biostudies-literatureKaldy JEIntramural EPA1-17https://www.ebi.ac.uk/biostudies/studies/S-EPMC9347230biostudies-literatureUnknown689Altered primary productivity associated with eutrophication impacts not only ecosystem structure but also the biogeochemical cycling of oxygen and carbon. We conducted laboratory experiments to empirically determine how residence time (1, 3, 10 d) influences eutrophication responses in a simplified Pacific Northwest <i>Zostera marina</i>-green macroalgal community. We expected long-residence time (RT) systems to exhibit eutrophication impairments. Instead, we observed an accumulation of nutrients at all RTs and a shift in the dissolved inorganic carbon speciation away from CO_{2 (aq)} with unexpected consequences for eel grass plant condition, including shoot mortality. Most metrics responded more strongly to temperature treatments than to RT treatments. No dramatic shifts in the rMarine ecology progress seriesCarbon limitation in response to nutrient loading in an eelgrass mesocosm: influence of water residence time.PMC9347230EPA999999Pacella SRBrown CAKaldy JEfalseCarbon limitation in response to nutrient loading in an eelgrass mesocosm: influence of water residence time.Altered primary productivity associated with eutrophication impacts not only ecosystem structure but also the biogeochemical cycling of oxygen and carbon. We conducted laboratory experiments to empirically determine how residence time (1, 3, 10 d) influences eutrophication responses in a simplified Pacific Northwest <i>Zostera marina</i>-green macroalgal community. We expected long-residence time (RT) systems to exhibit eutrophication impairments. Instead, we observed an accumulation of nutrients at all RTs and a shift in the dissolved inorganic carbon speciation away from CO_{2 (aq)} with unexpected consequences for eel grass plant condition, including shoot mortality. Most metrics responded more strongly to temperature treatments than to RT treatments. No dramatic shifts in the r2022-01-01T00:00:00Z2022 May2025-04-19T23:04:31.25Z2025-04-19T23:04:31.25ZS-EPMC93472303593805510.3354/meps14061