An explosion of phytoplankton has reached alarming levels in the Baltic Sea consuming outrageous amounts of precious oxygen and choking out aquatic life creating one of the largest marine “dead zones” on the planet. As part of nature’s cycle, small blooms are the status quo but with plenty of fuel of phosphorous and nitrogen from agricultural fertilizers and sewage, the Baltic ecosystem is literally being choked away.
According to National Geographic, the Baltic Sea is now home to seven of the of the world’s ten largest marine “dead zones”—areas where the sea’s oxygen has been used up by seabed bacteria that decompose the raining mass of dead algae. Intensifying the problem is overfishing of Baltic cod. The cod eat a sprats, a small fish that eats zooplankton which in turn eats the phytoplankton. Without the cod to keep the sprats in check, the zooplankton population is being diminished allowing the algae to blossom to deadly numbers. This vicious cycle gets worse as the spreading dead zones engulf the cod’s deep-water breeding grounds.
Beyond the ecological damage, the algae blooms leave a nasty layer of slime that is harmful to both animal and humans. The green layer also starves out light from sea prohibiting the growth of natural seaweeds that provide protection and habitat for other species.
A new action plan called the Baltic Sea Strategy is underway led by the European Union (EU) to help coordinate the efforts of the the eight EU members within the nine Baltic states—not including Russia—to revitalize their shared sea.
[via National Geographic]
Photo credit: Image courtesy Jeff Schmaltz, NASA (July 2005 satellite image)