s you may have seen by watching the news in 2018, several coastal areas of Florida has been impacted by major algae blooms. Some of these blooms are caused by various kinds of freshwater cyanobacteria, often referred to as blue-green algae. In addition, several coastal areas of southwest Florida, the panhandle, and, most recently, southwest Florida have been impacted by “red tides”, which in Florida area usually associated with a marine dinoflagellate called Karenia brevis.
While the two types of algae blooms are quite different in how and where they form, both cause significant environmental harm – including large fish kills. Toxins from Karenia brevis and certain kinds of freshwater cyanobacteria, particularly Microcystis and Anabaena species, can also have adverse impacts on human health.
Media and public discussions about these algal blooms have often been quite contentious, confusing, and, in some cases, outright wrong. Leading scientists have therefore attempted to communicate scientific knowledge directly to the public. For this discussion board exercise, you will begin thinking carefully about the (somewhat different!) thoughts of two well-respected scientific researchers:
– Dr. Michael Crosby, President of Mote Marine Laboratory – https://www.heraldtribune.com/opinion/20180817/gue…
– Dr. Karl Havens, Director of the Florida Sea Grant Program – https://www.gainesville.com/opinion/20180815/karl-havens-what-is-causing-floridas-algae-crisis.
After reading both of these articles, answer the following three questions:
1) Based on what you have learned so far about the typical limiting nutrient in freshwater ecosystems (and, yes, Lake Okeechobee is freshwater), what nutrient would you generally expect to be the most likely limiting resource for Lake Okeechobee?
2) How do Crosby and Havens each describe the role of nutrient contamination, particularly phosphorus and nitrogen, in initiating freshwater cyanobacteria (aka, blue-green algae blooms) blooms in Lake Okeechobee? What other factors do either of these researchers cite as a potential “trigger” for the cyanobacteria blooms to form in Lake Okeechobee?
3) Based on your reading of both Crosby and Havens (as well as any materials from lecture or other sources), describe why and how severe freshwater cyanobacteria blooms frequently occur in normally brackish ecosystems like the St. Lucie River estuary (on the east coast) and Caloosahatchee River estuary (on the west coast). (Hint – freshwater cyanobacteria normally would not survive in a saltwater estuary environment.)