ice and, consequently, the paleoclimate signal. Long-term isotope trends documented in these records are correlated broadly to traditional ice core records from Mt. Logan (S.W. Yukon) and Greenland to evaluate regional and hemispheric coherence of isotopic and climatic transitions, and attributed to changing boundary conditions and local climate. Last, this talk aims to shift traditional notions of permafrost, commonly regarded simply ‘a subterranean thermal state’ but shown here as a viable proxy archive with untapped potential to advance our knowledge of the Arctic system.


 

Spring 2018:

Date Speaker Title
     
Jan 29th Dan Sousa
LDEO
Coupled Spatiotemporal Characterization of Monsoon Cloud Cover and Vegetation Phenology
Feb 5th Billy D'Andrea
LDEO
A High Arctic Perspective on Holocene Climate Change
Feb 26th Robert Poirier
LDEO
Assessing potential for diagenetic overprinting of climatic signals in benthic foraminifera: Preliminary results
Mar 19th Ivona Cetinić
NASA
EXPORTS: understanding the functioning of the Ocean’s Biological Carbon pump
Mar 26th Lora Stevens
CSULB
A Swiftly Tilting Climate: Variations in Effective Moisture during the Little Ice Age of Vietnam
Apr 2nd Maria Gandolfo
Cornell
Plant Evolutionary Processes in the Fossil Record of Patagonia
Apr 9th Anne Cohen
WHOI
Stressful Times: Skeletal signatures of coral reef bleaching in the central equatorial Pacific
Apr 16th Jennifer Cherrier
CUNY
The Green Horizon: Can Green Infrastructure Address Urban Water Management Challenges?
Apr 23rd Trevor Porter
UToronto
A 50,000 year record of relict ice, precipitation isotopes and climate in Eastern Beringia
Apr 30th Erika Wise
UNC-Chapel Hill
 
May 3rd B. B. Cael
MIT
Re-examining parameterizations of particulate organic carbon flux
May 4th Michael O'Connor
Texas A&M