scholarly journals Using acoustic technology to improve the modelling of the transportation and distribution of juvenile gadoids in the Barents Sea

2009 ◽  
Vol 66 (6) ◽  
pp. 1048-1054 ◽  
Author(s):  
Geir O. Johansen ◽  
Olav R. Godø ◽  
Morten D. Skogen ◽  
Terje Torkelsen
Keyword(s):  
Vertical Distribution ◽  
Conceptual Model ◽  
Prediction Models ◽  
Barents Sea ◽  
Transport Model ◽  
Spatial Scales ◽  
Growth And Survival ◽  
The Barents Sea ◽  
Vertical Distributions ◽  
Tracking Model

Abstract Johansen, G. O., Godø, O. R., Skogen, M. D., and Torkelsen, T. 2009. Using acoustic technology to improve the modelling of the transportation and distribution of juvenile gadoids in the Barents Sea. – ICES Journal of Marine Science, 66: 1048–1054. Transport of the juvenile stages of gadoids by oceanic currents in the Barents Sea is governed by interactions between the vertical positioning of the fish and the horizontal movement of the water masses. The resulting geographical distribution is important for growth and survival. There is need for observations at proper temporal and spatial scales to improve the representation of vertical distribution in models of the transport process. Stationary acoustic systems are suitable for this purpose. We use such a system to quantify the vertical dynamics of 0-group gadoids with reference to a conceptual model of the temporal variation. The vertical distribution from the conceptual model is applied within a Lagrangian, particle-tracking model. This approach performs better in predicting the geographic distribution of the 0-group during the first 10 months after hatching than a model with random, vertical distribution. The potential of stationary acoustic systems to provide high-quality vertical distributions that improve the predictive power of the transport model is demonstrated. Extensive sampling programmes based on the principles presented here can provide the observations needed to obtain more realistic recruitment–prediction models.

Vertical distribution of tintinnids and associated microplankton in the upper layer of the Barents Sea

Sarsia ◽  
1991 ◽  
Vol 76 (3) ◽  
pp. 141-151 ◽  
Author(s):  
Demetrio Boltovskoy ◽  
Sandra M. Vivequin ◽  
Neil R. Swanberg
Keyword(s):  
Vertical Distribution ◽  
Barents Sea ◽  
The Barents Sea

A conceptual model of distribution of capelin in the Barents Sea

Sarsia ◽  
1992 ◽  
Vol 77 (2) ◽  
pp. 147-156 ◽  
Author(s):  
Jarl Giske ◽  
Hein Rune Skjoldal ◽  
Dag L. Aksnes
Keyword(s):  
Conceptual Model ◽  
Barents Sea ◽  
The Barents Sea

scholarly journals Benthic-pelagic coupling in the Barents Sea: an integrated data-model framework

2020 ◽  
Vol 378 (2181) ◽  
pp. 20190359 ◽  
Author(s):  
Felipe S. Freitas ◽  
Katharine R. Hendry ◽  
Sian F. Henley ◽  
Johan C. Faust ◽  
Allyson C. Tessin ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ecosystem Functioning ◽  
Barents Sea ◽  
Transport Model ◽  
Large Fraction ◽  
Model Framework ◽  
Reactive Material ◽  
The Barents Sea ◽  
Degradation Rates ◽  
The Future

The Barents Sea is experiencing long-term climate-driven changes, e.g. modification in oceanographic conditions and extensive sea ice loss, which can lead to large, yet unquantified disruptions to ecosystem functioning. This key region hosts a large fraction of Arctic primary productivity. However, processes governing benthic and pelagic coupling are not mechanistically understood, limiting our ability to predict the impacts of future perturbations. We combine field observations with a reaction-transport model approach to quantify organic matter (OM) processing and disentangle its drivers. Sedimentary OM reactivity patterns show no gradients relative to sea ice extent, being mostly driven by seafloor spatial heterogeneity. Burial of high reactivity, marine-derived OM is evident at sites influenced by Atlantic Water (AW), whereas low reactivity material is linked to terrestrial inputs on the central shelf. Degradation rates are mainly driven by aerobic respiration (40–75%), being greater at sites where highly reactive material is buried. Similarly, ammonium and phosphate fluxes are greater at those sites. The present-day AW-dominated shelf might represent the future scenario for the entire Barents Sea. Our results represent a baseline systematic understanding of seafloor geochemistry, allowing us to anticipate changes that could be imposed on the pan-Arctic in the future if climate-driven perturbations persist. This article is part of the theme issue ‘The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning’.

Do Thermoclines Explain the Vertical Distributions of Larval Fishes in the Dynamic Coastal Waters of South-eastern Australia?

1996 ◽  
Vol 47 (2) ◽  
pp. 183 ◽  
Author(s):  
CA Gray
Keyword(s):  
Vertical Distribution ◽  
Coastal Waters ◽  
Spatial Scales ◽  
Major Influence ◽  
Larval Fishes ◽  
Larval Behaviour ◽  
Eastern Australia ◽  
Water Columns ◽  
Vertical Distributions ◽  
Deep Depth

This study examined whether the position and strength of the thermocline influenced the vertical distributions of larval fishes in the coastal waters off Sydney. Depth-stratified sampling of larval assemblages was done in stratified and non-stratified conditions. Larval assemblages were depth- stratified, and individual taxa displayed specific depth distributions in all types of water columns. In stratified and non-stratified water columns some species were characteristic of shallow, mid and deep depth strata. The presence of a thermocline did not appear to influence broad-scale patterns of vertical distribution of larval fishes, and it was not considered a good predictor of larval vertical distribution. Larval behaviour appeared to be the major influence determining vertical distributions of larval fishes. It is argued that thermoclines may not be important to larval fishes in waters characterized by dynamic oceanography, such as those off Sydney, where the position and integrity of the thermocline can vary greatly over small temporal and spatial scales. Greater emphasis needs to be placed on teasing out the importance of various interacting biotic and abiotic features of the water column in structuring vertical distributions of larval fishes.

scholarly journals Changes and Predictions of Vertical Distributions of Global Light-Absorbing Aerosols Based on CALIPSO Observation

2020 ◽  
Vol 12 (18) ◽  
pp. 3014
Author(s):  
Zigeng Song ◽  
Xianqiang He ◽  
Yan Bai ◽  
Difeng Wang ◽  
Zengzhou Hao ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Vertical Distribution ◽  
Satellite Remote Sensing ◽  
Radiative Forcing ◽  
Prediction Models ◽  
Atmospheric Correction ◽  
Satellite Measurement ◽  
Vertical Distributions ◽  
Absorbing Aerosols ◽  
The Vertical Distribution

Knowledge of the vertical distribution of absorbing aerosols is crucial for radiative forcing assessment, and its quasi real-time prediction is one of the keys for the atmospheric correction of satellite remote sensing. In this study, we investigated the seasonal and interannual changes of the vertical distribution of global absorbing aerosols based on satellite measurement from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and proposed a neural network (NN) model to predict the vertical distribution of global absorbing aerosols. Gaussian fitting was proposed to derive the maximum fitted particle number concentration (MFNC), altitude corresponding to MFNC (MFA), and standard deviation (MFASD) for vertical distribution of dust and smoke aerosols. Results showed that higher MFA values of dust and smoke aerosols mainly occurred over deserts and tropical savannas, respectively. For dust aerosol, the MFA is mainly observed at 0.5 to 6 km above deserts, and low MFNC values occur in boreal spring and winter while high values in summer and autumn. The MFA of smoke is systematically lower than that of dust, ranging from 0.5 to 3.5 km over tropical rainforest and grassland. Moreover, we found that the MFA of global dust and smoke had decreased by 2.7 m yr−1 (statistical significance p = 0.02) and 1.7 m yr−1 (p = 0.02) over 2007–2016, respectively. The MFNC of global dust has increased by 0.63 cm−3 yr−1 (p = 0.05), whereas that of smoke has decreased by 0.12 cm−3 yr−1 (p = 0.05). In addition, the determination coefficient (R2) of the established prediction models for vertical distributions of absorbing aerosols were larger than 0.76 with root mean square error (RMSE) less than 1.42 cm−3, which should be helpful for the radiative forcing evaluation and atmospheric correction of satellite remote sensing.

The Barents Sea Benthic Silica Cycle and its Sensitivity to Change: a Stable Isotopic and Reaction-Transport Model Study

2020 ◽  
Author(s):  
James Ward ◽  
Felipe Sales de Freitas ◽  
Hong Chin Ng ◽  
Katharine Hendry ◽  
Sandra Arndt ◽  
...  
Keyword(s):  
Pore Water ◽  
Barents Sea ◽  
Transport Model ◽  
Northern Region ◽  
Benthic Flux ◽  
Pore Waters ◽  
Transport Modelling ◽  
Diagenetic Processes ◽  
The Barents Sea ◽  
Reaction Transport

<p>Biogeochemical cycling of silicon (Si) in the high latitudes has an important influence on the marine Si budget. The Barents Sea is divided aproximately equally into Arctic and Atlantic water (ArW and AW respectively) domains.  However, increases in the temperature and inflow of AW across the Barents Sea opening is driving an expansion of the AW realm. While the sensitivity of pelagic processes pertaining to primary production is receiving increasingly more attention, less is known of the effect on the benthic Si cycle. This knowledge gap could prove integral, as the flux of Si across the sediment-water interface (SWI) from Arctic shelf sediments could be up to 20% higher than that of riverine sources. This benthic flux is largely controlled by early diagenetic processes in sediment pore waters, including biogenic silica (bSi) dissolution and authigenic precipitation.</p><p>To improve our understanding of benthic Si dynamics in the Barents Sea and examine its sensitivity to future change, we analysed pore water and sediment samples from both the AW and ArW realms between 2017-2019 for dissolved silica (dSi) concentrations and stable silicon isotopic compositions. Moreover, to determine the composition and content of bSi, as well as Si sorbed onto metal oxides, we conducted a sequential digestion of surface sediment. Following this we coupled our analyses with reaction transport modelling to further improve our mechanistic understanding of the system and to quantitatively disentangle the relative importance of these diagenetic processes to pore water Si chemistry and benthic fluxes.</p><p>Our work suggests that both interannual and spatial variability of dSi are increased in the southern, AW region of the Barents Sea. Benthic flux estimates for the southern sites have been found to more than double (~30 to 100 mmol m<sup>-2 </sup>yr<sup>-2</sup>) between cruise years, compared to a more consistent flux in the north (~80 mmol m<sup>-2 </sup>yr<sup>-2</sup>). Therefore, future Atlantification of the northern region may enance the variability of dSi supply from the benthos to bottom waters, with potential consequences for diatom productivity in the region.</p>

Method application of optimal multi-parameter analysis to assess the distribution of water masses as an example of CTD data of the Barents Sea in summer 2017

2019 ◽  
pp. 38-51
Author(s):  
Valeriy G. Yakubenko ◽  
Anna L. Chultsova
Keyword(s):  
Barents Sea ◽  
Field Measurements ◽  
Structural Similarity ◽  
Water Masses ◽  
Parameter Analysis ◽  
Water Dynamics ◽  
Phosphorus Concentration ◽  
Nitrogen And Phosphorus ◽  
The Barents Sea ◽  
Expert Assessments

Identification of water masses in areas with complex water dynamics is a complex task, which is usually solved by the method of expert assessments. In this paper, it is proposed to use a formal procedure based on the application of the method of optimal multiparametric analysis (OMP analysis). The data of field measurements obtained in the 68th cruise of the R/V “Academician Mstislav Keldysh” in the summer of 2017 in the Barents Sea on the distribution of temperature, salinity, oxygen, silicates, nitrogen, and phosphorus concentration are used as a data for research. A comparison of the results with data on the distribution of water masses in literature based on expert assessments (Oziel et al., 2017), allows us to conclude about their close structural similarity. Some differences are related to spatial and temporal shifts of measurements. This indicates the feasibility of using the OMP analysis technique in oceanological studies to obtain quantitative data on the spatial distribution of different water masses.

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