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: It is suggested that the major effects on benthic fauna result from hypoxia rather than organic enrichment per se and suggests that the P-R model is descriptive rather than predictive, which is widely reported but actual predictions of the model have rarely been tested.
Abstract: Eutrophication is one of the most severe and widespread forms of disturbance affecting coastal marine systems. Whilst there are general models of effects on benthos, such as the Pearson-Rosenberg (P-R) model, the models are descriptive rather than predictive. Here we first review the process of increased organic matter production and the ensuing sedimentation to the seafloor. It is shown that there is no simple relationship between nutrient inputs and the vertical flux of particulate organic matter (POM). In particular, episodic hydrographic events are thought to be the key factor leading to high rates of sedimentation and accompanying hypoxia. We extend an earlier review of effects of hypoxia to include organisms living in the water column. In general, fishes are more sensitive to hypoxia than crustaceans and echinoderms, which in turn are more sensitive than annelids, whilst molluscs are the least sensitive. Growth is affected at oxygen concentrations between 6.0 and 4.5 mg O 2 l -1 , other aspects of metabolism are affected at between 4 and 2 mg O 2 l -1 and mortality occurs where concentrations are below 2.0 to 0.5 mg O 2 l -1 . Field studies, however, show that complex behavioural changes also occur as hypoxia increases, and these are described herein. The areas where hypoxia occurs are frequently areas that are stagnant or with poor water exchange. Thus again, hydrographic factors are key processes determining whether or not hypoxia and eutrophication occur. Tolerance to ammonia and hydrogen sulphide is also reviewed, as these substances are found at near zero concentrations of oxygen and are highly toxic to most organisms. However, the effects of interactions between oxygen, ammonia and hydrogen sulphide only occur below oxygen concentrations of ca. 0.5 mg O 2 l -1 , since only below this concentration are hydrogen sulphide and oxygen released into the water. Models of eutrophication and the generation of hypoxia are discussed, and in particular the P-R model is analysed. Although agreement with the model is widely reported the actual predictions of the model have rarely been tested. Our review suggests that the major effects on benthic fauna result from hypoxia rather than organic enrichment per se and suggests that the P-R model is descriptive rather than predictive. Finally, a managerial tool is proposed, based on the stages of effects of hypoxia and organic enrichment suggested by the P-R model and on an earlier study. The proposed strategy involves rapid assessment tools and indicates where more detailed surveys are needed. Managers are advised that remedial action will not produce rapid results and that recovery from eutrophication will probably take decades. Thus it is essential to detect potential hypoxia and eutrophication effects at early stages of development.
938 citations
"Effects of habitat quality on secon..." refers background in this paper
...…or ammonia) was hypothesized to be primary stressor to the macrobenthos (e.g., Fenchel and Riedl 1970; Pearson and Rosenberg 1978; Jørgensen 1996; Gray et al. 2002); as opposed to persistent hypoxia associated with deeper, vertically stratified portions of Chesapeake Bay and its tributaries…...
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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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...…(e.g., sulfides or ammonia) 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…...
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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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TL;DR: On both the basis of biomass and biogeochemical reactivity, benthic microalgae play significant roles in system productivity and trophic dynamics, as well as such habitat characteristics as sediment stability.
Abstract: The microphytobenthos consists of unicellular eukaryotic algae and cyanobacteria that grow within the upper several millimeters of illuminated sediments, typically appearing only as a subtle brownish or greenish shading. The surficial layer of the sediment is a zone of intense microbial and geochemical activity and of considerable physical reworking. In many shallow ecosystems, the biomass of benthic microalgae often exceeds that of the phytoplankton in the overlying waters. Direct comparison of the abundance of benthic and suspended microalgae is complicated by the means used to measure biomass and by the vertical and horizontal distribution of the microphytobenthos in the sediment. Where biomass has been estimated as chlorophyll a, there may be negligible to large (40%) error due to interference by degradation products, except where chlorophyll is measured by high-performance liquid chromatography. The vertical distribution of microphytobenthos, aside from mat-forming species, is determined by the opposing effects of their vertical migration, which tends to concentrate them near the surface, and physical mixing by overlying currents, which tends to cause an even vertical distribution through the mixed layer of sediment. Uncertainties in vertical distribution are compounded by frequently patchy horizontal distribution. Under-sampling on small (<1 m) scales can lead to errors in the estimate that are comparable to the ranges of seasonal and geographic variation. These uncertainties are compounded by biases in the techniques used to estimate production by the microphytobenthos. In most environments studied, biomass (as chlorophyll a) and light availability appear to be the principal determinants of benthic primary production. The effect of variable light intensities on integral production can be described by a functional response curve. When normalized to the chlorophyll content of the surficial sediment, the residual variation in the data described by the functional response curve is due to changes in the chlorophyll-specific response to irradiance. Production by the benthos is often a significant fraction of production in the water column and microphytobenthos may contribute directly to water column production when they are resuspended. Thus on both the basis of biomass and biogeochemical reactivity, benthic microalgae play significant roles in system productivity and trophic dynamics, as well as such habitat characteristics as sediment stability. *** DIRECT SUPPORT *** A01BY074 00003
894 citations
"Effects of habitat quality on secon..." refers background in this paper
...…(Cummins and Wuycheck 1971) that are supported by high levels of benthic and planktonic primary production (Tenore 1988; Cloern et al. 1996; MacIntyre et al. 1996; Miller et al. 1996), as well as upland and salt marsh production (Goñi et al. 1997; Mitsch and Gosselink 2000; Seitzinger et…...
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TL;DR: In this paper, Long-term observation and research in San Francisco Bay illustrates some patterns of phytoplankton spatial and temporal variability and the underlying mechanisms of this variability.
Abstract: Phytoplankton blooms are prominent features of biological variability in shallow coastal ecosystems such as estuaries, lagoons, bays, and tidal rivers. Long-term observation and research in San Francisco Bay illustrates some patterns of phytoplankton spatial and temporal variability and the underlying mechanisms of this variability. Blooms are events of rapid production and accumulation of phytoplankton biomass that are usually responses to changing physical forcings originating in the coastal ocean (e.g., tides), the atmosphere (wind), or on the land surface (precipitation and river runoff). These physical forcings have different timescales of variability, so algal blooms can be short-term episodic events, recurrent seasonal phenomena, or rare events associated with exceptional climatic or hydrologic conditions. The biogeochemical role of phytoplankton primary production is to transform and incorporate reactive inorganic elements into organic forms, and these transformations are rapid and lead to measurable geochemical change during blooms. Examples include the depletion of inorganic nutrients (N, P, Si), supersaturation of oxygen and removal of carbon dioxide, shifts in the isotopic composition of reactive elements (C, N), production of climatically active trace gases (methyl bromide, dimethylsulfide), changes in the chemical form and toxicity of trace metals (As, Cd, Ni, Zn), changes in the biochemical composition and reactivity of the suspended particulate matter, and synthesis of organic matter required for the reproduction and growth of heterotrophs, including bacteria, zooplankton, and benthic consumer animals. Some classes of phytoplankton play special roles in the cycling of elements or synthesis of specific organic molecules, but we have only rudimentary understanding of the forces that select for and promote blooms of these species. Mounting evidence suggests that the natural cycles of bloom variability are being altered on a global scale by human activities including the input of toxic contaminants and nutrients, manipulation of river flows, and translocation of species. This hypothesis will be a key component of our effort to understand global change at the land-sea interface. Pursuit of this hypothesis will require creative approaches for distinguishing natural and anthropogenic sources of phytoplankton population variability, as well as recognition that the modes of human disturbance of coastal bloom cycles operate interactively and cannot be studied as isolated processes.
758 citations
TL;DR: The idea that microbes attached to sediment and detritus particles constitute the major food source for deposit feeders is being replaced by more complex models that incorporate interactions between animals and the food sources in the sedimentary matrix.
Abstract: Deposit-feeding animals acquire food by swallowing large volumes of sediment. Possible food sources include organic debris and sediment-associated microbes. The relative importance of these classes of food is currelty an area of active research. The idea that microbes attached to sediment and detritus particles constitute the major food source for deposit feeders is being replaced by more complex models that incorporate interactions between animals and the food sources in the sedimentary matrix. Many deposit feeders appear to require both microbial and detrital foods. Deposit feeders display many adaptations appear to be cosistent with the energy maximization principle of optimal foraging theory, but rigorous testing of foraging models has proven to be difficult. Elucidation of deposit-feeding strategies may develop as optimal foraging theory is integrated with physiological energetics.
618 citations
"Effects of habitat quality on secon..." refers background in this paper
...…proximity to the uplands results in the delivery of large amounts of detritus from salt marshes and other upland plants, which support benthic bacteria and deposit feeding organisms (Heip et al. 1995; Lopez and Levinton 1987), as well as a large amount of nutrients and dissolved organic matter....
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