Algae blooms threaten to choke Baltic Sea
6 Comments
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)
Wonder how much DMS is spit out from that bloom?
http://reefbuilders.com/2010/03/06/healthy-coral-reefs-produce-clouds-and-precipitation-rain/
March 8th, 2010 at 3:29 pm
Those swirl patterns might suggest it is still blooming and not declining. I would suspect it would be less striated as bloom runs it’s course.
March 8th, 2010 at 3:31 pm
That picture really is quite stunning, showing the intensity of the bloom. Scary stuff!
March 8th, 2010 at 6:36 pm
[...] Alright yall, this could not be a more perfect current events issue for what we are talking about. Its got algal blooms, cultural eutrophication, overfishing, food webs, dead zones, D.O., and government intervention of course! Its pretty much exactly what we are talking about but a real world example. Crazy picture too. http://reefbuilders.com/2010/03/08/algae-blooms-threaten-choke-baltic-sea/ [...]
March 8th, 2010 at 7:05 pm
I think that this picture was taken 2005, a year which was extraordinary with regards to the bloom of Nodularia spumigena. Take care to directly connect spectacuolar visible effects with the oxygen deprivation in the deep waters. It is very difficult to show that these surface algal blooms indeed have increased when looking at satellite photography. N. spumigena is toxic (nodularin), which is causing alarm and it does look very spectacular when it blooms properly. However, I am quite certain that when you look at the causes of the anoxia and hypoxia och the deep waters, there are other far more important factors such as the virtually invisible spring bloom of dinoflagellates and the summer-cyanobacteria Aphanizomenon sp. that has a biomass maximum at 5-10m depth and is non-toxic. The Baltic Sea is eutrophied and many believe that large phosphorus deposits in the deep waters are being released as the hypoxia worsen, eutrophing the sea even more. Yes, it was shocking that 2005 looked the way it did, but blooms have been present in the Baltic Sea for several thousands of years and were probably a good source of nitrogen for the, at the time oligotrophic sea. This is also the problem, the Baltic Sea probably has a very nutrient poor “origin”, meaning little fish. We may even have more fish now than we did with the oligotrophic sea of the past. Nonetheless, the vicious circle in which we are currently stuck needs to slow down. As a final note: The Baltic Sea is brackish and has an extremely strong stratification. Hypoxia and anoxia in the very deep basins is NORMAL (seen over a few thousends of years) and not a cause of concern. Todays extent of this hypocia and anoxia is a cause of concern.
April 1st, 2010 at 3:18 am
This is a satellite report. Every natural phenomena is followed by other. Hope that after decay of all phytoplankton,it is the time of nutrient cycling .
April 19th, 2010 at 1:18 am