Rising Temperatures Could Upset Natural Ocean Cycles
September 9, 2013

Ocean Temperatures Could Have Drastic Impact On Chemical Cycles

redOrbit Staff & Wire Reports - Your Universe Online

Rising water temperatures will have an adverse impact on plankton, serving as the catalyst for a series of events that will upset the balance of essential oceanic chemical cycles, according to new research published in Sunday’s edition of the journal Nature Climate Change.

Scientists from the University of East Anglia (UEA) in the UK examined the impact that ocean temperatures can have on the plankton ecosystems found in the world’s largest bodies of water.

They explain that plankton plays a key role in the ocean’s carbon cycle by removing half of all CO2 from the atmosphere during photosynthesis. That carbon dioxide winds up being stored under the sea, isolated from the atmosphere for several centuries, they added.

Lead author Dr. Thomas Mock and colleagues from the UEA School of Environmental Sciences and the School of Computing Sciences examined the impact of ocean warming on micro-algae and other phytoplankton – microscopic plant-like organisms that rely on photosynthesis to reproduce and grow.

“Phytoplankton, including micro-algae, are responsible for half of the carbon dioxide that is naturally removed from the atmosphere,” Dr. Mock said. “As well as being vital to climate control, it also creates enough oxygen for every other breath we take, and forms the base of the food chain for fisheries so it is incredibly important for food security.”

“Previous studies have shown that phytoplankton communities respond to global warming by changes in diversity and productivity. But with our study we show that warmer temperatures directly impact the chemical cycles in plankton, which has not been shown before,” he added.

The UEA team created computer-generated models to craft a model of the global ecosystem which accounted for the world’s ocean temperatures, as well as 1.5 million plankton DNA sequences obtained from samples and other biochemical data.

They found that temperature plays a crucial role in driving the cycling of chemicals like carbon dioxide, nitrogen and phosphorous in marine micro-algae. In fact, Dr. Mock said that he and his colleagues found that temperatures affect those reactions as much as light and nutrients, which experts had not previously known.

“Under warmer temperatures, marine micro-algae do not seem to produce as many ribosomes as under lower temperatures,” he explained. “Ribosomes join up the building blocks of proteins in cells.”

“They are rich in phosphorous and if they are being reduced, this will produce higher ratios of nitrogen compared to phosphorous, increasing the demand for nitrogen in the oceans,” Dr. Mock added. “This will eventually lead to a greater prevalence of blue-green algae called cyanobacteria which fix atmospheric nitrogen.”