Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Absence of an effect of freshwater input on the stable isotope and fatty acid signatures of intertidal filter-feeders

Absence of an effect of freshwater input on the stable isotope and fatty acid signatures of... Freshwater input is known to have the potential to influence marine pelagic and benthic communities through the export of nutrients, sediments and detritus. The increase in nutrients of riverine origin in coastal environments can enhance primary production in coastal areas, supporting a diverse and rich fauna. However, it is not clear how and to what extent these freshwater inputs influence marine populations. We investigated the potential effects of freshwater input on the diets of intertidal benthic organisms in situ on the east coast of South Africa, analysing their δ13C and δ15N stable isotope and fatty acid content. Specifically, we investigated the dietary regime of three barnacle and one mussel species in relation to their proximity to the mouths of large rivers. Strong dissimilarities among species were recorded with both techniques; however, no significant effect of freshwater input was observed for any of them. There are several possible explanations for these results, including rapid dilution, with fresh water near the river mouth being thoroughly mixed with seawater, resulting in a riverine influence being too weak to be detectable in the signatures of benthic populations. Our results contrast with a previous study conducted in the same area, where it was suggested that demersal organisms relied on freshwater-derived organic matter. Our study, however, showed no freshwater effect either within a few metres or tens of kilometres from the nearest large river mouths, supporting the notion that freshwater input does not play an important role for the benthic intertidal community in the ecosystems studied. Given that freshwater input is likely to diminish in the future, because of increased human abstraction of water, any potential effects of freshwater input on these marine populations are likely to be further reduced. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png African Journal of Marine Science Taylor & Francis

Absence of an effect of freshwater input on the stable isotope and fatty acid signatures of intertidal filter-feeders

Download PDF

Absence of an effect of freshwater input on the stable isotope and fatty acid signatures of intertidal filter-feeders

Abstract

Freshwater input is known to have the potential to influence marine pelagic and benthic communities through the export of nutrients, sediments and detritus. The increase in nutrients of riverine origin in coastal environments can enhance primary production in coastal areas, supporting a diverse and rich fauna. However, it is not clear how and to what extent these freshwater inputs influence marine populations. We investigated the potential effects of freshwater input on the diets of...
Loading next page...
 
/lp/taylor-francis/absence-of-an-effect-of-freshwater-input-on-the-stable-isotope-and-BhgbKw2XsD
Publisher
Taylor & Francis
Copyright
© 2016 NISC (Pty) Ltd
ISSN
1814-2338
eISSN
1814-232X
DOI
10.2989/1814232X.2016.1227277
Publisher site
See Article on Publisher Site

Abstract

Freshwater input is known to have the potential to influence marine pelagic and benthic communities through the export of nutrients, sediments and detritus. The increase in nutrients of riverine origin in coastal environments can enhance primary production in coastal areas, supporting a diverse and rich fauna. However, it is not clear how and to what extent these freshwater inputs influence marine populations. We investigated the potential effects of freshwater input on the diets of intertidal benthic organisms in situ on the east coast of South Africa, analysing their δ13C and δ15N stable isotope and fatty acid content. Specifically, we investigated the dietary regime of three barnacle and one mussel species in relation to their proximity to the mouths of large rivers. Strong dissimilarities among species were recorded with both techniques; however, no significant effect of freshwater input was observed for any of them. There are several possible explanations for these results, including rapid dilution, with fresh water near the river mouth being thoroughly mixed with seawater, resulting in a riverine influence being too weak to be detectable in the signatures of benthic populations. Our results contrast with a previous study conducted in the same area, where it was suggested that demersal organisms relied on freshwater-derived organic matter. Our study, however, showed no freshwater effect either within a few metres or tens of kilometres from the nearest large river mouths, supporting the notion that freshwater input does not play an important role for the benthic intertidal community in the ecosystems studied. Given that freshwater input is likely to diminish in the future, because of increased human abstraction of water, any potential effects of freshwater input on these marine populations are likely to be further reduced.

Journal

African Journal of Marine Science – Taylor & Francis

Published: Dec 2, 2016

Keywords: benthos; marine ecology; primary consumers; rocky shore; spatial scale; trophic ecology

References

  • The gas chromatograph in practical analyses of common and uncommon fatty acids for the 21st century
  • Permutation tests for multi-factorial analysis of variance
  • A new method for non-parametric multivariate analysis of variance
  • Influence of the Danube River inputs on C and N stable isotope ratios of the Romanian coastal waters and sediment (Black Sea)
  • Non-methylene-interrupted fatty acids from marine invertebrates: occurrence, characterization and biological properties
  • Storage metabolism in the Pacific oyster (Crassostrea gigas) in relation to summer mortalities and reproductive cycle (West Coast of France)
  • The horizontal zonation of two species of intertidal barnacle in South Africa
  • Studying trophic ecology in marine ecosystems using fatty acids: a primer on analysis and interpretation
  • Primary production: marine ecosystems
  • Eutrophication in Portuguese estuaries evidenced by δ15N of macrophytes
  • Intensification of extreme European summer precipitation in a warmer climate
  • Annual variations in river flow and primary production in the South San Francisco Bay Estuary (USA)
  • Marine protected areas export larvae of infauna, but not of bioengineering mussels to adjacent areas
  • Sedimentation in the cliff-bound, microtidal Mtamvuna Estuary, South Africa
  • Morphologic and facies trends through the fluvial–marine transition in tide-dominated depositional systems: a schematic framework for environmental and sequence-stratigraphic interpretation
  • Trophodynamic linkage between river runoff and coastal fishery yield elucidated by stable isotope data in the Gulf of Lions (NW Mediterranean)
  • Processes controlling the benthic food web of a mesotrophic bight (KwaZulu-Natal, South Africa) revealed by stable isotope analysis
  • Nutrient enrichment studies in a coastal plain estuary: phytoplankton growth in large-scale, continuous cultures
  • The effects of the filter-feeding clam Mercenaria mercenaria on carbon cycling in experimental marine mesocosms
  • Climate change impacts on marine ecosystems
  • Effects of river regulation and diversion on marine fish and invertebrates
  • δ13C measurements as indicators of carbon flow in marine and freshwater ecosystems
  • Impact of changes in flow of freshwater on estuarine and open coastal habitats and the associated organisms
  • An experimental study on variations in stable carbon and nitrogen isotope fractionation during growth of Mysis mixta and Neomysis integer
  • Filtration, respiration and assimilation in the black mussel Choromytilus meridionalis
  • How do riverine plumes of different sizes influence fish larvae: do they enhance recruitment?
  • The impacts of climate change in coastal marine systems
  • What happens to terrestrial organic matter in the ocean?
  • Effects of food quality on tissue-specific isotope ratios in the mussel Perna perna
  • Biogeographic and nearshore–offshore trends in isotope ratios of intertidal mussels and their food sources around the coast of southern Africa
  • Temporal and spatial variability in stable isotope ratios of SPM link to local hydrography and longer term SPM averages suggest heavy dependence of mussels on nearshore production
  • Direct FAME synthesis for rapid total lipid analysis from fish oil and cod liver oil
  • Organisms as ecosystem engineers
  • Effects of storage and preservation on the δ13C and δ15N signatures of selected marine organisms
  • Trophic structure of the marine food web at the Prince Edward Islands (Southern Ocean) determined by δ13C and δ15N analysis
  • Fatty acids as dietary tracers in benthic food webs
  • The function of marine critical transition zones and the importance of sediment biodiversity
  • Upwelling at the inshore edge of the Agulhas Current
  • Spatial and temporal variations in beach litter on the Transkei coast of South Africa
  • Changes in food web structure under the influence of increased anthropogenic nitrogen inputs to estuaries
  • Response of a rocky intertidal ecosystem engineer and community dominant to climate change
  • Rivers
  • The nutrient characteristics of the Natal Bight, South Africa
  • Stepwise enrichment of 15N along food chains: further evidence and the relation between δ15N and animal age
  • Changes in the deposition of terrestrial organic matter on the Laptev Sea shelf during the Holocene: evidence from stable carbon isotopes
  • The influence of land-use patterns in the Ruvu river watershed on water quality in the river system
  • Remineralization and nutrient cycling in coastal marine ecosystems
  • Mass and metabolism of a mussel bed
  • Hydrobiological studies on the Tugela River system
  • Temporal variability of nitrogen stable isotopes in primary uptake compartments in four streams differing in human impacts
  • Changes in fatty acid composition of Mytilus galloprovincialis (Lmk) fed on microalgal and wheat germ diets
  • Man-made changes in the freshwater input rates of Hudson and James Bays
  • A review of primary production and related processes on the Agulhas Bank
  • Does proximity to urban centres affect the dietary regime of marine benthic filter feeders?
  • Hierarchical effects of biogeography and upwelling shape the dietary signatures of benthic filter feeders
  • Temporal shifts in the fatty acid profiles of rocky intertidal invertebrates
  • Fatty acid profiles reveal temporal and spatial differentiation in diets within and among syntopic rocky shore suspension-feeders
  • Shelf currents, lee-trapped and transient eddies on the inshore boundary of the Agulhas Current, South Africa: their relevance to the KwaZulu-Natal sardine run
  • Freshwater-flow requirements of estuarine fisheries in tropical Australia: a review of the state of knowledge and application of a suggested approach
  • The mechanisms of filter feeding: some theoretical considerations
  • 15N natural abundance in oceanic suspended particulate matter
  • Transport of organic carbon in the world’s rivers
  • Sea level variability in South African estuaries
  • Coastal environmental impacts brought about by alterations to freshwater flow in the Gulf of Mexico
  • The uptake of organic matter and the release of inorganic nutrients by bivalve suspension feeder beds
  • Regionalization of daily flow characteristics in part of the Eastern Cape, South Africa
  • Comparison of feeding and biodeposition of three bivalves at different food levels
  • Application of organic carbon and nitrogen stable isotope and C/N ratios as source indicators of organic matter provenance in estuarine systems: evidence from the Tay estuary, Scotland
  • Fractionation and turnover of stable carbon isotopes in animal tissues: implications for δ13C analysis of diet
  • Autochthonous and allochthonous contributions to mesozooplankton diet in a tidal river and estuary: integrating carbon isotope and fatty acid constraints
  • Spatial and temporal variations of metals in Richards Bay Harbour (RBH), South Africa
  • The importance of estuarine-derived carbon for the nearshore marine environment: studies on two contrasting South African estuaries
  • Fate of nutrient enrichment on continental shelves as indicated by the C/N content of bottom sediments
  • River flow and fish abundance in a South African estuary
  • The pathway of the biosynthesis of non-methylene-interrupted dienoic fatty acids in molluscs