scholarly journals Seasonal cycling of zinc and cobalt in the south-eastern Atlantic along the GEOTRACES GA10 section

2021 ◽  
Vol 18 (14) ◽  
pp. 4265-4280
Author(s):  
Neil J. Wyatt ◽  
Angela Milne ◽  
Eric P. Achterberg ◽  
Thomas J. Browning ◽  
Heather A. Bouman ◽  
...  
Keyword(s):  
Surface Water ◽  
Mixed Layer ◽  
Surface Waters ◽  
Early Spring ◽  
External Input ◽  
The South ◽  
Austral Spring ◽  
South Eastern ◽  
Eastern Atlantic Ocean ◽  
Offshore Transport

Abstract. We report the distributions and stoichiometry of dissolved zinc (dZn) and cobalt (dCo) in sub-tropical and sub-Antarctic waters of the south-eastern Atlantic Ocean during austral spring 2010 and summer 2011/2012. In sub-tropical surface waters, mixed-layer dZn and dCo concentrations during early spring were 1.60 ± 2.58 nM and 30 ± 11 pM, respectively, compared with summer values of 0.14 ± 0.08 nM and 24 ± 6 pM. The elevated spring dZn concentrations resulted from an apparent offshore transport of elevated dZn at depths between 20–55 m, derived from the Agulhas Bank. In contrast, open-ocean sub-Antarctic surface waters displayed largely consistent inter-seasonal mixed-layer dZn and dCo concentrations of 0.10 ± 0.07 nM and 11 ± 5 pM, respectively. Trace metal stoichiometry, calculated from concentration inventories, suggests a greater overall removal for dZn relative to dCo in the upper water column of the south-eastern Atlantic, with inter-seasonally decreasing dZn / dCo inventory ratios of 19–5 and 13–7 mol mol−1 for sub-tropical surface water and sub-Antarctic surface water, respectively. In this paper, we investigate how the seasonal influences of external input and phytoplankton succession may relate to the distribution of dZn and dCo and variation in dZn / dCo stoichiometry across these two distinct ecological regimes in the south-eastern Atlantic.

scholarly journals Seasonal cycling of zinc and cobalt in the Southeast Atlantic along the GEOTRACES GA10 section

2020 ◽  
Author(s):  
Neil J. Wyatt ◽  
Angela Milne ◽  
Eric P. Achterberg ◽  
Thomas J. Browning ◽  
Heather A. Bouman ◽  
...  
Keyword(s):  
Water Column ◽  
Mixed Layer ◽  
Surface Waters ◽  
Early Spring ◽  
External Input ◽  
Austral Spring ◽  
Linear Relationships ◽  
Vertical Distributions ◽  
Offshore Transport ◽  
Seasonal Signal

Abstract. We report the distributions of dissolved zinc (dZn) and cobalt (dCo) in sub-tropical and sub-Antarctic waters of the Southeast Atlantic Ocean during austral spring 2010 and summer 2011/12. A strong seasonal signal was observed in sub-tropical surface waters with early spring mixed-layer dZn and dCo concentrations of 3.16 ± 1.35 nM and 39 ± 9 pM, respectively, compared with summer values depleted well below these levels by biological activity. The elevated spring mixed-layer dZn concentrations resulted from an apparent offshore transport of elevated dZn at depths between 20–50 m, derived from lithogenic inputs from the Agulhas Bank. In contrast, open-ocean sub-Antarctic surface waters displayed largely consistent inter-seasonal mixed-layer dZn and dCo concentrations of 0.11 ± 0.08 nM and 11 ± 5 pM, respectively. The vertical distributions of dZn and dCo in the upper water column were similar to that of phosphate (PO43−), with positive linear relationships during each of the seasons and across dynamic biogeochemical regimes, suggesting surface biological drawdown and shallow remineralisation of these metals in this region largely influences their distribution. The ecological stoichiometries for dZn and dCo, calculated from the linear regression with PO43−, suggest a greater overall use of dZn relative to dCo in the upper water column of the Southeast Atlantic with an inter-seasonal Zn:Co ratio ranging between 9 and 29. Sub-tropical surface water Zn:Co ratios were found to decrease between spring and summer indicating a preferential removal of dZn relative to dCo between seasons. In this paper we investigate how the seasonal influences of external input and phytoplankton succession may relate to the distribution of dZn and dCo, and variation in Zn:Co ecological stoichiometry, across two distinct ecological regimes in the Southeast Atlantic.

Beach wrack as a potential natural resource in the South-Eastern Baltic

2020 ◽  
Author(s):  
Julia Gorbunova ◽  
Boris Chubarenko
Keyword(s):  
Early Spring ◽  
Quality Characteristic ◽  
Coastal Protection ◽  
Spatial And Temporal Variability ◽  
Western Coast ◽  
Northern Coast ◽  
The South ◽  
South Eastern ◽  
Kaliningrad Oblast ◽  
Eastern Baltic

<p>Beach wrack (BW) – biological marine materials as algae, sea grasses and other, which are thrown from the sea to the seashore, becoming a polluter and cause of inconvenience. Problem of BW is present in the Kaliningrad Oblast of Russia, South-Eastern Baltic. From time to time, large amounts of BW appear in various places along its seashore. However, BW can be used as an organic resource, so nuisance could be converted into resource and asset. The study on BW spatial and quantitative distribution and its potential use in the South-Eastern Baltic is carry out within the Project #R090 CONTRA of the Interreg Baltic Sea Region Programme and accompanied by researches of algae species composition basing on partly support of the State assignment of IO RAS (Theme No. 0149-2019-0013).</p><p>An observations of the Baltic seashore within the Kaliningrad Oblast was carried out in March-December 2019 with the aim of quantity and quality characteristic of BW emissions. The BW emissions were recorded (measured, described and geo-referenced using GPS navigation) and sampled on two model sites monthly and the alongshore survey was carried out seasonally. Monitoring of the time of residence of the BW emissions was carried out three times per day at the selected model site using a web camera. It was found that the distribution of BW was characterized by significant spatial and temporal variability. In general, large amounts of BW emissions were observed on the northern coast of the Sambian Peninsula, in contrast to the western coast and Curonian and Vistula spits. The largest accumulations of BW were local and mainly near the coastline protrusions as capes (natural) and breakwaters, slipways, bunes (man-made). The time of residence of BW storage varied greatly and was often limited to a few days. Their further transformation could be carried out in several ways - by flushing back to the sea, covering under the thickness of sand or small pebbles, and a wind-wave dispersal along the beach. BW mainly contains Radophyta algae in the early spring and autumn-winter periods, in contrast to summer, when there are also Chlorophyta and Phaeophyta.</p><p>The preliminary estimations show that the industrial use of BW is limited by the spatial and temporal irregularity of their emissions in the Kaliningrad Oblast. However, the problem of BW collection and utilization exists. A possible solution could be use of BW for coastal protection greenery as nutrients that is similar to a natural process. These experiments were initiated in the Curonian Spit National Park in 2019. In this way BW could be involved in soft engineering techniques to manage the coastline.</p>

scholarly journals Increasing the Resolution of Ocean pCO2 Maps in the South Eastern Atlantic Ocean Merging Multifractal Satellite-Derived Ocean Variables

2018 ◽  
Vol 56 (11) ◽  
pp. 6596-6610 ◽  
Author(s):  
Ismael Hernandez-Carrasco ◽  
Veronique Garcon ◽  
Joel Sudre ◽  
Christoph Garbe ◽  
Hussein Yahia
Keyword(s):  
Atlantic Ocean ◽  
The South ◽  
South Eastern ◽  
Eastern Atlantic Ocean

scholarly journals Two decades observing smoke above clouds in the south-eastern Atlantic Ocean: Deep Blue algorithm updates and validation with ORACLES field campaign data

2019 ◽  
Vol 12 (7) ◽  
pp. 3595-3627 ◽  
Author(s):  
Andrew M. Sayer ◽  
N. Christina Hsu ◽  
Jaehwa Lee ◽  
Woogyung V. Kim ◽  
Sharon Burton ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Optical Depth ◽  
Data Sets ◽  
The South ◽  
Validation Data ◽  
Field Campaign ◽  
Airborne Measurements ◽  
South Eastern ◽  
Eastern Atlantic Ocean ◽  
Uncertainty Estimates

Abstract. This study presents and evaluates an updated algorithm for quantification of absorbing aerosols above clouds (AACs) from passive satellite measurements. The focus is biomass burning in the south-eastern Atlantic Ocean during the 2016 and 2017 ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) field campaign deployments. The algorithm retrieves the above-cloud aerosol optical depth (AOD) and underlying liquid cloud optical depth and is applied to measurements from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), Moderate Resolution Imaging Spectroradiometer (MODIS), and Visible Infrared Imaging Radiometer Suite (VIIRS) from 1997 to 2017. Airborne NASA Ames Spectrometers for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) and NASA Langley High Spectral Resolution Lidar 2 (HSRL2) data collected during ORACLES provide important validation for spectral AOD for MODIS and VIIRS; as the SeaWiFS mission ended in 2010, it cannot be evaluated directly. The 4STAR and HSRL2 comparisons are complementary and reveal performance generally in line with uncertainty estimates provided by the optimal estimation retrieval framework used. At present the two MODIS-based data records seem the most reliable, although there are differences between the deployments, which may indicate that the available data are not yet sufficient to provide a robust regional validation. Spatiotemporal patterns in the data sets are similar, and the time series are very strongly correlated with each other (correlation coefficients from 0.95 to 0.99). Offsets between the satellite data sets are thought to be chiefly due to differences in absolute calibration between the sensors. The available validation data for this type of algorithm are limited to a small number of field campaigns, and it is strongly recommended that such airborne measurements continue to be made, both over the southern Atlantic Ocean and elsewhere.

scholarly journals Mixed Layer Budget Terms on Acoustic Propagation A Study based on the Butterfly Track Experiment in the South Eastern Arabian Sea

2019 ◽  
Vol 69 (2) ◽  
pp. 156-162
Author(s):  
P. A. Maheswaran ◽  
V. K. Unny ◽  
S. Sateesh Kumar ◽  
C. P. Uthaman ◽  
T. Pradeep Kumar
Keyword(s):  
Surface Layer ◽  
Mixed Layer ◽  
Arabian Sea ◽  
Acoustic Propagation ◽  
Series Data ◽  
The South ◽  
Night Time ◽  
South Eastern ◽  
Salt Budget ◽  
Eastern Arabian Sea

A butterfly type of repeat track cruise was carried out in the South Eastern Arabian Sea (off Minicoy) onboard INS Sagardhwani during July 2016 to Aug 2016. We have also made use of the data from OMNI buoy, AD09, which is about 6 km close to the centre station of butterfly track. Air sea flux, the horizontal current data from AD09 and the time series data collected from the butterfly experiment were analyzed to compute the mixed layer heat and salt budget. The short-term thermo-haline variability off Minicoy, relative contribution of heat/salt budget terms in MLD and its effects on acoustic propagation are addressed in this paper. In this study, we found that most dominating term in the mixed layer heat budget estimation is net surface heat flux followed by the advective terms. However the salinity in the mixed layer is dominated by the contribution of buoyancy mixing due to night time evaporative cooling. During the calm, sunny day, the so-called afternoon effect due to the diurnal heating restricts the sonar range. But during the windy day, the wind/wave mixing prevents the warming of the surface layer which in turn enhances the sonar range. Similarly, the night time cooling also enhance the acoustic propagation range. The presence of Arabian Sea High Salinity Watermass in the surface layer also enhances the acoustic propagation.

Water Mass Transformation and Subduction in the South Atlantic

2005 ◽  
Vol 35 (10) ◽  
pp. 1841-1860 ◽  
Author(s):  
J. Donners ◽  
S. S. Drijfhout ◽  
W. Hazeleger
Keyword(s):  
Surface Water ◽  
Indian Ocean ◽  
Mixed Layer ◽  
Water Mass ◽  
South Atlantic ◽  
Water Masses ◽  
Intermediate Water ◽  
Tropical Atlantic ◽  
The South ◽  
The Indian Ocean

Abstract The transformation of water masses induced by air–sea fluxes in the South Atlantic Ocean is calculated with a global ocean model, Ocean Circulation and Climate Advanced Modeling (OCCAM), and has been compared with several observational datasets. Air–sea interaction supplies buoyancy to the ocean at almost all density levels. The uncertainty of the estimates of water mass transformations is at least 10 Sv (Sv ≡ 106 m3 s−1), largely caused by the uncertainties in heat fluxes. Further analysis of the buoyancy budget of the mixed layer in the OCCAM model shows that diffusion extracts buoyancy from the water column at all densities. In agreement with observations, water mass formation of surface water by air–sea interaction is completely balanced by consumption from diffusion. There is a large interocean exchange with the Indian and Pacific Oceans. Intermediate water is imported from the Pacific, and light surface water is imported from the Indian Ocean. South Atlantic Central Water and denser water masses are exported to the Indian Ocean. The air–sea formation rate is only a qualitative estimate of the sum of subduction and interocean exchange. Subduction generates teleconnections between the South Atlantic and remote areas where these water masses reemerge in the mixed layer. Therefore, the subduction is analyzed with a Lagrangian trajectory analysis. Surface water obducts in the South Atlantic, while all other water masses experience net subduction. The subducted Antarctic Intermediate Water and Subantarctic Mode Water reemerge mainly in the Antarctic Circumpolar Current farther downstream. Lighter waters reemerge in the eastern tropical Atlantic. As a result, the extratropical South Atlantic has a strong link with the tropical Atlantic basin and only a weak direct link with the extratropical North Atlantic. The impact of the South Atlantic on the upper branch of the thermohaline circulation is indirect: water is significantly transformed by air–sea fluxes and mixing in the South Atlantic, but most of it reemerges and subducts again farther downstream.

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