Blog #286 HABS and Osprey: Danger Ahead?

 Toxic harmful algal blooms (HABs) look like different colored foam, scum, floating mats,  or a discolored film floating on the water’s surface. HABs are caused by a wide variety  of blue-green bacteria—planktonic cyanobacteria—and not algae at all. Microcystis is  the most common bloom-forming genus, and is almost always toxic. When these  naturally occurring colonies become overabundant, they become problematic.  Cyanobacteria use sunlight to create food and thrive in warm, stagnant conditions with  high nutrient availability (particularly phosphorus). HABs are becoming more frequent in  waters like Cayuga Lake, which receive high nutrient inputs from fertilizers used in  agriculture, golf courses, lawns, and gardens.  

Discolored water of a HABs in Owasco Lake. Courtesy of DEC. 

HABs are troubling for three reasons: their decaying bodies deplete water bodies of  dissolve oxygen (hypoxia) killing fish and other aquatic organisms; the sheer abundance  of biomass produced by blooms lowers food quality, clogs animal’s gills, and decreases  photosynthesis of underwater vegetation altering littoral habitats: and they produce at  least three kinds of toxins.

Cyanobacteria produce cyanotoxins, in the form of neurotoxins affecting the nervous  system, hepatotoxins, which damage livers, or dermatoxins that affect the skin.  Microcystis and several other genera of cyanobacteria produce the potent cyclic peptide  toxins called microcystins, which are hepatotoxins (liver toxins). These toxins are  harmful to fish and aquatic organisms, water birds, and animals including humans. 

A HAB last summer in Cayuga Lake looked like spilt paint, courtesy of DEC. 

Fish-eating waterfowl, gulls, and colonial water birds, including Osprey, have presented  with steatitis, an often lethal inflammation of adipose (fatty) tissue after being exposed  to algal blooms with Microcystis. Birds exposed to the microcystins produced become  emancipated, lethargic, unable to fly, and develop an unusually hard abdomen due to  excessive deposits of waxy, yellow fat throughout the abdomen and body cavity. Gross  necropscopic findings of these birds also show unusually large counts of the  cyanobacterium (blue-green algae) Microcystis in their tissues. Toxins that kill fish,  could in turn poison fish-eating birds of prey such as Bald Eagles and Ospreys through  skin contact, ingestion, and possibly inhalation. 

Research shows that microcystins are not accumulated or biomagnified in the aquatic  food web, but rather biodiluted. This means that Ospreys are not receiving high doses  accumulated in the fish they ingest, but rather are impacted by coming into contact with  the algal bloom indirectly by eating a fish that has left a bloom, or directly by diving in a  bloom and making skin contact with the toxins, or flying near a bloom and inhaling the  toxins. 

HABs can look like clumps or parallel streaks in the water, courtesy of DEC. 

HABs appear sporadically during the summer months on Cayuga, but are predicted to  become more prevalent as temperatures increase because of global warming trends.  More efforts to reduce high nutrient runoff from farms and suburbs must be  implemented to prevent extensive problems in the future. While not a threat so far for  the Osprey yet, HABs may become a serious threat to them in the future. 

Floating mats of spirogyra algae and bubbly scum are not hazardous, courtesy of DEC. 

The Community Science Institute works locally with volunteers from the Cayuga Lake  Watershed Network and Discover Cayuga Lake to understand and hopefully manage  HABs in the future. If you see a suspicious bloom, avoid contact with the water and  immediately report the blooms online, to habshotline @gmail.com, or by calling the CSI lab at (607) 257-6606. Do this for your health, the health of the lake, and that of our lake’s watchdogs, the Osprey. Thank you! 

Eyes to the sky!  

Candace  

Candace E. Cornell  

Friends of Salt Point 

Lansing, NY  

cec222@gmail.com 

ALL EYES ON OSPREYS 

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