Interannual variability of Emiliania huxleyi blooms in the Barents Sea: In situ data 2014–2018

2020 ◽  
Vol 158 ◽  
pp. 111392 ◽  
Author(s):  
Vladimir Silkin ◽  
Larisa Pautova ◽  
Mario Giordano ◽  
Marina Kravchishina ◽  
Vladimir Artemiev
Keyword(s):  
Interannual Variability ◽  
Barents Sea ◽  
Emiliania Huxleyi ◽  
In Situ Data ◽  
The Barents Sea

Sea Ice Thickness Forecast Performance in the Barents Sea

2020 ◽  
Author(s):  
Laura Hume-Wright ◽  
Emma Fiedler ◽  
Nicolas Fournier ◽  
Joana Mendes ◽  
Ed Blockley ◽  
...  
Keyword(s):  
Sea Ice ◽  
Barents Sea ◽  
Forecast Model ◽  
The Arctic ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
Forecast Performance ◽  
In Situ Data ◽  
The Barents Sea ◽  
Ice Conditions

Abstract The presence of sea ice has a major impact on the safety, operability and efficiency of Arctic operations and navigation. While satellite-based sea ice charting is routinely used for tactical ice management, the marine sector does not yet make use of existing operational sea ice thickness forecasting. However, data products are now freely available from the Copernicus Marine Environment Monitoring Service (CMEMS). Arctic asset managers and vessels’ crews are generally not aware of such products, or these have so far suffered from insufficient accuracy, verification, resolution and adequate format, in order to be well integrated within their existing decision-making processes and systems. The objective of the EU H2020 project “Safe maritime operations under extreme conditions: The Arctic case” (SEDNA) is to improve the safety and efficiency of Arctic navigation. This paper presents a component focusing on the validation of an adaption of the 7-day sea ice thickness forecast from the UK Met Office Forecast Ocean Assimilation Model (FOAM). The experimental forecast model assimilates the CryoSat-2 satellite’s ice freeboard daily data. Forecast skill is evaluated against unique in-situ data from five moorings deployed between 2015 and 2018 by the Barents Sea Metocean and Ice Network (BASMIN) Joint Industry Project. The study shows that the existing FOAM forecasts produce adequate results in the Barents Sea. However, while studies have shown the assimilation of CryoSat-2 data is effective for thick sea ice conditions, this did not improve forecasts for the thinner sea ice conditions of the Barents Sea.

scholarly journals Growth of the coccolithophore <i>Emiliania huxleyi</i> in light- and nutrient-limited batch reactors: relevance for the BIOSOPE deep ecological niche of coccolithophores

2016 ◽  
Vol 13 (21) ◽  
pp. 5983-6001 ◽  
Author(s):  
Laura Perrin ◽  
Ian Probert ◽  
Gerald Langer ◽  
Giovanni Aloisi
Keyword(s):  
Ecological Niche ◽  
Deep Ocean ◽  
Emiliania Huxleyi ◽  
Physiological Parameters ◽  
Phosphate Limitation ◽  
Batch Reactors ◽  
In Situ Data ◽  
Physiological Modelling ◽  
In Situ Conditions

Abstract. Coccolithophores are unicellular calcifying marine algae that play an important role in the oceanic carbon cycle via their cellular processes of photosynthesis (a CO2 sink) and calcification (a CO2 source). In contrast to the well-studied, surface-water coccolithophore blooms visible from satellites, the lower photic zone is a poorly known but potentially important ecological niche for coccolithophores in terms of primary production and carbon export to the deep ocean. In this study, the physiological responses of an Emiliania huxleyi strain to conditions simulating the deep niche in the oligotrophic gyres along the BIOSOPE transect in the South Pacific Gyre were investigated. We carried out batch culture experiments with an E. huxleyi strain isolated from the BIOSOPE transect, reproducing the in situ conditions of light and nutrient (nitrate and phosphate) limitation. By simulating coccolithophore growth using an internal stores (Droop) model, we were able to constrain fundamental physiological parameters for this E. huxleyi strain. We show that simple batch experiments, in conjunction with physiological modelling, can provide reliable estimates of fundamental physiological parameters for E. huxleyi that are usually obtained experimentally in more time-consuming and costly chemostat experiments. The combination of culture experiments, physiological modelling and in situ data from the BIOSOPE cruise show that E. huxleyi growth in the deep BIOSOPE niche is limited by availability of light and nitrate. This study contributes more widely to the understanding of E. huxleyi physiology and behaviour in a low-light and oligotrophic environment of the ocean.

scholarly journals Barents Sea thermal frontal zones variability in 1960–2018

Trudy VNIRO ◽  
2020 ◽  
Vol 180 ◽  
pp. 60-71
Author(s):  
V. A. Ivshin ◽  
A. G. Trofimov ◽  
O. V. Titov
Keyword(s):  
Temperature Gradient ◽  
Interannual Variability ◽  
Barents Sea ◽  
Temperature Gradients ◽  
The Barents Sea ◽  
Mean Temperature ◽  
Frontal Zones ◽  
The 1960S ◽  
Centers Of Mass ◽  
Grid Nodes

This paper discusses our research on the interannual variability in the Barents Sea thermal frontal zones. The length index of the thermal frontal zones (the number of grid nodes with a relevant temperature gradient) and their mean temperature gradients at 50 m depth in August-September 1960–2018 were calculated for an area between 73–78°N, 15–43°E, where the frontal zones are more evident. Thermal frontal zones were identified in the areas where temperature gradients exceeded 0.04 °C/km. Since the beginning of this century, the length index of thermal frontal zones in the Barents Sea has been decreasing and temperature gradients in them have been weakening; in 2010, the length index of frontal zones and the mean temperature gradient reached record low values since 1960. To estimate interannual variability in the positions of thermal frontal zones, their geographical centroids (weighted centers of mass for grid nodes with a relevant temperature gradient) were calculated, taking into account horizontal temperature gradients as weighting coefficients. From the 1960s to the 2010s, the decadal mean centroids of frontal zones shifted northeastwards by 150 km.

Barents Sea thermal frontal zones in 1960–2017: variability, weakening, shifting

2019 ◽  
Vol 76 (Supplement_1) ◽  
pp. i3-i9
Author(s):  
Viktor A Ivshin ◽  
Alexander G Trofimov ◽  
Oleg V Titov
Keyword(s):  
Interannual Variability ◽  
Barents Sea ◽  
Temperature Gradients ◽  
The Barents Sea ◽  
Mean Temperature ◽  
Frontal Zones ◽  
The 1960S

Abstract This paper discusses our research on the interannual variability in the Barents Sea thermal frontal zones. The extent of the frontal zones and their mean temperature gradients at 50 m depth in August–September 1960–2017 were estimated for an area between 73–78°N and 15–43°E, where the frontal zones are more evident. Thermal frontal zones were identified in areas where temperature gradients exceeded 0.04°C km−1. Since the beginning of this century, the extent of the frontal zones has been decreasing and temperature gradients have been weakening. From the 1960s to the 2010s, the decadal mean centroids of thermal frontal zones shifted northeastwards by 150 km.

scholarly journals Methods and results of in situ target-strength measurements of Atlantic cod (Gadus morhua) during combined trawl-acoustic surveys

2009 ◽  
Vol 66 (6) ◽  
pp. 1225-1232 ◽  
Author(s):  
Viacheslav A. Ermolchev
Keyword(s):  
Gadus Morhua ◽  
Barents Sea ◽  
Atlantic Cod ◽  
Biological Data ◽  
Target Strength ◽  
Fish Length ◽  
The Barents Sea ◽  
Total Fish ◽  
Acoustic Surveys

Abstract Ermolchev, V. A., 2009. Methods and results of in situ target-strength measurements of Atlantic cod (Gadus morhua) during combined trawl-acoustic surveys. – ICES Journal of Marine Science, 66: 1225–1232. This paper presents methods for collecting acoustic and biological data, including in situ target-strength (TS) estimates of fish, with results presented for Atlantic cod (Gadus morhua) obtained from combined trawl-acoustic surveys. These include fish in the small, average, and maximum length classes, within the range 5–136 cm (total fish length, LT). The investigations were done using Simrad EK500/EK60 echosounders with split-beam transducers and special post-processing software. Based on an analysis of data collected in the Barents Sea during 1998–2007, a relationship TS = 25.2 log10(LT) − 74.8 was obtained for Atlantic cod at 38 kHz, with TS in dB and LT in centimetres. Seasonally, and for depths between 50 and 500 m, the variability in cod TS was 3.1 dB, decreasing with depth. The largest day–night difference in mean TS was in August–September, with changes as large as 1.0–1.7 dB. In the other seasons, the day–night difference was <1.0 dB.

scholarly journals Sea ice in the Barents Sea: seasonal to interannual variability and climate feedbacks in a global coupled model

2008 ◽  
Vol 32 (7-8) ◽  
pp. 1119-1138 ◽  
Author(s):  
Torben Koenigk ◽  
Uwe Mikolajewicz ◽  
Johann H. Jungclaus ◽  
Alexandra Kroll
Keyword(s):  
Sea Ice ◽  
Interannual Variability ◽  
Barents Sea ◽  
Coupled Model ◽  
Climate Feedbacks ◽  
The Barents Sea ◽  
Global Coupled Model

Optical impact of an Emiliania huxleyi bloom in the frontal region of the Barents Sea

2014 ◽  
Vol 130 ◽  
pp. 228-240 ◽  
Author(s):  
Erlend Kjeldsberg Hovland ◽  
Kasper Hancke ◽  
Morten Omholt Alver ◽  
Ken Drinkwater ◽  
Jo Høkedal ◽  
...  
Keyword(s):  
Barents Sea ◽  
Emiliania Huxleyi ◽  
Frontal Region ◽  
The Barents Sea ◽  
Optical Impact

In situ Measurements of the Characteristics of Suspended Particles in the Barents Sea by the LISST-Deep Laser Diffractometer

Oceanology ◽  
2020 ◽  
Vol 60 (5) ◽  
pp. 650-663
Author(s):  
A. S. Lokhov ◽  
M. D. Kravchishina ◽  
A. A. Klyuvitkin ◽  
A. I. Kochenkova
Keyword(s):  
Barents Sea ◽  
Suspended Particles ◽  
In Situ Measurements ◽  
The Barents Sea

scholarly journals Variability in retention of Calanus finmarchicus in the Nordic Seas

2005 ◽  
Vol 62 (7) ◽  
pp. 1301-1309 ◽  
Author(s):  
Thomas Torgersen ◽  
Geir Huse
Keyword(s):  
Interannual Variability ◽  
Retention Index ◽  
Vertical Migration ◽  
Barents Sea ◽  
Calanus Finmarchicus ◽  
Nordic Seas ◽  
Physical Forcing ◽  
The Barents Sea ◽  
Initial Location ◽  
Number Of Particles

Abstract Using a regional ocean circulation model and particle tracking, we have studied the probability of the copepod Calanus finmarchicus being retained within the Nordic Seas' population as a function of its initial location, its vertical migration pattern, and the interannual variability in physical forcing. Defining a retention index in terms of the number of particles remaining within the Nordic Seas divided by the initial number of particles released, we found that spatial location had the greatest effect on the retention index during the study period, 1988–1991. Variability as a result of differences in physical forcing among years and among different seasonal vertical migration patterns had smaller but similar effects. The seasonal vertical migration behaviours with the highest advective loss rates and the most sensitive to interannual physical forcing were those that ascended early and descended late from a shallow summer depth. Average retention within the Nordic Seas was 0.40 after one year in simulations with diffusion and advection, and 0.42 in simulations with advection only. The average retention at the end of the four-year sequence was 0.10 and 0.12 with and without diffusion, respectively. Particles located in the western areas of the Nordic Seas had the highest retention, while those along the Norwegian coast showed little or no retention after four years. Initial location has a larger influence on retention than interannual variability in advective fields. C. finmarchicus offspring tend to reside in areas different from their parents, with different probabilities of retention. This spatial variability in retention rate is also experienced as inter-generational variability by members of the population. Model results suggest that almost all of the C. finmarchicus that are advected into the Barents Sea originate from off the Norwegian coast. Thus, predicting C. finmarchicus inflow into the Barents Sea requires knowledge of their abundance on the Norwegian Shelf.

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