DOI•
Effects of habitat quality on secondary production in shallow estuarine waters and the consequences for the benthic-pelagic food web
01 Jan 2010-
TL;DR: In this article, the authors discuss the impact of habitat degradation on second-person production in the Saline Estuary and the Tidal Freshwater watershed in the state of Illinois.
Abstract: ................................................................................................................... ix CHAPTER I. ASSESSMENT OF HABITAT DEGRADATION IN THE COASTAL ZONE AND THE CONSEQUENCES FOR RESIDENT BlOT A .................................. .2 Introduction .............................................................................................................. 3 Motivations and Investigative Approach ............................................................... 12 Literature Cited ...................................................................................................... 15 CHAPTER II. THE INFLUENCE OF HABIT AT QUALITY ON SECONDARY PRODUCTION IN SHALLOW ESTUARINE WATERS ............................................ 28 Abstract .................................................................................................................. 29 Introduction ............................................................................................................ 30 Materials and Methods ........................................................................................... 33 Site Selection ................................................................................................... 33 Data Collection ..................................................................... , .......................... 34 Analysis ............................................................................................................ 37 Results .................................................................................................................... 39 Discussion .............................................................................................................. 41 Interpreting the Saline Estuary ........................................................................ .42 Interpreting the Tidal Freshwater .................................................................... .46 Some Comments on Biodiversity and Productivity ........................................ .47 Conclusions ............................................................................................................ 49 Literature Cited ...................................................................................................... 50 CHAPTER Ill. THE INFLUENCE OF HABIT AT QUALITY AND MACROBENTHIC COMMUNITY COMPOSITION ON NEKTON UTILIZATION OF SECONDARY PRODUCTION AS A FOOD SOURCE ........................................................................ 68 Abstract .................................................................................................................. 69 Introduction ............................................................................................................ 70 Materials and Methods ........................................................................................... 74 Site Selection ................................................................................................... 7 4 Data Collection ................................................................................................ 74 Analysis ............................................................................................................ 77 Results .................................................................................................................... 80 Site Characterization ........................................................................................ 80
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Journal Article•
TL;DR: In this article, the stable isotope compositions (C, N, and S) of hve, senescent, and standing dead Spartina alterniflora were compared in order to determine the effects of aerial decomposition on the isotopic signature of aboveground S. alternjflora entering the food chain, which indicated that N2fixing microorganisms associdated with microalgal communities were an important source of N to salt marsh consumers.
Abstract: The stable isotope compositions (C, N, and S) of hve, senescent, and standing dead Spartina alterniflora were compared in order to determine the effects of aerial decomposition on the isotopic signature of aboveground S. dlterniflora tissue entering the food chain. Aerial decomposition of aboveground S. alterniflora resulted in a 6 to 18% increase in P S , and a 2 to 3 % decrease in 615N values; 613c values were unchanged. We describe mechanisms whereby the activity of fungi and epiphytic microorganisms may contribute to the observed shlfts in and 6I5N, respectively. The 613c value of salt marsh benthic and eplphytic microalgae ranged from -13.0% in summer to -17.6%0 in early spring. Average 6'\" values of microalgae and standing dead S. altemiflora were -0 3 and l.?%, respectively, reflecting the activity of NZ-fixing microorganisms. The 615N values for omnivorous and herbivorous salt marsh macrofauna ranged between 7.5 and 2.2% and for predatory Fundulus spp. averaged 9.2%. Given a presumptive + 3 % trophic shift in N assimilation, these results suggest that N2-fixing microorganisms associdted with microalgal communities were an important source of N to salt marsh consumers. The 6% 6'\"N, and 6\"'s values of primary producers were compared to the values of the following consumers: Fundulus spp., Uca spp., Ilyanassa obsoleta, and Littoraria irrorata. 6I3C VS 6 1 5 ~ and 613C vs 63JS dual isotope plots demonstrated that microalgae and standing dead S. alternjflora are important food resources in the North Carolina (USA) marshes we sampled. In addition, a compilation of literature values suggests that this is true in salt marshes throughout the East and Gulf coasts of North America. Future isotope studies of marsh food webs should include detrital Spartina spp. material in analyses of trophic structure.
9 citations
TL;DR: The ecological analysis showed that total phosphorus concentration, temperature and salinity were the main environmental parameters affecting community structure of the Parila lagoon, and six species listed as frequent have a potential to be used as indicators of habitat quality.
Abstract: The aim of the study was to describe epibenthic macroinvertebrates and demersal fish and to identify links between spatial patterns and habitat characteristics (sediment, salinity, oxygen and temperature). The research was performed in the Parila lagoon in Croatia; an important nursery ground where conditions in epibenthic community can have significant direct and indirect impact on fisheries. Diversity (30 species) and abundance (from 0 to 7 ind m−2) of epibenthic assemblages was low on all stations and showed remarkable seasonal changes. Such patchiness could support the estuarine quality paradox idea, i.e. the most abundant species are well adapted to changing conditions in a variable environment. The ecological analysis showed that total phosphorus concentration (TP), temperature (T) and salinity (S) were the main environmental parameters affecting community structure of the Parila lagoon. Six species listed as frequent (Nerophis ophidion, Zosterisessor ophiocephalus, Syngnathus typhle, Cerastoderma glaucum, Palaemon adspersus and Carcinus aestuarii) have a potential to be used as indicators of habitat quality. In terms of trophic diversity, community was dominated by carnivores and omnivores. Fish trophic index (above 2.7) indicated upward shift of the local food chain and towards mostly carnivorous species, while the absence of herbivorous species pointed to low environmental quality. The present study gives an insight into the current ecological conditions in the Parila lagoon. Further research about the sensitivity of these potential indicators to different types of pressure is necessary in order to select robust early-warning indicators framework.
4 citations
Cites background from "Effects of habitat quality on secon..."
...and economically important nekton that use such habitat during their lifecycle as nurseries (Gillet 2010)....
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...…ecological measurement of environmental disturbances that reflects in the ecological functioning, which in turn will be realized throughout the ecosystem via shifts in trophic relationships, nutrient cycling, and other key processes, and eventually provisioning of ecosystem services (Gillet 2010)....
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...In estuarine food webs, they represent a link between highly productive organic matter sources of the shallows and ecologically and economically important nekton that use such habitat during their lifecycle as nurseries (Gillet 2010)....
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...throughout the ecosystem via shifts in trophic relationships, nutrient cycling, and other key processes, and eventually provisioning of ecosystem services (Gillet 2010)....
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...real relationships in the ecosystem (Gillet 2010)....
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References
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TL;DR: The feeding behavior of three species of spionid polychaetes varied with water velocity, apparently in response to increased flux of suspended matter at high flows rather than to flow velocity alone.
Abstract: The feeding behavior of three species of spionid polychaetes varied with water velocity. At moderate flows the worms ceased deposit feeding, formed their feeding tentacles into helices, and lifted them into the water column to capture material in suspension. This behavior was apparently a response to increased flux of suspended matter at high flows rather than to flow velocity alone. Organisms capable of switching their feeding behavior may be common in dynamically variable benthic environments.
191 citations
"Effects of habitat quality on secon..." refers background in this paper
...…– those relatively non-mobile organisms that are capable of feeding upon organic matter collected from the water column or on the sediment surface, many of which are capable of switching between the two depending upon hydrodynamics and food availability (Pohlo 1982; Taghon et al. 1980)....
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TL;DR: The range in isotopic abundances and molecular compositions of the sediments was greater than that obtained from the plants, indicating that additional, presently unidentified sources of organic matter contribute to the Cape Lookout Bight sediments.
Abstract: We examined the isotopic compositions of fatty acids, sterols, and hydrocarbons isolated from three coastal macrophytes (Ze within each lipid class varied by up to 5.6%0. Trends in the isotopic compositions of lipids were consistent with #Xc compounds obtained from Z. marina were the most enriched in “C and those from J. roemerianus were tb: most depleted. The range in isotopic abundances and molecular compositions of the sediments was greater than that obtained from the plants, indicating that additional, presently unidentified sources of organic matter contribute to the Cape Lookout Bight sediments. Similarity between the signatures for suspended particulate matter and the sediments indicates that much of the sedimentary organic matter is derived from algal and bacterial sources. Bacterial sources of organic matter are likely greater during summer/early fall, and incorporation of 13C-enriched bacterial biomass may contribute to observed seasonal shifts in SY,,, in the surficial sediments.
175 citations
TL;DR: In this paper, a dual stable isotope study in an estuary heavily influenced by alluvial runoff was conducted to examine the influence of river-borne organic material on estuarine communities.
Abstract: To examine the influence of river-borne organic material on estuarine communities, we conducted a dual stable isotope study in an estuary heavily influenced by alluvial runoff. Despite significant alluvial influence, secondary production in Apalachicola Bay depends more upon estuarine primary production than upon a detrital food web supported by floodplain primary production. Two simple mixing models, floodplain-marine and floodplain-estuarine, indicated that the upper limits for the contribution of terrestrial organic matter to estuarine consumer diets averaged 37, 25, and 27% and 20, 19, and 25% for East Bay, Cat Point, and Dry Bar, respectively. Systematic δ 13 C variation of consumer organisms was found for differing locations and attributed to increasing influence of terrestrial organic matter and 13 C-depleted dissolved inorganic carbon (DIC) closer to the river mouth. The δ 34 S data exhibited significant variation with river flow that was attributed to an admixture of terrestrial floodplain detritus with estuarine and marine organic matter. Both δ 13 C and δ 34 S isotope data demonstrated clear distinctions between benthic and water column feeding types. Our results suggest that the estuary is dependent on riverine inflows to provide floodplain detritus during the high-flow period and dissolved nutrients for estuarine primary productivity during the low-flow season. Any alteration of river hydrology may adversely affect estuarine secondary production, especially during the low-flow period when the estuary is dependent on input of dissolved nutrients to maintain a high level of primary productivity.
172 citations
TL;DR: Using stable isotopes, this article assessed the effects of long-term sewage inputs within Boston Harbor and extending into adjacent Massachusetts Bay, and found that the incorporation of sewage-derived effluent particulates into sediments of the harbor and into Massachusetts Bay was apparent in the δ15N values of surface sediments and in sediment profiles.
169 citations
TL;DR: N. succinea was able to assimilate carbon from sterile plant detritus which suggests that some of the carbon needed to balance the budget may come from direct uptake of the plant substrate.
Abstract: A partial carbon budget was calculated for a population of the deposit feeding polychaete Nereis succinea (Frey and Leuckart) for a North Carolina, USA salt marsh in order to determine if the ingestion and assimilation of microbial carbon was sufficient to meet the carbon requirement. Carbon required by the population was estimated by calculating annual production, 2.1 g C m-2, and respiration, 9.4 g. There was no net release of dissolved organic carbon. Annual consumption of microbial carbon (as determined by ATP) was estimated to be 5.2 g m-2. Assimilation efficiency of heterotrophic, detrital microbes was estimated to be 57%. If this value is used for all the microbial carbon, then total assimilation was 3.0 g C m-2, or about one-fourth the carbon requirement. N. succinea was able to assimilate carbon from sterile plant detritus which suggests that some of the carbon needed to balance the budget may come from direct uptake of the plant substrate. Other possible additional sources of carbon include consumption of meiofauna and uptake of dissolved organic matter.
167 citations