Researchers have found melt ponds on Arctic sea ice contains food source for marine life. Photo by Heidi Louise Sørensen/SDU
March 30 (UPI) -- Scientists found mats of algae and bacteria evolve in melt ponds formed from Arctic snow and sea ice melt, which may lead to new food source for marine life.
The melt ponds, which are increasing due to global warming, can form their own small ecosystems. Sea ice melts during the summer months, and algae and bacteria formed in the melt ponds, are released into the surrounding seawater, providing an additional food source for marine life, researchers report in a recent study published in the journal Polar Biology.
Heidi Louise Sorensen, a doctoral student at the University of Southern Denmark, researched the phenomenon in a number of melt ponds in North-Eastern Greenland.
Sorensen found that some of the food from the melt ponds is ingested by marine life higher up in the water column while other food sinks to the bottom, feeding the creatures on the seabed.
The higher part of the water column contains mainly krill and copepods that can benefit from nutrient-rich algae and bacteria in melt ponds. Seabed dwellers like sea cucumbers and brittle sea stars eat the algae that sinks to the bottom.
Sorensen studied why some melt ponds contain biological organisms and others do not. She found the key is nutrients like phosphorus and nitrogen that get into melt ponds and allow algae and microorganisms to grow.
Nutrients get into melt ponds in many ways, including by waves of sea water, transported by dust storms from the mainland, washed with soil from the coast during rain or from migratory birds landing on the ice.
Researchers studied six melt ponds in Young Sound in North-Eastern Greenland, consisting of two natural and four artificial basins. Phosphorus and nitrogen were added in various combinations to four ponds, while two were control ponds.
Sorensen observed the ponds for 13 days and measured the content of Chlorophyll a, a pigment that allows algae to absorb energy from light. She found the chlorophyll content of the ponds enriched with phosphorus and nitrogen was two to 10 times higher than in the control ponds.
The increase in melt ponds can lead to more and more food sources for sea life in the Arctic.
"Climate change is accompanied by more storms and more precipitation, and we must expect that more nutrients will be released from the surroundings into the melt ponds," said Ronnie Glud, a professor in the Department of Biology at the University of Southern Denmark. "These conditions, plus the fact that the distribution of areas of melt ponds is increasing, can contribute to increased productivity in plant and animal life in the Arctic seas."
