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dc.contributor.authorLever, Mark A.
dc.contributor.authorValiela, Ivan
dc.date.accessioned2011-04-21T15:29:31Z
dc.date.available2011-04-21T15:29:31Z
dc.date.issued2005-06-09
dc.identifier.citationMarine Ecology Progress Series 294 (2005): 117-129en_US
dc.identifier.urihttp://hdl.handle.net/1912/4487
dc.descriptionAuthor Posting. © Inter-Research, 2005. This article is posted here by permission of Inter-Research for personal use, not for redistribution. The definitive version was published in Marine Ecology Progress Series 294 (2005): 117-129, doi:10.3354/meps294117.en_US
dc.description.abstractEffects of eutrophication on the relative importance of nutrients and macroherbivores as controls of microphytobenthic standing crop were examined in estuaries with different nitrogen loading rates: Sage Lot Pond (14 kg ha–1 yr–1), Green Pond (178 kg ha–1 yr–1), and Childs River (601 kg ha–1 yr–1). We selected 5 sites with similar salinity ranges on shallow-water, sandy substrates per estuary. In year-round experiments, we fertilized sediments with nitrogen + phosphorus to examine nutrient limitation. We conducted exclusion experiments to determine the significance of macroherbivores as controls of microphytobenthic biomass and examined possible interactions between nutrients and grazing in cages fertilized with nitrogen + phosphorus. Cages fertilized with nitrogen only were also included to determine if nitrogen availability was limiting. Nitrogen + phosphorus addition increased sediment chlorophyll a (chl a) content (herein used as a proxy for biomass) by a similar magnitude across estuaries. Grazer exclusion also increased chl a, but to a different extent across estuaries: the magnitude of the response increased with increasing nitrogen loading rates. We found no interactions between nutrients and grazing. Strong chl a increases in response to nitrogen only addition indicated N limitation in Sage Lot Pond and Green Pond. In the highly eutrophic Childs River estuary we found virtually no response to nitrogen-only additions, suggesting the possibility of phosphorus limitation in this estuary.en_US
dc.description.sponsorshipThis study was supported by a Sounds Conservancy Fellowship awarded by the Québec-Labrador- Foundation.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoenen_US
dc.publisherInter-Researchen_US
dc.relation.urihttps://doi.org/10.3354/meps294117
dc.subjectMicrophytobenthosen_US
dc.subjectBiomassen_US
dc.subjectNutrientsen_US
dc.subjectGrazersen_US
dc.subjectEutrophicationen_US
dc.subjectNitrogen loaden_US
dc.titleResponse of microphytobenthic biomass to experimental nutrient enrichment and grazer exclusion at different land-derived nitrogen loadsen_US
dc.typeArticleen_US
dc.identifier.doi10.3354/meps294117


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