Navigation Links
Study reveals strong links between Antarctic climate, food web

A long-term study of the links between climate and marine life along the rapidly warming West Antarctic Peninsula reveals how changes in physical factors such as wind speed and sea-ice cover send ripples up the food chain, with impacts on everything from single-celled algae to penguins.

The study, published in today's issue of Nature Communications, is authored by Dr. Grace Saba, an alumna of William & Mary's Virginia Institute of Marine Science (now at Rutgers University); VIMS professor Deborah Steinberg; Dr. Vincent Saba, a VIMS alumnus now at NOAA's National Marine Fisheries Service; and colleagues with the Polar Oceans Research Group, Lamont-Doherty Earth Observatory, Woods Hole Oceanographic Institution, and the University of Colorado at Boulder.

The authors are members of the Palmer Long-Term Ecological Research program (PAL-LTER), which conducts annual shipboard surveys along the western side of the Antarctic Peninsula, including the coastal ocean near Palmer Station--one of the three U.S. research stations in Antarctica. Program scientists began studying the fast-changing region in 1990.

Steinberg, one of the Palmer program's lead scientists since 2008, says the current study provides one of the few instances where marine researchers have a dataset of sufficient length and detail to reveal how climate signals can reverberate through a polar food web.

"That's the importance of long-term ecosystem monitoring," says Steinberg. "It provides the data needed to separate a signal from the noise, and to determine how plants and animals interact with both their physical environment and each other. That knowledge is critical as climate warming continues to impact this polar ocean ecosystem." The West Antarctic Peninsula is one of the fastest warming regions on Earth, with annual winter temperatures increasing by 11F during the last 50 years.

The team's research shows that populations of photosynthetic algaethe tiny drifting plants that support the polar food webpeak every four to six years in the waters along the West Antarctic Peninsula. These blooms correlate with a negative phase of the "Southern Annular Mode," or SAM, a seesaw shift in atmospheric pressure between mid-latitudes and Antarctica.

In winter during a negative phase of SAM, cold southerly winds blow across the Peninsula, increasing the extent of winter ice. From spring into summer, winds are significantly reduced, delaying ice retreat.

"The combination of a windy winter with heavy sea ice followed by a calm spring favors the development and persistence of a stable water column in the summer along the West Antarctic Peninsula," says Saba. This stable, or stratified water column, with a layer of fresher, less-dense ice-melt floating atop a saltier layer below, encourages phytoplankton growth, likely by keeping the tiny plants nearer the sunlit surface and in proximity to the iron-rich glacial meltwater they need to thrive.

Moving up the food chain, the team's sampling reveals that the area's periodic, climate-driven phytoplankton blooms are a key to krill "recruitment"the addition of new, young individuals into the krill population. Adlie penguins and other top predators in the Antarctic food web rely on a robust population of krill prey for their own health and reproductive success.

"When climate conditionsa negative SAM and stable water columnlead to peaks in the abundance of phytoplankton and krill, Adlie penguins don't have to go far to forage," explains Saba. "But when SAM is positive, warm northwesterly winds blow over the Peninsula region, bringing less sea ice and a less-stable water columnfactors that discourage the large blooms of phytoplankton on which krill rely. Penguins then have to forage further, and thus end up delivering less food to their chicks. That can decrease their reproductive success."

Ongoing work by Palmer scientists shows that the population of Adlie penguins near Palmer Station has fallen 85% since 1974. Though the researchers stop short of attributing this decline solely to a climate-related shortage of krill, they do express concern for the future given that climate models project an increase in the occurrence of positive SAM episodes during the coming century.

"Projections from global climate models under 'business-as-usual' emission scenarios up to the year 2100 suggest a further increase in temperature and in the occurrence of positive-SAM conditions," says Saba. "If even one positive SAM episode lasted longer than the krill lifespan4 or 6 years with decreased phytoplankton abundance and krill recruitmentit could be catastrophic to the krill population."

In addition to Adlie penguins, krill are the main food source for Antarctic fur seals, macaroni and gentoo penguins, and albatross. They also feed baleen whales such as humpbacks.


Contact: David Malmquist
Virginia Institute of Marine Science

Related biology news :

1. Researchers receive $12.6 million NIH grant to study genetics of Alzheimers
2. Doctoral students to study biology, mechanics connection under NIH grant
3. Insect diet helped early humans build bigger brains, study suggests
4. Flood fear has temporary effect on property prices: QUT study
5. Plants respond to leaf vibrations caused by insects chewing, MU study finds
6. NIH study reveals gene critical to the early development of cilia
7. Study of animal urination could lead to better-engineered products
8. New study: Ancient Arctic sharks tolerated brackish water 50 million years ago
9. Comparison study of planting methods shows drilling favorable for organic farming
10. A step closer to bio-printing transplantable tissues and organs: Study
11. Fathers ethnic background influences birthweight, study finds
Post Your Comments:
Related Image:
Study reveals strong links between Antarctic climate, food web
(Date:11/12/2015)... , Nov. 11, 2015   Growing ... reliable analytical tools has been paving the way ... qualitative determination of discrete analytes in clinical, agricultural, ... are being predominantly used in medical applications, however, ... environmental sectors due to continuous emphasis on improving ...
(Date:11/10/2015)... , Nov. 10, 2015 ... biometrics that helps to identify and verify the ... is considered as the secure and accurate method ... of a particular individual because each individual,s signature ... results especially when dynamic signature of an individual ...
(Date:11/4/2015)... York , November 4, 2015 ... a new market report published by Transparency Market Research "Home ... Growth, Trends and Forecast 2015 - 2022", the global home ... US$ 30.3 bn by 2022. The market is estimated ... forecast period from 2015 to 2022. Rising security needs ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... ... 25, 2015 , ... A long-standing partnership between the Academy ... been formalized with the signing of a Memorandum of Understanding. , AMA Executive ... Karl Minter and Capt. Albert Glenn Tuesday, November 24, 2015, at AMA Headquarters ...
(Date:11/24/2015)... (PRWEB) , ... November 24, 2015 , ... The United ... recipient of the 2016 USGA Green Section Award. Presented annually since 1961, the USGA ... his or her work with turfgrass. , Clarke, of Iselin, N.J., is ...
(Date:11/24/2015)... , ... November 24, 2015 , ... ... of the year and one of the premier annual events for pharmaceutical manufacturing: ... from 8–11 November 2015, where ISPE hosted the largest number of attendees in ...
(Date:11/24/2015)... ... November 24, 2015 , ... The Academy of Model Aeronautics (AMA), led ... also known as Multirotor Grand Prix, to represent the First–Person View (FPV) racing community. ... members have embraced this type of racing and several new model aviation pilots have ...
Breaking Biology Technology: