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Scientists research Chukchi biodiversity Fieldwork in 2015 observed and sampled many species while measuring the ocean currents and seawater composition By ALAN BAILEY Petroleum News
A team of scientists conducting a five-year study into the biodiversity of the Chukchi Sea has reported some of the results of its first field season, conducted during the 2015 open water season. The study, funded by the Bureau of Ocean Energy Management, the National Oceanic and Atmospheric Administration and Shell Exploration and Production Co., is called the Arctic Marine Biodiversity Observing Network, or AMBON, and involves a team of university and government researchers.
According to a report from BOEM, during the 2015 field season the researchers conducted sampling across the entire Chukchi shelf, from north to south across the shelf and from nearshore to more than 150 miles offshore. The AMBON cruise succeeded in sampling about 80 percent of the species anticipated on the seafloor and about 90 percent of the expected species of bottom living fish. BOEM said that its interest in the research is the acquisition of data that will improve environmental impact assessments, develop better metrics for cumulative impact analysis and achieve a broader perspective of the Chukchi Sea ecosystem.
General findings The fieldwork conducted in 2015 established that, although northward flowing water along the Alaska coast in association with the Alaska Coastal Current is relatively warm, the salinity is not as low as expected. Water column chlorophyll, a common measure of food availability for marine organisms, proved particularly abundant in the northern and southern sectors of the study area, with chlorophyll in ocean-floor sediments reflecting a similar pattern.
However, the amount of biomass and the diversity of species living on the seafloor did not particularly correlate with the chlorophyll levels, with concentrations of these organisms being much higher in the northern Chukchi Sea than in the southern part of the sea. On the other hand, concentrations of fauna such as clams and tube worms, which live in rather than on the sediments, appeared to closely follow the pattern of chlorophyll levels. Walrus closer to shore Pacific walrus were most common in the northern part of the study region, where the bottom-living invertebrates that provide the animal’s prime food source are particularly abundant. However, as the sea ice recedes, the walrus have to haul out and rest on land, rather than on ice floes, thus causing the animals to seek food resources closer to shore, the BOEM report said.
The researchers observed a variety of seabirds, with highest concentrations occurring in the northernmost and southernmost parts of the region. Seabird concentrations were particularly high around Barrow Canyon, an area off the northwestern tip of Alaska, where physical processes tend to concentrate the birds’ prey. Some species such as murres are especially abundant in areas with strong currents and high organic productivity, while bottom-feeding birds such as eiders tend to live nearshore. An observing network The general objectives of the AMBON study are to demonstrate the observation of the biodiversity of organisms ranging in scale from microbes to whales, to close gaps in the current knowledge of the biodiversity of the Chukchi shelf; to integrate and synthesize the results of past and continuing research on the Arctic continental shelf; to make observed biodiversity data publicly accessible; to demonstrate how a sustainable observing network can be developed; and to link with other international scientific programs across the Arctic.
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