Compound-specific isotopic analysis of amino acids reveals dietary changes in mesophotic coral-reef fish

Bradley, Christina J.; Longenecker, Ken; Pyle, Richard L.; Popp, Brian N.

doi:10.3354/meps11872

Cited by 17 publications

(20 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results here suggest increased coral heterotrophy and/or substitute feeding on plankton may additionally buffer “coral‐obligate” fish from depth‐related declines in the availability and hypothesized declines in nutritional quality of preferred corals. Similar depth‐related nutritional shifts are evident in the isotopic space occupied by less coral associated and more generalist fish taxon and feeding guilds (Bradley et al, ; Goldstein et al, ). Together, these data suggest significantly altered energy pathways may be a key mechanism supporting a variety of consumers on deeper reefs.…”

Section: Discussionmentioning

confidence: 69%

“…Consequently, dietary flexibility along a depth gradient may facilitate the persistence of refuge populations in deeper water following disturbance, thereby mediating local extinction risks. Depth-related dietary flexibility has been demonstrated for non-coral-associated K E Y W O R D S carbon pathways, coral reef fish, depth gradient, energy acquisition, functional strategies, range margin, refuge generalist planktivorous (Goldstein et al, 2017) and invertivorous (Bradley, Longenecker, Pyle, & Popp, 2016) reef fishes. However, the extent to which dietary flexibility across depth may mediate population declines in highly vulnerable coral-obligate species remains unknown.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Alternative functional strategies and altered carbon pathways facilitate broad depth ranges in coral‐obligate reef fishes

et al. 2019

View full text Add to dashboard Cite

Spatial refuges in peripheral habitats will become increasingly important for species persistence as climate change and other disturbances progressively impact habitat quality and assemblage compositions. However, the capacity for persistence will be determined in part by species‐specific abilities to absorb costs related to altered or decreased quantities and quality of resources at range peripheries. We compared variations in dietary strategies and energy acquisition trade‐offs along depth gradients in two obligate corallivores that differ in level of diet specialization. We also assessed depth‐related changes in energy pathways and energy content of their mixotrophic prey. We found no changes in feeding effort or total resource availability (total coral cover) towards deep range margins, but availability of the preferred resource (Acropora coral) decreased. While both species selectively targeted Acropora, the more specialized species (Chaetodon baronessa) exhibited limited feeding plasticity along the depth gradient. The degree of selectivity towards the preferred coral increased rather than decreased with depth, being 40 times greater than expected, given availability, at their range periphery. In contrast, the generalist's diet (Chaetodon octofasciatus) varied greatly in response to changes in resource availability with depth. Unexpectedly, the energy content of Acropora did not decline with depth, likely due to increased coral heterotrophy in deeper water, indicated by shifts in their molecular isotope geochemistry. This shift was accompanied by a 20% increase in plankton‐sourced carbon in the muscle tissue of deep‐resident fish, despite no observations of direct feeding on plankton food sources. Our results indicate that deep ranges in coral‐obligate reef fishes are supported by multiple mechanisms of trophic versatility in both the fish and corals. This nutritional plasticity likely serves a compensatory role in the resilience and eventual adaptation of organisms at their range peripheries. For species vulnerable to increasing anthropogenic impacts at range cores, variable and multi‐trophic functional responses can act to buffer against costs and increase the refuge potential of range peripheries. Specialist consumers may also be supported indirectly at range margins via trophic plasticity within their preferred prey. A free Plain Language Summary can be found within the Supporting Information of this article.

show abstract

Section: Discussionmentioning

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Alternative functional strategies and altered carbon pathways facilitate broad depth ranges in coral‐obligate reef fishes

et al. 2019

View full text Add to dashboard Cite

show abstract

“…The superior precision and accuracy of this method makes it suitable for studies attempting to resolve fine-scale variability in N sources and TPs. For instance, among primary or secondary consumers in marine pelagic systems, temporal and spatial variability in TP is usually around the order of ±0.4 TP (Hannides et al 2009;Choy et al 2012;Décima et al 2013;Choy et al 2015;Miyachi et al 2015;Bradley et al 2016;Laiz-Carrión et al 2019). Even small shifts in TP can be associated with significant food web disruptions and represent considerable changes in energy transfer up to higher level consumers (Vander Zanden et al 1999).…”

Section: Comments and Recommendationsmentioning

confidence: 99%

“…This approach assumes that analytical and methodological errors are similar for CSIA-AA and bulk SIA. However, Elemental Analyzer -Isotope Ratio Mass Spectrometry (EA-IRMS) used in bulk SIA typically operates with an analytical precision (0.1 -0.2 ‰) that is substantially higher than what is reported in CSIA-AA studies (0.4 -1.0 ‰; Bradley et al 2016;Broek and McCarthy 2014;Broek et al 2013;Chikaraishi et al 2015;Hetherington et al 2017;Nuche-Pascual et al 2018;Ogawa et al 2013;Ruiz-Cooley et al 2017;Vane et al 2018;Vokhshoori et al 2019). This lower precision is the result of a lengthy and time-consuming analytical process inherent to the Gas Chromatography-Combustion-IRMS (GC-C-IRMS) used for almost all CSIA-AA work.…”

Section: Introductionmentioning

confidence: 98%

Errors associated with compound specific δ¹⁵N analysis of amino acids in preserved fish samples purified by high pressure liquid chromatography

Swalethorp

Aluwihare

Thompson

et al. 2019

Preprint

View full text Add to dashboard Cite

During the past decade compound specific nitrogen (N) isotopic analysis of amino acids (CSIA-AA) has become an increasingly used method for tracking the origin and fate of N in ecological and biogeochemical studies. CSIA-AA has the potential for resolving finer scale trophic dynamics than previously possible with bulk stable isotope analysis (SIA) and for reconstructing past food webs using historical archives of organismal samples. However, there is little information on the effects of chemical preservation used in historical archives on δ 15 NAA values, and conventional CSIA conducted on derivatized AAs using gas chromatographycombustion -isotope ratio mass spectrometry (GC-C-IRMS) has analytical errors in the range of what may be expected from chemical preservation. Here we present analytical errors across 11 underivatized AA standards analyzed by high pressure liquid chromatography followed by offline elemental analysis -IRMS (HPLC/EA-IRMS) an approach originally developed by Broek and McCarthy (2014). Using this method, we test the effects of ethanol and formaldehyde preservation (1½ and 27 years) on δ 15 NAA in Northern Anchovy (Engraulis mordax). We found minimal isotopic fractionation from the HPLC/EA-IRMS approach in 8 AAs and more than twice the precision (0.15 ± 0.08 ‰) typically reported for GC-C-IRMS. Preservation effects on δ 15 NAA were similar regardless of duration and type of preservative used. Although several AAs differed significantly from frozen control samples (average +1.0 ± 0.8 ‰), changes in trophic position (TP) estimates were insignificant. These results are encouraging for resolving the finescale natural variability expected in most low TP organisms via high precision HPLC/EA-IRMS and for the use of chemically preserved sample archives in reconstructing biogeochemical records and trophic dynamics over long time scales.

show abstract

“…Application of compound specific amino acid analysis (AA-CSIA) and Bayesian mixing-model techniques can assist in defining these baselines (McMahon et al, 2015). AA-CSIA can provide better baselines by looking at specific amino acids that fractionate with each trophic step (Bradley et al, 2016). AA-CSIA can also reduce the number of samples for analysis by eliminating the need for an exhaustive baseline.…”

Section: Biochemical Tracersmentioning

confidence: 99%

Trophodynamics as a Tool for Understanding Coral Reef Ecosystems

et al. 2018

View full text Add to dashboard Cite

The increased frequency of publications concerning trophic ecology of coral reefs suggests a degree of interest in the role species and functional groups play in energy flow within these systems. Coral reef ecosystems are particularly complex, however, and assignment of trophic positions requires precise knowledge of mechanisms driving food webs and population dynamics. Competent analytical tools and empirical analysis are integral to defining ecosystem processes and avoiding misinterpretation of results. Here we examine the contribution of trophodynamics to informing ecological roles and understanding of coral reef ecology. Applied trophic studies of coral reefs were used to identify recent trends in methodology and analysis. Although research is increasing, clear definitions and scaling of studies is lacking. Trophodynamic studies will require more precise spatial and temporal data collection and analysis using multiple methods to fully explore the complex interactions within coral reef ecosystems.

show abstract

Compound-specific isotopic analysis of amino acids reveals dietary changes in mesophotic coral-reef fish

Cited by 17 publications

References 56 publications

Alternative functional strategies and altered carbon pathways facilitate broad depth ranges in coral‐obligate reef fishes

Alternative functional strategies and altered carbon pathways facilitate broad depth ranges in coral‐obligate reef fishes

Errors associated with compound specific δ¹⁵N analysis of amino acids in preserved fish samples purified by high pressure liquid chromatography

Trophodynamics as a Tool for Understanding Coral Reef Ecosystems

Contact Info

Product

Resources

About

Compound-specific isotopic analysis of amino acids reveals dietary changes in mesophotic coral-reef fish

Cited by 17 publications

References 56 publications

Alternative functional strategies and altered carbon pathways facilitate broad depth ranges in coral‐obligate reef fishes

Alternative functional strategies and altered carbon pathways facilitate broad depth ranges in coral‐obligate reef fishes

Errors associated with compound specific δ15N analysis of amino acids in preserved fish samples purified by high pressure liquid chromatography

Trophodynamics as a Tool for Understanding Coral Reef Ecosystems

Contact Info

Product

Resources

About

Errors associated with compound specific δ¹⁵N analysis of amino acids in preserved fish samples purified by high pressure liquid chromatography