Arctic marine mammals on thin ice

Apr 23, 2008

The loss of sea ice due to climate change could spell disaster for polar bears and other Arctic marine mammals. The April Special Issue of Ecological Applications examines such potential effects, puts them in historical context, and describes possible conservation measures to mitigate them. The assessment reflects the latest thinking of experts representing multiple scientific disciplines.

Sea ice is the common habitat feature uniting these unique and diverse Arctic inhabitants. Sea ice serves as a platform for resting and reproduction, influences the distribution of food sources, and provides a refuge from predators. The loss of sea ice poses a particularly severe threat to Arctic species, such as the hooded seal, whose natural history is closely tied to, and depends on, sea ice.

The Arctic undergoes dramatic seasonal transformation. Arctic marine mammals appear to be well adapted to the extremes and variability of this environment, having survived past periods of extended warming and cooling.

“However, the rate and scale of current climate change are expected to distinguish current circumstances from those of the past several millennia. These new conditions present unique challenges to the well-being of Arctic marine mammals,” says Sue Moore (NOAA/Alaska Fisheries Science Center).

Climate change will pose a variety of threats to marine mammals. For some, such as polar bears, it is likely to reduce the availability of their prey, requiring them to seek alternate food. Authors Bodil Bluhm and Rolf Gradinger (University of Alaska, Fairbanks) note that while some Arctic marine mammal species may be capable of adjusting to changing food availability, others may be handicapped by their very specific food requirements and hunting techniques. Species such as the walrus and polar bear fall under this category, while the beluga whale and bearded seal are among those who are more opportunistic in their eating habits and therefore potentially less vulnerable, at least in this regard.

Using a quantitative index of species sensitivity to climate change, Kristin Laidre (University of Washington) and colleagues found that the most sensitive Arctic marine mammals appear to be the hooded seal, polar bear, and the narwhal, primarily due to their reliance on sea ice and specialized feeding.

Shifts in the prey base of Arctic marine mammals would likely lead to changes in body condition and potentially affect the immune system of marine mammals, according to Kathy Burek (Alaska Veterinary Pathology Services). She and fellow researchers point out that climate change may alter pathogen transmission and exposure to infectious diseases, possibly lowering the health of marine mammals and, in the worst case, their survival. Changing environmental conditions, including more frequent bouts of severe weather and rising air and water temperatures, also could impact the health of Arctic marine mammals.

The effects of climate change will be compounded by a host of secondary factors. The loss of ice will open the Arctic to new levels of shipping, oil and gas exploration and drilling, fishing, hunting, tourism, and coastal development. These, in turn, will add new threats to marine mammal populations, including ship strikes, contaminants, and competition for prey.

Timothy Ragen (US Marine Mammal Commission) and colleagues describe how conservation measures may be able to address the secondary effects of climate change, but that only reductions in greenhouse gas emissions can—over the long-term—conserve Arctic marine mammals and the Arctic ecosystems on which they depend.

Source: Ecological Society of America

Explore further: Plants with dormant seeds give rise to more species

add to favorites email to friend print save as pdf

Related Stories

The Isthmus of Panama: Out of the Deep Earth

Apr 01, 2014

As dates in geologic history go, the formation of the slender land bridge that joins South America and North America is a red-letter one. More than once over the past 100 million years, the two great landmasses ...

Exxon Valdez Runs Aground in 1989

Mar 24, 2014

Early on March 24, 1989, Dean Fosdick, the Alaska bureau chief of The Associated Press, was awakened around 5:30 a.m. by a phone call. The caller had a tip that a tanker had run aground outside Valdez.

Recommended for you

Plants with dormant seeds give rise to more species

15 hours ago

Seeds that sprout as soon as they're planted may be good news for a garden. But wild plants need to be more careful. In the wild, a plant whose seeds sprouted at the first warm spell or rainy day would risk disaster. More ...

Researchers successfully clone adult human stem cells

18 hours ago

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

User comments : 0

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Male monkey filmed caring for dying mate (w/ Video)

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Researchers develop new model of cellular movement

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.