Modeling controls of phytoplankton production in the southwest Pacific sector of the Southern Ocean

2003 ◽  
Vol 50 (3-4) ◽  
pp. 769-798 ◽  
Author(s):  
Katja Fennel ◽  
Mark R. Abbott ◽  
Yvette H. Spitz ◽  
James G. Richman ◽  
David M. Nelson
Keyword(s):  
Southern Ocean ◽  
Phytoplankton Production ◽  
Southwest Pacific

Antarctic marine primary production, biogeochemical carbon cycles and climatic change

1992 ◽  
Vol 338 (1285) ◽  
pp. 289-297 ◽  
Keyword(s):  
Climate Change ◽  
Southern Ocean ◽  
Primary Production ◽  
Climatic Change ◽  
Carbon Fixation ◽  
Algal Growth ◽  
Ice Cover ◽  
Phytoplankton Production ◽  
Numerical Predictions ◽  
Model Predictions

In the Southern Ocean, inorganic macronutrients are very rarely depleted by phytoplankton growth. This has led to speculation on possible additional CO 2 drawdown in this region. However, the effects of climate change can only be predicted once the role of environmental and biotic factors limiting phytoplankton carbon fixation are understood. It is clear that the Southern Ocean is heterogeneous, and no single factor controls prim ary production overall. Ice cover and vertical mixing influence algal growth rates by m odulating radiance flux. Micronutrients, especially iron, may limit growth in some areas. Primary production is also suppressed by high removal rates of algal biomass. Grazing by zooplankton is the major factor determining magnitude and quality of vertical particle flux. Several of the physical controls on phytoplankton production are sensitive to climate change. Although it is impossible to make numerical predictions of future change on the basis of our present knowledge, qualitative assessments can be put forward on the basis of model predictions of climate change and known factors controlling prim ary production. Changes in water temperature and in windinduced mixing are likely to be slight and have little effect. Model predictions of changes in sea-ice cover vary widely, making prediction of biogeochemical effects impossible. Even if climatic change induces increased nutrient uptake, there are several reasons to suspect that carbon sequestration will be ineffective in comparison with continuing anthropogenic CO 2 emission.

scholarly journals Impact of sea ice on the marine iron cycle and phytoplankton productivity

2014 ◽  
Vol 11 (17) ◽  
pp. 4713-4731 ◽  
Author(s):  
S. Wang ◽  
D. Bailey ◽  
K. Lindsay ◽  
J. K. Moore ◽  
M. Holland
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Phytoplankton Production ◽  
Iron Cycle ◽  
Surface Ocean ◽  
Antarctic Sea Ice ◽  
Iron Concentrations

Abstract. Iron is a key nutrient for phytoplankton growth in the surface ocean. At high latitudes, the iron cycle is closely related to the dynamics of sea ice. In recent decades, Arctic sea ice cover has been declining rapidly and Antarctic sea ice has exhibited large regional trends. A significant reduction of sea ice in both hemispheres is projected in future climate scenarios. In order to adequately study the effect of sea ice on the polar iron cycle, sea ice bearing iron was incorporated in the Community Earth System Model (CESM). Sea ice acts as a reservoir for iron during winter and releases the trace metal to the surface ocean in spring and summer. Simulated iron concentrations in sea ice generally agree with observations in regions where iron concentrations are relatively low. The maximum iron concentrations simulated in Arctic and Antarctic sea ice are much lower than observed, which is likely due to underestimation of iron inputs to sea ice or missing mechanisms. The largest iron source to sea ice is suspended sediments, contributing fluxes of iron of 2.2 × 108 mol Fe month−1 in the Arctic and 4.1 × 106 mol Fe month−1 in the Southern Ocean during summer. As a result of the iron flux from ice, iron concentrations increase significantly in the Arctic. Iron released from melting ice increases phytoplankton production in spring and summer and shifts phytoplankton community composition in the Southern Ocean. Results for the period of 1998 to 2007 indicate that a reduction of sea ice in the Southern Ocean will have a negative influence on phytoplankton production. Iron transport by sea ice appears to be an important process bringing iron to the central Arctic. The impact of ice to ocean iron fluxes on marine ecosystems is negligible in the current Arctic Ocean, as iron is not typically the growth-limiting nutrient. However, it may become a more important factor in the future, particularly in the central Arctic, as iron concentrations will decrease with declining sea ice cover and transport.

scholarly journals Constraining early to middle Eocene climate evolution of the southwest Pacific and Southern Ocean

2016 ◽  
Vol 433 ◽  
pp. 380-392 ◽  
Author(s):  
Edoardo Dallanave ◽  
Valerian Bachtadse ◽  
Erica M. Crouch ◽  
Lisa Tauxe ◽  
Claire L. Shepherd ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Middle Eocene ◽  
Southwest Pacific ◽  
Climate Evolution

scholarly journals Climatically modulated dust inputs from New Zealand to the Southwest Pacific sector of the Southern Ocean over the last 410 kyr

2021 ◽  
Author(s):  
Yi Wu ◽  
Andrew P. Roberts ◽  
Katharine M. Grant ◽  
David Heslop ◽  
Brad J. Pillans ◽  
...  
Keyword(s):  
New Zealand ◽  
Southern Ocean ◽  
Southwest Pacific

scholarly journals Impacts of sea ice on the marine iron cycle and phytoplankton productivity

2014 ◽  
Vol 11 (2) ◽  
pp. 2383-2418 ◽  
Author(s):  
S. Wang ◽  
D. Bailey ◽  
K. Lindsay ◽  
K. Moore ◽  
M. Holland
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Phytoplankton Production ◽  
Iron Cycle ◽  
Surface Ocean ◽  
Antarctic Sea Ice ◽  
Arctic Sea ◽  
Iron Concentrations

Abstract. Iron is a key nutrient for phytoplankton growth in the surface ocean. At high latitudes, the iron cycle is closely related to sea ice. In recent decades, Arctic sea ice cover has been declining rapidly and Antarctic sea ice has exhibited large regional trends. A significant reduction of sea ice in both hemispheres is projected in future climate scenarios. To study impacts of sea ice on the iron cycle, iron sequestration in ice is incorporated to the Biogeochemical Elemental Cycling (BEC) model. Sea ice acts as a reservoir of iron during winter and releases iron to the surface ocean in spring and summer. Simulated iron concentrations in sea ice generally agree with observations, in regions where iron concentrations are lower. The maximum iron concentrations simulated in the Arctic sea ice and the Antarctic sea ice are 192 nM and 134 nM, respectively. These values are much lower than observed, which is likely due to missing biological processes in sea ice. The largest iron source to sea ice is suspended sediments, contributing fluxes of iron of 2.2 × 108 mol Fe month−1 to the Arctic and 4.1 × 106 mol Fe month−1 to the Southern Ocean during summer. As a result of the iron flux from ice, iron concentrations increase significantly in the Arctic. Iron released from melting ice increases phytoplankton production in spring and summer and shifts phytoplankton community composition in the Southern Ocean. Simulation results for the period of 1998 to 2007 indicate that a reduction of sea ice in the Southern Ocean will have a negative influence on phytoplankton production. Iron transport by sea ice appears to be an important process bringing iron to the central Arctic. Impacts of iron fluxes from ice to ocean on marine ecosystems are negligible in the current Arctic Ocean, as iron is not typically the growth-limiting nutrient. However, it may become a more important factor in the future, particularly in the central Arctic, as iron concentrations will decrease with declining sea ice cover and transport.

scholarly journals First records of winter sea ice concentration in the southwest Pacific sector of the Southern Ocean

2015 ◽  
Vol 30 (11) ◽  
pp. 1525-1539 ◽  
Author(s):  
Alexander J. Ferry ◽  
Xavier Crosta ◽  
Patrick G. Quilty ◽  
David Fink ◽  
William Howard ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Sea Ice Concentration ◽  
Southwest Pacific ◽  
Ice Concentration

scholarly journals Glacial-interglacial productivity in the Polar Frontal Zone, southwest Pacific Ocean

2021 ◽  
Author(s):  
◽  
Melanie Anne Liston
Keyword(s):  
Calcium Carbonate ◽  
Southern Ocean ◽  
Biogenic Silica ◽  
Frontal Zone ◽  
Atmospheric Co2 ◽  
Climate Change Research ◽  
Southwest Pacific ◽  
Polar Frontal Zone ◽  
Co2 Concentrations ◽  
Atmospheric Co2 Concentrations

<p>The Southern Ocean has a central role in regulating global climate change. Research has shown evidence of changes in biological productivity are coincident with increased iron deposition and rising atmospheric CO2 concentrations. The current data suggests these processes occur homogenously throughout the Southern Ocean, where research largely focuses on changes in biogenic silica as a proxy for upwelling and enhanced opal production. The role of calcium carbonate productivity, however, is rarely discussed, or is referred to in terms of preservation changes associated with shoaling and deepening of the lysocline. This assumption ignores potentially important effects of carbonate productivity and inter-basin complexities on ocean-atmosphere CO2 exchange. Two gravity cores (TAN1302-96 and TAN1302-97) collected from the southwest Pacific Polar Frontal Zone (PFZ) provide more insight into productivity changes and inter-basin differences across glacial-interglacial timescales. Detailed geochemical analysis, together with δ18O stratigraphy and 14C chronology, were used to reconstruct glacial-interglacial changes in terrigenous input and paleoproductivity in the PFZ. Sedimentological and biological analyses provide additional information to support the geochemical observations. This study highlights two distinct productivity modes (i.e. biogenic silica and calcium carbonate) that vary over glacial-interglacial timescales and with respect to the position of the Polar Front (PF). Key findings include; 1) a systematic series of key biological changes are repeated during glacial Terminations I (TI) and II (TII), the order of which depends on the position relative to the PF; 2) calcium carbonate productivity dominates the early part of the Termination north of the PF, whereas the production of biogenic silica dominates the early Termination south of the PF; 3) following TI and TII, calcium carbonate leads productivity in the early interglacials (i.e. MIS 5e and the Holocene), followed by the production of biogenic silica during the late interglacials, concurrent with declining atmospheric CO2 concentrations.</p>

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