scholarly journals A mosaic of phytoplankton responses across Patagonia, the SE Pacific and SW Atlantic Ocean to ash deposition and trace metal release from the Calbuco 2015 volcanic eruption

2020 ◽  
Author(s):  
Maximiliano J. Vergara-Jara ◽  
Mark J. Hopwood ◽  
Thomas J. Browning ◽  
Insa Rapp ◽  
Rodrigo Torres ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Phytoplankton Bloom ◽  
Major Ions ◽  
Phytoplankton Growth ◽  
Total Alkalinity ◽  
Fixed Nitrogen ◽  
Load Following ◽  
Sw Atlantic ◽  
Ash Plume ◽  
Time Of Year

Abstract. Following the April 2015 eruption of the Calbuco volcano, an extensive ash plume spread across northern Patagonia and into the SE Pacific and SW Atlantic Ocean. Here we report the results of field surveys conducted in the marine region receiving the highest ash load following the eruption (Reloncaví Fjord). The fortuitous location of a long-term monitoring station in Reloncaví Fjord provided data to evaluate inshore phytoplankton bloom dynamics and carbonate chemistry during April–May 2015. Satellite derived chlorophyll-a measurements over the ocean regions affected by the ash plume in May 2015 were obtained to determine the spatial-temporal gradient in offshore phytoplankton response to ash. Additionally, leaching experiments were performed to quantify the release of total alkalinity, trace elements (Fe, Mn, Pb, Co, Cu, Ni and Cd) and major ions (Fl, Cl, SO4, NO3, Li, Na, NH4, K, Mg, Ca) from ash into solution. Within Reloncaví Fjord, integrated peak diatom abundances during the May 2015 austral bloom were higher than usual (up to 1.4 × 1011 cells m−2, integrated to 15 m depth), with the bloom intensity perhaps moderated due to high ash loadings in the two weeks following the eruption. In the offshore SE Pacific, a short duration phytoplankton bloom corresponded closely in space and time to the maximum observed ash plume, potentially in response to Fe-fertilization of a region where phytoplankton growth is typically Fe-limited at this time of year. Conversely, no clear fertilization was found in the area subject to an ash plume over the SW Atlantic where the availability of fixed nitrogen is thought to limit phytoplankton growth which was consistent with no significant release of fixed nitrogen from ash. In addition to release of nanomolar concentrations of dissolved Fe from ash suspended in seawater, it was observed that low loadings (

scholarly journals A mosaic of phytoplankton responses across Patagonia, the southeast Pacific and the southwest Atlantic to ash deposition and trace metal release from the Calbuco volcanic eruption in 2015

Ocean Science ◽  
2021 ◽  
Vol 17 (2) ◽  
pp. 561-578
Author(s):  
Maximiliano J. Vergara-Jara ◽  
Mark J. Hopwood ◽  
Thomas J. Browning ◽  
Insa Rapp ◽  
Rodrigo Torres ◽  
...  
Keyword(s):  
Phytoplankton Bloom ◽  
Major Ions ◽  
Coastal Region ◽  
Phytoplankton Growth ◽  
Total Alkalinity ◽  
Ash Deposition ◽  
Fixed Nitrogen ◽  
Southwest Atlantic ◽  
Southeast Pacific ◽  
Ash Plume

Abstract. Following the eruption of the Calbuco volcano in April 2015, an extensive ash plume spread across northern Patagonia and into the southeast Pacific and southwest Atlantic oceans. Here, we report on field surveys conducted in the coastal region receiving the highest ash load following the eruption (Reloncaví Fjord). The fortuitous location of a long-term monitoring station in Reloncaví Fjord provided data to evaluate inshore phytoplankton bloom dynamics and carbonate chemistry during April–May 2015. Satellite-derived chlorophyll a measurements over the ocean regions affected by the ash plume in May 2015 were obtained to determine the spatial–temporal gradients in the offshore phytoplankton response to ash. Additionally, leaching experiments were performed to quantify the release from ash into solution of total alkalinity, trace elements (dissolved Fe, Mn, Pb, Co, Cu, Ni and Cd) and major ions (F−, Cl−, SO42-, NO3-, Li+, Na+, NH4+, K+, Mg2+ and Ca2+). Within Reloncaví Fjord, integrated peak diatom abundances during the May 2015 austral bloom were approximately 2–4 times higher than usual (up to 1.4 × 1011 cells m−2, integrated to 15 m depth), with the bloom intensity perhaps moderated due to high ash loadings in the 2 weeks following the eruption. Any mechanistic link between ash deposition and the Reloncaví diatom bloom can, however, only be speculated on due to the lack of data immediately preceding and following the eruption. In the offshore southeast Pacific, a short-duration phytoplankton bloom corresponded closely in space and time to the maximum observed ash plume, potentially in response to Fe fertilisation of a region where phytoplankton growth is typically Fe limited at this time of year. Conversely, no clear fertilisation on the same timescale was found in the area subject to an ash plume over the southwest Atlantic where the availability of fixed nitrogen is thought to limit phytoplankton growth. This was consistent with no significant release of fixed nitrogen (NOx or NH4) from Calbuco ash. In addition to the release of nanomolar concentrations of dissolved Fe from ash suspended in seawater, it was observed that low loadings (< 5 mg L−1) of ash were an unusually prolific source of Fe(II) into chilled seawater (up to 1.0 µmol Fe g−1), producing a pulse of Fe(II) typically released mainly during the first minute after addition to seawater. This release would not be detected (as Fe(II) or dissolved Fe) following standard leaching protocols at room temperature. A pulse of Fe(II) release upon addition of Calbuco ash to seawater made it an unusually efficient dissolved Fe source. The fraction of dissolved Fe released as Fe(II) from Calbuco ash (∼ 18 %–38 %) was roughly comparable to literature values for Fe released into seawater from aerosols collected over the Pacific Ocean following long-range atmospheric transport.

Gelatinous zooplankton (ctenophores, salps and medusae): an important food resource of fishes in the temperate SW Atlantic Ocean

2017 ◽  
Vol 13 (6) ◽  
pp. 630-644 ◽  
Author(s):  
Luciana Diaz Briz ◽  
Felisa Sánchez ◽  
Noemí Marí ◽  
Hermes Mianzan ◽  
Gabriel Genzano
Keyword(s):  
Atlantic Ocean ◽  
Food Resource ◽  
Gelatinous Zooplankton ◽  
Important Food ◽  
Sw Atlantic

Estimation of the seasonal input of freshwater in the Kara sea surface layer using hydrochemical proxies

2021 ◽  
Author(s):  
Uliana Kazakova ◽  
Alexander Polukhin
Keyword(s):  
Surface Layer ◽  
Coastal Zone ◽  
Dissolved Inorganic Carbon ◽  
Major Ions ◽  
Kara Sea ◽  
Total Alkalinity ◽  
Shirshov Institute ◽  
Arctic Water ◽  
Total Contribution ◽  
Continental Runoff

&lt;p&gt;The Kara Sea receives about 55 % of the total continental runoff to the Siberian Arctic. Water of the Yenisei and Ob Rivers with low salinity (mineralization), flowing into the sea, forms a surface desalinated layer. The desalinated layer spreads over the sea area under the influence of hydrological and meteorological factors. Meltwater generated by the melting of marine and riverine ice and precipitation contribute to the formation of a surface desalinated layer along with continental runoff.&lt;/p&gt;&lt;p&gt;Determining the amount of fresh water is not accurate enough if only the salinity of surface water is considered. It is possible to identify riverine water and meltwater using hydrochemical proxies. The ratio of the major ions in seawater differs from that in riverine and meltwater. River waters are characterized by an increased content of silicate and reduced values of total alkalinity. At the same time, it is possible to identify the waters of the Ob and Yenisei Rivers by the estimated values of the total alkalinity and dissolved inorganic carbon obtained during the research expeditions to the Kara sea from 1993 to 2020.&lt;/p&gt;&lt;p&gt;The calculation of the parts of waters of different origin is done as a result of solving a system of equations. It includes the salinity and alkalinity values of the observed surface waters and those presumably involved in the mixing process. The salinity and alkalinity values of meltwater are taken as 0 and 134 &amp;#181;M respectively.&lt;/p&gt;&lt;p&gt;The total contribution of the Ob and Yenisei runoff ranges from 20 to 90% as it approaches the estuarine areas. The correlation coefficient between the proportion of river water and the salinity of the surface layer is quite high, it is equal to -0.9. This characterizes the inverse linear relationship. The separate contribution of the waters of the Yenisei differs from the contribution of the waters of the Ob, which is related to the hydrological conditions of the rivers.&lt;/p&gt;&lt;p&gt;The contribution of meltwater to the formation of the surface layer of the Kara Sea did not exceed 20%, with the exception of the coastal zone of the Novaya Zemlya. In this coastal zone, meltwater provides the greatest contribution compared to the other sources, which is associated with glacial runoff.&lt;/p&gt;&lt;p&gt;The work is implemented in the framework of the state assignment of the Shirshov Institute of Oceanology RAS (theme No. 0149-2019-0008), with the support of the Russian Scientific Foundation (project &amp;#8470; 19-17-00196) and the grant of President of Russian Federation &amp;#8470; MK-860.2020.5.&lt;/p&gt;

Structure of the wedge-top and foredeep of the Magallanes-Malvinas basins between 62° W and 67° W (SW Atlantic Ocean)

2019 ◽  
Vol 93 ◽  
pp. 364-381 ◽  
Author(s):  
Juan Pablo Ormazabal ◽  
Alejandro Tassone ◽  
Federico Esteban ◽  
José Isola ◽  
Lubin Eric Cayo ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Sw Atlantic

scholarly journals Solute Acquisition in Glacial Melt Waters. II Argentière (French Alps): Bulk Melt Waters with Open-System Characteristics

1984 ◽  
Vol 30 (104) ◽  
pp. 44-48 ◽  
Author(s):  
A.G. Thomas ◽  
R. Raiswell
Keyword(s):  
Carbon Dioxide ◽  
Ground Water ◽  
Open System ◽  
Closed System ◽  
Atmospheric Carbon Dioxide ◽  
Major Ions ◽  
Total Alkalinity ◽  
Flow Conditions ◽  
Solute Acquisition ◽  
System Characteristics

AbstractVariations in dissolved cations, total alkalinity, sulphate, and field pH are recorded for subglacial melt and bulk melt waters (those emerging from the portal) at Argentière (France), in peak and recession flow conditions. Calcium and bicarbonate are the major ions and the bulk melt waters are demonstrated to have acquired solutes by weathering and dissolution in a system open to atmospheric carbon dioxide. Subglacial melt waters have closed-system characteristics, are close to saturation with calcite and quartz, and must be in near-equilibrium with weathered particulates. Recession-flow bulk melt waters are chemically similar to subglacial melt but have open-system characteristics, either due to re-equilibration with the atmosphere for ground-water mixing.

Spatio-Temporal Changes in Basal Food Source Assimilation by Fish Assemblages in a Large Tropical Bay in the SW Atlantic Ocean

2020 ◽  
Vol 43 (4) ◽  
pp. 894-908
Author(s):  
Edjane Pereira Santos ◽  
Mario Vinicius Condini ◽  
Alexandre Clistenes Alcântara Santos ◽  
Heiddy Marquez Alvarez ◽  
Leonardo Evangelista de Moraes ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Food Source ◽  
Fish Assemblages ◽  
Temporal Changes ◽  
Sw Atlantic ◽  
Spatio Temporal ◽  
Tropical Bay

scholarly journals Numerical simulations of the competition between wind-driven mixing and surface heating in triggering spring phytoplankton blooms

2015 ◽  
Vol 72 (6) ◽  
pp. 1926-1941 ◽  
Author(s):  
Rica Mae Enriquez ◽  
John R. Taylor
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Mixed Layer ◽  
Turbulent Mixing ◽  
Phytoplankton Bloom ◽  
Mixed Layer Depth ◽  
Phytoplankton Growth ◽  
Surface Heating ◽  
Surface Mixed Layer ◽  
Critical Depth

Abstract About 60 years ago, Sverdrup formalized the critical depth hypothesis to explain the timing of the spring phytoplankton bloom in terms of the depth of the surface mixed layer. In recent years, a number of refinements and alternatives to the critical depth hypothesis have been proposed, including the critical turbulence hypothesis which states that a bloom can occur when turbulent mixing is sufficiently weak, irrespective of the mixed layer depth. Here, we examine the relative influence of wind-driven mixing and net surface heating on phytoplankton growth. Of particular interest is whether wind-driven mixing can delay the spring bloom after winter convection gives way to net surface warming. We address these questions using high-resolution large-eddy simulations (LES) coupled with a simple phytoplankton model. We also describe an analytical phytoplankton model with a formulation for the turbulent mixing based on the LES results. For a constant, prescribed surface heat flux, net phytoplankton growth is seen when the windstress is smaller than a critical value. Similarly, for a constant windstress, a critical heat flux separates cases with growing and decaying phytoplankton populations. Using the LES results, we characterize the critical windstress and critical heat flux in terms of other physical and biological parameters and propose a simple expression for each based on the analysis of the analytical model. Phytoplankton growth begins when the mixing depth shoals above the critical depth, consistent with the critical depth hypothesis. Our results provide a framework to interpret blooms in other conditions where both the depth and the intensity of turbulent mixing might be crucial factors in influencing phytoplankton growth.

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