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 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.

Download Full-text

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

Biogeosciences ◽

10.5194/bg-17-5599-2020 ◽

2020 ◽

Vol 17 (22) ◽

pp. 5599-5613

Author(s):

Yota Harada ◽

Rod M. Connolly ◽

Brian Fry ◽

Damien T. Maher ◽

James Z. Sippo ◽

...

Keyword(s):

Amino Acids ◽

Time Series ◽

Stable Isotope ◽

Stable Isotope Analysis ◽

Extreme Event ◽

Isotope Analysis ◽

Series Data ◽

Drought Event ◽

Ecosystem Recovery ◽

Impacted Site

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.

Download Full-text

Long-term performance of the Gasbench isotope ratio mass spectrometry system for the stable isotope analysis of carbonate microsamples

Rapid Communications in Mass Spectrometry ◽

10.1002/rcm.5037 ◽

2011 ◽

Vol 25 (11) ◽

pp. 1683-1685 ◽

Cited By ~ 31

Author(s):

Christoph Spötl

Keyword(s):

Mass Spectrometry ◽

Stable Isotope ◽

Stable Isotope Analysis ◽

Isotope Ratio ◽

Isotope Analysis ◽

Isotope Ratio Mass Spectrometry ◽

Mass Spectrometry System ◽

Long Term Performance ◽

Term Performance

Download Full-text

Stable isotope analysis of consumer food webs indicates ecosystem recovery following prolonged drought in a subtropical estuarine lake

African Journal of Marine Science ◽

10.2989/1814232x.2016.1220979 ◽

2016 ◽

Vol 38 (3) ◽

pp. 411-422 ◽

Cited By ~ 2

Author(s):

MS Bird ◽

R Perissinotto ◽

NAF Miranda ◽

N Peer ◽

JL Raw

Keyword(s):

Stable Isotope ◽

Food Webs ◽

Stable Isotope Analysis ◽

Isotope Analysis ◽

Ecosystem Recovery ◽

Prolonged Drought

Download Full-text

Pan-North Pacific comparison of long-term variation in Neocalanus copepods based on stable isotope analysis

Progress In Oceanography ◽

10.1016/j.pocean.2011.11.007 ◽

2012 ◽

Vol 97-100 ◽

pp. 63-75 ◽

Cited By ~ 12

Author(s):

Sanae Chiba ◽

Hiroya Sugisaki ◽

Akira Kuwata ◽

Kazuaki Tadokoro ◽

Toru Kobari ◽

...

Keyword(s):

Stable Isotope ◽

Stable Isotope Analysis ◽

North Pacific ◽

Isotope Analysis ◽

Term Variation

Download Full-text

Evidence of microbial provisioning of essential amino acids in an endotherm: Combining compound-specific stable isotope analysis with NexGen sequencing

10.1603/ice.2016.94514 ◽

2016 ◽

Author(s):

Seth Newsome

Keyword(s):

Amino Acids ◽

Stable Isotope ◽

Stable Isotope Analysis ◽

Isotope Analysis ◽

Essential Amino Acids

Download Full-text

A synthesis of tissue-preservation effects on carbon and nitrogen stable isotope signatures

Canadian Journal of Zoology ◽

10.1139/z02-007 ◽

2002 ◽

Vol 80 (2) ◽

pp. 381-387 ◽

Cited By ~ 175

Author(s):

Helen C Sarakinos ◽

Michael L Johnson ◽

M Jake Vander Zanden

Keyword(s):

Stable Isotope ◽

Food Web ◽

Stable Isotope Analysis ◽

Isotope Analysis ◽

Tissue Preservation ◽

Isotope Signature ◽

Web Studies ◽

Data Preservation ◽

Clam Corbicula

Stable-isotope analysis is a powerful method for characterizing flows of mass and energy through ecosystems. Long-term food-web studies using stable isotopes are valuable but rare because the required samples are not readily available. We examine the feasibility of using preserved specimens from natural-history collections as a source of long-term data for food-web studies and test whether chemical preservation affects the stable-isotope signature of tissues. We experimentally determined the effects of tissue preservation and fixation with 75% ethanol and 10% formalin, respectively, on δ13C and δ15N of three aquatic consumers: Sacramento sucker, Catostomus occidentalis, Asian clam, Corbicula fluminea, and a caddisfly, Hydropsyche sp. Using both our results and previously published literature results, we characterize preservation effects across many different consumer taxa including invertebrates, fish, and birds. Overall, only formalin fixation systematically affected isotope signature, causing an average depletion of 1.65 in δ13C, a bias that can easily be corrected for prior to interpreting data. Preservation affected mean δ15N values with far lower frequency and magnitude, although variability increased with preservation for some taxa but not others. These findings suggest that preserved specimens may be used for stable-isotope analysis and open up the possibility of using archived collections to reconstruct food webs and biogeochemical changes at scales of tens to hundreds of years.

Download Full-text

Long-term food web change in Lake Superior

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f09-151 ◽

2009 ◽

Vol 66 (12) ◽

pp. 2118-2129 ◽

Cited By ~ 39

Author(s):

Stephanie N. Schmidt ◽

M. Jake Vander Zanden ◽

James F. Kitchell

Keyword(s):

Stable Isotope ◽

Great Lakes ◽

Food Web ◽

Stable Isotope Analysis ◽

Native Species ◽

Trophic Position ◽

Lake Superior ◽

Isotope Analysis ◽

Food Web Structure

Restoration and rehabilitation of native species in the Laurentian Great Lakes is a priority for fisheries management agencies. Restoration efforts are increasingly incorporating a perspective that considers species within a broader food web context. We used stable isotope analysis and museum-preserved specimens to describe and quantify 100 years of food web changes in the Lake Superior fish community. We validated stable isotope analysis of museum specimens by showing a positive correlation between isotope- and diet-based estimates of trophic position. While introductions have created a more trophically diverse food web than historically found in Lake Superior, two separate metrics revealed little community-wide change in the food web. Our species-specific analysis revealed trophic niche differences between shortjaw ( Coregonus zenithicus ) and shortnose ( Coregonus reighardi ) ciscoes, two species previously argued to be indistinguishable based on morphological characteristics. By providing a historical context, our findings show the ability of the Lake Superior food web to accommodate non-native species introductions over the last century while still supporting native species populations. This long-term information about food web structure can help guide management and restoration goals in Lake Superior. Furthermore, Lake Superior can serve as a basis for comparing food web changes in other, more highly altered Great Lakes.

Download Full-text