Experimental determination of stable carbon and nitrogen isotope fractionation between mangrove leaves and crabs

Herbon, Carolin Maria; Nordhaus, Inga

doi:10.3354/meps10421

Cited by 36 publications

(19 citation statements)

References 68 publications

(111 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, our Δδ 13 C (crab-mangrove) is close to C discrimination values recorded for R. apiculata in the grapsid crabs E. singaporense (5.1‰) and E. versicolour (4.1‰) [63]. Interestingly, our value also only slightly deviates from the mean (5.2) and median (5.6) of the Δδ 13 C values of the grapsid crab-mangrove leaf potential feeding link reported in the literature (Table 2).…”

Section: Discussionsupporting

confidence: 87%

Does ‘You Are What You Eat’ Apply to Mangrove Grapsid Crabs?

Bui

Lee

2014

PLoS ONE

View full text Add to dashboard Cite

In tropical mangroves, brachyuran crabs have been observed to consume high percentages of leaf litter production. However, questions concerning their ability to assimilate this low-quality food remain, as stable isotope analysis of C and N does not seem to support assimilation. Individuals of the common eastern Australian mangrove grapsid Parasesarma erythodactyla feeding on a mangrove leaf litter or mangrove+microphytobenthos diet developed a significantly higher hepatosomatic index than those with access to only sediment. Lipid biomarker analysis and feeding experiments using 13C and 15N-enriched mangrove leaf litter confirmed rapid assimilation of mangrove C and N by P. erythodactyla. Eight-week feeding experiments utilizing three food types (mangrove leaf litter, microphytobenthos and prawn muscle) established different food-specific trophic discrimination values (Δδ13C and Δδ15N) that are significantly different from those commonly applied to mixing model calculations. The mean Δδ13C(crab-mangrove) of +5.45‰ was close to the mean and median literature values for grapsid-mangrove pairs in 29 past studies (+5.2±1.8‰ and +5.6‰, respectively), suggesting that this large discrimination may generally be characteristic of detritivorous grapsid crabs. Solutions from the IsoConc mixing model using our determined trophic discrimination values suggest significantly higher and dominant contributions of mangrove C to the diet than those based on the global mean trophic discrimination values. Our results reaffirm the physiological capacity for and important mediating role of grapsid crabs in processing low-quality mangrove C in tropical estuaries, and caution against the use of global trophic discrimination values in stable isotope analysis of food-web data, especially those involving detritivores. While recent studies have questioned the trophic significance of mangrove detritus in coastal food chains, the contribution of this productive carbon source needs to be re-assessed in the light of these data.

show abstract

Section: Discussionsupporting

confidence: 87%

Does ‘You Are What You Eat’ Apply to Mangrove Grapsid Crabs?

Bui

Lee

2014

PLoS ONE

View full text Add to dashboard Cite

show abstract

“…It was therefore decided to maintain the universal values of Δ 13 C = +0.4‰ and Δ 15 N = +2.3‰ in this survey when leaf eating crabs feed on animal prey and MPB. However, recent evidence suggests that the trophic discrimination of crabs feeding on mangrove leaf litter deviates considerably from the universal values with Δ 13 C up to +6‰ and Δ 15 N up to +5‰ (Herbon and Nordhaus ; Bui and Lee ). To test the consequences of such deviation, the mixing models were solved as a function of leaf litter Δ 13 C by stepwise scanning from the global average of around 0‰ to an upper limit of +7‰, which is beyond the highest reported value for leaf‐eating sesarmid crabs.…”

Section: Methodsmentioning

confidence: 99%

“…The nutritional challenge of leaf‐eating crabs has been addressed by several studies on food selectivity (e.g., Skov and Hartnoll ; Kristensen et al ), and is still the focus of ongoing discussion in the literature (e.g., Herbon and Nordhaus ; Bui and Lee ; Riley et al ; Bergamino and Richoux ; Harada and Lee ). It has been debated if relatively nutrient‐poor mangrove leaf litter can constitute the sole diet of crabs (e.g., Kristensen et al ; Mazumder and Saintilan 2010).…”

mentioning

confidence: 99%

“…The most commonly used discrimination values per trophic level in aquatic foodweb studies are +0.4‰ for 13 C and +2.3‰ for 15 N, which are global means for a large range of aquatic animals foraging on different food sources (McCutchan et al ). The use of such universal discrimination values for crab species consuming mangrove leaf litter has recently been questioned (Herbon and Nordhaus ; Bui and Lee ). These studies have presented experimental evidence that Δ 13 C range from +4‰ to +6‰ and Δ 15 N range from 0‰ to +5‰ for sesarmid crabs feeding solely on mangrove leaf litter.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Trophic discrimination of stable isotopes and potential food source partitioning by leaf‐eating crabs in mangrove environments

Kristensen

Lee

Mangion

et al. 2017

Limnology & Oceanography

View full text Add to dashboard Cite

Diet composition of leaf-eating mangrove crabs is a puzzle among mangrove ecologists. Nutrient-poor leaf litter can in most cases not support animal growth. Food partitioning (mangrove leaves, animal tissue, and microphytobenthos [MPB]) of sesarmid and ucidid mangrove crabs from eight locations in four countries was assessed using the concentration-dependent stable isotope mixing model, IsoConc. While stable C and N isotopes have the potential to track the origin and proportion of food sources for these crabs, only few values of trophic discrimination are available. This problem was addressed here for crabs foraging on leaf litter to identify discrimination values that provide a balanced diet with sufficient nutrients (i.e., N) when combined with other food sources. The data from all mangrove locations suggest that sesarmid and ucidid crabs ingest and assimilate mixtures of available food items. Leaf litter in the form of brown leaves was always the most important C source, while animal tissue in the form live and dead "prey" or MPB in the form of diatoms at the sediment surface were the dominant N sources. Model scenarios were generated to obtain the upper thresholds of trophic 13 C discrimination between the examined crab species and leaf litter, while complying with the molar C/N < 20 requirement for sustainable invertebrate nutrition. The model predicts litter 13 C discrimination thresholds of 11.5& to 16.0& for sesarmid crabs and 20.3& to 10.6& for ucidid crabs. The difference is probably caused by metabolic disparities between these two crab families. Deviations in 15 N discrimination have in most cases only minor influence on the model-based 13 C discrimination thresholds. The present findings lead us to suggest a modified Optimal Foraging Theory for leaf-eating mangrove crabs. *Correspondence: ebk@biology.sdu.dk 2097 LIMNOLOGY and OCEANOGRAPHY

show abstract

“…The diets fed by consumers take time to be assimilated and accumulated in their bodies, causing time delay in stable isotope signature. In feeding experiments tracing stable isotope signatures of crabs and their food sources (detritus and litter), it took 3 weeks or more to detect the influences of food sources (Dittel et al 2000;Herbon and Nordhaus 2013). Considering assimilation and accumulation time in crabs, we put a 1-month time lag between δ 13 C of sediment and crabs, which led to higher correlations except for the frozen sediment period (November and March) (Spearman correlation test on group I and II: p < 0.05, r s = 0.68 for site 1 and p < 0.05, r s = 0.79 for site 2).…”

Section: Discussionmentioning

confidence: 99%

Intraspecific diet shifts of the sesarmid crab, Sesarma dehaani, in three wetlands in the Han River estuary, South Korea

Yang

Han

2019

j ecology environ

View full text Add to dashboard Cite

Background: Han River estuary is a national wetland reserve near the Demilitarized Zone (DMZ) between South Korea and North Korea. This trans-boundary estuary area has been well preserved and shows distinctive plant communities along the salinity gradient. To elucidate energy flows and nutrient cycling in this area, we studied trophic relations between the dominant sesarmid crab, Sesarma dehaani, and food sources in three wetlands with different environments along the estuarine gradients. Results: Stable isotope signatures (δ 13 C and δ 15 N) of the crabs were significantly different among the sites and body size classes. Seasonal changes in δ 13 C of small crabs were distinct from those of large individuals at all the sites. The isotopic values and fatty acid profiles of the crabs were more different among the sites in September than in May. In May, large-sized crabs utilized more plant materials compared to other dietary sources in contrast to small-sized crabs as revealed by a stable isotope mixing modeling, whereas contributions to diets of crabs were not dominated by a specific diet for different body size in September except at site 1. Based on PCA loadings, fatty acid content of 18:3ω3, known as a biomarker of plant materials, was the main factor to separate size groups of crabs in May and September. The δ 13 C value of sediment had high correlation with those of small-sized crabs at site 1 and 2 when 1-month time lag was applied to the value for crabs during the surveyed period. Conclusions: Based on the stable isotope and fatty acid results, the consumption habits of S. dehaani appear to be distinguished by sites and their size. In particular, smaller size of S. dehaani appears to be more dependent on fewer food sources and is influenced more by the diet sources from the sediments in Han River estuary.

show abstract

Experimental determination of stable carbon and nitrogen isotope fractionation between mangrove leaves and crabs

Cited by 36 publications

References 68 publications

Does ‘You Are What You Eat’ Apply to Mangrove Grapsid Crabs?

Does ‘You Are What You Eat’ Apply to Mangrove Grapsid Crabs?

Trophic discrimination of stable isotopes and potential food source partitioning by leaf‐eating crabs in mangrove environments

Intraspecific diet shifts of the sesarmid crab, Sesarma dehaani, in three wetlands in the Han River estuary, South Korea

Contact Info

Product

Resources

About