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January 1, 2014

Climate Change Could Cause Significant Marine-Life Losses

Ranjini Raghunath for redOrbit.com - Your Universe Online

Climate change could cause a severe decline in plant and animal populations living on the ocean floor within the next hundred years, according to new research published in the journal Global Change Biology.

The study predicts that ocean-bed life forms, from tiny bacteria to sponges and deep water lobsters and crabs, could decline by nearly 40 percent in the North Atlantic Ocean and over 5 percent worldwide. More than 80 percent of deep-water “hotspots” of biodiversity such as canyons and coral reefs could be hit by climate change.

The resulting loss could affect deep-sea fisheries and marine-life-based drug development, and throw ocean food chains and nutrient levels off-balance.

Because they live deep underwater beyond the reach of sunlight, ocean-bed creatures such as sponges and sea anemones depend on nutrients and remains of other ocean-dwelling creatures that fall down to the floor for food and energy.

With the climate becoming increasingly erratic, however, global ocean circulation patterns could slow down, gaps between water masses would grow - restricting the flow of nutrients underwater – and numbers of surface-dwelling animals will start dropping. All these results, in turn, could affect the lives of those creatures living on the ocean floor.

The study is the first to predict and calculate potential losses in ocean-bed marine life, and was carried out by an international team of scientists from Australia, Canada, France and the UK. The study was supported by the UK’s Natural Environment Research Council (NERC) as part of the Marine Environmental Mapping Programme (MAREMAP).

Led by the National Oceanography Center in the UK, the team used advanced climate models to predict how food supply in the ocean would change in climate extremes and how this would affect different communities, particularly those at the bottom.

"We were expecting some negative changes around the world, but the extent of changes, particularly in the North Atlantic, were staggering. Globally we are talking about losses of marine life weighing more than every person on the planet put together,” Daniel Jones, lead author and National Oceanography Center scientists stated, in a recent statement.

The models predict that while some areas such as the Arctic Ocean might experience a slight increase in deep water population numbers, most other areas including the Atlantic, Pacific and Indian Oceans would all experience major losses in deep water marine life. The models also predict that, under climate stress, marine animals will start becoming smaller, taking in and using energy from food less efficiently, which would, in turn, affect food chains throughout the ocean.

Further research could help to highlight other ripple effects of marine life loss such as increase in temperature, reduced oxygen levels and increased pollutant levels in the ocean, the researchers wrote.