Net community production and dark community respiration in a (Davis) bloom in West Florida coastal waters, USA.

Oxygen-based productivity and respiration rates were determined in West Florida coastal waters to evaluate the proportion of community respiration demands met by autotrophic production within a harmful algal bloom dominated by . The field program was adaptive in that sampling during the 2006 bloom occurred where surveys by the Florida Wildlife Research Institute indicated locations with high cell abundances. Net community production (NCP) rates from light-dark bottle incubations during the bloom ranged from 10 to 42 µmole O L day with highest rates in bloom waters where abundances exceeded 10 cells L. Community dark respiration () rates in dark bottles ranged from <10 to 70 µmole O L day over 24 h. Gross primary production derived from the sum of NCP and varied from ca. 20 to 120 µmole O L day. The proportion of GPP attributed to NCP varied with the magnitude of during day and night periods. Most surface communities exhibited net autotrophic production (NCP > ) over 24 h, although heterotrophy (NCP < ) characterized the densest sample where cell densities exceed 10 cells L.