Written By: Emma Websdale
Significant population loss of remote deep-sea creatures as a direct result of climate change, new study warns.
The study, conducted by an international team of scientists from the UK, Australia, France and Canada, is the first of its kind to calculate the effects of climate change on future losses of deep-sea marine species.
In the study, scientists used advanced climate models to predict how biochemical changes caused by climate change would affect the food supply within the world’s oceans. The relationship between this food supply and marine biomass was then calculated using a large database of marine life.
Deep-ocean species depend heavily upon the steady supply of dead marine life falling from surface waters, particularly phytoplankton (microscopic plants). However, the effects of climate change, including the warming and increased acidity of our oceans, are causing a decline in populations of such surface-dwelling species. The climate modeling estimates indicate that phytoplankton will be particularly hard hit, which in the long term will sharply reduce deep-ocean life.
Results showed that seafloor-dwelling marine species could decline as much as 5% worldwide (and as much as 38% in the North Atlantic) within the next century. Although a decline of 5% may sound small, the weight of these lost creatures would be greater than the combined weight of all the people on Earth.
The study also showed that climate impacts -including slowing of the ocean’s circulation and increased separation between layers of water (known as stratification) -are already reducing the population size of deep-sea species. In all, over 80% of known deep-water biodiversity hotspots around the globe -including cold-water coral reefs, canyons, and seamounts -will suffer losses in total biomass.
Such loss of biomass could become extremely lethal to oceans because it will reduce important ecosystem services, such as elemental cycling and carbon sequestration.
“We were expecting some negative changes around the world, but the extent of changes, particularly in the North Atlantic, were staggering”, says Daniel Jones, lead author of the study.
He adds, “The deep sea is one of the last truly wild places left on Earth, where we never know what we are going to find. We don’t even know what we are destroying.”