BACI-type ANOVA results for effects of treatments and interactions on benthic algae biomass, nekt... more BACI-type ANOVA results for effects of treatments and interactions on benthic algae biomass, nekton abundance, and nekton biomass.
We compared processing and fate of dissolved NO3− in two New England salt marsh ecosystems, one r... more We compared processing and fate of dissolved NO3− in two New England salt marsh ecosystems, one receiving natural flood tide concentrations of ∼1–4 μmol NO3−/L and the other receiving experimentally fertilized flood tides containing ∼70–100 μmol NO3−/L. We conducted simultaneous 15NO3− (isotope) tracer additions from 23 to 28 July 2005 in the reference (8.4 ha) and fertilized (12.4 ha) systems to compare N dynamics and fate. Two full tidal cycles were intensively studied during the paired tracer additions. Resulting mass balances showed that essentially 100% (0.48–0.61 mol NO3‐N·ha−1·h−1) of incoming NO3− was assimilated, dissimilated, sorbed, or sedimented (processed) within a few hours in the reference system when NO3− concentrations were 1.3–1.8 μmol/L. In contrast, only 50–60% of incoming NO3− was processed in the fertilized system when NO3− concentrations were 84–96 μmol/L; the remainder was exported in ebb tidewater. Gross NO3− processing was ∼40 times higher in the fertilized...
Journal of Experimental Marine Biology and Ecology, 2008
Responses of infaunal saltmarsh benthic invertebrates to whole-ecosystem fertilization and predat... more Responses of infaunal saltmarsh benthic invertebrates to whole-ecosystem fertilization and predator removal were quantified in Plum Island Estuary, Massachusetts, USA. Throughout a growing season, we enriched an experimental creek on each flooding tide to 70 μM NO3− and 4 μM PO4− 3 (a 10× increase in loading above background), and we reduced Fundulus heteroclitus density by 60% in a branch of the fertilized and a reference creek. Macroinfauna and meiofauna were sampled in creek (mudflat and creek wall), marsh edge (tall-form Spartina alterniflora) and marsh platform (Spartina patens and stunted S. alterniflora) habitats before and after treatments were begun; responses were tested with BACI-design statistics. Treatment effects were most common in the mid-range of the inundation gradient. Most fertilization effects were on creek wall where ostracod abundance increased, indices of copepod reproduction increased and copepod and annelid communities were altered. These taxa may use epiph...
Coastal systems serve many human uses and as a result are susceptible to anthropogenic activities... more Coastal systems serve many human uses and as a result are susceptible to anthropogenic activities such as nutrient loading and overfishing. In soft sediments, infauna frequently serve as key indicators of such activities. To use infauna effectively as bioindicators, it is important to understand how infaunal abundances and community patterns vary naturally within ecosystems. We examined the spatial and temporal dynamics of infaunal annelids in four tidal creeks of the Plum Island Estuary, Massachusetts, USA, from June to October 2003, sampling along a tidal inundation gradient that crossed five distinct habitats from creek bottoms to the vegetated high marsh platform. Annelids comprised 97% of the total number of macroinfauna. Highest densities were found in creek wall habitats (33,418–65,535 individuals m−2), and lowest densities (2,421–10,668 individuals m−2) were found inSpartina patens habitats. Five numerically abundant species comprised 87% of the annelid assemblage and three ...
We compared processing and fate of dissolved NO 3 − in two New England salt marsh ecosystems, one... more We compared processing and fate of dissolved NO 3 − in two New England salt marsh ecosystems, one receiving natural flood tide concentrations of 14 μmol NO 3 − /L and the other receiving experimentally fertilized flood tides containing 70100 μmol NO 3 − /L. We ...
BACI-type ANOVA results for effects of treatments and interactions on benthic algae biomass, nekt... more BACI-type ANOVA results for effects of treatments and interactions on benthic algae biomass, nekton abundance, and nekton biomass.
We compared processing and fate of dissolved NO3− in two New England salt marsh ecosystems, one r... more We compared processing and fate of dissolved NO3− in two New England salt marsh ecosystems, one receiving natural flood tide concentrations of ∼1–4 μmol NO3−/L and the other receiving experimentally fertilized flood tides containing ∼70–100 μmol NO3−/L. We conducted simultaneous 15NO3− (isotope) tracer additions from 23 to 28 July 2005 in the reference (8.4 ha) and fertilized (12.4 ha) systems to compare N dynamics and fate. Two full tidal cycles were intensively studied during the paired tracer additions. Resulting mass balances showed that essentially 100% (0.48–0.61 mol NO3‐N·ha−1·h−1) of incoming NO3− was assimilated, dissimilated, sorbed, or sedimented (processed) within a few hours in the reference system when NO3− concentrations were 1.3–1.8 μmol/L. In contrast, only 50–60% of incoming NO3− was processed in the fertilized system when NO3− concentrations were 84–96 μmol/L; the remainder was exported in ebb tidewater. Gross NO3− processing was ∼40 times higher in the fertilized...
Journal of Experimental Marine Biology and Ecology, 2008
Responses of infaunal saltmarsh benthic invertebrates to whole-ecosystem fertilization and predat... more Responses of infaunal saltmarsh benthic invertebrates to whole-ecosystem fertilization and predator removal were quantified in Plum Island Estuary, Massachusetts, USA. Throughout a growing season, we enriched an experimental creek on each flooding tide to 70 μM NO3− and 4 μM PO4− 3 (a 10× increase in loading above background), and we reduced Fundulus heteroclitus density by 60% in a branch of the fertilized and a reference creek. Macroinfauna and meiofauna were sampled in creek (mudflat and creek wall), marsh edge (tall-form Spartina alterniflora) and marsh platform (Spartina patens and stunted S. alterniflora) habitats before and after treatments were begun; responses were tested with BACI-design statistics. Treatment effects were most common in the mid-range of the inundation gradient. Most fertilization effects were on creek wall where ostracod abundance increased, indices of copepod reproduction increased and copepod and annelid communities were altered. These taxa may use epiph...
Coastal systems serve many human uses and as a result are susceptible to anthropogenic activities... more Coastal systems serve many human uses and as a result are susceptible to anthropogenic activities such as nutrient loading and overfishing. In soft sediments, infauna frequently serve as key indicators of such activities. To use infauna effectively as bioindicators, it is important to understand how infaunal abundances and community patterns vary naturally within ecosystems. We examined the spatial and temporal dynamics of infaunal annelids in four tidal creeks of the Plum Island Estuary, Massachusetts, USA, from June to October 2003, sampling along a tidal inundation gradient that crossed five distinct habitats from creek bottoms to the vegetated high marsh platform. Annelids comprised 97% of the total number of macroinfauna. Highest densities were found in creek wall habitats (33,418–65,535 individuals m−2), and lowest densities (2,421–10,668 individuals m−2) were found inSpartina patens habitats. Five numerically abundant species comprised 87% of the annelid assemblage and three ...
We compared processing and fate of dissolved NO 3 − in two New England salt marsh ecosystems, one... more We compared processing and fate of dissolved NO 3 − in two New England salt marsh ecosystems, one receiving natural flood tide concentrations of 14 μmol NO 3 − /L and the other receiving experimentally fertilized flood tides containing 70100 μmol NO 3 − /L. We ...
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