Macroalgal production and nutrient relations in oligotrophic area of Florida Bay
Lapointe BE. 1989. Macroalgal production and nutrient relations in oligotrophic area of Florida Bay. Bulletin of Marine Science. 44(1):312-323
Abundant macroalgae of southern Florida Bay were assayed for nitrogen (N) and phosphorus (P) limitation of productivity by enrichment effects on in situ growth rate, tissue C:N:P molar ratios, and capacity of alkaline phosphatase. Growth of two frondose rhodophytes, Gracilaria tikyahiae and Laurencia poaei. was stimulated primarily by P (although N was also limiting during winter) as was growth of two frondose phaeophytes. Sargassum polyceratium and Sargassum pteropleurn. Tissue C:P and N:P ratios of the unenriched rhodophytes were elevated, ranging from 1,080 to 1,939 and 75 to 147, respectively; C:P and N:P ratios of the unenriched phaeophytes were lower, ranging from 550 to 1,307 and 23 to 25, respectively. These tissue ratios support the primary P limitation suggested by the growth assays and suggest that phylogenetic differences may exist in storage and utilization of N and P compounds relative to C. Levels of dissolved inorganic nutrients (NH4, NO3, and PO) in seawater during these studies also suggest that P, relative to N, was most limiting during summer months when NO, and NH4 were seasonally elevated and seawater N:P ratios were > 30:1. Assays for alkaline phosphatase activity in phylogenetically diverse forms of Florida Bay macroalgae indicated broadly different capacities of this exoenzyme, with the highest rates observed for Dictyota divaricala and L. poitei and the lowest rates for G. tikvahiae. Considering that D. divaricata and L. poitei had the greatest observed capacity for this enzyme and that these related species are particularly abundant in southern Florida Bay, utilization of dissolved organic phosphat pools appears to be ecologically important to sustaining productivity of indigenous frondose macroalgae in P-limited Florida Bay. Abstract provided by author.
- Type
- Journal Article
- Authors
- Lapointe, Brian
- Units
- BISC , EVER
- Keywords
- Agriculture, Algae, Benthic Fauna, Calcareous, Canalization, chlorophytes, Dictyota, Drainage, Ecology, Frondose phaeophytes, Frondose rhodophytes, Gracilaria tikvahiae, Irradiance, Laurencia poitei, Macroalgae, Macronutrients, macrophytes, Nitrogen (N), Nutrient availability, Nutrient Cycling, Oligotrophic, Phosphorus (P), Population Density, Production, Sargassum polyceratium, Sargassum pteropleuron, Syringodium filiforme, Temperature, Thalassia testudinum