The Arctic has a complex climate. There is little sunlight in winter, the summer days are long, the storms can include hurricane force winds, bitter cold temperatures, and at times, even rainfall. Ice is present as snow, ice caps, glaciers and sea ice. Permafrost, frozen soil, is a prominent feature in the Arctic and it is quite sensitive to even small temperature increases.
The Arctic’s coastal plains can consist of river deltas, barrier islands and lagoons. All of these features are vulnerable to the effects of climate change, flooding as a consequence of sea level rise, and “increased storm surges resulting from increases in both storminess and open water”.
An unusually large, long-lasting and powerful cyclone churned over the Arctic in early August 2012Over the decades, the sea ice has thinned and decreased in extent. The National Snow and Ice Data Center in a January 3, 2018 post notes the following, “Arctic sea ice extent in December 2017 was below average in both the far northern Atlantic and the Bering Sea, and notably high temperatures prevailed over most of the Arctic, especially over Central Alaska”.
Recently, polar scientists have found that melting sea ice is increasing the flow of nutrients into the central Arctic from the continental shelf.
Oceans Deeply writes on a study that confirms there is a huge threat below the sea ice in Eurasia, ocean warming.
Russia – is becoming more and more like the ice-free waters of the Atlantic Ocean as warm currents creep in. This “atlantification” has caused weaker stratification in the ocean’s unique water column, heating up the cold surface layer. The sudden shift has wide-reaching implications for everything from the ocean’s response to acidification to changes in nutrient productivity to sea ice loss.
Unlike the Atlantic and Pacific oceans, the coldest water layer in most of the Arctic Ocean lies at the surface. Warmer Atlantic waters are located farther down at intermediate depths and separated from the surface by the halocline layer, a thick, band of cold, salty water that prevents the two from mixing. But beginning in the 1970s, the halocline layer in the eastern Eurasian Basin began to weaken.
Climate Wire reports on the erosion study that suggests wave action and thawing permafrost are increasing the amount of soil and other sediments from the Russian coast into the central Arctic ocean. It will impact the marine food web.
A new study published yesterday in the journal Science Advances suggests that there's been an increase in the amount of soils or sediments flowing from the Arctic shore into the ocean over the last decade. And the researchers say climate change is likely to blame. As Arctic sea ice continues to melt, it's exposing the shallow regions around the coast to more wind and wave action, causing the waters to churn and draw sediments up from the continental shelf into the water column.
These sediments have likely carried an influx of carbon and other nutrients with them, which—if the pattern continues—could fuel an increase in plankton and algae in the water. And because plankton are a major food source for small fish and other marine organisms, the shift could cause a major change in the numbers and types of animals that populate the region.
It's hard to say how these changes might affect the Arctic ecosystem as a whole, said Matthew Charette, a scientist at the Woods Hole Oceanographic Institution and one of the study's authors. There could be both positive and negative effects.
"You take away ice, you take away potential habitats for polar bears," he noted. "But then that may in turn lead to increases in fish stocks, for example, if you have increases at the base of the food chain."
x xYouTube VideoWoods Hole Oceanographic Institution (WHOI) in a news release
The research team, led by Woods Hole Oceanographic Institution (WHOI), suspects that melting sea ice has left more open water near the coast for winds to create waves. The wave action reaches down to the shallow shelves and stirs up sediments, releasing radium that is carried to the surface and away into the open ocean. The same mechanism would likely also mobilize and deliver more nutrients, carbon, and other chemicals into the Arctic Ocean, fueling the growth of plankton at the bottom of the food chain. That, in turn, could have significant impacts on fish and marine mammals and change the Arctic ecosystem.
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Scientists aboard the icebreaker Healy measured seawater chemistry across the Arctic Ocean and found that levels of radium-228 have almost doubled over the last decade in the middle of the ocean. The radium was transported from land and shallow continental shelves by currents such as the Transpolar Drift. The surprising finding is evidence that rapid climate change is causing large-scale changes along the Arctic coast, such as diminishing sea ice. These coastal changes, in turn, could also deliver more nutrients, carbon, and other chemicals into the Arctic Ocean and have significant impacts on the Arctic food web. (Natalie Renier, Woods Hole Oceanographic Institiution)Scientists have long used radium-228 to track the flow of material from land and sediments into the ocean. It is a naturally occurring isotope produced by the radioactive decay of thorium in sediments. But unlike thorium, it dissolves into water, where scientists can track the sources, amounts, rates, and direction of its flow, said Kipp, who is lead author of the study and a graduate student in the MIT-WHOI Joint Program in Oceanography.
Kipp led efforts to measure radium at 69 locations from the western edge of the Arctic Ocean to the Pole on a two-month voyage aboard the icebreaker Healy in the summer of 2015. The cruise was part of the international GEOTRACES program, which aims to measure chemical tracers in the world’s ocean to understand ocean circulation and provide a baseline to assess future chemical changes in the oceans. The U.S. GEOTRACES program and this study are both funded by the National Science Foundation.
To their surprise, the research team found that radium-228 concentrations in the central Arctic Ocean had increased substantially since measurements had last been made in 2007. What was its source and why had it increased?
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