News aggregator

Ghosts of Oceans Past - Science

Featured News - Fri, 11/13/2015 - 12:00
Accurately measuring historic sea levels isn't easy. Lamont-Doherty's Maureen Raymo discusses some of the challenges.

No boating yet and a sneak peek at phytoplankton

Chasing Microbes in Antarctica - Fri, 11/13/2015 - 09:33

The storms of the past week cleared most of the pack ice out of Arthur Harbor, although the land fast ice that we’ve been sampling from has survived.  In anticipation of the start of the boating season there was a flurry of activity yesterday as station personnel cleared off the boat ramp and got the zodiacs ready.  Unfortunately Jamie and I didn’t think to start the time lapse below until yesterday afternoon after most of the three-ring circus had died down, but you still get a sense of the activity.

There are two science groups waiting to start boating operations; our group and a group of penguin researchers (aka “the birders”).  Both groups are part of the Palmer LTER.  While we will spend the summer investigating water column processes however, the birders will spend their summer visiting the various penguin rookeries and maintaining a remarkable long term dataset of penguin population.

The birders do far more than just count penguins, they analyze diet, physiology, breeding success, and a host of other factors. The number of penguins alone however, tells an interesting story.

Taken from Ducklow et al. 2013.  The birders do far more than just count penguins; they analyze diet, physiology, breeding success, and a host of other factors. The number of penguins alone however, tells an interesting story.  Since the mid-1970’s the number of adélie penguins along the West Antarctic Peninsula (or at least at those rookeries that we can access and monitor) has declined sharply.  There are good indications that this is related to the general decline of sea ice in the area.  A high ice year like we are having right now might be good for the adélie’s but the situation is complex.  The ice has been good but the weather is also warm and wet.  Warm, wet conditions are extremely hard on adélie penguin chicks and can lead to large (at times total) breeding failures.

The birders were supposed to get their final zodiac training today, but although the harbor is clear of ice the winds are back up (gusting around 30 kts at the moment) so everything is getting shifted back.  In the meantime we will have a late night sampling another time point from the experiment that we started on Tuesday.  As I described in the previous post, for this experiment we are making use of the highly unusual ice conditions to study what happens to the microbial community when the ice is suddenly removed (as has happened to much of Arthur Harbor and the surrounding area in the last week).  Although we won’t know the results of most of our analyses for several months, we can make some interesting qualitative observations as the experiment progresses.

One of the interesting observations so far was the initial condition of the microbial community.  During a down moment yesterday I took a look at water from just 24 hours into our experiment to see what was growing (so this isn’t exactly the initial condition, but a close approximation of it).  What we found really surprised me.  Here are a couple of images that illustrate the phytoplankton community in our experiment:

By far the most abundant phytoplankton growing under the ice in Arthur Harbor right now. The size and teardrop shape suggest that it is a Cryptophyte.

By far the most abundant phytoplankton growing under the ice in Arthur Harbor right now. The size (about 10 microns) and teardrop shape suggest that it is a cryptophyte.  This is interesting because many cryptophtes are mixotrophic; in addition to undergoing photosynthesis they can consume bacteria as a source of carbon.

A small pennate diatom. This is the only one that I could find, but, this is purely speculative, like it might be dividing.

A small pennate diatom. This is the only one that I could find but, and this is purely speculative, it looks like it might be dividing.  Magnification is the same as the previous image, so I would guess that this cell is 10-20 microns in length.

The traditional wisdom would suggest that the spring phytoplankton bloom should start with diatoms.  Following the initial diatom bloom there are successive, mixed blooms of haptophytes, cryptophytes, dinoflagellates, and other groups of phytoplankton.  Observations from this time of year are very sparse however, so it is difficult to know if we are seeing something that is unique or the normal phytoplankton assemblage for this time of year.  The composition of the phytoplankton assemblage is not merely academic; it dictates how carbon will flow through the food web in a given season.  Large diatoms for example, are easily feed upon by krill, resulting in high krill biomass and more and more healthy top predators (e.g. penguins, seals, and whales).  Smaller phytoplankton (like cryptophytes) produce a more complex food web that might ultimately channel less carbon to the top trophic levels.  We will have to wait and see how the situation plays out this year…


From Copenhagen to Paris: Getting Beyond Talk

The 2015 Paris Climate Summit - Thu, 11/12/2015 - 15:44

logo-cop-21-carr-During the Copenhagen climate meetings in 2009, I posted a piece in the Huffington Post assessing the conference. At that time I observed that:

“There is a broad consensus about the need for reductions in the emissions that cause global warming. Copenhagen is providing the entire world a crash course in climate science and policy. Over the past decade, the politics of national and global climate policy has shifted from the fringes of the public policy agenda to the center. The real story of Copenhagen is the maturation of this key issue of global environmental policy. … Climate change is just the first global environmental problem we have come to understand. At Copenhagen we are barely discussing the other global environmental issues such as species extinction, the destruction of the oceans and degraded fresh water supplies. But we could.”

As we approach the Paris version of these endless talks, COP21, to be held next month, it’s fair to ask: What has changed over the past six years, and did Copenhagen stimulate any of these changes?

What has changed is the broad consensus on climate change has broadened, and recent polls show that even Republicans in the United States understand the nature of the problem. Globally, individual nations have volunteered greenhouse gas reduction targets in anticipation of the Paris meetings. Unlike Copenhagen, where calls for mandatory reductions and transfer payments to the developing world caused the collapse of any potential agreements, the world community seems more realistic as it approaches the Paris meetings. An agreement that codifies the reductions already pledged seems within reach, even if its value is more symbolic than real.

There remains a possibility that the call for transfer payments from wealthy nations to developing nations could disrupt the effort at building a global consensus. Previous aid promises were not fulfilled, and there is some political pressure to get the issue back on the global agenda. One of the major changes since 2009 is the clear perception that some nations once classified as developing, such as China, Brazil and India, can no longer be thought of in that way. While this was also the case in 2009, six years later, they are clearly in a category of their own.

Steve Cohen is executive director of The Earth Institute.

Steve Cohen is executive director of The Earth Institute.

My own view of the Paris talks and the ones that came before is that they have value, but it is important to understand their inherent limits. The climate issue is really an issue of the energy base of a nation’s economy. Modern economies require energy, and economic development depends on plentiful, reliable, reasonably priced energy. The issue is so central to economic growth and the stability of political regimes that no nation state will fundamentally limit its flexibility in delivering energy for any reason. It is central to sovereignty in the modern world. But communicating the dangers of fossil fuels and the need to transition to a renewable energy based economy is something these meetings have achieved, and the importance of that achievement should not be underestimated.

The climate issue seems to generate a high level of ideologically based politics, emotional rhetoric and political symbolism. It is time to move past symbols to pragmatism and political reality. We need to move toward an acceptance of nine fundamentals if we are to address the climate change crisis:

  1. Human induced climate change is real, already underway and will continue into the future.
  2. We cannot precisely predict the future impact of climate change on human settlements and economic well-being.
  3. Fossil fuels are the largest single generator of greenhouse gases.
  4. Our economic way of life and therefore the political stability of our world are highly dependent on energy that mainly comes from fossil fuels.
  5. The transition from fossil fuels to renewable energy is necessary but will take decades to accomplish.
  6. Reducing the use of fossil fuels by raising the price of these fuels is unlikely to achieve political support or be supported by the world’s governments.
  7. Reducing the use of fossil fuels by developing lower priced, reliable and renewable sources of energy requires additional technological development.
  8. Reduced energy costs will have great political appeal and positive economic impact.
  9. The increased use of current renewable energy technologies will be facilitated by government policy to attract capital and reduce the price of energy.

In my view, the battles over oil pipelines, fracking and divesting capital from fossil fuel companies are symbolic battles that serve to distract us from the operational issues that will facilitate the transition to a renewable energy economy. One issue to engage in is the coming battle to renew the favorable tax treatment of renewable energy in the U.S., now slated to end in December 2016. Ending that tax expenditure would slow down the growth of the solar and wind industry and have an immediate and dramatic impact on the production of greenhouse gases.

The Department of Energy and the National Science Foundation’s research budget for renewable energy technologies needs to be increased dramatically. The federal government should take the lead in purchasing electric vehicles and installing renewable energy. A federal fund to restore and build infrastructure will probably appear on the federal agenda during the next decade. Some part of that funding should be devoted to upgrading the electric grid to make it smarter and more efficient, funding public charging stations for electric vehicles, funding mass transit, and providing resources to make coastal infrastructure more resilient and better able to adapt to the impact of climate change.

The action required to transition off of fossil fuels and other single-use resources requires a sophisticated partnership between the public and private sectors.

The greatest danger to America’s transition to a renewable resource based economy is not industry, which will make plenty of money off of this transition, or the public, which appears ready to move, but the anti-government ideology that continues to paralyze our federal government.

The action required to transition off of fossil fuels and other single-use resources requires a sophisticated partnership between the public and private sectors. There will be some instances when the work that needs to be done—for example, basic research or infrastructure finance—will require federal funds. There will be other instances when the tax code or other incentives will be needed to attract private capital and companies into the market. And there will be even more instances when government action is not needed, and the best thing government can do is get out of the way and let the private sector act. By sophisticated partnership, I mean one that is guided by results-oriented pragmatism rather than symbols and ideology.

The climate talks in Paris will focus attention on the climate issue and increase understanding of the nature of the problem. Then the spotlight shifts to nations and cities, and hopefully from talk and chit-chat to funding and action. There are many signs that the transition from fossil fuels has begun. The speed of that transition is at issue and will require creativity, consensus and cash to be completed.

This post is one in a series reflecting on what has changed since the climate talks of 2009 in Copenhagen. 


How Panama Changed the World - PBS NOVA

Featured News - Thu, 11/12/2015 - 12:00
Lamont scientist Conny Class and former Lamont post-doc Esteban Gazel scan islands off Panama for clues to how the country formed and its impact on ocean circulation.

6 Places Where Melting Snow Means Less Drinking Water - National Geographic

Featured News - Thu, 11/12/2015 - 09:23
All basins will likely have less water from snowpack as the planet warms, but some regions will be in worse shape than others. A new study led by Lamont-Doherty's Justin Mankin highlights 32 that are most at risk.

The Paris Climate Change Conference – What You Need to Know

The 2015 Paris Climate Summit - Wed, 11/11/2015 - 12:00

Editors’ note: This is the first in a series of posts on the 2015 Paris climate summit. You can follow all of our coverage on a special State of the Planet feature page.


The difference in average surface temperatures from 1970-79 (bottom) to 2000-09 (top) due to global warming. Photo: NASA

What is it?

COP21, the 2015 United Nations Climate Change Conference, will be held outside of Paris in Le Bourget, France, from Nov. 30 to Dec. 11. It is called COP21 because it is the 21st annual meeting of the Conference of Parties to the 1992 United Nations Framework Convention on Climate Change. The parties meet each year to assess their progress in dealing with climate change; its objective is to achieve “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.”

Who’s participating?

The 195 countries who make up the UN Framework Convention on Climate Change will send over 40,000 delegates to the talks in Paris. At least 80 world leaders will attend, including the leaders of Germany, South Africa, Brazil and England, and those of the three biggest carbon emitting countries: President Barack Obama from the United States, Chinese President Xi Jinping and Indian Prime Minister Narendra Modi.

What is the goal?

The goal of COP21 is to negotiate a new international climate change agreement that can keep the average global temperature rise below 2° C by 2100 compared to pre-industrial levels. The agreement will be universal and include pledges from the parties to limit and reduce greenhouse gases, implement strategies to adapt to the impacts of climate change, and commit financial support to help developing countries deal with climate change. The agreement will also likely establish five-year reviews to make sure countries are keeping their commitments and to ratchet up emissions reduction targets in order to meet the 2˚C goal.

Why does it matter?

Human activities have generated greenhouse gases—carbon dioxide, methane, nitrous oxide and fluorinated gases—that have collected in the atmosphere and warmed the planet. Between 1990 and 2014, global greenhouse gases increased 36 percent. In 2011, Asia, Europe and the United States were responsible for 82 percent of total greenhouse gas emissions. Some of the carbon dioxide that we have already pumped into the atmosphere will remain there for hundreds of years.


The increase in greenhouse gases over the last 100 years has so far caused average global temperatures to rise .85˚C. Data for 2015 from the Met Office, the United Kingdom’s national weather service, shows that Earth’s global mean temperature will reach 1˚C above pre-industrial levels for the first time this year. While this does not sound like much, we are already feeling the effects of this warming with more extreme heat, heavy downpours, increased wildfires, insect outbreaks, loss of glaciers and sea ice, sea level rise and flooding.

Scientists and over 100 nations have agreed that limiting the global temperature rise to 2˚C is critical to avoiding more catastrophic climate change effects. According to the World Resources Institute, if we continue on a “business as usual” trajectory of generating greenhouse gases, we will reach 2˚C by 2045. This will increase the risk of sea level rise, intensify wildfires and make them more frequent, exacerbate heavy precipitation events and the severity of droughts, acidify the oceans, cause extinction of animal species and jeopardize our food supplies. With each degree above the 2˚C limit, the impacts of climate change will be more severe and the risks greater that tipping points could be passed, resulting in abrupt and irreversible changes in the global climate system.


The oldest Arctic sea ice is disappearing. Sea ice coverage in 1980 (bottom) and 2012 (top). Photo: NASA

In May, a UN Framework Convention on Climate Change report  concluded that 1.5˚C would be a preferable limit, but would require a faster reduction of energy demand and an immediate scaling up of low-carbon technologies to curb greenhouse gases.

When does COP21 go into effect?

In 1997, at COP3, 192 parties adopted the Kyoto Protocol (the United States did not ratify the protocol), which legally bound developed countries to reduce their emissions. Kyoto’s first commitment period went from 2008 to 2012. A second commitment period, known as the Doha Amendment, began in 2013 and ends in 2020. The COP21 agreement will take effect in 2020 when the Kyoto Protocol ends.

How will it work?

At COP15 in Copenhagen in 2009, the 195 countries involved in the UN Framework Convention on Climate Change pledged to reduce their greenhouse gas emissions by 2025-2030.

Global CO2

Ahead of COP21, all the states were invited to submit their “Intended Nationally Determined Contributions” that indicate what actions the countries will take to reduce their emissions. Each plan takes into account a country’s particular circumstances and capabilities, and may address adaptation to climate change impacts, and what support they will need from, or be willing to give to other countries.

One hundred-thirty-one of these “intended contributions” have been submitted. Here are a few examples.

The United States has pledged to reduce greenhouse gas emissions 26 to 28 percent below its 2005 levels by 2025, with best efforts to reduce emissions by 28 percent. Strategies to achieve the goal include the U.S. Environmental Protection Agency’s regulations to cut carbon pollution from new and existing power plants, tighter fuel economy standards for light and heavy-duty vehicles, and the development of standards to address methane emissions from landfills and oil and gas production.

China pledges that its carbon emissions will peak by 2030 or sooner if possible, and that the country will reduce carbon dioxide emissions for each unit of Gross Domestic Product (its “emissions intensity”) by 60 to 65 percent from 2005 levels, derive 20 percent of energy from non-fossil fuels, plant more forests and improve the country’s adaptation to climate change impacts.

India intends to reduce the emissions intensity of its GDP by 33 to 35 percent by 2030 from 2005 levels, increase forest and tree cover to provide additional carbon sinks and generate 40 percent of its electricity from non-fossil fuel sources by 2030 with help from the Green Climate Fund. (The Green Climate Fund was established by 194 nations in 2010 with the goal of raising $100 billion a year by 2020 to assist developing countries deal with climate change.)

Brazil will reduce its greenhouse gas emissions 37 percent below 2005 levels by 2025, then by 43 percent below 2005 levels by 2030. Strategies to achieve this include using renewable resources for 45 percent of its energy by 2030, stopping illegal deforestation by 2030, restoring forests and developing sustainable agriculture. It will also implement adaptation policies to make its population, ecosystems, infrastructure and production systems more resilient.

The European Union has committed to reduce greenhouse gas emissions 40 percent from 1990 levels by 2030, in part by getting 27 percent of its energy from renewable energy resources and improving energy efficiency 27 percent by 2030.

Are the climate pledges ambitious enough to meet the goal?

The Climate Action Tracker, an independent scientific analysis, estimates that the climate pledges submitted so far will result in an increase of 2.7˚C of warming by 2100. This is an improvement over the worst-case scenario of a 4.5 to 6° C increase, which is what scientists estimate will result if we continue with business as usual; but it does not get us where we need to go.


However, the goal of remaining under the 2° C mark is targeted for 2100; these first climate pledges extend to 2025 or 2030. Much greater emissions reduction efforts will be needed after 2025 and 2030 to achieve the 2˚C limit. So a five-year periodic review mechanism will be critical to spur countries to set increasingly ambitious goals to reduce emissions.

What would a successful COP21 look like?

COP21 may or may not produce a treaty that legally binds countries to meet their emissions targets. If it does not, this should not be considered a failing, since legally binding treaties can cause countries to make overly modest commitments for fear of falling short, or opt out altogether.

COP21 will be considered a success if it:

  • Results in countries agreeing on shared long-term goals to reduce carbon emissions and work towards climate resilience.
  • Recognizes that all countries must take action.
  • Creates a climate financing arrangement that is acceptable to both developed and developing countries.
  • Establishes five-year reviews to encourage countries to continually set more ambitious emissions reduction goals.
  • Ensures that countries are transparent about their progress and actions through an effective reporting and verification process.

Why should you care?

COP21 is the best opportunity for the world to finally slow the rate of climate change. Its outcome will affect our lives and those of our children and grandchildren. If successful, COP21 will hopefully help us avert the most disastrous and potentially irreversible effects of climate change. As President Obama said, “We are the first generation to feel the impact of climate change, and the last generation that can do something about it.”


Lamont Leads Student Research Along the Hudson River - Columbia Spectator

Featured News - Wed, 11/11/2015 - 09:09
“The students are collecting data that is going to be shared with other students; this means that it has to be solid data. That puts an extra responsibility on them,” said Lamont Education Coordinator Margie Turrin. “So it's really mimicked what science is like — that it's done by a community of scientists.”

Yemen Sees Unprecedented Tropical Cyclone Double-Whammy - WX Shift

Featured News - Tue, 11/10/2015 - 13:14
Yemen suffers back-to-back strikes as Cyclone Megh makes landfall just a week after Cyclone Chapala. Lamont's Suzana Camargo discusses potential El Nino connections to the extreme weather in the region.

One of the Driest Places on Earth, the Sahara, Once Ran with Water - USA Today

Featured News - Tue, 11/10/2015 - 12:00
A mighty river once coursed through what is now the Sahara Desert, one of the driest places in the world, new satellite images suggest. Lamont's Peter deMenocal says it's evidence that an entire region that lacks rainfall today once supported a large river system.

Tree-Ring Data Chronicles Historic Climate Conditions - Archaeology Magazine

Featured News - Tue, 11/10/2015 - 07:00
Tree ring chronologies from across Europe and the Mediterranean have been used to create a drought atlas of the Old World that reaches back more than 2,000 years. The atlas, led by Lamont's Ed Cook, is the third providing insights into the Northern Hemisphere, joining the North American Drought Atlas and Monsoon Asia Drought Atlas.

The Gould, a gale, and a bit more on SAM

Chasing Microbes in Antarctica - Mon, 11/09/2015 - 08:38

The Laurence M. Gould departed for Punta Arenas last night, taking Colleen with it and leaving Jamie and I on our own until reinforcements arrive in two weeks (you can check out Jamie’s blog here for more on what we’re up to this season).  That should work out fine although we’ll be very busy on sampling days – when and if we get sampling days.  We were supposed to get out today but the weather isn’t cooperating.

A small crowd gathers to send of the Gould. Colleen's enroute back to WHOI, leaving Jamie and I to handle things until reinforcements arrive in about two weeks.

A small crowd gathers to send off the Gould. Colleen’s now enroute back to WHOI, leaving Jamie and I to handle all the measurements until reinforcements arrive in about two weeks.

The ice is, or was, pretty thick in Arthur Harbor. 45 minutes after the Gould departed they'd made it this far. Eventually they cleared the harbor and made it to more open water.

The ice is, or was, pretty thick in Arthur Harbor. 45 minutes after the Gould departed they’d made it this far (you can see the same islet just behind the Gould in the previous picture). Eventually they cleared the harbor and made it to more open water.

Shortly after the Gould departed the wind started to increase.  Right now the Gould is getting 50 kt winds at the southern edge of the Drake Passage (sorry Colleen!), we’re getting a steady 35 kt wind the blew all night and should last through today.  I’m nervous about what that will do to our sampling plan.  So far the land fast ice where our ice station is has held together; it’s a nearly a meter thick and pretty well anchored to the land.  Sometime this season it’s going to give out though, and I’m hoping that we can sample from it a couple more times before that happens.

The flip side is that when the ice goes away we’ll be able to start using the zodiacs to sample at our regular stations, at least until the ice blows back in.  The worst case scenario is being in the awkward position of too much ice for the zodiacs, but no solid land fast ice from which to sample.  To get an idea of how fast things can change compare the ice conditions in the following pictures to the conditions when the Gould departed:

Four hours after the Gould departed open water is starting to appear in Arthur Harbor. The edge of the land fast ice is to the right in this image, the water is opening between the (hopefully!) stable land fast ice and the mobile pack ice.

Four hours after the Gould departed open water is starting to appear in Arthur Harbor. The edge of the land fast ice is to the right in this image, the water is opening between the (hopefully!) stable land fast ice and the mobile pack ice.  The little peninsula of ice at center-left in this image is an additional piece of land fast ice anchored to the east shore of Arthur Harbor.

And here's what it looks like this morning. The ice is pushed even further out (not that you can see very far!).

And here’s what it looks like this morning. The pack ice (beyond the ice peninsula) is pushed even further out (not that you can see very far!).

The fast departure of the ice underscores an important ecological concept that is central to this region.  The timing of the switch from ice covered to open water conditions has a major impact on the strength and timing of the spring phytoplankton bloom; the annual ecological event from which everything else derives (think of it like a burst of new green grass in the Serengeti).

Thanks to Jamie Collins for this light profile from our ice station earlier in the week. The grey line indicates the depth of the ice. The ice blocks nearly 95 % of the light that impacts the surface, the remainder is quickly extinguished in the water column.

Thanks to Jamie Collins for this light profile from our ice station earlier in the week. The grey line indicates the depth of the ice. The ice blocks about 94 % of the light that impacts the surface, the remainder is quickly extinguished in the water column.

In the springtime Antarctic phytoplankton are limited in growth only by the absence of light.  Nutrients have been replenishing all winter, there are no grazers around (yet), and the phytoplankton are relatively indifferent to temperature.  Right now at Palmer Station we have nearly 18 hours of daylight, what keeps the phytoplankton bloom from exploding right now is the ice.  Only 6 % of the light that hits the surface of the fast ice in Arthur Harbor is making its way down into the water.  That’s enough to support the growth of specialized ice algae and low-light adapted phytoplankton just below the ice, but not a major bloom deeper in the water column.  At just 10 m depth only about 0.01 % of the light that hits the surface remains; it is essentially totally dark.

So as soon as the ice departs the phytoplankton are primed to start growing.  In Arthur Harbor the wind is driving the ice away, does this mean a bloom is about to start?  Not necessarily.  For phytoplankton, what the wind gives it also takes away.  A strong wind induces strong vertical mixing in the water column.  This impact of vertical mixing on phytoplankton has been studied in places like the North Atlantic for a very long time.  Some phytoplankton can swim, but none can swim fast enough to outpace vertical mixing.  Under a stiff, sustained wind phytoplankton in the surface are mixed deep into the water column.  If they don’t go too deep that’s fine.  Below a certain point they can’t photosynthesize enough to meet their metabolic demands (we usually take this to be the 1 % light level), but like all organisms they have energy stores and can wait to get mixed back above this depth.  Pushed deep enough however, at what we call the critical depth a phytoplankton cell has insufficient energy stores to make it back to the surface.  Under these conditions, although phytoplankton may be growing at the surface, the formation of the bloom will be suppressed.

These two figures, from Ducklow et al. 2006, show the link between SAM, the sea ice anomaly, and primary production.

These two figures, from Ducklow et al. 2006, show the link between SAM, the sea ice anomaly, and primary production.

So what does this have to do with timing?  It’s no surprise that the strongest storms happen in the winter.  In low sea ice years, with less land fast ice and an earlier retreat of both land fast and pack ice, the surface of the Antarctic ocean is exposed to late winter storms and strong mixing.  Phytoplankton that have been overwintering safely in the stable water column below the ice start to grow, but are constantly mixed down below the critical depth.  Eventually this stock of phytoplankton is depleted (or much reduced), leaving insufficient numbers to initiate the bloom when conditions finally calm down.  This idea has been explored in a number of studies, including this great 1998 paper led by Kevin Arrigo at Stanford and this 2006 study led by Hugh Ducklow at the Lamont-Doherty Earth Observatory.  This latter study is particularly interesting because it implicates the Southern Annual Mode (SAM) in determining the strength of the spring bloom.  As the plot at right shows it’s clear that SAM isn’t the only thing that determines ice duration, extent, and the strength of the bloom, but it has a clear and logical role.

More recent studies have extended the link between sea ice and SAM to higher trophic levels, including krill.  One of my favorite Palmer LTER papers is this 2013 paper by Grace Saba et al., which does a great job of illustrating the link and exploring the idea in the context of climate change.  A negative phase in the SAM during the winter and springs leads to low wind and high ice conditions (a double bonus for phytoplanton).  These conditions set the stage for a strong bloom and good krill recruitment (a large number of juvenille krill being “recruited” to the sexually mature, adult size class).  A positive SAM during the winter and spring leads to low ice, high wind, and a taxonomically different and overall smaller phytoplankon bloom.  This leads to fewer krill with a direct negative impact on penguins, seals, seabirds, and whales.

Taken from Saba et al. 2013. A negative SAM leads to low wind and high ice conditions. Good for phytoplankton and by extension good for krill. A positive SAM does the opposite, suppressing the spring bloom and reducing the food available for krill.

Taken from Saba et al. 2013. A negative SAM leads to low wind and high ice conditions. Good for phytoplankton and by extension good for krill. A positive SAM does the opposite, suppressing the spring bloom and reducing the food available for krill.

This post is getting long (this is what happens when a sampling day gets weathered out) so I want to end by wrapping it back around to the current season.  As I described in a previous post things are a little different this year.  The SAM index has generally been positive with some dips into the negative.  Only for the month of October was the mean SAM negative, and not very.  Despite this there is a definite positive sea ice anomaly.  This seems to be driven by the strong, persistent El Niño in the equatorial Pacific that shows no sign of abating any time soon.  Regardless of SAM, ice conditions are good this year, in a few weeks we’ll see what that means for the spring bloom when the ice clears out for good!

// The current sea ice conditions have defied the SAM index, underscoring the complexity of the relationship between climate, physical conditions, and the ecosystem.

Monthly mean SAM index for 2015. Taken from the NOAA Climate Prediction Center at The current sea ice conditions have defied the SAM index, underscoring the complexity of the relationship between climate, physical conditions on the ground, and the ecosystem.

What Do Trees Tell Us about Climate Change? - Christian Science Monitor

Featured News - Sun, 11/08/2015 - 12:00
The new Old World Drought Atlas uses tree-rings to map droughts and periods of extreme rain through 2,000 years of European history. The project, led by Lamont's Ed Cook and involving dendrochronologists across Europe, joins drought atlases for North America and Asia to create a view of the Northern Hemisphere.

A New Drought Atlas Tracks Europe's Extreme Weather Through History - Smithsonian Magazine

Featured News - Fri, 11/06/2015 - 15:44
The Old World Drought Atlas, led by Lamont-Doherty's Ed Cook and based on thousands of tree ring samples, fills in details about past events and could help improve climate modeling for the future.

New Atlas Shows Europe's Catastrophic Droughts - Der Spiegel

Featured News - Fri, 11/06/2015 - 12:00
A new atlas based on tree ring research and led by Lamont-Doherty's Ed Cook of the Tree Ring Lab documents the reach of Europe's historic droughts in detail.

Things are looking up as the snow comes down…

Chasing Microbes in Antarctica - Thu, 11/05/2015 - 20:23

After a tough couple of weeks things are starting to look up.  I’ve got the flow cytometer up and running, and Colleen’s instrument received a complete makeover (thanks to the über instrument tech at Palmer) and is producing good data.  The big question is whether I can gain enough proficiency over the next two days to keep it going after Colleen leaves on Sunday.

The operational instrument status comes just in time; yesterday we went back to the sea ice station that we established on Tuesday to do some science.  In addition to collecting some pretty novel data it was a good chance to practice the measurements we’ll be making all season for the Palmer LTER.  It felt good to get out but hopefully for most of the season it will be a little warmer, however.  That it would be cold in early spring in Antarctica is kind of a no-brainer, but that didn’t keep it from surprising me yesterday.  And the downside to doing fieldwork cold is that it takes longer, so you end up getting colder, and things take even longer…

Jamie, Nicole, and I get escorted off the ice by a lone adélie penguin. The adélie seemed pretty interested in what we were up to at the ice station and followed us the whole way back. Thanks to Rebecca Shoop, the Palmer Station manager, for the photo.

Jamie, Nicole, and I get escorted off the ice by a lone adélie  penguin. The adélie seemed pretty interested in what we were up to at the ice station and followed us the whole way back. Thanks to Rebecca Shoop, the Palmer Station manager, for the photo.

In addition to making all the core LTER measurements (see the end for descriptions); chlorophyll a, nutrients (inorganic nitrogen and phosphorous), primary production, bacterial production, dissolved organic carbon, particulate organic carbon, bacterial abundance, photosynthetically active radiation, and UV, we took multiple RNA and DNA samples (my main focus for this trip), large amounts of water for lipidomics (Jamie’s project) and samples to measure hydrogen peroxide.  This last measurement was a consolation prize since we couldn’t measure superoxide – the two species have some similarities – and it gives us some indication of what to expect now that Colleen’s instrument is up and running.

So what did we find?  It’s early in the season, and there isn’t that much happening yet below the ice.  Everything is driven by light, and it’s pretty dark under there.  But things are starting to happen, and all the action is near the ice.  We measured only two depths in the water column (and that still took us over three hours), just below the ice and 2 meters further down.  Even over that short distance there was a big difference in what’s going on.  The concentration of hydrogen peroxide – a byproduct of photosynthesis – was much higher near the ice, and there were about four times as many bacteria just beneath the ice than 2 meters below it.

Hopefully, if the weather’s good we’ll get a chance to go back out on Monday.  If the ice holds together for just a couple more weeks we’ll be able to document the transition from an ice-covered to an ice-free state, and get the data to test some hypotheses about how bacteria and phytoplankton respond to this transition.  In the meantime yesterday’s bitterly cold wind has given way to calm conditions and outside the snow is falling.  The woodstove in the Palmer Station galley is putting out a nice glow and the stress of fieldwork is dissipating for a moment…

As promised here’s a quick description of the core LTER measurements:

Chlorophyll a: The principal (but certainly not only) photosynthetic pigment in phytoplankton.  Oceanographers having been measuring the concentration of chlorophyll a in the water for a long time as a measure of phytoplankton biomass, and as an estimate of how much primary production is happening.

Primary production: The amount of carbon dioxide that is being taken up by phytoplankton and converted into organic carbon.  The whole food web depends on primary production, and much of our work is focused on what aspects of the ecosystem control the amount that happens.

Bacterial production: Sort of the inverse of primary production, this is the amount of organic carbon taken up by bacteria.  We can’t measure this directly so we estimate it from the uptake of certain carbon compounds that we can track.

Dissolved organic carbon: One of the most mysterious types of carbon out there (see this article for some indication why).  This is organic carbon in pieces small enough for bacteria to take them up.

Particulate organic carbon: Phytoplankton die, they become particulate organic carbon.  It’s sad.

Bacterial abundance: The number of bacteria in the water, measured on our now operational flow cytometer.

Nutrients: Nutrients in the ocean are operationally divided into macro and micro categories, depending on their biologically relevant concentrations.  We measure nitrogen and phosphorous, the principal macronutrients.

Photosynthetically active radiation (PAR): In addition to nutrients phytoplankton need light to grow.  PAR is the part of the electromagnetic spectrum that can actually be used in photosynthesis.  Too little PAR (like under thick, snow covered ice) and you get very little photosynthesis.  Too much PAR (like at the surface of the ocean during the Antarctic summer) also produces very little photosynthesis!

Scientists Warned the President about Global Warming 50 Years Ago Today - Guardian

Featured News - Thu, 11/05/2015 - 17:00
On Nov. 5, 1965, climate scientists summarized the risks associated with rising carbon pollution in a report for Lyndon Johnson. Lamont's Wally Broecker was among them.

What Is Attribution When It Comes to Climate Change? - Green TV

Featured News - Thu, 11/05/2015 - 12:00
In this short video, Lamont's Jason Smerdon explains connections between climate change and extreme weather.

Antarctic Journal: Packing for the End of the World - Nature

Featured News - Thu, 11/05/2015 - 10:19
Nature follows an expedition to study the fate of Antarctica's ice. The ROSETTA-Ice expedition includes the IcePod team led by Lamont-Doherty's Robin Bell.

El Niño: Meet the Man Who Tries to Predict the Unpredictable - SciDev

Featured News - Wed, 11/04/2015 - 15:00
In 1985, El Niño research pioneers Mark Cane and Steve Zebiak came up with the first computer model that successfully predicted the periodic Pacific Ocean warming event the following year. Thirty years later, models have improved, but El Niño remains elusive, says Lamont-Doherty's Cane.

Robin Bell: Science Is Like Running a Small Business, Where the Currency Is Ideas - Forecast Podcast

Featured News - Wed, 11/04/2015 - 14:40
Science is like running a small business, where the currency is ideas, Lamont-Doherty's Robin Bell tells Michael White, Nature’s editor for climate science.



Subscribe to Lamont-Doherty Earth Observatory aggregator