scholarly journals Estimating the value of mangrove leaf litter in sesarmid crab diets: the importance of fractionation factors

2020 ◽  
Vol 96 (3) ◽  
pp. 501-520
Author(s):  
Richard A MacKenzie ◽  
Nicole Cormier ◽  
Amanda W Demopoulos
Keyword(s):  
Food Web ◽  
Leaf Litter ◽  
Isotope Analysis ◽  
R Package ◽  
Enrichment Factors ◽  
Mangrove Forests ◽  
Web Studies ◽  
Carbon And Nitrogen ◽  
Trophic Enrichment ◽  
Species Specific

Sesarmid crabs play an important role in organic matter and carbon cycling of mangrove forests. Visual observations and gut content studies have verified that sesarmid crabs are feeding on mangrove leaves, yet stable isotopes of carbon and nitrogen (13C and 15N) have indicated that leaf litter is not assimilated as a food source. Sesarmid crabs tend to be much more enriched in 13C than leaf litter (0.9‰ – 11.6‰) and have C values that are often more like microphytobenthos (MPB). General 13C trophic enrichment factors (TEF; 0.1‰ – 0.5‰) suggest crabs feed more heavily on MPB. Field and laboratory-based evidence reveal that general 13C TEF for crabs feeding on mangrove leaves may be incorrect and much greater than 0.1‰ – 0.5‰. A food web study conducted annually over 2 yrs revealed a shift in the δ13C and δ15N of Parasesarma sp. crabs similar to mangrove leaves also sampled. This suggested Parasesarma sp. may be feeding more heavily on mangrove leaves than previously reported despite crabs being 4.4‰ – 11.6‰ more enriched in 13C than mangrove leaves. A laboratory feeding study confirmed that average 13C TEF between Parasesarma sp. and decayed Rhizophora sp. leaves was 3.3‰ (SE 0.5). The Stable Isotope Analysis in R package (SIAR) used with our TEF and the general 0.5‰ 13C TEF revealed that published TEFs may underestimate mangrove leaf contributions to sesarmid crab diets on average by 33.3% (SE 0.1) and overestimate MPB and epiphytic algal contributions by 31.3% (SE 0.1). Food web studies in mangroves and other ecosystems will continue to inaccurately identify important food resources or food web structures unless more accurate and species-specific isotope fractionation values are determined.

The Use of Carbon and Nitrogen Stable Isotope Analysis to Characterize Food Web Changes in Aquatic Systems for Reclamation of Oil Sands Process-Affected Materials

2009 ◽  
Vol 44 (4) ◽  
pp. 313-322 ◽  
Author(s):  
Monalisa Elshayeb ◽  
Michael D. MacKinnon ◽  
D. George Dixon ◽  
Michael Power
Keyword(s):  
Food Web ◽  
Oil Sands ◽  
Isotope Analysis ◽  
Naphthenic Acid ◽  
Carbon Sources ◽  
Nitrogen Isotope ◽  
Isotopic Signatures ◽  
Carbon And Nitrogen ◽  
Aquatic Food ◽  
Northern Alberta

Abstract One strategy for reclamation of oil sands leases in northern Alberta is the construction of lakes and wetlands by capping oil sands process-affected material (OSPM) with water. To assess this approach, experimental sites containing a range of OSPM have been constructed to monitor the evolution of the resulting aquatic habitats. Stable isotopes of carbon and nitrogen were used to assess the effects of OSPM on aquatic food webs. Carbon and nitrogen isotopic signatures of sediment, dissolved inorganic and organic carbon, particulate organic matter, periphyton, plants, plankton, aquatic invertebrates, and fish were used to assess differences related to the naphthenic acid (NA) concentration in OSPM and reference sites. NAs are a principal contaminant of concern in OSPM. Sites were grouped into low (0 to 4 mg/L), medium (4 to 15 mg/L), and high (>15 mg/L) NA concentrations. There were no significant differences in food web area or length among the three NA groupings. In most cases, carbon isotope analyses of samples from low, medium, and high NA concentration sites were not significantly different, suggesting that OSPM is not a significant contributor to food web carbon sources. Significant differences were found in nitrogen isotope signatures between low, medium, and high NA sites. Ammonia from OSPM is suggested as the main contributor to δ15N enrichment.

scholarly journals Closely Related Tree Species Differentially Influence the Transfer of Carbon and Nitrogen from Leaf Litter Up the Aquatic Food Web

Ecosystems ◽  
2014 ◽  
Vol 18 (2) ◽  
pp. 186-201 ◽  
Author(s):  
Zacchaeus G. Compson ◽  
Bruce A. Hungate ◽  
George W. Koch ◽  
Steve C. Hart ◽  
Jesse M. Maestas ◽  
...  
Keyword(s):  
Food Web ◽  
Leaf Litter ◽  
Tree Species ◽  
Aquatic Food Web ◽  
Carbon And Nitrogen ◽  
Aquatic Food

A seasonal survey of the food web in the Lapalme Lagoon (northwestern Mediterranean) assessed by carbon and nitrogen stable isotope analysis

2007 ◽  
Vol 73 (1-2) ◽  
pp. 299-315 ◽  
Author(s):  
Antoine Carlier ◽  
Pascal Riera ◽  
Jean-Michel Amouroux ◽  
Jean-Yves Bodiou ◽  
Karine Escoubeyrou ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Food Web ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Nitrogen Stable Isotope ◽  
Carbon And Nitrogen ◽  
Northwestern Mediterranean

Revisiting the Fates of Dead Leaves That Fall into Streams

2019 ◽  
Vol 50 (1) ◽  
pp. 547-568 ◽  
Author(s):  
Jane C. Marks
Keyword(s):  
Organic Matter ◽  
Food Web ◽  
Leaf Litter ◽  
Microbial Growth ◽  
Aquatic Invertebrates ◽  
Trophic Levels ◽  
Carbon And Nitrogen ◽  
Nitrogen Fluxes ◽  
Detrital Carbon ◽  
Constituent Elements

As terrestrial leaf litter decomposes in rivers, its constituent elements follow multiple pathways. Carbon leached as dissolved organic matter can be quickly taken up by microbes, then respired before it can be transferred to the macroscopic food web. Alternatively, this detrital carbon can be ingested and assimilated by aquatic invertebrates, so it is retained longer in the stream and transferred to higher trophic levels. Microbial growth on litter can affect invertebrates through three pathways, which are not mutually exclusive. First, microbes can facilitate invertebrate feeding, improving food quality by conditioning leaves and making them more palatable for invertebrates. Second, microbes can be prey for invertebrates. Third, microbes can compete with invertebrates for resources bound within litter and may produce compounds that retard carbon and nitrogen fluxes to invertebrates. As litter is broken down into smaller particles, there are many opportunities for its elements to reenter the stream food web. Here, I describe a conceptual framework for evaluating how traits of leaf litter will affect its fate in food webs and ecosystems that is useful for predicting how global change will alter carbon fluxes into and out of streams.

scholarly journals Stable isotopes dissect food webs from top to the bottom

2013 ◽  
Vol 10 (9) ◽  
pp. 14923-14952 ◽  
Author(s):  
J. J. Middelburg
Keyword(s):  
Stable Isotopes ◽  
Food Web ◽  
Food Webs ◽  
Nitrogen Isotopes ◽  
Web Studies ◽  
Carbon And Nitrogen ◽  
Challenges And Opportunities ◽  
Recent Developments ◽  
End To End ◽  
Small Producers

Abstract. Stable isotopes have been used extensively to study food web functioning, i.e. the flow of energy and matter among organisms. Traditional food-web studies are based on the natural variability of carbon and nitrogen isotopes and are limited to larger organisms that can be physically separated from their environment. Recent developments allow isotope ratio measurements of microbes and this in turn allows then measurement of entire food webs, i.e. from small producers at the bottom to large consumers at the top. Here, I provide a concise review on the use and potential of stable isotope to reconstruct end-to-end food webs. I will first discuss food web reconstruction based on natural abundances isotope data and will then show that the use of stable isotopes as deliberately added tracers provides complementary information. Finally, challenges and opportunities for end-to-end food web reconstructions in a changing world are discussed.

Assigning hydrogen, carbon, and nitrogen isotope values for phytoplankton and terrestrial detritus in aquatic food web studies

Inland Waters ◽  
2014 ◽  
Vol 4 (2) ◽  
pp. 233-242 ◽  
Author(s):  
Carol Yang ◽  
Grace Wilkinson ◽  
Jonathan Cole ◽  
Stephen Macko ◽  
Michael Pace
Keyword(s):  
Food Web ◽  
Nitrogen Isotope ◽  
Aquatic Food Web ◽  
Web Studies ◽  
Carbon And Nitrogen ◽  
Aquatic Food

Carbon sources for aquatic food webs of riverine and lacustrine tropical waterholes with variable groundwater influence

2017 ◽  
Vol 68 (3) ◽  
pp. 442 ◽  
Author(s):  
N. E. Pettit ◽  
D. M. Warfe ◽  
P. G. Close ◽  
B. J. Pusey ◽  
R. Dobbs ◽  
...  
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Isotope Analysis ◽  
Carbon Sources ◽  
Freshwater Wetlands ◽  
Food Sources ◽  
Web Studies ◽  
Aquatic Food Webs ◽  
Aquatic Food ◽  
Groundwater Reserves

Food web studies integrate ecological information and provide understanding of ecosystem function. Aquatic ecosystems of the Kimberley region (north-western Australia) have high conservation significance as hotspots for maintaining local and regional biodiversity. This study investigated the influence of waterhole type and persistence on the strength of consumer reliance on local energy resources for aquatic food webs. Changes in water isotopic composition indicated groundwater inputs were enough to overcome evaporative losses in some waterholes. Other waterholes had varying levels of isotope enrichment suggesting insufficient groundwater input to ‘compensate’ for evaporative loss. C and N isotope analysis indicated considerable overlap among energy sources in waterholes between macrophytes and periphyton but gradient analysis indicated that periphyton is a major carbon source for aquatic consumers. Groundwater-fed waterholes appeared to have higher quality food sources (indicated by lower C:N ratios), but there was minimal evidence that direct groundwater contributions were related to food web processes. Nonetheless, in a region where groundwater is influential in maintaining aquatic habitats, future development of groundwater reserves will likely affect the ecological and cultural value of freshwater wetlands by either reducing their permanence or size or indirectly through possible alteration to the role of periphyton in supporting the food web.

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