scholarly journals Dietary Shifts and Risks of Artifact Ingestion for Argentine Shortfin Squid Illex argentinus in the Southwest Atlantic

2021 ◽  
Vol 8 ◽  
Author(s):  
Ssu-Wei Chang ◽  
Ruei-Gu Chen ◽  
Tsung-Han Liu ◽  
Yao-Chang Lee ◽  
Chih-Shin Chen ◽  
...  
Keyword(s):  
Marine Pollution ◽  
Trophic Levels ◽  
Southwest Atlantic ◽  
Plastic Materials ◽  
Large Populations ◽  
Illex Argentinus ◽  
Dietary Shifts ◽  
Aquatic Food ◽  
Taxonomic Groups ◽  
Southward Migration

Cephalopods play an important role in both ecology and fisheries. Variations in the dietary compositions of squids with large populations further promote interactions between different trophic levels in marine ecosystems. Moreover, due to marine pollution, squids are also at risks of artifact ingestion, and there is limited understanding about the influence of artifacts on the feeding behavior of squids. We examined 296 stomachs of the Argentine shortfin squid Illex argentinus collected through commercial catches across the Southwest Atlantic from February to April of 2018 and 2019 to establish the monthly dietary compositions and risks of artifact ingestion. The results supported typical observations that the Argentine shortfin squids switched from a diet dominated by crustaceans at small sizes to consuming larger prey, predominantly fishes and/or cephalopods, at large sizes during their growth and southward migration. Significantly higher consumption of fishes was observed in recent years compared with that observed in other studies since 1992. The ingested artifacts examined were composed of plastic and non-plastic materials. Artifacts were observed in 19.9% of the total number of stomachs, with 20.5% of the empty stomachs containing artifact remains. The results indicate that although the main dietary compositions of the Argentine shortfin squid maintain the taxonomic groups of prey compositions, the dietary structure, i.e., composition percentage, is varying. The detection of artifacts suggests that environmental monitoring is needed in this region in order to manage and conserve the squid and safeguard aquatic food safety.

scholarly journals Variation in the isotopic composition of striped weakfish Cynoscion guatucupa of the Southwest Atlantic Ocean in response to dietary shifts

2017 ◽  
Vol 78 (2) ◽  
pp. 202-210 ◽  
Author(s):  
M. N. Paso Viola ◽  
L. Riccialdelli ◽  
A. Jaureguizar ◽  
H. O. Panarello ◽  
H. L. Cappozzo
Keyword(s):  
Atlantic Ocean ◽  
Isotopic Composition ◽  
Isotope Composition ◽  
Trophic Levels ◽  
Sampling Location ◽  
Southwest Atlantic ◽  
Δ13c And Δ15n ◽  
Size Classes ◽  
Cynoscion Guatucupa ◽  
Dietary Shifts

Abstract The aim of this study was to analyze the isotopic composition in muscle of striped weakfish Cynoscion guatucupa from Southwest Atlantic Ocean in order to evaluate a possible variation in δ13C and δ15N in response to dietary shifts that occur as animals grow. We also explored for isotopic evidence of differences between sample locations. The results showed an agreement between isotope analysis and previous conventional studies. Differences in the isotope composition between sampling location were not observed. A positive relation exists between isotope values and total body length of the animals. The Cluster analysis defined three groups of size classes, validated by the MDS. Differences in the relative consumption of prey species in each size class were also observed performing isotope mixing models (SIAR). Variation in δ15N among size classes would be associated with the consumption of a different type of prey as animals grow. Small striped weakfish feed on small crustaceans and progressively increase their consumption of fish (anchovy, Engraulis anchoita), increasing by this way their isotope values. On the other hand, differences in δ13C values seemed to be related to age-class specific spatial distribution patterns. Therefore, large and small striped weakfish remain specialized but feeding on different prey at different trophic levels. These results contribute to the study of the diet of striped weakfish, improve the isotopic ecology models and highlight on the importance of accounting for variation in the isotopic composition in response to dietary shifts with the size of one of the most important fishery resources in the region.

scholarly journals Elevated temperature and browning increase dietary methylmercury, but decrease essential fatty acids at the base of lake food webs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pianpian Wu ◽  
Martin J. Kainz ◽  
Fernando Valdés ◽  
Siwen Zheng ◽  
Katharina Winter ◽  
...  
Keyword(s):  
Climate Change ◽  
Fatty Acids ◽  
Organic Matter ◽  
Food Webs ◽  
Essential Fatty Acids ◽  
Trophic Levels ◽  
Climate Change Scenarios ◽  
Essential Nutrients ◽  
Aquatic Food Webs ◽  
Aquatic Food

AbstractClimate change scenarios predict increases in temperature and organic matter supply from land to water, which affect trophic transfer of nutrients and contaminants in aquatic food webs. How essential nutrients, such as polyunsaturated fatty acids (PUFA), and potentially toxic contaminants, such as methylmercury (MeHg), at the base of aquatic food webs will be affected under climate change scenarios, remains unclear. The objective of this outdoor mesocosm study was to examine how increased water temperature and terrestrially-derived dissolved organic matter supply (tDOM; i.e., lake browning), and the interaction of both, will influence MeHg and PUFA in organisms at the base of food webs (i.e. seston; the most edible plankton size for zooplankton) in subalpine lake ecosystems. The interaction of higher temperature and tDOM increased the burden of MeHg in seston (< 40 μm) and larger sized plankton (microplankton; 40–200 μm), while the MeHg content per unit biomass remained stable. However, PUFA decreased in seston, but increased in microplankton, consisting mainly of filamentous algae, which are less readily bioavailable to zooplankton. We revealed elevated dietary exposure to MeHg, yet decreased supply of dietary PUFA to aquatic consumers with increasing temperature and tDOM supply. This experimental study provides evidence that the overall food quality at the base of aquatic food webs deteriorates during ongoing climate change scenarios by increasing the supply of toxic MeHg and lowering the dietary access to essential nutrients of consumers at higher trophic levels.

scholarly journals Aquatic food web research in mesocosms: a literature survey

2020 ◽  
Author(s):  
Csenge Póda ◽  
Ferenc Jordán
Keyword(s):  
Food Web ◽  
Multiple Stressors ◽  
Experimental Testing ◽  
Literature Survey ◽  
Trophic Levels ◽  
Combined Effects ◽  
Theoretical Concepts ◽  
Aquatic Food ◽  
Emerging Topics ◽  
Web Research

Food web research feeds ecology with elementary theoretical concepts that need controlled experimental testing. Mesocosm facilities offer multiple ways to execute experimental food web research in a rigorous way. We performed a literature survey to overview food web research implementing the mesocosm approach. Our goal was to summarise quantitatively how the mesocosm approach has formerly been used and question how to best utilise mesocosms for the emerging topics in food web research in the future. We suggest increasing the number of replicates, extending the duration of the experiments, involving higher trophic levels and addressing the combined effects of multiple stressors.

scholarly journals Patterns, dynamics and consequences of microplastic ingestion by the temperate coral, Astrangia poculata

2019 ◽  
Vol 286 (1905) ◽  
pp. 20190726 ◽  
Author(s):  
Randi D. Rotjan ◽  
Koty H. Sharp ◽  
Anna E. Gauthier ◽  
Rowan Yelton ◽  
Eliya M. Baron Lopez ◽  
...  
Keyword(s):  
Rhode Island ◽  
Marine Invertebrates ◽  
Trophic Levels ◽  
Coastal Environments ◽  
Monitoring Tool ◽  
Astrangia Poculata ◽  
Temperate Coral ◽  
Inhibit Food Intake ◽  
Aquatic Food ◽  
Behavioural Dynamics

Microplastics (less than 5 mm) are a recognized threat to aquatic food webs because they are ingested at multiple trophic levels and may bioaccumulate. In urban coastal environments, high densities of microplastics may disrupt nutritional intake. However, behavioural dynamics and consequences of microparticle ingestion are still poorly understood. As filter or suspension feeders, benthic marine invertebrates are vulnerable to microplastic ingestion. We explored microplastic ingestion by the temperate coral Astrangia poculata . We detected an average of over 100 microplastic particles per polyp in wild-captured colonies from Rhode Island. In the laboratory, corals were fed microbeads to characterize ingestion preference and retention of microplastics and consequences on feeding behaviour. Corals were fed biofilmed microplastics to test whether plastics serve as vectors for microbes. Ingested microplastics were apparent within the mesenterial tissues of the gastrovascular cavity. Corals preferred microplastic beads and declined subsequent offerings of brine shrimp eggs of the same diameter, suggesting that microplastic ingestion can inhibit food intake. The corals co-ingested Escherichia coli cells with microbeads. These findings detail specific mechanisms by which microplastics threaten corals, but also hint that the coral A. poculata , which has a large coastal range, may serve as a useful bioindicator and monitoring tool for microplastic pollution.

scholarly journals Selenium Interactions with Algae: Chemical Processes at Biological Uptake Sites, Bioaccumulation, and Intracellular Metabolism

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 528 ◽  
Author(s):  
Dominic E. Ponton ◽  
Stephanie D. Graves ◽  
Claude Fortin ◽  
David Janz ◽  
Marc Amyot ◽  
...  
Keyword(s):  
Food Webs ◽  
Mechanistic Model ◽  
Trophic Levels ◽  
Primary Producers ◽  
Organic Selenium ◽  
Selenium Uptake ◽  
Aquatic Food Webs ◽  
Uptake Sites ◽  
Aquatic Food ◽  
Lentic Systems

Selenium (Se) uptake by primary producers is the most variable and important step in determining Se concentrations at higher trophic levels in aquatic food webs. We gathered data available about the Se bioaccumulation at the base of aquatic food webs and analyzed its relationship with Se concentrations in water. This important dataset was separated into lotic and lentic systems to provide a reliable model to estimate Se in primary producers from aqueous exposure. We observed that lentic systems had higher organic selenium and selenite concentrations than in lotic systems and selenate concentrations were higher in lotic environments. Selenium uptake by algae is mostly driven by Se concentrations, speciation and competition with other anions, and is as well influenced by pH. Based on Se species uptake by algae in the laboratory, we proposed an accurate mechanistic model of competition between sulfate and inorganic Se species at algal uptake sites. Intracellular Se transformations and incorporation into selenoproteins as well as the mechanisms through which Se can induce toxicity in algae has also been reviewed. We provided a new tool for risk assessment strategies to better predict accumulation in primary consumers and consequently to higher trophic levels, and we identified some research needs that could fill knowledge gaps.

Habitat, trophic levels and migration patterns of the short-finned squid Illex argentinus from stable isotope analysis of beak regions

Polar Biology ◽  
2019 ◽  
Vol 42 (12) ◽  
pp. 2299-2304 ◽  
Author(s):  
José P. Queirós ◽  
Richard A. Phillips ◽  
Alexandra Baeta ◽  
José Abreu ◽  
José C. Xavier
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Trophic Levels ◽  
Migration Patterns ◽  
Illex Argentinus ◽  
And Migration

Zooplankton growth and survival differentially respond to interactive warming and acidification effects

2020 ◽  
Vol 42 (2) ◽  
pp. 189-202
Author(s):  
Jessica Garzke ◽  
Ulrich Sommer ◽  
Stefanie M H Ismar-Rebitz
Keyword(s):  
Ocean Acidification ◽  
Single Species ◽  
Functional Trait ◽  
Trophic Levels ◽  
Growth And Survival ◽  
Geographical Regions ◽  
Wide Range ◽  
Set Up ◽  
Taxonomic Groups ◽  
Zooplankton Growth

Abstract The copepod Acartia tonsa is a key component of a wide range of marine ecosystems, linking energy transfer from phytoplankton to higher trophic levels, and has a central role in productivity and biogeochemistry. The interaction of end-of-century global warming and ocean acidification scenarios with testing moderate temperature effects on a seminatural copepod community is needed to understand future community functioning. Here, we deployed a mesocosm experimental set-up with a full factorial design using two temperatures (13°C and 19°C) crossed with a pCO2 gradient ranging from ambient (550 μatm) to 3000 μatm. We used the natural bacteria, phyto- and microzooplankton species composition and biomass of the Kiel Bight and tested the response of A. tonsa development, carbon growth, mortality, size and condition. The tested traits were differently affected by the interaction of temperature and acidification. Ocean acidification increased development, carbon growth, size and mortality under the warming scenario of 19°C. At 13°C mortality rates decreased, while carbon growth, size and condition increased with acidification. We conclude from our experimental approach that a single species shows a variety of responses depending on the focal functional trait. Trait-specific mesozooplankton responses need to be further investigated and compared between geographical regions, seasons and taxonomic groups.

The Lake Ontario Life Support System

1987 ◽  
Vol 44 (12) ◽  
pp. 2230-2240 ◽  
Author(s):  
D. R. S. Lean ◽  
H-J. Fricker ◽  
M. N. Charlton ◽  
R. L. Cuhel ◽  
F. R. Pick
Keyword(s):  
Primary Productivity ◽  
Life Support ◽  
Lake Ontario ◽  
Trophic Levels ◽  
Phosphorus Concentration ◽  
Nutrient Regeneration ◽  
Particulate Carbon ◽  
Calcium Carbonate Precipitation ◽  
Mixing Processes ◽  
Aquatic Food

Primary productivity provides most of the energy to support aquatic food chains. The rate is not only influenced by available solar radiation but also by temperature, availability of phosphorus, and the influence of physical mixing processes. The special features of Lake Ontario such as changes in phosphorus concentration, calcium carbonate precipitation, and silica deficiency on primary productivity, concentration of particulate carbon, and chlorophyll are discussed. Our lack of understanding of food chain and nutrient regeneration processes is illustrated through our failure to balance carbon production with losses through zooplankton grazing and sedimentation. It was demonstrated, however, that bacteria are not responsible for nutrient regeneration through "mineralization" but nutrients are effectively recycled in the water column at the second and third trophic levels.

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