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Pelagic microplastics in surface water of the Eastern Indian Ocean during monsoon transition period: Abundance, distribution, and characteristics

Abstract.

"Microplastics (MPs) have been documented in almost all marine environments, including coastal regions, the open ocean, and the deep sea. However, relatively little knowledge was available about MP pollution in the open ocean, especially the Indian Ocean. We conducted field observations at 36 stations in the Eastern Indian Ocean (EIO), using a typical manta trawl with a mesh size of 330 μm for surface water sampling. Ours is the first study to obtained comprehensive and comparable baseline data about MPs in the EIO, including abundance, spatial distribution and characteristics[...]"

 

Source: Science Direct 
Authors: Changjun Li et al.
DOI: https://doi.org/10.1016/j.scitotenv.2020.142629

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Reviews and syntheses: Present, past, and future of the oxygen minimum zone in the northern Indian Ocean

Abstract.

"Decreasing concentrations of dissolved oxygen in the ocean are  fuconsidered one of the main threats to marine ecosystems as they jeopardize the growth of higher organisms. They also alter the marine nitrogen cycle, which is strongly bound to the carbon cycle and climate. While higher organisms in general start to suffer from oxygen concentrations < ∼ 63 µM (hypoxia), the marine nitrogen cycle responds to oxygen concentration below a threshold of about 20 µM (microbial hypoxia), whereas anoxic processes dominate the nitrogen cycle at oxygen concentrations of < ∼ 0.05 µM (functional anoxia). The Arabian Sea and the Bay of Bengal are home to approximately 21 % of the total volume of ocean waters revealing microbial hypoxia. While in the Arabian Sea this oxygen minimum zone (OMZ) is also functionally anoxic[...]"

 

Source: Biogeosciences 
Authors:  Tim Rixen et al.
DOI: https://doi.org/10.5194/bg-17-6051-2020

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Distribution of iron in the Western Indian Ocean and the Eastern tropical South pacific: An inter-basin comparison

Abstract.

"The Western Indian Ocean (WIO) and Eastern Tropical South Pacific (ETSP) are distinctly different regimes, yet they share several important features. These include a strong upwelling system, a large oxygen minimum zone (OMZ) with active denitrification, a spreading center with extensive hydrothermal activity, and a vast oligotrophic upper water column. Here, we show that the distribution and geochemistry of iron shows remarkable similarities as well. [...]"

Source: Chemical Geology
Authors: James W. Moffett and Christopher R. German
DOI: 10.1016/j.chemgeo.2019.119334

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Diversity of culturable Sulphur-oxidising bacteria in the oxygen minimum zones of the northern Indian Ocean

Abstract.

"Oxygen minimum zones (OMZs) are unique, widely spread and well-studied features of the global ocean, varying in seasonality and intensity. The Northern Indian Ocean contains OMZs in the Arabian Sea (AS-OMZ) and the Bay of Bengal (BB-OMZ) having unique biogeochemical features. OMZ water column harbours distinct microbial communities that play vital roles in ocean biogeochemical cycles. Sulphur cycling processes facilitated by OMZ microbial communities are poorly understood with regards to different microbial groups involved, spatially and temporally. [...]"

Source: Journal of Marine Systems (2018)
Authors: Larissa Menezes et al.
DOI: 10.1016/j.jmarsys.2018.05.007

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Finding forced trends in oceanic oxygen

Abstract.

"Anthropogenically forced trends in oceanic dissolved oxygen are evaluated in Earth system models in the context of natural variability. A large ensemble of a single Earth system model is used to clearly identify the forced component of change in interior oxygen distributions and to evaluate the magnitude of this signal relative to noise generated by internal climate variability. The time of emergence of forced trends is quantified on the basis of anomalies in oxygen concentrations and trends. [...]"

Source: Global Biogeochemical Cycles
Authors: Matthew C. Long, Curtis Deutsch and Taka Ito
DOI: 10.1002/2015GB005310 

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