Monday, March 21, 2016

Algal Blooms Producing Deadly Toxins
            Over the past few years, algal blooms have become a serious issue that affects humans and aquatic organisms. They occur when the temperatures and nutrient inputs, such as phosphorous, are high (Townhall). These conditions are favorable for algal blooms because it allows for fast growth (Townhall). Algal blooms find their way into aquatic organisms from being consumed by zooplankton, clams, mussels, and shellfish and then they move up the food web when those organisms are consumed (Townhall). Algal blooms can also create dangerous toxins that can have huge impacts on the organisms that consume them. Two of the toxins that have been found in marine systems are domoic acid, which is produced by an alga called Pseudo-nitzschia (shown above), and saxitoxin, produced by dinoflagellates (nwfsc). Domoic acid causes brain damage in affected organisms which can lead to deficits in spatial memory (Townhall). It also causes seizures in sea lions (nwfsc). This toxin increases the likelihood of death due to not remembering how to forage, avoid ship strikes, or migrate (Townhall). Saxitoxin causes PSP (paralytic seafood poisoning) in clams (Townhall).

     Recently, both these toxins were found in marine mammals in Alaskan waters which is very unusual since the waters are normally too cold for blooms to occur (nwfsc). Samples from 900 marine mammals of 13 different species, including whales, walruses, sea lions, seals, porpoises and sea otters were found to contain these toxins and from all regions of Alaska (nwfsc). As of now, warming trends seem to be the cause of the blooms that contain these toxins (Townhall). Alaska is not the only place to experience these blooms and toxins. Last year, a record-breaking algal bloom off the Pacific coast occurred where domoic acid concentrations were 10 to 30 times higher than a normal bloom (cbsnews). Because these blooms occur from May through October, California and other neighboring states temporarily executed a freeze on shellfish harvesting ( This particular bloom caused fisheries to close for a while because toxin levels were so high ( Normally the levels of domoic acid are not enough to cause harm to humans while swimming, but it can be harmful when eating seafood that contains large quantities of domoic acid (cbsnews). However, there are forms of algae that can cause human harm if there is major contact. This type of algae was found in Lake Erie last year due to high concentrations of phosphorous from runoff from all the precipitation that occurred during the summer (Time). Scientists confirmed that it was toxic cyanobacteria and that if any human were to go swimming in it, they risk intestinal distress, liver damage, or dermatitis (Time). Because Lake Erie a source of freshwater for many people, there was discussion of treating the water to get rid of this harmful toxin to prevent it from polluting drinking sources. However it is more expensive for water treatment when there are algal blooms and it takes a great amount of effort to clean it all up (Time).
These are just a few examples of marine systems that are affected by algal blooms and the resulting toxins. Humans need to decrease nutrient inputs in order for these harmful toxins to stop being a problem and continue to reduce global warming trends in order for real change to be observed.


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