Stable isotopes track the ecological and biogeochemical legacy of mass mangrove forest dieback in the Gulf of Carpentaria, Australia

Abstract. A combination of elemental analysis, bulk stable isotope analysis (bulk SIA) and compound-specific stable isotope analysis of amino acids (CSIA-AA) was used to assess and monitor carbon (C), nitrogen (N) and sulfur (S) cycling of a mangrove ecosystem that suffered mass dieback of trees in the Gulf of Carpentaria, Australia in 2015–2016, attributed to an extreme drought event. Three field campaigns were conducted 8, 20 and 32 months after the event over a period from 2016 to 2018 to obtain biological time-series data. Invertebrates and associated organic matter including mangroves and sediments from the impacted ecosystem showed enrichment in 13C, 15N and 34S relative to those from an adjacent unimpacted reference ecosystem, likely indicating lower mangrove carbon fixation, lower nitrogen fixation and lower sulfate reduction in the impacted ecosystem. For example, invertebrates representing the feeding types of grazing, leaf feeding and algae feeding were more 13C enriched at the impacted site, by 1.7 ‰–4.1 ‰, and these differences did not change over the period from 2016 to 2018. The CSIA-AA data indicated widespread 13C enrichment across five essential amino acids and all groups sampled (except filter feeders) within the impacted site. The seedling density increased from 0.2 m−2 in 2016 to 7.1 m−2 in 2018 in the impacted forest, suggesting recovery of the vegetation. Recovery of CNS cycling, however, was not evident even after 32 months, suggesting a biogeochemical legacy of the mortality event. Continued monitoring of the post-dieback forest is required to predict the long-term trajectory of ecosystem recovery. This study shows that time-series SIA can track biogeochemical changes over time and evaluate recovery of an impacted ecosystem from an extreme event.

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Stable isotopes track the ecological and biogeochemical legacy of mass mangrove forest dieback in the Gulf of Carpentaria, Australia

10.5194/bg-2019-468 ◽

2020 ◽

Cited By ~ 1

Author(s):

Yota Harada ◽

Rod M. Connolly ◽

Brian Fry ◽

Damien T. Maher ◽

James Z. Sippo ◽

...

Keyword(s):

Stable Isotope ◽

Stable Isotope Analysis ◽

Carbon Fixation ◽

Isotope Analysis ◽

Essential Amino Acids ◽

Mangrove Ecosystem ◽

Drought Event ◽

Ecosystem Recovery ◽

Impacted Site

Abstract. A combination of elemental analysis and stable isotope analysis (SIA) was used to assess and monitor C, N and S cycling of a mangrove ecosystem that suffered mass dieback of trees in the Gulf of Carpentaria, Australia in 2015–16, attributed to an extreme drought event. Three field campaigns were conducted over a period from 2016 to 2018, at 8, 20 and 32 months after the event. Samples including invertebrates, mangroves, and sediment were analysed for CNS elemental and isotopic compositions including compound-specific stable isotope analysis (CSIA) of amino acid carbon. Samples collected from the impacted ecosystem were enriched in 13C, 15N and 34S relative to those from an adjacent unimpacted reference ecosystem, likely indicating lower mangrove carbon fixation, lower nitrogen fixation and lower sulfate reduction in the impacted ecosystem. For example, invertebrates representing the feeding types of grazing, leaf feeding, and algae feeding were more 13C enriched at the impacted site, by 1.7–4.1 ‰ and these differences did not change over the period from 2016 to 2018. The CSIA data indicated widespread 13C enrichment across five essential amino acids and all groups sampled (except filter feeders) within the impacted site. Mangrove seedling and sapling populations increased substantially from 2016 to 2018 in the impacted forest, suggesting recovery of the mangrove vegetation. Recovery of CNS cycling, however, was not evident even after 32 months, suggesting a biogeochemical legacy of the mortality event. Continued monitoring of the post-dieback forest would help to predict the long-term trajectory of ecosystem recovery. In such long-term monitoring programs, SIA that can track biogeochemical changes over time can help to detect underlying biological mechanisms that drive changes and recovery of the mangrove ecosystem. To gain further insight, our use of CSIA can help show feeding dependencies in mangrove food webs and their response to disturbances.

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Decision letter for "Tracking long-distance migration of marine fishes using compound-specific stable isotope analysis of amino acids"

10.1111/ele.13496/v2/decision1 ◽

2020 ◽

Keyword(s):

Amino Acids ◽

Stable Isotope ◽

Stable Isotope Analysis ◽

Isotope Analysis ◽

Marine Fishes ◽

Long Distance

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Review for "Tracking long-distance migration of marine fishes using compound-specific stable isotope analysis of amino acids"

10.1111/ele.13496/v1/review1 ◽

2019 ◽

Keyword(s):

Amino Acids ◽

Stable Isotope ◽

Stable Isotope Analysis ◽

Isotope Analysis ◽

Marine Fishes ◽

Long Distance

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Preparative separation of underivatized amino acids for compound-specific stable isotope analysis and radiocarbon dating of hydrolyzed bone collagen

Journal of Separation Science ◽

10.1002/jssc.200500247 ◽

2006 ◽

Vol 29 (1) ◽

pp. 41-48 ◽

Cited By ~ 36

Author(s):

Jennifer A. Tripp ◽

James S. O. McCullagh ◽

Robert E. M. Hedges

Keyword(s):

Amino Acids ◽

Stable Isotope ◽

Stable Isotope Analysis ◽

Radiocarbon Dating ◽

Isotope Analysis ◽

Bone Collagen ◽

Preparative Separation ◽

Underivatized Amino Acids

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A multi‐biomarker approach supports the use of compound‐specific stable isotope analysis of amino acids to quantify basal carbon source use in a salt marsh consumer

Rapid Communications in Mass Spectrometry ◽

10.1002/rcm.8538 ◽

2019 ◽

Vol 33 (23) ◽

pp. 1781-1791 ◽

Cited By ~ 1

Author(s):

Jessica J. Johnson ◽

Jill A. Olin ◽

Michael J. Polito

Keyword(s):

Amino Acids ◽

Salt Marsh ◽

Stable Isotope ◽

Carbon Source ◽

Stable Isotope Analysis ◽

Isotope Analysis ◽

Source Use

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Stable nitrogen isotope analysis of amino acids as a new tool to clarify complex parasite-host interactions within marine food webs

10.1101/2021.03.04.433913 ◽

2021 ◽

Author(s):

Philip Riekenberg ◽

Tijs Joling ◽

Lonneke L. IJsseldijk ◽

Andreas M. Waser ◽

Marcel van der Meer ◽

...

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Stable Isotope ◽

Food Webs ◽

Stable Isotope Analysis ◽

Trophic Interactions ◽

Trophic Position ◽

Isotope Analysis ◽

Isotopic Analysis ◽

Parasitic Interactions

AbstractTraditional bulk isotopic analysis is a pivotal tool for mapping consumer-resource interactions in food webs but has largely failed to adequately describe parasite-host relationships. Thus, parasite-host interactions remain largely understudied in food web frameworks despite these relationships increasing linkage density, connectance, and ecosystem biomass. Compound-specific stable isotopes from amino acids provides a promising novel approach that may aid in mapping parasitic interactions in food webs. However, to date it has not been applied to parasitic trophic interactions.Here we use a combination of traditional bulk stable isotope analyses and compound-specific isotopic analysis of the nitrogen in amino acids to examine resource use and trophic interactions of five parasites from three hosts from a marine coastal food web (Wadden Sea, European Atlantic). By comparing isotopic compositions of bulk and amino acid nitrogen, we aimed to characterize isotopic fractionation occurring between parasites and their hosts and to clarify the trophic position of the parasites.Our results showed that parasitic trophic interactions were more accurately identified when using compound-specific stable isotope analysis due to removal of underlying source isotopic variation for both parasites and hosts, and avoidance of the averaging of amino acid variability in bulk analyses through use of multiple trophic amino acids. The compound-specific method provided clear trophic discrimination factors in comparison to bulk isotope methods, however, those differences varied significantly among parasite species.Amino acid compound specific isotope analysis has widely been applied to examine trophic position within food webs, but our analyses suggest that the method is particularly useful for clarifying the feeding strategies for parasitic species. Baseline isotopic information provided by source amino acids allows clear identification of the fractionation occurring due to parasite metabolism by integrating underlying isotopic variations from the host tissues. However, like for bulk isotope analysis, the application of a universal trophic discrimination factor to parasite-host relationships remains inappropriate for compound-specific stable isotope analysis. Despite this limitation, compound-specific stable isotope analysis is and will continue to be a valuable tool to increase our understanding of parasitic interactions in marine food webs.

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