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Many of Florida’s 700+ springs have undergone dramatic shifts in autotroph dominance (from submerged aquatic vegetation to benthic filamentous algae), yet the drivers of these changes remain ambiguous. While nitrogen enrichment has been implicated, new data suggest other drivers are at play in these unique spring-fed karst ecosystems.
In research by PhD student Dina Liebowitz, surveys revealed a negative relationship between gastropod biomass and algal abundance across and within springs. Her study expands on these observational findings by conducting in situ grazing experiments to examine three linked hypotheses developed to help explain patterns of algal density in Florida’s springs. These are (1) that the dominant gastropod grazers can control algal accumulation; (2) that there is potential for hysteretic behavior, i.e. once an algal bloom forms, even abundant grazers cannot exert enough grazing pressure to induce a low-algae state; and (3) dissolved oxygen (DO) influences the distribution and grazing efficiency of gastropods. |
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| Title: | Experimental evidence for grazer control of filamentous algae in a spring-fed river. In Prep. 2013. |
| Authors: | Liebowitz, D., M.J. Cohen, T.K. Frazer, J. Heffernan |
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