The impact of epibenthic predators foraging on macroinfaunal communities was analysed in Great Sippewissett salt marsh (MA, U.S.A.) by installing experimental cages in the most productive sediments of the marsh (77g dry weight m−2year−1). The most productive macroinfaunal species in these sediments wereMarenzelleria viridis(43·1g dry weight m−2year−1)Heteromastus filiformis(13·7g dry weight m−2year−1) andNeanthes arenaceodonta(7·6g dry weight m−2year−1). Macroinfaunal densities peaked in June following the spring recruitment. Density and biomass inside the cages were significantly higher during the growing season, however, density declined in July and August following the seasonal cycle observed outside cages, while biomass did not suffer this decline. The absence of epibenthic predators favored growth and accumulation of larger organisms, especiallyM. viridis, and included higher presence of predaceous infauna (Glycera americana,Neanthes succinea,Neanthes virens,Eteone heteropodaand Nemerteans). At the end of the experiment, there was 22·2g dry weight m−2more macroinfaunal biomass in the complete cages than in ambient sediments. The absence of epibenthic predators also increased secondary production;M. viridisdoubled production in the sediments inside cages compared with outside cages. The most common benthic predaceous fishes in the marsh were the killifishes,Fundulus heteroclitusandFundulus majalis, and some seasonal invasive fishes (Gasterosteus aculeatus,Tautoga onitis,Centropristes striatusandPleuronectes americanus). While invasive fishes preyed mainly on benthic invertebrates and grew faster, resident fishes shifted their diets through the season. The values of macroinfaunal secondary production obtained in these sediments can support the energy requirements of the predators of the marsh; in this way the pulse of secondary production created by the macroinfaunal populations travels up the saltmarsh food web.

Previous articleNext article No AccessECOLOGYDissolved Inorganic Nitrogen Flux and Mineralization in Waquoit Bay Sediments as Measured by Core IncubationsJ. Kirkpatrick, K. Foreman, and I. ValielaJ. Kirkpatrick Search for more articles by this author , K. Foreman Search for more articles by this author , and I. Valiela Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Biological Bulletin Volume 195, Number 2October 1998 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.2307/1542859 Views: 3Total views on this site Copyright © 1998 by Marine Biological LaboratoryPDF download Crossref reports no articles citing this article.

Hurricane Bob, a category 3 storm, made landfall on Cape Cod in August 1991, and its effects on watersheds and adjoining estuaries were detected in the ongoing studies being carried out as part of the Waquoit Bay Land Margin Ecosystems Research project. On land, Bob had only minor overall effects on forests; localized wind bursts did snap and break trees in small and widely scattered forest parcels. Wind stripped up to half the leaves of deciduous trees and many herbaceous plants on the watershed, and most remaining leaves were damaged by salt, so that by the end of Aug, Cape Cod forests were defoliated. Damaged growing tips of exposed trees were evident for several growing seasons. The salt exposure was followed by a burst of growth and bloom in some plants during Sep-Oct. Forest invertebrates were disturbed by the storm. Nests of hornets and wasps, for example, were apparently destroyed and the survivors became a serious pest problem: hospital records show a ten-fold increase in cases of wasp stings just after Bob. Populations of these insects did not return to earlier abundance for several years. Birds and mammals did not appear to have suffered much damage. Leaching of salt to soils released previously-adsorbed soil ammonium. Such loss of critical nitrogen may be in part responsible for the characteristically dwarfed near-shore coastal forests, as well as adds nitrogen to groundwater that in turn transports the nitrogen to receiving waters. On the Bay, Bob thoroughly mixed the water column, but the stratification was restored within 1-2 days after passage of the storm. Short recovery times might be characteristic of shallow bays with short (2-3 d) water residence times. Bob opened a new inlet to Waquoit Bay, which remains open. The new inlet exerts only minor effects on circulation within the Bay, but did create localized damage to dune and eelgrass habitats near the new inlet. The mixing of the water column released major amounts of nutrients that were held within the macroalgal canopy and upper sediments, into the upper layers, and prompted a short-lived (2-3 d) phytoplankton bloom. Biomass of unattached macroalgae was not affected by Bob. Respiration and nitrogen content of the dominant macroalgal species were elevated after passage of the storm, but returned to normal rates after several days. Nearly all above-sediment eelgrass biomass was removed, but returned to previous biomass during the next growing season. There was no visible damage to fringing salt marsh habitats. Damage to aquatic animals appears to have been minimal. A small decrease in water temperature and increased respiration by macroalgae led to decreased total net ecosystem production and increased net ecosystem respiration, but the decreases disappeared after 2 d. The effects of Hurricane Bob seemed more intense and protracted on land than on aquatic ecosystems. Recovery from the various disturbances took hours to days in the aquatic system, but months to decades in terrestrial components. Rigid, larger organisms attached or rooted to substrates seem most subject to storm-related disturbances.

Macroalgal blooms are produced by nutrient enrichment of estuaries in which the sea floor lies within the photic zone. We review features of macroalgal blooms pointed out in recent literature and summarize work done in the Waquoit Bay Land Margin Ecosystems Research project which suggests that nutrient loads, water residence times, presence of fringing salt marshes, and grazing affect macroalgal blooms.Increases in nitrogen supply raise macroalgal N uptake rates, N contents of tissues, photosynthesis‐irradiance curves and Pmax and accelerate growth of fronds. The resulting increase in macroalgal biomass is the macroalgal bloom, which can displace other estuarine producers. Fringing marshes and brief water residence impair the intensity of macroalgal blooms. Grazing pressure may control blooms of palatable macroalgae, but only at lower N loading rates. Macroalgal blooms end when growth of the phytoplankton attenuates irradiation reaching the bottom. In estuaries with brief water residence times, phytoplankton may not have enough time to grow and shade macrophytes. High phytoplankton division rates achieved at high nutrient concentrations may compensate for the brief time to divide before cells are transported out of the estuary.Increased N loads and associated macroalgal blooms pervasively and fundamentally alter estuarine ecosystems. Macroalgae intercept nutrients regenerated from sediments and thus uncouple biogeochemical sedimentary cycles from those in the water column. Macroalgae take up so much N that water quality seems high even where N loads are high. Macroalgal C moves more readily through microbial and consumer food webs than C derived from seagrasses that were replaced by macroalgae. Macroalgae dominate O2 profiles of the water columns of shallow estuaries and thus alter the biogeochemistry of the sediments. More frequent hypoxia and habitat changes associated with macroalgal blooms also changes the abundance of benthic fauna in affected estuaries.Approaches to remediation of the many pervasive effects of macroalgal blooms need to include interception of nutrients at their watershed sources and perhaps removal by harvest of macroalgae or by increased flushing. Although we have much knowledge of macroalgal dynamics, all such management initiatives will require additional information.

Hurricane Bob, a category 3 storm, made landfall on Cape Cod in August 1991, and its effects on watersheds and adjoining estuaries were detected in the ongoing studies being caried out as part of the Waquoit Bay Land Margin Ecosystems Research project. On land, Bob had only minor overall effects on forests; localized wind bursts did snap and break trees in small and widely scattered forest parcels. Wind stripped up to half the leaves of deciduous trees and many herbaceous plants on the watershed, and most remaining leaves were damaged by salt, so that by the end of Aug, Cape Cod forests were defoliated. Damaged growing tips of exposed trees were evident for several growing seasons. The salt exposure was followed by a burst of growth and bloom in some plants during Sep-Oct. Forest invertebrates were disturbed by the storm. Nests of hornets and wasps, for example, were apparently destroyed and the survivors became a serious pest problem: hospital records show a ten-fold increase in cases of wasp stings just after Bob. Populations of these insects did not return to earlier abundance for several years. Birds and mammals did not appear to have suffered much damage. Leaching of salt to soils released previously-adsorbed soil ammonium. Such loss of critical nitrogen may be in part responsible for the characteristically dwarfed near-shore coastal forests, as well as adds nitrogen to groundwater that in turn transports the nitrogen to receiving waters.On the Bay, Bob thoroughly mixed the water column, but the stratification was restored within 1-2 days after passage of the storm. Short recovery times might be characteristic of shallow bays with short (2-3 d) water residence times. Bob opened a new inlet to Waquoit Bay, which remains open. The new inlet exerts only minor effects on circulation within the Bay, but did create localized damage to dune and eelgrass habitats near the new inlet. The mixing of the water column released major amounts of nutrients that were held within the macroalgal canopy and upper sediments, into the upper layers, and prompted a short-lived (2-3 d) phytoplankton bloom. Biomass of unattached macroalgae was not affected by Bob. Respiration and nitrogen content of the dominant macroalgal species were elevated after passage of the storm, but returned to normal rates after several days. Nearly all above-sediment eelgrass biomass was removed, but returned to previous biomass during the next growing season. There was no visible damage to fringing salt marsh habitats. Damage to aquatic animals appears to have been minimal. A small decrease in water temperature and increased respiration by macroalgae led to decreased total net ecosystem production and increased net ecosystem respiration, but the decreases disappeared after 2 d.The effects of Hurricane Bob seemed more intense and protracted on land than on aquatic ecosystems. Recovery from the various distubances took hours to days in the aquatic system, but months to decades in terrestrial components. Rigid, larger organisms attached or rooted to substrates seem most subject to storm-related disturbances.

The animal-habitat relationships and seasonal dynamics of the benthic macroinfauna were investigated from November 1986 to October 1988 in the Great Sippewissett salt marsh (Massachusetts, USA), Total macrofaunal abundance varied seasonally, displaying a peak in late spring and early summer, then declining sharply during late summer and recovering briefly in fall before collapsing in winter. Three macroinfaunal assemblages were found in the marsh, distributed along gradients of environmental factors. These included a sandy non-organic sediment assemblage, a sandy organic sediment assemblage and a muddy sediment assemblage. The species groups characteristic of unstable sandy non-organic sediments included the polychaetes Leitoscoloplos fragilis, Aricidea jefreyssi, Magelona rosea and Streptosyllis verrilli, the oligochaete Paranais litoralis, and the crustacean Acanthohaustorius millsi. Sandy organic sediments were characterized by the polychaetes Marenzelleria viridis, Capitella capitata, Neanthes succinea, N. arenaceodonta, Polydora ligni and Heteromastus filiformis, the oligochaete Lumbricillus sp., and the mollusc Gemma gemma. In muddy sites, the polychaete Streblospio benedicti and the oligochaetes Paranais litoralis and Monopylephorus evertus were the dominant species. Secondary production of benthic macroinfauna in each of these habitats was estimated. The highest values of biomass and production were recorded in the sandy organic sediments. Secondary production was estimated to be 1850 kJ m(-2) yr(-1) in sandy organic areas, but only 281 kJ m(-2) yr(-1) in sandy non-organic areas and 113 kJ m(-2) yr(-1) in muddy areas. This results in an area-weighted average production of 505 kJ m(-2) yr(-1) for the unvegetated areas of the marsh. The Great Sippewissett salt marsh has an area of 483 800 m(2), the total secondary production of the macroinfauna for the whole unvegetated area of the marsh was estimated as 4651 kg dry wt yr(-1), expressed as somatic growth. This production value seems consistent with production data obtained for other intertidal North Atlantic environments.

Are benthic marine food webs controlled by predation (top-down) or resources (bottom-up)? Although both top-down and bottom-up processes operate in all ecosystems, the aquatic literature on communities has been dominated by early work done on rocky or hard substrates, which emphasizes top-down controls. Further research to assess the importance of resources on food webs of these communities is needed. Manipulative experiments in which top-down and bottom-up factors are simultaneously varied in the field should be undertaken is to adequately evaluate is relative importance of predation and resources. Our work on the benthos of Great Sippewissett Salt Marsh in Massachusetts, USA, examined the effects of both nutrient additions to increase resources, and caging to reduce predation by epibenthic fish and crabs. It illustrates the value of such field manipulations in evaluating controls on aquatic food webs.

Previous articleNext article No AccessECOLOGY: BIOGEOCHEMISTRY AND NUTRIENT CYCLINGEffects of Nitrogen Loading and Salt Marsh Habitat on Gross Primary Production and Chlorophyll a in Estuaries of Waquoit BayD. W. Callaway, I. Valiela, K. Foreman, and L. A. SoucyD. W. Callaway, I. Valiela, K. Foreman, and L. A. SoucyPDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Biological Bulletin Volume 189, Number 2October 1995 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.1086/BBLv189n2p254 Views: 26Total views on this site Copyright © 1995 by Marine Biological LaboratoryPDF download Crossref reports no articles citing this article.

Population dynamics and production of the spionid polychaete Marenzelleria viridis were studied at Great Sippewissett salt marsh (Massachusetts, USA) for two years. Marenzelleria viridis was the main contributor in biomass and production to the macroinfaunal assemblages of the sandy organic sediments of the marsh. Marenzelleria viridis spawned during the cold part of the year and the appearance of settled larvae on sediments was observed from January to May. The density of M. viridis rose sharply from winter to late spring followed by a striking drop through summer. The estimated mean annual production of M. viridis was 60 . 0 g dry weight m(2) during the first year and 26 . 3 g dry weight m(2) during the second year. The population of M. viridis is affected by different processes during the year. The number of initial recruits seems to be largely governed by meteorological conditions. The numbers of recruits are then affected by competition for resources, and later, as predators become active, predation pressure determines the abundance of the population of M. viridis.

Previous articleNext article No AccessECOLOGY: BIOGEOCHEMISTRY AND NUTRIENT CYCLINGThe Effect of Residential and Forested Watershed Land Cover on Nutrient Loading to Hamblin and Jehu Ponds, Waquoit Bay, MassachusettsS. A. Chaplin, C. H. MacGregor, I. Valiela, K. Foreman, and L. SoucyS. A. Chaplin Search for more articles by this author , C. H. MacGregor Search for more articles by this author , I. Valiela Search for more articles by this author , K. Foreman Search for more articles by this author , and L. Soucy Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Biological Bulletin Volume 189, Number 2October 1995 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.1086/BBLv189n2p247 Views: 11Total views on this site Copyright © 1995 by Marine Biological LaboratoryPDF download Crossref reports no articles citing this article.

Previous articleNext article No AccessECOLOGY: FISH AND INVERTEBRATESDifferences in Benthic Invertebrate Assemblages in Two Estuaries of Waquoit Bay Receiving Disparate Nutrient LoadsR. Sárda, K. Foreman, and I. ValielaR. Sárda Search for more articles by this author , K. Foreman Search for more articles by this author , and I. Valiela Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Biological Bulletin Volume 189, Number 2October 1995 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.1086/BBLv189n2p245 Views: 7Total views on this site Copyright © 1995 by Marine Biological LaboratoryPDF download Crossref reports no articles citing this article.

Previous articleNext article No AccessECOLOGY: PHYTOPLANKTON DYNAMICSThe Effects of Wind Speed and Direction on Stratification and Phytoplankton Production in an Estuary of Waquoit Bay, MassachusettsL. Z. Santiago Vázquez, J. L. Boxhill, T. R. Harrison, J. N. Kremer, and K. ForemanL. Z. Santiago Vázquez Search for more articles by this author , J. L. Boxhill Search for more articles by this author , T. R. Harrison Search for more articles by this author , J. N. Kremer Search for more articles by this author , and K. Foreman Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Biological Bulletin Volume 187, Number 2October 1994 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.1086/BBLv187n2p285 Views: 22Total views on this site Copyright © 1994 by Marine Biological LaboratoryPDF download Crossref reports no articles citing this article.

Previous articleNext article No AccessECOLOGY: PHYTOPLANKTON DYNAMICSDaily Variation in Phytoplankton Production in Two Subestuaries of Waquoit Bay, MassachusettsJ. L. Boxhill, L. S. Vázquez, T. R. Harrison, K. Foreman, and J. N. KremerJ. L. Boxhill Search for more articles by this author , L. S. Vázquez Search for more articles by this author , T. R. Harrison Search for more articles by this author , K. Foreman Search for more articles by this author , and J. N. Kremer Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Biological Bulletin Volume 187, Number 2October 1994 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.1086/BBLv187n2p284 Views: 8Total views on this site Copyright © 1994 by Marine Biological LaboratoryPDF download Crossref reports no articles citing this article.

Previous articleNext article No AccessECOLOGY: IMPACT OF NUTRIENT LOADING ON ESTUARIES AND MARSHESDissolved Organic Nitrogen in Groundwater Bordering Estuaries of Waquoit Bay, Massachusetts: Relations with Watershed Landscape MosaicsM. Rudy, K. McDonnell, I. Valiela, and K. ForemanM. Rudy Search for more articles by this author , K. McDonnell Search for more articles by this author , I. Valiela Search for more articles by this author , and K. Foreman Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Biological Bulletin Volume 187, Number 2October 1994 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.1086/BBLv187n2p278 Views: 7Total views on this site Copyright © 1994 by Marine Biological LaboratoryPDF download Crossref reports no articles citing this article.

Previous articleNext article No AccessECOLOGY: PHYTOPLANKTON DYNAMICSComparison of Phytoplankton and Ecosystem Gross Production in the Quashnet River, an Estuary of Waquoit Bay, MassachusettsT. R. Harrison, J. L. Boxhill, L. Z. Santiago Vázquez, K. Foreman, and J. N. KremerT. R. Harrison Search for more articles by this author , J. L. Boxhill Search for more articles by this author , L. Z. Santiago Vázquez Search for more articles by this author , K. Foreman Search for more articles by this author , and J. N. Kremer Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmailPrint SectionsMoreDetailsFiguresReferencesCited by The Biological Bulletin Volume 187, Number 2October 1994 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.1086/BBLv187n2p287 Views: 12Total views on this site Copyright © 1994 by Marine Biological LaboratoryPDF download Crossref reports no articles citing this article.

Previous articleNext article No AccessECOLOGY: IMPACT OF NUTRIENT LOADING ON ESTUARIES AND MARSHESThe Effect of Coastal Land Use on Inorganic Nutrient Concentrations in Groundwater Entering Estuaries of Waquoit Bay, MassachusettsK. McDonnell, M. Rudy, I. Valiela, and K. ForemanK. McDonnell Search for more articles by this author , M. Rudy Search for more articles by this author , I. Valiela Search for more articles by this author , and K. Foreman Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmailPrint SectionsMoreDetailsFiguresReferencesCited by The Biological Bulletin Volume 187, Number 2October 1994 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.1086/BBLv187n2p276 Views: 12Total views on this site Citations: 4Citations are reported from Crossref Copyright © 1994 by Marine Biological LaboratoryPDF download Crossref reports the following articles citing this article: C. H. MacGregor , S. A. Chaplin , and I. Valiela Land Cover Effects on Inorganic Nutrients in Groundwater and the Role of Salt Marshes in Interception of Land-Derived Nutrients Entering Estuaries of Waquoit Bay, Massachusetts, The Biological Bulletin 189, no.22 (Sep 2016): 248–249.https://doi.org/10.1086/BBLv189n2p248M. Rudy, K. McDonnell, I. Valiela, and K. Foreman Dissolved Organic Nitrogen in Groundwater Bordering Estuaries of Waquoit Bay, Massachusetts: Relations with Watershed Landscape Mosaics, The Biological Bulletin 187, no.22 (Sep 2016): 278–279.https://doi.org/10.1086/BBLv187n2p278A. Horne, J. McClelland, and I. Valiela The Growth and Consumption of Macroalgae in Estuaries: The Role of Invertebrate Grazers Along a Nutrient Gradient in Waquoit Bay, Massachusetts, The Biological Bulletin 187, no.22 (Sep 2016): 279–280.https://doi.org/10.1086/BBLv187n2p279A. Chalfoun, J. McClelland, and I. Valiela The Effect of Nutrient Loading on the Growth Rate of Two Species of Bivalves, Mercenaria mercenaria and Mya arenaria, in Estuaries of Waquoit Bay, Massachusetts, The Biological Bulletin 187, no.22 (Sep 2016): 281–281.https://doi.org/10.1086/BBLv187n2p281

Previous articleNext article No AccessECOLOGY: IMPACT OF NUTRIENT LOADING ON ESTUARIES AND MARSHESLong-Term Changes of Macroinfaunal Assemblages in Experimentally Enriched Salt Marsh Tidal CreeksR. Sardá, K. Foreman, and I. ValielaR. Sardá Search for more articles by this author , K. Foreman Search for more articles by this author , and I. Valiela Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Biological Bulletin Volume 187, Number 2October 1994 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.1086/BBLv187n2p282 Views: 6Total views on this site Copyright © 1994 by Marine Biological LaboratoryPDF download Crossref reports no articles citing this article.