MEPS 218:87-93 (2001)  -  doi:10.3354/meps218087

ABSTRACT: In southern California estuaries, the green macroalga Enteromorpha intestinalis experiences wide fluctuations in both nitrogen (N) supply and salinity. We investigated the effects of simultaneous variation in N and salinity on the growth, biomass accumulation and tissue nutrient dynamics of E. intestinalis. We conducted a fully crossed 2-factor experiment in which we varied N enrichment (low, medium and high) and salinity (15, 25 and 35 psu). Overall, addition of N enhanced algal growth while salinity reduction decreased growth. High N enrichment mitigated the negative effects that reduced salinity had on dry biomass, wet:dry biomass ratios, tissue nutrients and ability to remove phosphorus from the water column. Largely, E. intestinalis abundance was governed by N availability rather than salinity, indicating that blooms of macroalgae will likely continue to proliferate in estuaries unless nutrient loading is reduced.

KEY WORDS: Enteromorpha intestinalis · Macroalgae · Nitrogen · Salinity · Estuaries · Southern California