IngentaConnect Evidence that phosphorus limits phytoplankton growth in a Gulf of...

Authors: Murrell, Michael C.; Stanley, Roman S.; Lores, Emile M.; DiDonato, Guy T.; Smith, Lisa M.; Flemer, David A.

Source: Bulletin of Marine Science, Volume 70, Number 1, January 2002 , pp. 155-167(13)

Publisher: University of Miami - Rosenstiel School of Marine and Atmospheric Science

Abstract:

Nutrient limitation bioassays were conducted on six dates from November 1998 to September 1999 at two sites, including oligohaline (Upper Bay) and mesohaline regions (Lower Bay), in Pensacola Bay, Florida. Phytoplankton growth responses (measured as changes in chlorophyll a concentration) to inorganic nitrogen (N) and phosphorus (P) additions were monitored for three days. The results showed that, in eight of twelve experiments, phytoplankton growth was stimulated by P additions in comparison with N-amended and un-amended treatments. Nitrogen additions alone did not stimulate growth over P additions in any experiment. The spatial patterns suggest that the potential for P limitation was similar in Upper and Lower Bays. The four experiments with statistically non-significant results were all conducted during winter and spring, suggesting a lower potential for nutrient limitation during the cooler months when nutrient demand (i.e., productivity) is typically low and nutrient supply (i.e., freshwater runoff) is typically high. This study adds to a small but growing literature suggesting that P limitation of phytoplankton growth may be relatively common in warm temperate estuarine systems such as those along the Gulf of Mexico coast.

Evidence that phosphorus limits phytoplankton growth in a Gulf of Mexico estuary: Pensacola Bay, Florida, USA