Biological chain reaction threatens Baltic Sea

Summer heat and overheating give battered ecosystem the rest

Baltic Sea NASA / Modis
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With the summer of the century, the Baltic Sea is threatening dramatic consequences - including the collapse of entire ecosystems. Due to the long-lasting heat and sun explosive poisonous blue-green algae have developed, which in turn threaten the wildlife of the Baltic Sea in a kind of biological chain reaction. Now, the German Environmental Aid (DUH) and the Society for the Protection of Marine Mammals e. V. (GSM).

Yellowish algae carpets slosh these days to many beaches in the Baltic Sea. What is bothersome for the bathers, and sometimes also dangerous, threatens the animal world existentially. The cause is cyanobacteria. These often poisonous algae are spreading at breakneck speed under the current conditions in the Baltic Sea.

Overfertilisation blamed on unchecked growth

The algae plague is favored by the high nutrient content of the seawater - and guilt is the human being: "While nitrates and phosphates by nature constitute so-called minimum substances that once limited algae growth, the fertilizers of modern agriculture with their mass production cause over-fertilization - in almost all waters, "explains marine biologist and chair of GSM Petra Deimer.

The filamentous blue-green algae initially make the sea look like a noodle soup, before current and wind drive them together to form disgusting carpets. "The Baltic Sea is in a borderline situation that can end in an ecological catastrophe, " warned Hamburg marine biologist Professor Olaf Giere in 2003. Because after the collapse of the blue-green-bloom the remainders are degraded at the soil, but this consumes enormous amounts of oxygen there. In addition, the toxic substances remain in the ecosystem.

Deep zones ecologically dead

Already, almost all deep zones of the Baltic Sea are ecologically dead and could hardly regenerate due to the lack of fresh oxygenated water from the North Sea. The carpets of blue algae and dead seaweed extract additional oxygen from the seawater. In this respect, spa administrators who try with considerable effort to master the seagrass glut on the beaches, not only for the well-being of their guests, but also earned the Baltic Sea fauna. Deimer: "Every ounce of seagrass that is driven off the beach and does not rot in the sea with further oxygen depletion is a blessing." display

Natural cleaning mechanisms failed

Green-brown filamentous algae, which also multiply violently, lay like shrouds on mussel beds and other living animals and kill them by suffocation. Affected by lack of oxygen and mass extinction are fish and other living things, such as crayfish, barnacles or mussels, which under normal circumstances fulfill a kind of "cleaning filter function" in the water. Blue-green algae, which occur in more than 2, 000 species worldwide, sometimes release toxins during their death, threatening and killing even aquatic birds that drink from the water.

Jellyfish plague after algae plague

Another symptom of the stress burden of the Baltic Sea ecosystem is the mass development of jellyfish following the algae plague. Last time was the case in the heat summer of 2003. Too many jellyfish eat too many young fish and other small creatures. "When a seaweed plague broke out in the northern Atlantic Ocean in 1988, not only fish in large numbers died, but many dolphins as well, " recalls Deimer. "They ate poisoned fish and poisoned fish can become life-threatening for the harbor porpoise in the Baltic Sea." The convalescence of the sick Baltic Sea is becoming more and more serious in the belief that the nature conservationists are harassing every year, and the possible consequences for the animal world are becoming ever more threatening.

(German Environmental Aid, 09.08.2006 - NPO)