‘Dead zones’ within the world’s oceans – where there is almost no oxygen to sustain life – could be expanding far quicker than currently thought, a new study suggests.
The regions are created when large amounts of organic material produced by algae sinks towards the seafloor, using up the oxygen present in the deep water.
Computer models can predict the spread of these zones, with the aim being to provide an insight into the impact they might have on the wider marine environment.
However, a study published in Global Biogeochemical Cycles suggests that dark carbon fixation – caused by the presence of anaerobic bacteria in the deeper water column – needs to be incorporated into these models.
The research was led by Dr Sabine Lengger, a scientist at the University of Plymouth, and involved researchers from universities in the UK and the Netherlands.
They measured the stable isotopes of organic carbon in sediment cores taken from the floor of the Arabian Sea, one of the world’s large natural dead zones, in order to get a clear understanding about what is contributing to the organic matter contained within them.
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