Warming Climate impacts Food Web base in Western Antarctic Peninsula

Populations of adelie penguins, whose lifestyle requires an Antarctic climate, have dropped sharply in recent years in parts of the peninsula. (Chris Linder, Woods Hole Oceanographic Institution)

A paper published this March in Science shows for the first time that the warming climate is changing the numbers and composition of phytoplankton—the base of the food web—along the western shelf of the Antarctic Peninsula.

Summertime levels of phytoplankton have decreased by 12 percent over the past 30 years off the Western Antarctic Peninsula, reports the team, which was led by Martin Montes-Hugo of the Institute of Marine and Coastal Sciences at Rutgers University.

The climate of the western shelf of the Antarctic Peninsula is undergoing rapid physical climate change. Over the past half-century, winter air temperatures warmed at almost five times the global average rate—the most rapid warming of the past 500 years. In addition, seasonal sea ice in this region now arrives later in autumn and leaves earlier in spring, a trend that has displaced populations of sea ice-dependent animals.

'With the striking climate change we’ve observed in Antarctica, scientists have known that higher organisms like penguins are being affected,' said Scott Doney, a marine geochemist at the Woods Hole Oceanographic Institution (WHOI) who assisted Montes-Hugo with the numerical analysis of the satellite and field data. 'But this is the first evidence we’ve seen that those changes are having an impact on the base of the food web.'

For this study, Montes-Hugo analyzed 30 years of satellite and field data on ocean color, temperature, sea ice, cloud cover, and wind speed to determine the changes in phytoplankton along the WAP.

'This important scientific discovery is a result of the synergy between satellite data and time series data,' Doney added. 'Being able to tie these data together was a critical new step.'

This paper stems from work done as part of the National Science Foundation Office of Polar Program’s Long-Term Ecological Research (LTER) project at Palmer Station, Antarctica. Besides Montes-Hugo and Doney, the paper’s co-authors are Hugh Ducklow, co-director of the Ecosystems Center at the Marine Biological Laboratory (MBL), Oscar Schofield, Rutgers University’s Institute of Marine and Coastal Sciences; William Fraser, Polar Oceans Research Group, Sheridan, Montana; Douglas Martinson, Columbia University’s Lamont-Doherty Earth Observatory; and Sharon E. Stammerjohn, University of California at Santa Cruz.

EXTRACT: Phytoplankton Changing Along the Antarctic Peninsula as Climate Warms, Rutgers Scientists Find.

As the cold, dry climate of the western Antarctic Peninsula becomes warmer and more humid, phytoplankton – the bottom of the Antarctic food chain – is decreasing off the northern part the peninsula and increasing further south, Rutgers marine scientists have discovered. In research to be published (tomorrow) in the journal Science, Martin Montes-Hugo and Oscar Schofield report that levels of phytoplankton off the western Antarctic Peninsula have decreased 12 percent over the past 30 years.

Their paper, Recent Changes in Phytoplankton Communities Associated with Rapid Regional Climate Change Along the Western Antarctic Peninsula, draws on 30 years of satellite data and field studies. Montes-Hugo is a postdoctoral researcher and Schofield is a professor of marine science at the Institute of Marine and Coastal Sciences in the School of Environmental and Biological Sciences at Rutgers University.

The Antarctic Peninsula is the northernmost part of Antarctica, stretching north to within 640 miles of Tierra del Fuego in South America.

'What is new is that we're showing for the first time that there is an ongoing change in phytoplankton concentration and composition along the western shelf of the Antarctic Peninsula that is associated with a long-term climate modification,' Montes-Hugo said. 'These phytoplankton changes may explain in part the observed decline of some penguin populations'

Researchers have noticed that populations of adelie penguins, whose lifestyle requires an Antarctic climate, have dropped sharply in recent years in the northern part of the peninsula, while populations of sub-Antarctic penguins, such as chin-strap penguins, have increased.

'Now we know that climate changes are impacting at the base of the food web and forcing their effects on up through the food chain,' said Hugh Ducklow, co-author of the paper and co-director of the Ecosystems Center at the Marine Biological Laboratory in Woods Hole, Massachusetts. 'Martin Montes-Hugo’s elegant work, utilizing different satellite streams of data, nailed that down.'

Scientists have long noted that the Antarctic Peninsula is warming faster than any part of the Earth during winter.

Read the full release at Rutgers University New Jersey. click here

The R/V Laurence M. Gould, docked after a 2002 winter cruise, dwarfs the buildings of the U.S. research outpost at Palmer Station, Antarctica. (Peter Wiebe, Woods Hole Oceanographic Institution)

The Woods Hole Oceanographic Institution is a private, independent organization in Falmouth, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the oceans and their interaction with the Earth as a whole, and to communicate a basic understanding of the oceans’ role in the changing global environment.

http://www.whoi.edu/