Metabolism of a nitrogen-enriched coastal marine lagoon during the summertime

摘要: We measured metabolism rates in a shallow, nitrogen-enriched coastal marine ecosystem on Cape Cod (MA, USA) during seven summers using an open-water diel oxygen method. compared two basins, one directly receiving most of the nitrogen (N) load (“Snug Harbor”) and another further removed from N better flushed (“Outer Harbor”). Both dissolved pH varied greatly over day, increasing daylight decreasing at night. The more N-enriched basin frequently went hypoxic night, both basins was low (compared to standard seawater) when levels were low, due elevated carbon dioxide. Day-to-day variation gross primary production (GPP) high linked part light. Whole-ecosystem respiration tended track this short-term GPP, suggesting that by producers often dominated whole-system respiration. GPP higher N-loaded Snug Harbor. Seagrasses covered 60 % area better-flushed, Outer Harbor throughout our study major contributors there. 20 for first 5 years study, their contribution relatively small. seagrasses died off completely 6th year, but remained then subsequent year. Overall, phytoplankton benthic micro- macro-algae may be dominant years. Net variable year showing net heterotrophy some autotrophy others, with trend towards 7 reported here.