Benthic Macroalgal Blooms as an Indicator of System Eutrophy in the Barnegat Bay–Little Egg Harbor Estuary

Macroalgal blooms develop during the spring-summer period in the Barnegat Bay–Little Egg Harbor Estuary, a highly eutrophic coastal lagoon in New Jersey, and these blooms are detrimental to seagrass habitat in the system. Recurring blooms of drifting red and green macroalgae (e.g., Gracilaria tikvahiae and Ulva lactuca) attenuate or block light transmission to seagrass beds and also produce extensive organic mats that can alter biogeochemical processes in bottom sediments. Investigations of macroalgal blooms in the estuary over a six-year period documented 55 occurrences (2.23 blooms m-2) of Early Bloom (70%–80% macroalgal cover) and Full Bloom (>80% macroalgal cover) events, which resulted in increased mortality of seagrass leading to reduced biomass and bare-bottom areas within the beds.