scholarly journals Assimilation of shrimp farm sediment by Holothuria scabra: a coupled fatty acid and stable isotope approach

2020 ◽  
Vol 33 ◽  
pp. 3
Author(s):  
Margaux Mathieu-Resuge ◽  
Fabienne Le Grand ◽  
Gauthier Schaal ◽  
Edouard Kraffe ◽  
Anne Lorrain ◽  
...  
Keyword(s):  
Organic Matter ◽  
Fatty Acid ◽  
Stable Isotope ◽  
Fish Meal ◽  
Shrimp Farming ◽  
Food Sources ◽  
Alternative Source ◽  
Additional Food ◽  
Integrated Aquaculture ◽  
Holothuria Scabra

Deposit-feeding sea cucumbers are efficient nutrient recyclers and have the potential to contribute to the limitation of organic matter load in polyculture or integrated aquaculture systems. Assessing how they assimilate organic matter originating from other farmed species is therefore important for the development of such multi-species farming systems. Here, a coupled stable isotope − fatty acid approach was used to characterize the assimilation of organic matter from shrimp (Penaeus stylirostris) farming by Holothuria scabra in an experimental culture system. H. scabra were reared in mesocosms on shrimp farming-originating sediment with and without additional food sources (maize and fish meals). Although fatty acid results did indicate that shrimp-farming sediment was assimilated by holothurids, we found no evidence of maize waste and fish meal contribution to H. scabra organic carbon (no effect on δ13C, no accumulation of meal-specific fatty acids). However, a strong effect of fish meal on H. scabra δ15N was observed, suggesting that this additional food source could represent an alternative source of nitrogen for holothurids. Finally, this study supports the culture of H. scabra as a perspective to reduce sedimentary organic matter excess associated with shrimp farms, and suggest that the addition of selected food sources might contribute to increasing the content in some nitrogen organic compounds in holothurid tissues.

Methyl mercury in zooplankton—the role of size, habitat, and food quality

2002 ◽  
Vol 59 (10) ◽  
pp. 1606-1615 ◽  
Author(s):  
Martin Kainz ◽  
Marc Lucotte ◽  
Christopher C Parrish
Keyword(s):  
Organic Matter ◽  
Fatty Acid ◽  
Body Size ◽  
Methyl Mercury ◽  
Size Fraction ◽  
Food Sources ◽  
Calanoid Copepods ◽  
Bacterial Food

Pathways of methyl mercury (MeHg) accumulation in zooplankton include ingestion of organic matter (OM). We analyzed fatty acid (FA) biomarkers in zooplankton to (i) investigate the effect of allochthonous and autochthonous OM ingestion on MeHg concentrations ([MeHg]) in zooplankton and (ii) examine how algal and bacterial food sources affect MeHg bioaccumulation. We partitioned bulk zooplankton samples (i.e., >500, 202, 100, and 53 μm) from Lake Lusignan (Québec) and measured [MeHg] and [FA] in each fraction. [MeHg] increased with increasing body size and was significantly higher in pelagic than in littoral macrozooplankton (>500 μm). The amount of the ingested terrestrial FA biomarker 24:0 indicated that less than 1% of the total FA in zooplankton was derived from allochthonous sources. More than 60% of the ingested FA originated from algal biomarkers and <10% from bacterial biomarkers. Relative amounts of algal-derived essential FA and bacterial FA were not associated with [MeHg] in any size fraction. In pelagic zones, the amount of MeHg in zooplankton related positively to the number of large organisms such as Calanoid copepods and Daphnia. We propose that the accumulation of MeHg in lacustrine zooplankton depends on the zooplankton habitat rather than on the quality of ingested food.

Tracing sewage-derived organic matter into a shallow groundwater food web using stable isotope and fluorescence signatures

2011 ◽  
Vol 62 (2) ◽  
pp. 119 ◽  
Author(s):  
Adam Hartland ◽  
Graham D. Fenwick ◽  
Sarah J. Bury
Keyword(s):  
Organic Matter ◽  
Stable Isotope ◽  
Food Web ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Shallow Groundwater ◽  
Organic Pollution ◽  
Food Sources ◽  
Δ13c And Δ15n

Little is known about the feeding modes of groundwater invertebrates (stygofauna). Incorporation of sewage-derived organic matter (OM) into a shallow groundwater food web was studied using fluorescence and stable isotope signatures (δ13C and δ15N). Organic pollution was hypothesised to limit sensitive species’ abundances along the contamination gradient and isotope signatures of stygofauna consuming sewage-derived OM were expected to be enriched in δ15N. Stygofauna communities near a sewage treatment plant in New Zealand were sampled over 4 months and microbial biofilms were incubated in situ on native gravel for 1 month. As anticipated, OM stress-subsidy gradients altered stygofauna composition: the biomass of oligochaetes and Paraleptamphopus amphipods increased in OM-enriched groundwater (higher dissolved organic carbon (DOC) and tryptophan-like fluorescence), whereas other, probably less-tolerant taxa (e.g. ostracods, Dytiscidae) were absent. Isotopic signatures for stygofauna from polluted groundwater were consistent with assimilation of isotopically enriched sewage-N (δ15N values of 7–16‰), but highly depleted in δ13C relative to sewage. Negative 13C discriminations probably occur in Paraleptamphopus amphipods, and may also occur in oligochaetes and Dytiscidae, a finding with implications for the application of δ13C for determining food sources in groundwaters. Organic pollution of groundwaters may have serious repercussions for stygofauna community structure with potentially irreversible consequences.

Trophic transfer between coastal habitats in a seagrass-dominated macrotidal embayment system as determined by stable isotope and fatty acid signatures

2013 ◽  
Vol 64 (12) ◽  
pp. 1169 ◽  
Author(s):  
Hyun Je Park ◽  
Eun Jung Choy ◽  
Kun-Seop Lee ◽  
Chang-Keun Kang
Keyword(s):  
Organic Matter ◽  
Fatty Acid ◽  
Stable Isotope ◽  
Principal Component ◽  
Feeding Guilds ◽  
Suspended Particulate ◽  
Shallow Subtidal ◽  
Intertidal Habitats ◽  
Isotopic Mixing ◽  
Fatty Acid Biomarkers

Stable isotope and fatty acid analyses were used to examine trophic transfers within a seagrass bed and its adjacent shallow subtidal and intertidal habitats in a macrotidal embayment system in Korea. Suspended particulate organic matter (POM), sedimentary organic matter, benthic microalgae (BMA), green and decomposing leaves of Zostera marina, its epiphytes and a variety of consumers in different habitats were collected between May and June 2007. Z. marina, epiphytes and BMA were more 13C-enriched than offshore POM. The δ13C values of consumers from all habitats overlapped with those of BMA, Z. marina leaves and epiphytes, indicating the trophic importance of locally produced organic matter. Tissues of the dominant consumers in all habitats contained high quantities of fatty acid biomarkers for diatoms, but very low quantities of fatty acid biomarkers for seagrass. Principal component analysis based on fatty acids of consumers showed a very complex distribution, suggesting that they have diverse nutritive origins irrespective of feeding guilds and habitats. The isotopic mixing model showed that epiphytes and BMA served as major nutritional sources for consumer production in the seagrass and the adjacent intertidal habitats. Moreover, our results suggest that epiphytes and BMA outwell into the adjacent shallow subtidal habitats and provide considerable trophic subsidy for consumer production.

The diet of amphioxus in subtropical Hong Kong as indicated by fatty acid and stable isotopic analyses

2008 ◽  
Vol 88 (7) ◽  
pp. 1487-1491 ◽  
Author(s):  
Y. Chen ◽  
S.G. Cheung ◽  
P.K.S. Shin
Keyword(s):  
Hong Kong ◽  
Fatty Acid ◽  
Stable Isotope ◽  
Trophic Levels ◽  
Food Sources ◽  
Filter Feeder ◽  
Total Particulate Matter ◽  
Isotopic Analyses ◽  
Wide Range ◽  
Hong Kong Waters

Fatty acid profiles and carbon (δ13C) and nitrogen (δ15N) stable isotope markers were used to identify the diet of amphioxus in subtropical Hong Kong waters, and to evaluate the role of co-occurring Branchiostoma belcheri and B. malayanum in trophic transfer, in coastal ecosystems. The present results showed that while amphioxus is generally regarded as a filter feeder, total particulate matter in the water column might not be the main food supply. The diet of amphioxus could be traced to comprise a wide range of food sources, from microbes and microplankton to microalgae, based on the stable isotope analysis. Results of fatty acid profile analysis also revealed contributions from dinoflagellates, zooplankton, detritus and bacteria, and minor contribution from diatoms and fungi in the diet of amphioxus in Hong Kong waters. The use of fatty acid and stable isotope analyses further proved that amphioxus can, not only capture and partition such a different size-range of food particles during their feeding, but also assimilate most of them into their body tissue. The present findings suggested that amphioxus may play an important role in marine food webs by transferring microbial production to higher trophic levels through utilizing microbes in seawater as food.

scholarly journals Spatio–temporal variation in stable isotope signatures (δ13C and δ15N) of sponges on the Saba Bank

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5460 ◽  
Author(s):  
Fleur C. Van Duyl ◽  
Benjamin Mueller ◽  
Erik H. Meesters
Keyword(s):  
Organic Matter ◽  
Stable Isotope ◽  
Environmental Changes ◽  
Food Sources ◽  
Sponge Species ◽  
Isotopic Niche ◽  
Δ13c And Δ15n ◽  
Spatio Temporal ◽  
Species Specific ◽  
Potential Food

Sponges are ubiquitous on coral reefs, mostly long lived and therefore adaptive to changing environmental conditions. They feed on organic matter withdrawn from the passing water and they may harbor microorganisms (endosymbionts), which contribute to their nutrition. Their diets and stable isotope (SI) fractionation determine the SI signature of the sponge holobiont. Little is known of spatio–temporal variations in SI signatures of δ13C and δ15N in tropical sponges and whether they reflect variations in the environment. We investigated the SI signatures of seven common sponge species with different functional traits and their potential food sources between 15 and 32 m depth along the S-SE and E-NE side of the Saba Bank, Eastern Caribbean, in October 2011 and October 2013. SI signatures differed significantly between most sponge species, both in mean values and in variation, indicating different food preferences and/or fractionation, inferring sponge species-specific isotopic niche spaces. In 2011, all sponge species at the S-SE side were enriched in d13C compared to the E-NE side. In 2013, SI signatures of sponges did not differ between the two sides and were overall lighter in δ13C and δ15N than in 2011. Observed spatio–temporal changes in SI in sponges could not be attributed to changes in the SI signatures of their potential food sources, which remained stable with different SI signatures of pelagic (particulate organic matter (POM): δ13C −24.9‰, δ15N +4.3‰) and benthic-derived food (macroalgae: δ13C −15.4‰, δ15N +0.8‰). Enriched δ13C signatures in sponges at the S-SE side in 2011 are proposed to be attributed to predominantly feeding on benthic-derived C. This interpretation was supported by significant differences in water mass constituents between sides in October 2011. Elevated NO3 and dissolved organic matter concentrations point toward a stronger reef signal in reef overlying water at the S-SE than N-NE side of the Bank in 2011. The depletions of δ13C and δ15N in sponges in October 2013 compared to October 2011 concurred with significantly elevated POM concentrations. The contemporaneous decrease in δ15N suggests that sponges obtain their N mostly from benthic-derived food with a lower δ15N than pelagic food. Average proportional feeding on available sources varied between sponge species and ranged from 20% to 50% for benthic and 50% to 80% for pelagic-derived food, assuming trophic enrichment factors of 0.5‰ ± sd 0.5 for δ13C and 3‰ ± sd 0.5 for δ15N for sponges. We suggest that observed variation of SI in sponges between sides and years were the result of shifts in the proportion of ingested benthic- and pelagic-derived organic matter driven by environmental changes. We show that sponge SI signatures reflect environmental variability in space and time on the Saba Bank and that SI of sponges irrespective of their species-specific traits move in a similar direction in response to these environmental changes.

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