What happens when the oxygen runs out?
February 04, 2013
When darkness falls, the mangrove ponds of Bocas del Toro hold their breath. Pumped full of oxygen during the day by photosynthetic algae, at night the pools' diverse inhabitants consume the gas so voraciously that sometimes there is none left by daybreak.
Marine anoxia - severe oxygen depletion - is most often associated with coastal ‘dead zones' created by excessive nutrient pollution from industrial fertilizers. In the case of the Caribbean mangrove ponds studied by Keryn Gedan, a research associate at the Smithsonian Environmental Research Center (SERC), the daily cycle is natural.
Learning how organisms like mangrove trees, fish and phytoplankton have adapted to these extreme conditions could provide clues as to how - or if - marine flora and fauna may acclimatize to oxygen depletion from human activity.
“It's very stressful for these organisms but we still find all these aerobic organisms living there,” says Keryn, whose research is conducted with STRI and SERC colleagues. The pond environment also has high salinity, high acidity and temperature extremes. “We are thinking these ponds are potentially model systems for different types of anthropogenic stressors.”