Evaluation of recent limnological changes at Lake Apopka

Recent changes in submersed macrophytes and water quality variables have be en offered as the strongest evidence that the current restoration program a t Lake Apopka will be effective (Lowe et al., 2000); however, the new beds of submersed plants in Lake Apopka are found only on hard substrates on the fringes of the lake within 40 m of shore and are protected from waves by c attails (Typha spp.). They occupy only 0.02% of the lake area, and there is no indication that they can colonize the flocculent sediments that make up 90% of the lake area. There is no correlation between annual inputs of pho sphorus and total phosphorus concentrations in the lake, and patterns of ch ange in chlorophyll and other water quality variables do not follow changes in phosphorus loads. Rather than reflecting decreases in phosphorus loadin g, the recent changes could be related to the harvest of benthivorous fish or are just the normal fluctuations found in lakes that have not been pertu rbed. Regardless of the reason the macrophytes were lost in the 1940s, the new analyses confirm our previous findings that the high turbidities in Lak e Apopka are due to the resuspension of sediments, and that the fluid mud c annot support the colonization of submersed aquatic macrophytes. Even witho ut the fluid mud, the target phosphorus concentration of 55 mg m(-3) is too high to bring about the restoration of the former macrophyte beds in the l ake.