Run-off from fertilisers has made Bay of Bengal reach ‘tipping point’, say experts
Marine experts said run-off from farmland fertilisers was contaminating the Bay of Bengal, causing nutrient levels to increase, which in turn could impact global fishery stocks.
Marine scientists from the University of Oxford have highlighted threats facing the Bay of Bengal in a report to a United Nations panel to call for urgent action to introduce immediate legal protection to the world’s oceans and high seas.
The overview of risks facing oceans was presented to UN members at the latest round of negotiations towards a possible high seas treaty. It is expected to inform initiatives to set up a legal framework, under a new acronym — Biodiversity Beyond National Jurisdiction.
The Bay of Bengal was flagged in the report as being particularly at a “tipping point”, which could impact global fishery stocks. Run off from farmland fertilisers was contaminating the bay, causing nutrient levels to increase, the university said on Tuesday.
“Nutrients like nitrate act as a fertiliser to algae, stimulating bacteria growth, which competes with fish and marine organisms for oxygen. If oxygen levels in the Bay of Bengal decrease any further, the area is at risk of flipping to a ‘no oxygen’ status.
“This would result in the formation of new bacteria that then remove nitrates from the water, destabilising the bay’s ocean ecosystem. The denitrified water could then be carried away by ocean currents and reduce productivity elsewhere,” the report said.
Alex Rogers, a conservation biology professor at Oxford’s department of zoology, said: “This is very, very important. A lot of states are looking towards developing industrial activities in the ocean – fishing, deep-sea mining, renewable energy, even aquaculture offshore.
“It’s really vital that we come to some international agreement on how to protect or manage biodiversity on high seas in the face of all these pressures.”
More than 60% of the world’s oceans are said to lack effective conservation measures. The Oxford report was based on 271 academic studies published since the Rio+20 Earth Summit in 2012.
Lucy Woodall, co-author and researcher at the university’s ocean research and conservation group, added: “The function, complexity and connectivity of the oceans are highlighted in the report. It shows that the most remote places on our planet are very relevant to our lives every day.”
“Recognising the influence of the high seas it is important to ensure appropriate legal instruments are enacted.”