Experimental Drift Mapping of Indian Ocean Gyre Aircraft Debris

Lev M. Vozchikov; Lab Selena

doi:10.4236/ojapps.2016.62010

Observed changes in the South Indian Ocean gyre circulation, 1987–2002

Geophysical Research Letters ◽

10.1029/2004gl020506 ◽

2004 ◽

Vol 31 (15) ◽

Cited By ~ 12

Author(s):

Matthew D. Palmer

Keyword(s):

Indian Ocean ◽

The South ◽

South Indian Ocean ◽

South Indian ◽

Gyre Circulation ◽

Ocean Gyre

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The Role of Changing Indian Ocean Salinity in shaping Pleistocene Climate

10.5194/egusphere-egu2020-9828 ◽

2020 ◽

Author(s):

Sophie Nuber ◽

James W. B. Rae ◽

Morten B. Andersen ◽

Bas de Boer ◽

Xu Zhang ◽

...

Keyword(s):

Indian Ocean ◽

Tropical Indian Ocean ◽

Western Indian Ocean ◽

Ocean Surface ◽

Sea Surface Salinity ◽

Surface Salinity ◽

Mozambique Channel ◽

Pleistocene Climate ◽

Ocean Salinity ◽

Ocean Gyre

<p>Indian Ocean surface salinity dynamics are thought to play an important role in shaping glacial-interglacial climate through controlling Agulhas leakage efficiency. It is proposed that a strong Agulhas leakage supplies warm and salty Indian ocean surface waters to Atlantic surface currents influencing convective potential at North Atlantic deep-water formation sites. Here, we present new planktonic foraminiferal Mg/Ca and stable isotope-derived salinity reconstructions for the last 1.2Ma from the northern Mozambique channel. We find salinity increases well before terminations, followed by early decrease before glacial inception. We present a possible link between the hydrography in the northern Mozambique channel and whole ocean salinity changes due to unique surface circulation in the Indian ocean. Despite being a mostly tropical and subtropical ocean, salinity in the modern tropical Indian Ocean is fresher than at comparable latitudes in the Atlantic or Pacific. This is due to the inflow of freshwater from the Indonesian throughflow and recycling via an active Agulhas leakage. We show that salinity in the glacial western Indian Ocean was significantly higher due to a reduced ITF and a weaker Agulhas leakage. We hypothesise that opening and closing of these two gateways influences the development/diminishment of a strong subtropical Indian Ocean gyre which controls sea surface salinity and temperature of tropical Indian Ocean water masses and subsequently the efficiency of the Agulhas Leakage.</p>

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Bio-GO-SHIP: Shifts in bacterial communities reveal subtle biogeochemical regimes across the Indian Ocean

10.5194/egusphere-egu21-6238 ◽

2021 ◽

Author(s):

Melissa Brock ◽

Alyse Larkin ◽

Adam Martiny

Keyword(s):

Indian Ocean ◽

Microbial Communities ◽

Integrated Approach ◽

Amplicon Sequencing ◽

Geographic Area ◽

16S Rrna Amplicon Sequencing ◽

Large Geographic Area ◽

The Indian Ocean ◽

Transition Points ◽

Ocean Gyre

<p>Historically, our understanding of ecological responses to biogeochemical gradients and physical dynamics in the Indian Ocean has been limited to regional studies. Microbial communities represent in-situ biosensors that are sensitive to changes in the surface ocean. They can therefore be used to identify where subtle changes in the environment occur and to understand links between the ecology and surrounding environment. Here, we perform the largest study of microbial biodiversity in the Indian Ocean, using 505 DNA samples collected on GO-SHIP cruises I07N and I09N. This dataset spans a large geographic area, starting in the southern Indian Ocean gyre, crossing through the equatorial zone, and entering the Arabian Sea or the Bay of Bengal. We used 16S rRNA amplicon sequencing to identify transition points in bacterial community structure and to define ecological boundaries. We found that these boundaries aligned with shifts in geochemistry (e.g., nutrient availability) and/or physical dynamics (e.g., ocean fronts, eddies, and salinity), indicating fine-scale regional separation in biogeochemical functioning. Thus, our study demonstrates how using microbial communities provides an integrated approach for evaluating links between the ecology, geochemistry, and physical dynamics of the Indian Ocean.</p>

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