Owen Silvera (pictured bottom-center) together with his analysis staff at Lake Okeechobee. Picture by Owen Silvera.
Within the early mornings and late nights, from dawn to sunset, graduate pupil Owen Silvera and his colleagues launched into numerous expeditions in Lake Okeechobee.
“I recall spending whole days there, targeted on gathering sediment in hopes to disclose deeper truths concerning the chemistry that drives algal blooms, the predominant concern of Lake Okeechobee. We labored tirelessly on these days, in our boat; typically in areas of nationwide intrigue resembling Pahokee marina, simply ten ft from shore, which has so usually been the middle of protection on algal blooms by the media” says Silvera.
Nevertheless, Lake Okeechobee is an unlimited water physique which Silvera offers scale to by it being bigger than Nassau, Bahamas, the island of his start. Alongside the Geochemistry and Geochemical Sensing Laboratory at FAU, he has collected sediment from each attain of the Lake. Researching the sediments tells a narrative that extends past the mere job at hand, providing a glimpse into a bigger narrative that unfolds throughout Florida’s largest lake, Lake Okeechobee, regarding dangerous algal blooms.
Whereas dangerous algal blooms and nutrient dynamics are sometimes related to direct runoff from stormwater, sediments additionally play a major function. Owen Silvera’s analysis journey, supported by the Aylesworth Scholarship, has supplied him with the assist to check the interaction between sediments, dangerous algal blooms (HABs), and water high quality in huge shallow lakes like Lake Okeechobee.
“I’m obsessed with conducting analysis that immediately impacts the economic system, resembling dangerous algal blooms which may set off states of emergency. This facet of my work resonates deeply with me as a result of I attempt for tangible outcomes that positively have an effect on individuals’s lives,” says Silvera.
Blue-green algae at marina situated on Lake Okeechobee. Picture by Owen Silvera.
“Sediments play a pivotal function in ecosystem dynamics. In Lake Okeechobee, characterised by its shallow depth and susceptibility to robust winds, sediment resuspension emerges as a major phenomenon that swiftly introduces vitamins into the water column that may affect algal blooms.”
Sediment resuspension is the method by which small particles of rock from the bottom or settled on the backside of a physique of water are stirred up and introduced again into the water column by means of wave motion, currents, or turbulence, in addition to human actions like dredging or boating can lead to suspension. Although Lake Okeechobee stands as a case research, this analysis is relevant all through Florida.
“In Florida, we\’ve plenty of shallow lakes. When giant winds choose up, there could also be no wind blockage over the entire course of those lakes, driving waves and sooner currents. Since these lakes are shallow, sediments are very near the floor and there’s not a lot area for that power to dissipate, and so the sediments are simply resuspended,” says Silvera.
Explicit considerations are the vitamins inside sediments, notably nitrogen and phosphorus. Whereas algae predominantly depend on these parts, sediments harbor further substances like metals, with iron additionally being a focus of Owen’s analysis. The resuspension course of exacerbates nutrient hundreds and imbalances, which may doubtlessly immediately affect the bloom of species resembling microcystin-producing blue-green algae.
“From this analysis, we see that the sediments which are in suspension from Lake Okeechobee particularly have an effect on the a great deal of nitrogen and phosphorus which are going to the coasts. Certainly, new analysis reveals that nitrogen from Lake Okeechobee launched into the Caloosahatchee, is linked to even the crimson tide algal blooms within the Gulf of Mexico.”
Silvera assessing collected sediments within the lab. Picture by Owen Silvera.
Fieldwork Brings Native Views and Observations to Dangerous Algal Blooms
“In 2021, the Pahokee Marina made a number of nationwide headlines because of extreme blue-green algal blooms. Quick ahead to now, and we discover ourselves conducting our work amidst the robust odor emitted by the blue-green algae, which is notoriously foul-smelling. And these are the identical waters that individuals are fishing in. We\’re seeing these impacts firsthand on the atmosphere and group,” says Silvera.
Silvera and his analysis staff employs a mix of monitoring and experimental approaches to watch sediment and nutrient dynamics. Discipline expeditions usually contain water sampling and sediment assortment, whereas laboratory simulations of resuspension occasions assist us management and higher perceive nutrient dynamics throughout such occasions.
“In the course of the wintertime and spring, you get actually excessive winds over Lake Okeechobee, which restrict algal blooms. Although there\’s a lot sediment within the water column loaded with vitamins, the algae can’t make use of those vitamins when they\’re restricted by gentle. Nevertheless, within the summertime, when issues begin to settle out of the water column, the vitamins that stay are then slowly taken up by algae, and so they bloom just about each summer season. Particularly, we research sediment-water interactions to observe the circumstances which promote intense algal blooms of probably poisonous species as a result of there are nonetheless many unknowns which we are able to doubtlessly mitigate towards with higher data.”
Hurricanes are only one instance of a climate occasion after we would possibly anticipate sediments to be resuspended. The main target round such excessive climate occasions has primarily been on general adjustments in general water high quality. Nevertheless, land drainage and sediment resuspension act collectively to extend the full nutrient load, i.e., suspended within the water column. Owen’s analysis separates the complexity of combined inputs related to pure storm occasions and highlights the precise detriment of sediment inputs. Furthermore, all of those vitamins are then funneled in the direction of the Atlantic Ocean and Gulf of Mexico throughout launch durations. This water passes by means of the St. Lucie and Caloosahatchee estuaries, carrying with it at sure occasions poisonous algae, however all the time natural sediment to repeat cycles of eutrophication far past the central state lakes and agricultural watersheds.