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Effects of habitat quality on secondary production in shallow estuarine waters and the consequences for the benthic-pelagic food web

01 Jan 2010-

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

Topics: Benthic zone (55%), Pelagic zone (54%), Ecology (disciplines) (50%), Habitat (50%)

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Journal Article
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


Journal ArticleDOI
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.

3 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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Journal ArticleDOI
David M. Post1
01 Mar 2002-Ecology
Abstract: The stable isotopes of nitrogen (8'5N) and carbon (8'3C) provide powerful tools for estimating the trophic positions of and carbon flow to consumers in food webs; however, the isotopic signature of a consumer alone is not generally sufficient to infer trophic position or carbon source without an appropriate isotopic baseline. In this paper, I develop and discuss methods for generating an isotopic baseline and evaluate the assump- tions required to estimate the trophic position of consumers using stable isotopes in multiple ecosystem studies. I test the ability of two primary consumers, surface-grazing snails and filter-feeding mussels, to capture the spatial and temporal variation at the base of aquatic food webs. I find that snails reflect the isotopic signature of the base of the littoral food web, mussels reflect the isotopic signature of the pelagic food web, and together they provide a good isotopic baseline for estimating trophic position of secondary or higher trophic level consumers in lake ecosystems. Then, using data from 25 north temperate lakes, I evaluate how 815N and 8'3C of the base of aquatic food webs varies both among lakes and between the littoral and pelagic food webs within lakes. Using data from the literature, I show that the mean trophic fractionation of b'5N is 3.4%o (1 SD = 1%M) and of 8'3C is 0.4%o (1 SD = 1.3%o), and that both, even though variable, are widely applicable. A sen- sitivity analysis reveals that estimates of trophic position are very sensitive to assumptions about the trophic fractionation of '5 N, moderately sensitive to different methods for gen- erating an isotopic baseline, and not sensitive to assumptions about the trophic fractionation of 8'3C when 8'3C is used to estimate the proportion of nitrogen in a consumer derived from two sources. Finally, I compare my recommendations for generating an isotopic baseline to an alternative model proposed by M. J. Vander Zanden and J. B. Rasmussen. With an appropriate isotopic baseline and an appreciation of the underlying assumptions and model sensitivity, stable isotopes can help answer some of the most difficult questions in food web ecology.

5,071 citations


DOI
01 Jan 1978

3,442 citations


"Effects of habitat quality on secon..." refers background or methods in this paper

  • ...…is thought to be the aspect of eutrophication that was affecting the macrobenthos (e.g., Fenchel and Riedl 1970; Gray et al. 2002; Jørgensen 1996; Pearson and Rosenberg 1978); as opposed to persistent, stratification-driven hypoxia, which is typically observed in deeper parts of Chesapeake Bay…...

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  • ...Rakocinski and Zapf (2005) put forth a conceptual model of macrobenthic function related to eutrophication in marine ecosystems, based largely upon the paradigm of Pearson and Rosenberg (1978)....

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  • ...…in macrobenthic community structure: shifting from a diverse array large and small bivalves, crustaceans and annelids to a low diversity community composed primarily of small, opportunistic polychaete and oligochaete annelids (Gray et al. 2002; Pearson and Rosenberg 1978; Schwinghamer 1988)....

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  • ...Increased organic matter input to the benthos and subsequent increases in sulfides and ammonia have been linked with reduced species and trophic guild diversity, abundance, biomass, and the depth at which macrofauna are found (Pearson and Rosenberg 1978; Jørgensen 1996l; Gray et al. 2002)....

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  • ...Furthermore, degradation-driven changes in the prey community structure towards smaller, less motile fauna (e.g., Pearson and Rosenberg 1978; González-Oreja and Saiz-Salinas 1999; Gray et al. 2002) may limit the utility of the 2° production that is available as a food source to benthivoric nekton....

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Book
01 Jan 2006
Abstract: Isotope Notation and Measurement.- Using Stable Isotope Tracers.- Isotope Chi.- Mixing.- Isotope Additions.- Fractionation.- Scanning the Future.

1,928 citations


Journal ArticleDOI
TL;DR: The statistical literature on tests to compare treatments after the analysis of variance is reviewed, and the use of these tests in ecology is examined, and particular strategies are recommended.
Abstract: The statistical literature on tests to compare treatments after the analysis of variance is reviewed, and the use of these tests in ecology is examined. Monte Carlo simulations on normal and lognormal data indicate that many of the tests commonly used are inappropriate or inefficient. Particular tests are recommended for unplanned multiple comparisons on the basis of controlling experimentwise type I error rate and providing maximum power. These include tests for parametric and nonparametric cases, equal and unequal sample sizes, homogeneous and heterogeneous variances, non-independent means (repeated measures or adjusted means), and comparing treatments to a control. Formulae and a worked example are provided. The problem of violations of assumptions, especially variance heterogeneity, was investigated using simulations, and particular strategies are recommended. The advantages and use of planned comparisons in ecology are discussed, and the philosophy of hypothesis testing with unplanned multiple comparisons is consid- ered in relation to confidence intervals and statistical estimation.

1,819 citations


"Effects of habitat quality on secon..." refers background in this paper

  • ...These multiple comparisons obviously lead to a potential increase in Type I error (Day and Quinn 1989; Neter et al. 1990), but there was greater concern with minimizing the Type II error in the analyses and the potential of obscuring any caging artifacts in the interaction terms....

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01 Jan 1979
Abstract: Current information on the eating habits of polychaetes are reviewed. The polychaete families are arranged in alphabetical order and the feeding habits of each are summarized. Feeding guilds are defined based on a joint consideration of food, eating habits, and locomotory patterns. An understanding of the sympatric occurrance in the deep sea of several congeners with extremely limited morphological differentiation was of particular interest. This review contains 355 references, 23 figures, and 33 tables.

1,775 citations