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2011 Algae Blooms: Bad Year for Seagrasses <br /> Secondary bloom region: r.r sr,eir Southern <br /> Eau Gallie to Ft.Pierce Mosquito <br /> Lagoon <br /> o Moderately intense bloom <br /> T114!$VVII <br /> with Chlorophyll o <br /> Northern <br /> concentrations averaging Indian River <br /> Lagoon 20—30 ug/L. Levels near LagBanana <br /> River <br /> Sebastian Inlet reached cocoa "s Lagoon <br /> 50 ug/L during the peak of <br /> the bloom. <br /> Composed of a mix of <br /> Eau Gall C <br /> dominant species: <br /> Melhourne 1+� <br /> • Cyanobacteria,followed by <br /> diatoms&dinoflagellates <br /> Central <br /> in the Melbourne area. Indian <br /> Indian <br /> River <br /> • Co-dominance of diatoms Lagoon <br /> and dinoflagellates in the <br /> zaty su <br /> Vero Beach area. pe rbWorn area <br /> veno Beach <br /> 2011 secondary bloom area <br /> What Caused the Superbloom? <br /> No single factor explains the Superbloom,but several things stand out: <br /> 1. Long-term drought conditions:Salinities Increased <br /> In 8 of the past 12 years,rainfall in the region was below the 30-year <br /> average of 50". <br /> Low rainfall typically means less runoff and reduced nutrient <br /> loadings. <br /> • But,drought also means increased salinity as water evaporates. <br /> 2. Two extreme winters:Dec.2009—Jan.2010 and Dec.2010—Jan. <br /> 2011. Macro Algae affected by low water temperatures <br /> • Winter 2009/10 was the coldest since 1937 when records were first <br /> kept. <br /> • Extreme low water temperatures lasted over 2 weeks in January. <br /> 3. Possible internal nutrient loadings in the IRL Ecosystem. <br /> • Crash of macroalgae population in the IRL in Mid-2010. <br /> • Decay of this material added nutrients to system. <br /> 4. The lagoon may have reached a tipping point in terms of nutrient <br /> loadings <br /> • Seagrass stress may account for decreased trends in density of beds. <br /> '7 - A- 17 <br />