February 2007


10-week voyage yields likely new species, insights into polar ecology. Intrigued scientists find; herds of sea cucumbers on the move, fields of colonizing sea squirts, whales approach coast; deep-sea species at unusually shallow depths on uncapped seabed.

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Once roofed by ice for millennia, a 10,000 square km portion of the Antarctic seabed represents a true frontier, one of Earth’s most pristine marine ecosystem, made suddenly accessible to exploration by the collapse of the Larsen A and B ice shelves, 12 and five years ago respectively. Now it has yielded secrets to some 52 marine explorers who accomplished the seabed’s first comprehensive biological survey during a 10-week expedition aboard the German research vessel Polarstern.

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While their families at home in 14 countries were enjoying New Year’s dinners, experts on the powerful icebreaking research ship were logging finds from icy waters as deep as 850 meters off Antarctica – an area rapidly changing in fundamental ways. The recent report of the Intergovernmental Panel on Climate Change shows nowhere on Earth warming more quickly than this corner of Antarctica, a continent 1.5 times the size of continental USA.

The expedition forms part of the Census of Antarctic Marine Life (www.caml.aq), which has 13 upcoming voyages scheduled during International Polar Year, to be launched in Paris March 1. A project of the global Census of Marine Life (www.coml.org) collaboration, CAML is responsible for the synthesis of taxonomic data and supports the efforts of national programs the world over.

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A wildflower called White Fiesta Flower grows in the shady canyon near my house. In winter, it makes tiny white fly-pollinated flowers. If you get down at eye level, you can see these rather long-legged flies maintaining their patchwork of territories, sipping nectar, and fighting over mates. But this isn’t what strikes me as odd about these plants. Although the canyon, especially its shady side, is covered with plants, few other plants grow in the spot where it grows. Something is obviously keeping other plants out of the roughly ten foot diameter area it’s staked out. Normally, it reappears with the first rains in winter and fades away by late spring. In the warm, dry falls and late wet springs of the last two years, however, this circular patch of ground has been bare–no White Fiesta flowers and no other plants. In fact, I have noticed other failures of reliable wild flower clusters in the past two years. Assuming these conditions were to prevail, I wonder how long it would take for these bare patches to be recolonized with other plants? It’s amazing how climate affects native plants so quickly. –Mike Tidwell

Research shows links between collapse of fisheries and bottom-living species

Ecosystems along the continental shelf waters of the Northwest Atlantic Ocean–from the Labrador Sea south of Greenland all the way to North Carolina–are experiencing large, rapid changes, report oceanographers funded by the National Science Foundation (NSF) in the Feb. 23, 2007, issue of the journal Science.

While some scientists have pointed to the decline of cod from overfishing as the main reason for the shifting ecosystems, the paper emphasizes that climate change is also playing a big role.

“It is becoming increasingly clear that Northwest Atlantic ecosystems are being affected by climate forcing from the bottom up and overfishing from the top down,” said Charles Greene, an oceanographer at Cornell University in Ithaca, N.Y, and lead author of the Science paper. “Predicting the fate of these ecosystems will be one of oceanography’s grand challenges for the 21st century.”

Most scientists believe humans are warming the planet by burning fossil fuels and changing land surfaces. Early signs of this warming have appeared in the Arctic. Since the late 1980s, scientists have noticed that pulses of fresh water from increased precipitation and melting of ice on land and sea in the Arctic have flowed into the North Atlantic Ocean and made the water less salty.

At the same time, climate-driven shifts in Arctic wind patterns have redirected ocean currents. The combination of these processes has led to a freshening of the seawater along the North Atlantic shelf.

“Long time-series measurements, as well as research on large-scale ocean processes, are the key to improving our understanding of ecosystem shifts,” says Mary Elena-Carr, program director in NSF’s biological oceanography program. “This study brings together the important components: the atmosphere, freshwater flow, changes in currents and biological responses, all necessary to predicting future ecosystem responses to climate change.”

Under normal conditions in summer months a warmer, less salty layer of water floats on the surface (warmer, less salty water is also less dense and lighter). This surface layer is known as a “mixed” layer, because wind-driven turbulence mixes the water and creates a uniform temperature, salinity and density to depths that can range from 25 to 200 meters.

Similar to the flow of heating and cooling wax in a lava lamp, when the air temperature cools during autumn, temperature and density differences lessen between the surface mixed layer and the cooler, saltier waters below. As the density differences get smaller, mixing between the layers typically increases and the surface mixed layer deepens.

But Greene cites recent scientific studies that reveal the influx of fresh water from Arctic climate change is keeping the mixed layer buoyant, inhibiting its rapid deepening during autumn. A gradual rather than rapid deepening of the mixed layer has impacted the seasonal cycles of phytoplankton (tiny floating plants), zooplankton (tiny animals like copepods) and fish populations that live near the surface.

Normally, when the mixed layer deepens rapidly during autumn, phytoplankton numbers decline because they spend less time near the surface where they are exposed to the light necessary for growth. But with the mixed layer remaining relatively shallow, phytoplankton populations stay abundant throughout the fall. In turn, zooplankton that feed on phytoplankton have increased in number during the fall through the early winter. Herring populations also rose during the 1990s, which some scientists suspect may be because of more abundant zooplankton to feed on.

Greene’s paper also cites a link between the collapse of cod fisheries in the early 1990s and an increase in bottom-living species such as snow crabs and shrimp, which cod prey upon. Without cod, other animals that live in the water column and feed on zooplankton, including herring, may have increased.

While the herring story is still unclear, the authors contend that the crash of cod populations does not explain why phytoplankton and zooplankton populations at the base of the food chain have risen during autumn.

“We suggest that, with or without the collapse of cod, a bottom-up, climate-driven regime shift would have taken place in the Northwest Atlantic during the 1990s,” Greene said.


The Greenland ice sheet’s contribution to sea level rise increased from 0.23 millimeters [0.0091 inches] per year in 1996 to 0.57 millimeters [0.022 inches] per year in 2005. Several large outlet glaciers accelerated during this same period, and snow accumulation increases cannot compensate for the enhanced mass discharge. Stearns and Hamilton studied ice dynamics on the coastal portions of southeast Greenland’s Kangerdlugssuaq and Helheim glaciers, which have each lost at least 51 cubic kilometers [13 trillion U.S. gallons] of ice each year since 2001. Through analysis of digital elevation models derived from satellite images taken over the last five years, the authors show that the main contribution to this ice loss was dynamic thinning caused by the acceleration in flow of these glaciers. This thinning destabilized the ice mass, making it more susceptible to calving and melting. Based on their data, the authors estimate that together these glaciers have actually lost about 122 cubic kilometers [32.2 trillion U.S. gallons] each year since 2001, accounting for half the total ice mass lost from the entire Greenland ice sheet over this time.

Title: Rapid volume loss from two East Greenland outlet glaciers quantified using repeat stereo satellite imagery

Authors: Leigh A. Stearns and Gordon S. Hamilton: Climate Change Institute, University of Maine, Orono, Maine, U.S.A.

Source: Geophysical Research Letters (GRL) paper 10.1029/2006GL028982, 2007


The formation rate of North Atlantic Deep Water (NADW) and the intermediate-depth Labrador Sea Water (LSW) tightly governs the strength of the Atlantic meridional overturning circulation (AMOC) and thus the circulation of heat in the world’s oceans. Through complex ocean atmosphere circulation models, much past research has sought to observe whether global warming from increasing manmade greenhouse gas emissions will melt ice caps and introduce freshwater to the North Atlantic, thereby slowing NADW and LSW formation. Weaver et al. ran several models with varying initial conditions and found that the strength of the AMOC always declines when greenhouse gases are increased by one percent per year, with largest declines in those experiments with the strongest initial AMOC. Further, they confirm that changes in surface heat flux, rather than changes in surface freshwater flux (i.e., increased precipitation, evaporation, and river runoff), slow down the AMOC, an idea suggested by past research. Finally, the authors note that their models were strongly influenced by water vapor and snow/ice feedbacks, and were thus sensitive to mean climate conditions.

Title: The response of the Atlantic meridional overturning circulation to increasing atmospheric CO2: Sensitivity to mean climate state

Authors: Andrew J. Weaver and Michael Eby: School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia, Canada; Markus Kienast: Department of Oceanography, Dalhousie University, Halifax, Nova Scotia, Canada; Oleg A. Saenko: Canadian Centre for Climate Modelling and Analysis, University of Victoria, British Columbia, Canada.

Source: Geophysical Research Letters (GRL) paper 10.1029/2006GL028756, 2007

Mike Tidwell comments -It’s interesting to note that in the decades ahead the climate will become warmer than at anytime in the evolutionary of our species.

Global warming will take a toll on children’s health, according to a new report showing hospital admissions for fever soar as days get hotter.

The new study found that temperature rises had a significant impact on the number of pre-schoolers presenting to emergency departments for fever and gastroenteritis.The two-year study at a major children’s hospital showed that for every five-degree rise in temperature two more children under six years old were admitted with fever to that hospital.

The University of Sydney research is the first to make a solid link between climate changes and childhood illness.

“And now global warming is becoming more apparent, it is highly likely an increasing number of young children will be turning up at hospital departments with these kinds of common illnesses,” said researcher Lawrence Lam, a paediatrics specialist.

“It really demonstrates the urgent need for a more thorough investigation into how exactly climate change will affect health in childhood.”

Dr Lam said the results, collated from The Children’s Hospital at Westmead admissions, back up beliefs that children are less able to regulate their bodies against climate change than adults.

The brain’s thermal regulation mechanism is not as well developed in children, making them more susceptible to “overheating” and at risk of developing illness, he said.

“They’re particularly at risk of extreme changes, much more than other people.”

The study, published in the International Journal of Environmental Health Research, analysed several different climate factors, including UV index, rainfall and humidity, collected from the Bureau of Meteorology in 2001 and 2002.

Temperatures were the only negative risk factor, with findings linking heat to both fever and gastro disease but not to respiratory conditions.

Surprisingly, rates of gastroenteritis were lower on days with a high UV factor probably, says Dr Lam, because the rays “sterilised” the ground, killing more germs and reducing risk.

He said it was still unclear whether the heat directly triggered the illnesses or whether other heat-related problems, like pollution, were responsible.

A longer-term study was needed add strength to the findings, Dr Lam said.

Article here

Mike Tidwell comments -This all sounds positive, but it is important to keep in mind that our release of carbon is running at eight gigatons per year. Not only is the size of this release increasing but it also shows no sign of abating

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