scholarly journals Distribution and seasonal dynamics of bacterioplankton along the westernborder of the Barents Sea.

2020 ◽  
Vol 11 (5-2020) ◽  
pp. 37-50
Author(s):  
M.P. Venger ◽  

The structural characteristics of bacterioplankton were studied in the waters of the Cape`s Nordkap (cut I) and Zuydkap (cut II) of Mezhvezhiy island. Its abundance and biomass in the upper part of the photic layer of coastal and Atlantic waters in cut I was comparable and increased from the late spring to the summer season. Moreover, in cuts I and II, the values of summer maximum corresponded to the zone of the Polar Front and adjacent Arctic waters. By the beginning of the winter season, the level of development of communities in waters of different genesis decreased everywhere, but still did not reach the minimum, observed insummer in layers deeper than 200 m. The structure of bacterioplankton was determined by single cells of the smallest size, mainly of a cocci-form. The arrival of rod-shaped bacteria (contribution to the total biomass could reach 50%) was recorded in the summer period.

1996 ◽  
Vol 101 (C6) ◽  
pp. 14201-14221 ◽  
Author(s):  
A. Rost Parsons ◽  
Robert H. Bourke ◽  
Robin D. Muench ◽  
Ching-Sang Chiu ◽  
James F. Lynch ◽  
...  

Author(s):  
Martin Solan ◽  
Ellie R. Ward ◽  
Christina L. Wood ◽  
Adam J. Reed ◽  
Laura J. Grange ◽  
...  

Arctic marine ecosystems are undergoing rapid correction in response to multiple expressions of climate change, but the consequences of altered biodiversity for the sequestration, transformation and storage of nutrients are poorly constrained. Here, we determine the bioturbation activity of sediment-dwelling invertebrate communities over two consecutive summers that contrasted in sea-ice extent along a transect intersecting the polar front. We find a clear separation in community composition at the polar front that marks a transition in the type and amount of bioturbation activity, and associated nutrient concentrations, sufficient to distinguish a southern high from a northern low. While patterns in community structure reflect proximity to arctic versus boreal conditions, our observations strongly suggest that faunal activity is moderated by seasonal variations in sea ice extent that influence food supply to the benthos. Our observations help visualize how a climate-driven reorganization of the Barents Sea benthic ecosystem may be expressed, and emphasize the rapidity with which an entire region could experience a functional transformation. As strong benthic-pelagic coupling is typical across most parts of the Arctic shelf, the response of these ecosystems to a changing climate will have important ramifications for ecosystem functioning and the trophic structure of the entire food web. This article is part of the theme issue ‘The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning'.


Author(s):  
Bjarte O. Kvamme ◽  
Adekunle P. Orimolade ◽  
Sverre K. Haver ◽  
Ove T. Gudmestad

A study of the wave conditions in the North Sea, the Norwegian Sea and the Barents Sea is presented in this paper. For each region, one reference location for which there are buoy measurements is selected. For the selected locations, WAM10 hindcast data are obtained from the Norwegian Meteorological Institute (MET Norway). The hindcast data for each location cover the period from 1957 to 2014. First, the hindcast datasets were validated against available buoy measurements — both for extreme value predictions and for application of hindcast data for planning of marine operations. The validation was carried out considering the winter season and the summer season separately. For each season, the datasets for two consecutive months were used. A comparison of the time-series of the hindcast datasets against the buoy measurements showed that the hindcast datasets compared relatively well with the buoy measurements. However, a comparison of the statistical parameters of the hindcast datasets against the buoy measurements showed that the hindcast datasets are slightly conservative in the estimate of the significant wave height for the Barents Sea and the Norwegian Sea. Overall, the data compared well, and the hindcast datasets are therefore considered in the following analysis. Hindcast data from these 57 years show that the wave conditions in the selected Norwegian Sea location is harsher than the wave conditions in both the North Sea and the Barents Sea locations. This is in agreement with the general expected spatial trend in the wave climate on the Norwegian Continental Shelf (NCS). It was also observed that the wave conditions in the selected Barents Sea location are harsher than the wave conditions in the North Sea. These findings are also reflected in the NORSOK N-003 standard on “Actions and Action effects” (NORSOK, 2015). The weather windows for weather-sensitive marine operations, that is, operations with operational reference period not exceeding 72 hours, were established from the hindcast dataset for each of the locations. It was observed that the Norwegian Sea has shorter weather windows, especially in the winter seasons, compared to both the Barents Sea and the North Sea. It was expected that the operational windows would be shorter in the winter seasons in the Barents Sea, due to the occurrence of polar lows. However, the polar lows are few and cause more concern related to forecasting of the weather conditions to start actual marine operations. Generally, the month with the highest probability of weather windows exceeding 72 hours was found to be July for all three locations.


Water ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 101
Author(s):  
Pavel R. Makarevich ◽  
Veronika V. Vodopianova ◽  
Aleksandra S. Bulavina

Effects of the sea-ice edge and the Polar Frontal Zone on the distribution of chlorophyll-a levels in the pelagic were investigated during multi-year observations in insufficiently studied and rarely navigable regions of the Barents Sea. Samples were collected at 52 sampling stations combined into 11 oceanographic transects over a Barents Sea water area north of the latitude 75° N during spring 2016, 2018, and 2019. The species composition, abundance and biomass of the phytoplankton community, chlorophyll-a concentrations, hydrological and hydrochemical parameters were analyzed. The annual phytoplankton evolution phase, defined as an early-spring one, was determined throughout the transects. The species composition of the phytoplankton community and low chlorophyll-a levels suggested no phytoplankton blooming in April 2016 and 2019. Not yet started sea-ice melting prevented sympagic (sea-ice-associated) algae from being released into the seawater. In May 2018, ice melting began in the eastern Barents Sea and elevated chlorophyll-a levels were recorded near the ice edge. Chlorophyll-a concentrations substantially differed in waters of different genesis, especially in areas influenced by the Polar Front. The Polar Front separated the more productive Arctic waters with a chlorophyll-a concentration of 1–5 mg/m3 on average from the Atlantic waters where the chlorophyll-a content was an order of magnitude lower.


2003 ◽  
Vol 60 (4) ◽  
pp. 836-845 ◽  
Author(s):  
I. Smolyar ◽  
N. Adrov

Abstract The Barents Sea Atlantic Water (AW) is defined in eight different ways in the literature. These definitions can be consolidated into one statement (decision rule) that allows the separation of the AW of the Barents Sea from the rest of the water masses there. The decision rule defines AW as a straight-line function of temperature and salinity and non-Atlantic Water and Mixed Water by their proximity to AW on a temperature–salinity diagram. This rule is used to map the monthly-mean distribution of AW in the Barents Sea at 0, 30, 50 and 100 m depths. These maps demonstrate two stable seasons (winter and summer) of AW intrusion into the Barents Sea. The average duration of the AW-winter season is five months (January to May), whilst that of the AW-summer season is four months (July to October). During the winter, the area coverage of the AW at the surface equals 23% and varies slightly with depth. During summer, there is zero areal coverage of the AW at the surface, and with depth it varies considerably. The decision rule was used to map the monthly distribution of AW along latitude 74°30′N in the Barents Sea for the period 1975–1989. The maximum inflow of AW into the Barents Sea along 74°30′N occurs during March. The minimum inflow of AW occurs in August. The March/August inflow ratio is 1.55.


2014 ◽  
Vol 130 ◽  
pp. 219-227 ◽  
Author(s):  
Kasper Hancke ◽  
Erlend K. Hovland ◽  
Zsolt Volent ◽  
Ragnhild Pettersen ◽  
Geir Johnsen ◽  
...  

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