Algae Bloom ABC’s
By Dennis Katte
We all know that phosphate and nitrate products are nutrients to algae, and have been discussed by our water quality group for years. Excessive quantities can lead to algae growth. Water temperature and sunlight are also contributing factors as is improper septic discharge. Most form in sunnier summer months when the water is warmer, yet, information gathered by WA DOE has shown that Western Washington’s blooms are atypical, and can form in nearly any month with water temperatures as low as 45.
In 2010 Washington was one of 16 states to ban dishwasher detergents that contained high levels of phosphorous (over .5%). And, in the same year the American Cleaning Institute, which represents most of the soap manufacturers stated that their members had all adopted voluntary bans on phosphate use.
On January 1, 2013 WA ESHB 1489 (Engrossed Substitute House Bill) became effective which in most cases prohibits the sale of turf fertilizers that contain phosphorous. This bill had been proposed back in 2011.
So here we are with better environmentally friendly products, yet we are faced with more algae blooms. Why?
I grew up in WI spending summers at Crystal Lake, one much like Lake Cavanaugh. As far back as the 50’s we experienced an occasional algae bloom during the hot “dog days” of August. You might recall that Toledo, Ohio closed their water filtration plant off Lake Erie due to toxic blooms last summer. We had the first “big one” at Lake Cavanaugh on that hot May 17, 2008 weekend that also resulted in a massive fish kill. Algae blooms are happening with increasing frequency everywhere, and, for us, is somewhat frightening since we’ve not experienced many in the past and there’s very little we can do about them, especially now that phosphates and nitrates have largely been eliminated from most of the products we use, and there is little agriculture around the lake (nitrates still ok in agricultural fertilizers).
Wa DOE in May 2012 wrote a publication “Sunshine Causing Algae Blooms in Western Waters” which contains a lot of useful information on algae blooms. Algae is photosynthetic, creating energy from water, sunlight, and carbon dioxide. You can access it at: http://www.ecy.wa.gov/news/2012/136.html.
Another interesting DOE website is EOPS, or Eyes on Puget Sound, which photographs 20 areas of the Sound. It’s an interesting site with aerial photography clearly showing blooms as well as jellyfish schools and other items. The April 29 photos already show red algae blooms: http://www.ecy.wa.gov/programs/eap/mar_wat/eops/EOPS_2015_4_29.pdf
Now on to the classroom stuff.
Single celled organisms called phytoplankton occur naturally in any body of water. Their size varies, and you can frequently see them swimming about at night by shining a flashlight into the water. It can also form long strings called filamentous algae, which we know as moss. Algae can also be complex multi-celled forms as seaweeds. When the concentrations become excessive, it’s called a bloom. Although there are over 6000 types of algae world-wide, only 2% of them are “harmful”, and referred to as a HAB, or harmful algae bloom which can cause negative impacts to other organisms living in or consuming the water. It is also the new term for “red tide” in salt water. The cells have limited lives, and when they die, they sink to the bottom and their deterioration will consume dissolved oxygen and possibly cause fish kills from oxygen deprivation. Some create neurotoxins.
Bluegreen algae is now called cyanobacteria. This is the bad stuff. It can live up to two weeks, but can form a new group so the bloom can possibly go on for several months. DOE has published an excellent article on this type, available at: http://www.ecy.wa.gov/programs/wq/plants/algae/publichealth/GeneralCyanobacteria.html
This can (but doesn’t in all cases) produce the neurotoxins which can cause illness in humans or even death in pets. There are three types: Anabaena, Aphanizomenon, and Microcystis , sometimes called Annie, Fannie, and Mike. Annie and Mike produce the toxins. Fannie’s ok.
So far, we’ve not had a HAB. Blooms in the past have generally been harmless types. They’ve been Uroglena Americana, a strain of a “golden” algae which produces noticeable musty, earthy taste and odor when decomposing. The byproducts dissolve into the water which is why most taste and odor filters don’t do a real good job of removing unpleasantness. This is the type that plagued Lake Whatcom (where Bellingham gets its drinking water) for several years.
In summary, the bottom line is that although we can reduce or moderate blooms by eliminating nutrients, it doesn’t seem possible to eliminate some of Mother Nature’s natural occurrences such as algae blooms (or earthquakes).