Seminar at USF (St. Petersburg) on Thursday

[loquat149]

Sorry for the short notice, but I only just heard of this myself.

Dave

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ESPG/C-SPACE/Progress Energy Special Seminar

When: Thursday November 17th 2011, 3:30 pm
Where: University of South Florida St. Petersburg, Davis Hall Room 102 (DAV102), 140 7th Avenue South, St. Petersburg, FL 33701

“Eutrophication in Flowing Waters: Nutrient Enrichment, Primary Production and Algal Proliferation in Florida’s Springs”

Matthew Cohen, Ph.D., Associate Professor, Forest Water Resources, Hydrology, University of Florida, Gainesville, Florida

Abstract

Nutrient enrichment of surface and groundwater is a major environmental challenge. Of particular local relevance is the ongoing and ubiquitous nitrate enrichment of the Upper Floridan Aquifer, the source of water for our springs and most of our drinking water supply. Understanding the ecological effects of nutrient enrichment has been a research priority since the 1970’s, but our understanding and ability to predict these effects in flowing waters has lagged progress in other aquatic systems. In this seminar, I will present a general theory to help predict eutrophication in flowing waters in response to nutrient enrichment, and animate some of ideas in that theory with work in the spring-fed rivers of North and Central Florida. This new theory was derived to a large extent from looking at the results from deploying a new class of environmental sensor which greatly increases the sampling resolution of nitrate. I will also present some of the fundamentals of those new sensors, and the new avenues for aquatic ecosystem research that they create.

[FW]

Great topic, I wish I could make that one. If you get the chance, point out that is some systems (like Falmouth/Cathedral) the visibility was around 50' back in the late 70s, but is only about 5' now. We think it is due to "spray fields" in the recharge area.

[loquat149]

Well, his take home message was that these are very complex systems that are influenced by a variety of factors, not just nutrient inputs. The old dogma that algal blooms are the direct result of increased nutrient loads doesn't hold up against their empirical data. Since the water exiting the spring vents is continually moving, there is a constant replacement of any nutrients that might be taken up by algae or vascular plants. So, the idea of nutrient *concentration* being a good predictor of eutrophication works for, say, lakes but not spring fed rivers. Since there are springs with high nutrients levels and low algal biomass (and vice versa), something else is at work...including the presence of herbivorous snails, whose abundances are inversely proportional to flow rates and directly proportional to levels of dissolved oxygen, etc. Not as simple as one might expect, especially considering the water emanating from many of our springs is, on average, 30 yrs old.

Dave

[WEPIV]

Thanks for the report Dave. I had been told something similar awhile ago by state workers taking water samples from Troy.
Common sense though tells me that if you keep drawing water out of the aquifer coupled with pouring concrete, etc., all over the place (strip malls and subdivisions ad nauseam) our beloved springs are going to change.
Question is, how do we really address this before it's too late? (And as a realistic optimist, I'm hopeful that it is not too late.)