杏吧原创

Seagrass loss off the coast of Kenya is fuelling climate change

Seagrass meadows grow along shallow ocean shores and lock-up carbon, but satellite imagery reveals that human activity is killing off this vital habitat
Seagrass is being killed off by humans
Seagrass is being killed off by humans
Reinhard Dirscherl/Getty

Human聽activity has devastated a quarter of the seagrass beds along the聽coast of Kenya, resulting in the destruction of key habitats and contributing to climate change.

These aquatic plants grow along the shoreline in shallow ocean. They provide a home for marine animals such as turtles and fish, but also absorb carbon from the atmosphere through photosynthesis.

Mark Huxham at Edinburgh Napier University, UK, and his colleagues have used satellite images of Kenya to聽look in detail at seagrass coverage in East Africa, a region that has previously been poorly studied.

After comparing the current images聽of four sites with those from 15 and 30 years ago, the team concluded that Kenya鈥檚 seagrass meadows are shrinking by 1.6聽per聽cent聽every year聽 鈥 equivalent to聽losing an area the size of聽756 football fields annually. The decline shows no sign of slowing.

Huxham says human activities are the main drivers of the loss, especially fishing nets, boats and anchors ripping through the meadows.

What is more, carbon that would have been locked up by the seagrass at those four sites will end up in the atmosphere instead. The researchers estimated that this amounts to over 2聽million tonnes of carbon, equivalent to 7 million tonnes of carbon dioxide, in the region over the past 30 years.

Globally, seagrass meadows have been vanishing at a rate of more than 7 per cent a year since 1990, which is comparable to the loss of coral reefs and tropical rainforests. However, the impact could be felt particularly hard in Kenya, because seagrass has strong links to the health of fisheries.

鈥淎lthough rates of loss in Kenya are聽less than those in some other countries, given the high reliance of coastal people there on fisheries, we think this is a serious situation,鈥 says Huxham.

This article appeared in print under the headline 鈥淥cean meadow loss is adding to climate change鈥

Biology Letters

Topics: Climate change / Oceans