Wild Things

The weird and wonderful in the natural world

Sarah Zielinski

Wild Things


Wild Things

Sea ice algae drive the Arctic food web

Themisto libellula amphipod

Even organisms that live in open waters of the Arctic, such as this Themisto libellula amphipod, get a lot of their carbon from algae that live in sea ice, a new study finds.

Sponsor Message

As happens every summer, sea ice in the Arctic is shrinking as temperatures warm. But this year is a particularly warm year, and there is less sea ice than there usually is. Scientists say Earth is on track to matchor perhaps even exceed the record low extent of summertime sea ice seen in September 2012.

The disappearing sea ice is a symptom of a warming planet, and it is also a problem for organisms associated with the ice, such as algae that live in the brine-filled channels within sea ice. “These algae are adapted to grow under very low light conditions,” says Doreen Kohlbach of the Alfred Wegener Institute in Bremerhaven, Germany. These algae, along with algal species that live in the open ocean, form the base of the Arctic food web. And they are an important food source even for species that don’t live under the ice, a new study shows.

This indicates that climate change will not only affect organisms with a close connection to the sea ice, Kohlbach says, but it will also subsequently affect the pelagic, or open-ocean, system.

In the new study, Kohlbach and her colleagues looked at the percentage of carbon that various species of zooplankton — one step up on the Arctic food web — get from sea ice algae during late summer. Some of the organisms live near the sea ice, while others are considered pelagic species. By using fatty acids as a marker, the researchers determined how much carbon in each species came from sea ice algae.

Animals that lived beneath the sea ice, not surprisingly, got a lot of their carbon from sea ice algae — from 60 to 90 percent, the researchers report July 8 in Limnology and Oceanography. But even pelagic species obtained 20 to 50 percent of their dietary carbon from algae embedded in sea ice. “Our results showed that not only the ice-associated animals were living mainly from ice algae–produced carbon, but that also the pelagic species showed a significant dependency on ice algae–produced carbon,” says Kohlbach.

Scientists have yet to test higher levels of the food web, so they can’t yet predict how the loss of sea ice algae might affect larger species, such as fish or seals or polar bears. But it will probably have some effect, Kohlbach says. “If alterations of the sea ice system affect the low members of the food chain, it will consequently affect all following members.”

There’s also a chance that species that currently feed on sea ice algae could switch to feeding on other species if their preferred food disappears. But the concern is for those species that depend entirely on sea ice algae. “We cannot say for sure what will happen to the organisms that depend highly on sea ice,” Kohlbach says. Some of them might adapt to the changes with a changing feeding behavior. To determine the consequences on a species-level, we need to do more research.”

Animals

Electric eels play defense with a mighty leap

By Sarah Zielinski 3:00pm, June 9, 2016
A biologist finds evidence that a 200-year-old report of electric eels attacking horses may be true.
Animals,, Oceans

Maximum size of giant squid remains a mystery

By Sarah Zielinski 12:03pm, June 3, 2016
A scientist has come up with a new estimate of the maximum size of giant squid. He says the animals could be as long as two public buses.
Animals

Animals get safe spots to cross the road — and car collisions drop

By Sarah Zielinski 12:00pm, May 31, 2016
Over- and underpasses built for wildlife in Wyoming proved a success for both the animals and the humans traveling the roads.
Animals,, Conservation

Counting cats is hard, but we know the numbers aren’t good

By Sarah Zielinski 9:03am, May 27, 2016
Recent studies highlight the difficulty of counting big cats, but even imperfect counts show that these species are in trouble.
Animals

For baby sea turtles, it helps to have a lot of siblings

By Sarah Zielinski 8:31am, May 23, 2016
After hatching, baby sea turtles must dig themselves out of their nest. This requires less energy if there are lots of siblings, a new study finds.
Animals

These mystery mounds are actually giant piles of earthworm poop

By Sarah Zielinski 8:33am, May 20, 2016
The grassy mounds that dot a watery landscape in South America are created by giant earthworms, a new study finds.
Animals

The bizarre mating ritual of a bee parasite

By Sarah Zielinski 8:41am, May 18, 2016
Stylops ovinae insects — parasites found in mining bees — have short lives filled with trauma.
Animals

Vultures are vulnerable to extinction

By Sarah Zielinski 8:36am, May 11, 2016
Life history makes vultures more vulnerable to extinction than other birds, a new study finds, but humankind’s poisons are helping them to their end.
Animals

Crocodile eyes are optimized for lurking

By Sarah Zielinski 2:28pm, May 6, 2016
Crocodiles hang out at the water’s surface, waiting for a meal. A new study shows their eyes are optimized for spotting their prey from this position.
Animals,, Oceans

Cause of mass starfish die-offs is still a mystery

By Sarah Zielinski 11:53am, May 5, 2016
Sea stars off the U.S. west coast started dying off en masse in 2013. Scientists are still struggling to figure out the cause.
Subscribe to RSS - Wild Things