The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning

Abstract

One contribution of 18 to a theme issue 'The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning'.

Microbial Abundance and Enzyme Activity Patterns: Response to Changing Environmental Characteristics along a Transect in Kongsfjorden (Svalbard Islands)

“…The vertical distribution of Chl-a (st. 4) displayed a notable increase at the 25 and 50 m depth, with values five times higher than the surface, indicating a typical condition of the stratified water column. Total Chl-a concentrations measured in this study were comparable to those reported by Iversen and Seuthe [28] (0.18 ± 0.01 µg/L), who also found POC concentrations of 314 ± 46 µg/L in May and minimum ratios (4.6) of C:N. Wide variations in primary productivity are currently recorded in Kongsfjorden, due to pronounced seasonal variations in sunlight, glacier melting, and sea ice cover; all these conditions largely affect the downward export of biogenic matter [69]. Melted ice water inputs from several tidewater glaciers (Kongsbreen, Conwaybreen, Blomstrandbreen, Kronebreen, and Kongsvegen) enrich the fjord with particles of mineral and organic origin [31,32,70,71].…”

“…The intrusion of warm waters of Atlantic origin is particularly enhanced during late summer, while during fall and winter, the fjord water masses are replaced by fresher and cold Arctic waters [21]. In addition to the WSC inputs, in summer, the freshwater runoff from land and glaciers produces strong gradients inside the fjord, which also led to stratification at shallow depths [28]. Inter-annual variability in the water masses and Atlantic water intrusion, with a net outflow of surface freshwater from Kongsfjorden, has, however, recently been documented [35].…”

“…Moreover, connecting land to ocean, Arctic fjords play an important role in climate change in the overall area [26]. Pelagic and sea-ice algae production, as well as blue carbon stock in the shelf seafloor, are important sources of organic matter in these regions [27,28]; in addition, increased meltwater alters organic matter retention and processing, modifying the organic matter pool provided to coastal Arctic microbial communities [9]. Therefore, an understanding of microbial interactions with organic matter across salinity gradients is needed to evaluate the biogeochemical effects of increasing freshwater inputs from glacial melting.…”

The Importance of Benthic Nutrient Fluxes in Supporting Primary Production in the Laptev and East Siberian Shelf Seas

“…The Arctic Ocean is experiencing ongoing changes associated with receding sea ice, warming, and acidification that have large consequences for biological productivity and higher marine life (Solan et al, 2020;Stroeve & Notz, 2018;Terhaar et al, 2020). Elevated water temperatures have resulted in loss of summer sea ice, increased light transmission, a prolonged growing…”

“…

The Arctic Ocean is experiencing ongoing changes associated with receding sea ice, warming, and acidification that have large consequences for biological productivity and higher marine life (Solan et al, 2020;Stroeve & Notz, 2018;Terhaar et al, 2020). Elevated water temperatures have resulted in loss of summer sea ice, increased light transmission, a prolonged growing season (Serreze et al, 2007), and an increase in primary production by 30% over the period of 1998-2012, especially on the inner eastern Siberian shelf (Arrigo & Van Dijken, 2015).The Arctic shelf is the largest continental shelf on Earth and makes up >50% of the total Arctic Ocean area (Jakobsson, 2002).

…”