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: A conceptual model was developed and used to identify the linkages among watershed-scale stressors, physical and chemical exposures, and biological responses of tidal creeks to human development at the watershed scale and provides a visual representation of the manner in which human population growth is linked to changes in the physiochemical environment.
254 citations
"Effects of habitat quality on secon..." refers background in this paper
...…input and periodic hypoxia (typically at night when respiration exceeds oxygen production) impact the macrobenthic community structure and function, reducing diversity and selecting for more hypoxia-tolerant and opportunistic fauna (Lerberg et al. 2000; Holland et al. 2004; Gillett et al. 2007)....
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...…due to excess nutrient inputs from anthropogenic alterations of upland watersheds and atmospheric deposition (Nixon 1995; Dauer et al. 2001; Holland et al. 2004), there is a concurrent decrease in the amount of food available to benthivoric nekton, which are important ecological and…...
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...…for contaminant measurement is simple and can be done with broad spatial and temporal coverage (e.g., Long and Chapman 1985; Hyland et al. 1999; Holland et al. 2004), processing of large numbers of samples requires very specialized equipment (atomic adsorption spectrophotometry, gas…...
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...While these characteristics make them productive, they are also easily disturbed and are often the first portions of the estuary to show signs of anthropogenic degradation (e.g., Lerberg et al. 2000; Holland et al. 2004)....
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...The consensus from these studies is that most of the species of nekton that normally inhabit a particular area will continue to associate with the same, moderately degraded habitat, but at lower densities (Burke et al. 1993; Peterson et al. 2000; Holland et al. 2004)....
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TL;DR: In situ tracer experiments conducted on the North Carolina continental slope reveal that tube-building worms (Polychaeta: Maldanidae) can, without ingestion, rapidly subduct freshly deposited, algal carbon ( 13 C-labeled diatoms) and inorganic materials (slope sediment and glass beads) to depths of 10 cm or more in the sediment column.
Abstract: In situ tracer experiments conducted on the North Carolina continental slope reveal that tube-building worms (Polychaeta: Maldanidae) can, without ingestion, rapidly subduct freshly deposited, algal carbon ( 13 C-labeled diatoms) and inorganic materials (slope sediment and glass beads) to depths of 10 cm or more in the sediment column. Transport over 1.5 days appears to be nonselective but spatially patchy, creating localized, deep hotspots. As a result of this transport, relatively fresh organic matter becomes available soon after deposition to deep-dwelling microbes and other infauna, and both aerobic and anaerobic processes may be enhanced. Comparison of tracer subduction with estimates from a diffusive mixing model using 234 Th-based coefficients, suggests that maldanid subduction activities, within 1.5 d of particle deposition, could account for 25-100% of the mixing below 5 cm that occurs on 100-day time scales. Comparisons of community data from the North Carolina slope for different places and times indicate a correlation between the abundance of deep-dwelling maldanids and the abundance and the dwelling depth in the sediment column of other infauna. Pulsed inputs of organic matter occur frequently in margin environments and maldanid polychaetes are a common component of continental slope macrobenthos. Thus, the activities we observe are likely to be widespread and significant for chemical cycling (natural and anthropogenic materials) on the slope. We propose that species like maldanids, that rapidly redistribute labile organic matter within the seabed, probably function as keystone resource modifiers. They may exert a disproportionately strong influence (relative to their abundance) on the structure of infaunal communities and on the timing, location and nature of organic matter diagenesis and burial in continental margin sediments.
253 citations
TL;DR: Overall, a network representation is a suitable methodology for inter-ecosystem comparisons and there is an inverse correlation between the Finn Cycling Index (FCI) and the normalized internal ascendancy or system maturity.
Abstract: We compare six marine ecosystems worldwide, using a network analysis of carbon flows for the Swartkops and Ems estuaries, Chesapeake Bay, the Baltic Sea and the Peruvian and Benguela upwelling regions. We find that there is an inverse correlation between the Finn Cycling Index (FCI) and the normalized internal ascendancy or system maturity (A $\_{\text{i}}$ :C $\_{\text{i}}$ ). We also show that there is a clear distinction between system maturity (A $\_{\text{i}}$ :C $\_{\text{i}}$ ) and the production: biomass (P:B) ratio; in upwelling systems the P:B and A $\_{\text{i}}$ :C $\_{\text{i}}$ ratios are both high, whereas in estuarine systems the P:B ratio is low. The P:B ratio thus cannot be used as an indicator of marine ecosystem evolution. Contrary to current views on ecosystems, the aggregate amount of cycling of materials, such as carbon, is not seen as an indication of system maturity but rather of stress. The reason that higher stressed systems are associated with a higher throughout or FCI could be because perturbations frequently impact higher-level species to a greater extent than the lower trophic components. Any release of standing biomass from these higher levels could therefore be taken up through increased recycling via short intense loops. Overall, we conclude that a network representation is a suitable methodology for inter-ecosystem comparisons.
247 citations
242 citations
"Effects of habitat quality on secon..." refers background in this paper
...Changes in habitat quality for soft-sediment macrobenthic communities of temperate estuaries have been shown to produce predictable changes in abundance, biomass, and community composition (e.g., Bilyard 1987; Warwick 1988; Peterson et al. 1996)....
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...…Program, European Union [EU] Water Framework Directive) use macrobenthic communities as their target because of their relatively sessile nature, length of lifespan, and thei varied, important ecological functions they provide (Bilyard 1987; Dauer 1993; Weisberg et al. 1997; Casazza et al. 2002)....
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TL;DR: It is demonstrated that acidification of the samples results in a decrease in carbon stable isotope values for sedimentary organic matter, suspended particulate organic Matter, plankton and invertebrates with carbonated structures, so sample acidification for carbon analysis in these compartments should be avoided.
230 citations