scholarly journals Phytoplankton Fuel Fish Food Webs in a Low-Turbidity Temperate Coastal Embayment: A Stable Isotope Approach

2021 ◽  
Vol 8 ◽  
Author(s):  
Goutam Kumar Kundu ◽  
Changseong Kim ◽  
Dongyoung Kim ◽  
Riaz Bibi ◽  
Heeyong Kim ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Food Webs ◽  
Trophic Levels ◽  
Food Sources ◽  
Estuarine Fish ◽  
Multiple Sources ◽  
Terrestrial Organic Matter ◽  
Fish Food ◽  
High Productivity

Trophic contributions of diverse OM sources to estuarine and coastal food webs differ substantially across systems around the world, particularly for nekton (fish, cephalopods, and crustaceans), which utilize basal resources from multiple sources over space and time because of their mobility and feeding behaviors at multiple trophic levels. We investigated the contributions of putative OM sources to fish food webs and assessed the spatiotemporal patterns, structures, and trophic connectivity in fish food webs across four seasons from three closely spaced (10–15 km) sites: an estuarine channel (EC), a deep bay (DB), and an offshore (OS) region in Gwangyang Bay, a high-productivity, low-turbidity estuarine embayment off the Republic of Korea. While nearly all previous studies have focused on few representative species, we examined δ13C and δ15N values of whole nekton communities along with dominant benthic macro-invertebrates, zooplankton, and their putative primary food sources. The δ13C and δ15N values coupled with MixSIAR, a Bayesian mixing model, revealed that these communities utilized multiple primary producers, but phytoplankton comprised the primary trophic contributor (46.6–69.1%). Microphytobenthos (15.8–20.4%) and the seagrass Zostera marina (8.6–19.8%) made substantial contributions, but the role of river-borne terrestrial organic matter was negligible. Spatially different species composition and stable isotope values, but higher utilization of coastal phytoplankton by estuarine fish, indicated disparate food webs structures between the EC and DB/OS coastal areas, with considerable trophic connectivity. Greater overlaps in fish and cephalopod isotopic niches than among other consumers and a higher estimated carbon trophic enrichment factor for EC nekton confirmed feeding migration-mediated biological transport of coastal OM sources to the estuary. Further, the seasonally consistent structures and resource utilization patterns indicate that fish food webs are resilient to changes at lower trophic levels. Our results contrast with those for other highly turbid coastal systems depending highly on diversified basal sources, including exported terrestrial and wetland detritus alongside autochthonous phytoplankton. Finally, this study provides a novel perspective on the role of OM sources in such low turbidity and highly productive coastal embayments and enhances our understanding of marine ecosystems.

Trophic guilds of generalist feeders in soil animal communities as indicated by stable isotope analysis (15N/14N)

2010 ◽  
Vol 100 (5) ◽  
pp. 511-520 ◽  
Author(s):  
K. Oelbermann ◽  
S. Scheu
Keyword(s):  
Stable Isotope ◽  
Food Webs ◽  
Trophic Level ◽  
A Priori ◽  
Isotope Analysis ◽  
Trophic Levels ◽  
Soil Arthropods ◽  
Trophic Guilds ◽  
Natural Variations ◽  
Animal Communities

AbstractWe investigated if the commonly used aggregation of organisms into trophic guilds, such as detritivores and predators, in fact represent distinct trophic levels. Soil arthropods of a forest-meadow transect were ascribed a priori to trophic guilds (herbivores, detritivores, predators and necrovores), which are often used as an equivalent to trophic levels. We analysed natural variations in 15N/14N ratios of the animals in order to investigate the trophic similarity of organisms within (a priori defined) trophic guilds. Using trophic guilds as an equivalent to trophic level, the assumed stepwise enrichment of 15N by 3.4‰ per trophic level did not apply to detritivores; they were only enriched in 15N by on average 1.5‰ compared to litter materials. Predators on average were enriched in 15N by 3.5‰ compared to detritivores. Within detritvores and predators δ15N signatures varied markedly, indicating that these trophic guilds are dominated by generalist feeders which form a gradient of organisms feeding on different resources. The results indicate that commonly used trophic guilds, in particular detritivores and predators, do not represent trophic levels but consist of subguilds, i.e. subsets of organisms differing in resource utilization. In particular, in soil and litter food webs where trophic level omnivory is common, the use of distinct trophic levels may be inappropriate. Guilds of species delineated by natural variations of stable isotope ratios are assumed to more adequately represent the structure of litter and soil food webs allowing a more detailed understanding of their functioning.

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 What Is the Carcass-Usage Mode of the Collembola? A Case Study of Entomobrya proxima in the Laboratory

Insects ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 67 ◽  
Author(s):  
Lichao Feng ◽  
Liang Chang ◽  
Shaoqing Zhang ◽  
Xinyu Zhu ◽  
Sina Adl ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Food Preference ◽  
Feeding Habits ◽  
Food Resource ◽  
Food Preferences ◽  
Trophic Levels ◽  
Food Sources ◽  
Body Parts ◽  
Animal Food ◽  
Rhizopus Sp

Collembola display a variety of feeding habits, and prey on many types of food at different trophic levels in the soil. In most cases, their feeding selections are widely varied. In the interest of the food preferences of E. proxima, we attempted to confirm how the Collembola utilize food when feeding on carrion (unusual sources). Four different soil animals (with different stable isotope values and increasing trophic levels) were used to examine whether collembolans can use dead insects as a food resource in specific manners, depending on food preference. Our results demonstrated that the food preference of a collembolan changed significantly after feeding on insects with different feeding habits for 60 days. We found that stable isotope values (δ13C) of Entomobrya proxima approached those of the food sources. A large proportion of the diet (more than 50%) should directly consist of insect body parts, with the remainder consisting of indirectly used, mixed microorganisms naturally growing on animal food, such as fungi (Rhizopus sp., Alternaria sp., Penicillium sp., and Aspergillus sp.) and bacteria (Bacillus sp1. and Bacillus sp2.). Based on this research, the food preference of collembolans is more focused on carcasses (dead insect bodies) than microorganisms during the animal-food decomposition process.

Flexible diet and trophic position of dreissenid mussels as inferred from stable isotopes of carbon and nitrogen

2005 ◽  
Vol 62 (5) ◽  
pp. 1119-1129 ◽  
Author(s):  
David W Garton ◽  
Christopher D Payne ◽  
Joseph P Montoya
Keyword(s):  
Stable Isotope ◽  
Dreissena Polymorpha ◽  
Lake Erie ◽  
Trophic Position ◽  
Nitrogen Isotope ◽  
Isotope Ratios ◽  
Trophic Levels ◽  
Food Sources ◽  
Stable Isotope Ratios ◽  
Western Lake

In this study, the trophic position and food-web impacts of invading zebra mussels (Dreissena polymorpha) were investigated by sampling mussels, seston (= phytoplankton), macrophytes, zooplankton, and surficial sediment in two small inland lakes (1999–2002) and similarly in western Lake Erie (1999 only). Tissues from quagga mussels (Dreissena bugensis) from Lake Erie were also analyzed. Stable-isotope ratios (15N/14N and 13C/12C) were used to identify likely food sources and estimate relative trophic position. For Lake Erie, stable-isotope ratios indicated no diet differences between the two mussel species. For all lakes, zooplankton δ13C was indicative of phytoplanktivory. The 13C stable isotope ratios indicated that seston comprised ~50% of food sources for mussels in Lake Erie, but 73%–97% and 52%–100% of the diet of mussel populations in Lake Wawasee and Clark Lake, respectively. Stable nitrogen isotope ratios placed zooplankton at trophic levels equal to or higher than those of mussels in seven of eight comparisons. Dreissena polymorpha and D. bugensis are able to exploit suspended detritus as a significant energy source, as well as compete directly with zooplankton for seston as a food source and with each other in areas of sympatry.

scholarly journals Interpreting stable isotopes in food webs: Recognizing the role of time averaging at different trophic levels

2002 ◽  
Vol 47 (1) ◽  
pp. 306-309 ◽  
Author(s):  
C. M. O'Reilly ◽  
R. E. Hecky ◽  
A. S. Cohen ◽  
P.-D. Plisnier
Keyword(s):  
Stable Isotopes ◽  
Food Webs ◽  
Trophic Levels ◽  
Time Averaging

Trophic analyses of opportunistic polychaetes (Ophryotrocha cyclops) at salmonid aquaculture sites

2015 ◽  
Vol 95 (4) ◽  
pp. 713-722 ◽  
Author(s):  
Flora Salvo ◽  
Dounia Hamoutene ◽  
Suzanne C. Dufour
Keyword(s):  
Stable Isotope ◽  
Trace Element ◽  
Trace Element Analysis ◽  
Food Sources ◽  
Spatial And Temporal Variation ◽  
Element Analysis ◽  
Associated Bacteria ◽  
Stable Isotope Analyses ◽  
Isotope Analyses

A new species of dorvilleid polychaete,Ophryotrocha cyclops, has been observed on the rocky seafloor underneath deep salmonid aquaculture sites on the south coast of Newfoundland, Canada. The distribution of these opportunistic worms is likely related to organic matter accumulation on the seafloor, and this species may have a role in remediation processes. To better understand the functional role ofO. cyclopsat aquaculture sites, it is important to know what they feed upon. Here, stable isotope analyses (δ13C, δ15N and δ34S) and trace element analyses were performed on dorvilleids and their potential food sources at three aquaculture sites. Stable isotope analyses revealed spatial and temporal variation in the isotopic carbon signature ofO. cyclops, highlighting possible differences in the food sources of individual dorvilleids within and between sites. The isotopic composition of dorvilleids was closest to that of fish pellets; the presence of abundant lipid droplets in gut epithelial cells ofO. cyclopssuggests the assimilation of fish pellet-derived lipids. Trace element analysis indicated thatO. cyclopsdoes not concentrate the aquaculture tracers Zn or Cu to a large extent. However, concentrations of sulphur were high inO. cyclopscompared with other sources. Taken together, results show thatO. cyclopsmost likely consume both fish pellets and flocculent matter-associated bacteria. As such, they are involved in sulphur cycling and fish pellet degradation at aquaculture sites.

‘Hitchhiker’ polynoid polychaetes in cold deep waters and their potential influence on benthic soft bottom food webs

2010 ◽  
Vol 22 (4) ◽  
pp. 399-407 ◽  
Author(s):  
Stefano Schiaparelli ◽  
Maria Chiara Alvaro ◽  
Jehns Bohn ◽  
Giancarlo Albertelli
Keyword(s):  
Food Webs ◽  
Ross Sea ◽  
Trophic Levels ◽  
Tropical Environments ◽  
Deep Waters ◽  
New Association ◽  
Definition Of ◽  
The Impact ◽  
True Predator

AbstractWe describe a new association for Antarctica, involving an holothuroid host,Bathyplotes bongrainiVaney, 1914, and a parasitic polynoid polychaete,Eunoe opalinaMcIntosh, 1885, which lives on the host body. Both species have never been recorded in the study area, the Ross Sea. The ecological definition of this partnership is difficult to assess, being a mix of phoresis, protective association, parasitism and, possibly, kleptocommensalism.Eunoe opalinaemerges also as a true predator, ingesting several food items that do not belong to the diet ofBathyplotes. We compare this association with analogous examples known from shallow tropical environments as well as bathyal and abyssal depths. Given the conspicuous similarities between the deep water and high latitude examples of this kind of association, a possible common origin is hypothesized. Although the role of such a kind of parasitic relationships in Antarctic communities remains to be fully evaluated, it seems evident that, at high latitudes, where trophic levels are simplified and food webs do not have much redundancy, the impact of such a ‘multitasking’ predator-parasite asE. opalinamight be of a greater magnitude than its shallow water tropical counterpart.

scholarly journals Kindergarten Children’s Perception about the Ecological Roles of Living Organisms

2020 ◽  
Vol 12 (22) ◽  
pp. 9565
Author(s):  
Claudia Melis ◽  
Per-Arvid Wold ◽  
Anna Maria Billing ◽  
Kathrine Bjørgen ◽  
Børge Moe
Keyword(s):  
Ecosystem Services ◽  
Food Webs ◽  
Intrinsic Value ◽  
Trophic Levels ◽  
Kindergarten Children ◽  
Ecological Role ◽  
The Public ◽  
Raising Awareness ◽  
Living Organisms

Young children will inherit the biosphere; therefore, it is crucial that they recognize the importance of all living organisms based on their intrinsic value and ecosystem function, not only on their “cuteness”. However, children’s knowledge about the interdependence among organisms has been little investigated. We interviewed 56 kindergarten children (5–6 years old) in Norway. The aim of the study was to investigate their perception of the importance for nature of six organisms, representing different trophic levels of food webs (producers, consumers, decomposers) and providing different ecosystem services (production, decomposition, and pollination). There was no difference in ranking between sexes or between ordinary and farm-based kindergartens. Bumblebees and earthworms were perceived as the most important organisms, followed by squirrel, trees, and wolf. None of the children recognized the ecological role of mushrooms. Our results show that, although upon completing kindergarten many children had gained an early understanding of the role of different organisms in nature, they missed the importance of plants and fungi. Kindergarten children’s “fungi blindness” might reflect a neglect of the public for this extremely important, diverse, and dominating taxon. We should therefore put more emphasis in raising awareness about the interdependence among trophic levels in food webs.

Trophic relationships among animals associated with drifting wrack

2018 ◽  
Vol 69 (8) ◽  
pp. 1248 ◽  
Author(s):  
Ryan J. Baring ◽  
Rebecca E. Lester ◽  
Peter G. Fairweather
Keyword(s):  
Stable Isotope ◽  
Food Webs ◽  
Sandy Beach ◽  
Sandy Beaches ◽  
Trophic Levels ◽  
Trophic Relationships ◽  
Gut Contents ◽  
Future Research ◽  
Δ13c And Δ15n ◽  
Trophic Pathways

Wrack accumulates commonly in surf zones of sandy beaches and can be a semipermanent feature. Very few studies have investigated the trophic pathways associated with wrack accumulations in sandy beach surf zones, despite their potential importance to nearshore food webs. In the present study, we were specifically interested in determining the fish–wrack trophic associations in the nearshore. Macrophytes, macroinvertebrates and fish were sampled from drifting wrack at two sites with different macrophyte compositions (i.e. algae v. an algae–seagrass mix) in South Australia. The gut contents of fish were sampled, and the δ13C and δ15N stable isotope signatures of fish, macroinvertebrates and macrophytes were analysed. Using both the stable isotope and diet data, we identified that fish are feeding among wrack accumulations, but some unexplained trophic pathways suggest that fish are also likely to be foraging over multiple habitats elsewhere for food. In contrast, there was more evidence that grazing macroinvertebrates may be feeding on and around macrophytes within the accumulations, as well as using them as habitat. Thus, the present study established some baseline trophic pathways associated with wrack accumulations in sandy beach surf zones. Given the modest evidence for use of wrack as a food source, the lower trophic levels of the food webs identified remain unknown and should be an area for future research.

scholarly journals Food Web Fuel Differs Across Habitats and Seasons of a Tidal Freshwater Estuary

2020 ◽  
Vol 44 (1) ◽  
pp. 286-301
Author(s):  
Matthew Young ◽  
Emily Howe ◽  
Teejay O’Rear ◽  
Kathleen Berridge ◽  
Peter Moyle
Keyword(s):  
Food Web ◽  
Food Webs ◽  
San Francisco ◽  
Aquatic Vegetation ◽  
Environmental Variability ◽  
Spatial Scales ◽  
Water Channel ◽  
Trophic Levels ◽  
Food Sources ◽  
Primary Producers

AbstractEstuarine food webs are fueled by multiple different primary producers. However, identifying the relative importance of each producer to consumers is difficult, particularly for fishes that utilize multiple food sources due to both their mobility and their generally high trophic levels. Previous studies have documented broad spatial differences in the importance of primary producers to fishes within the Upper San Francisco Estuary, California, including separation between pelagic and littoral food webs. In this study, we evaluated the importance of primary producers to adult fishes in three closely spaced subregions that represented disparate habitat types (a tidal wetland channel, a turbid backwater channel, and a deep open-water channel), each a potential outcome of local restoration projects. Using stable isotope analysis coupled with a Bayesian mixing model, we identified significant differences in primary-producer contribution to fishes and invertebrates across habitats and seasons, especially in the relative contribution of submersed aquatic vegetation and phytoplankton. Most fishes utilized multiple primary producers and showed little segregation between pelagic and littoral food webs among habitats. Availability of primary producers differs seasonally and across multiple spatial scales, helping to buffer environmental variability and thus enhancing food web resilience. Ecosystem restoration may improve with emphasis on restoring a wide variety of primary producers to support consumers.

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