Effects of Bythotrephes on the trophic position of native macroinvertebrates

2010 ◽  
Vol 67 (1) ◽  
pp. 58-69 ◽  
Author(s):  
Sophie E. Foster ◽  
W. Gary Sprules
Keyword(s):  
Stable Isotopes ◽  
Trophic Position ◽  
Nitrogen Isotope ◽  
Diet Overlap ◽  
Invertebrate Predators ◽  
Invasion Impacts ◽  
Isotopic Baseline ◽  
Zooplankton Communities

We measured the δ15N and δ13C stable isotopes of pelagic invertebrate predators in six central Ontario lakes, three invaded by Bythotrephes and three not invaded, to determine the effects of Bythotrephes invasion on diet overlap and trophic position of the predators. Seasonally averaged, lake-specific isotope signatures of bulk zooplankton were used as the isotopic baseline for determining nitrogen-based trophic position or carbon enrichment of the predators. Trophic positions of native Chaoborus , Leptodora , and Mysis in invaded lakes were not elevated compared with noninvaded lakes, suggesting that these predators do not feed directly on Bythotrephes. Nitrogen signatures of Mysis and Chaoborus were similar as were those of Leptodora and Bythotrephes, suggesting that invasion impacts will be greatest on Leptodora as has been observed. The trophic position of large Mysis was generally the highest and most variable of all predators, probably because it feeds on copepods that are more enriched in the heavier nitrogen isotope than bulk zooplankton and because Bythotrephes tends to decrease the ratio of cladocerans to copepods in invaded zooplankton communities.

Assessment of indigeneity in fossil organic matter: amino acids and stable isotopes

1991 ◽  
Vol 333 (1268) ◽  
pp. 367-374 ◽  
Keyword(s):  
Amino Acids ◽  
Stable Isotopes ◽  
Organic Matter ◽  
New Technologies ◽  
Trophic Position ◽  
Stable Carbon Isotope ◽  
Nitrogen Isotope ◽  
Alternative Methods ◽  
Stable Carbon ◽  
Residual Organic Matter

Whereas the presence of amino acids in fossil materials is clearly related to biosynthesis, an indigenous relationship with the fossil may be suspect. At present, attempts to establish the indigeneity of amino acids in fossils are based on distribution and stereochemistry. However, fossil systems are not closed and racemization may be retarded in organic materials within a fossil matrix. The advent of new technologies has resulted in alternative methods for evaluating the authenticity of fossil organic matter. A comparison of the stable carbon isotope compositions of the D- and L-enantiomers of individual amino acids facilitates the evaluation of indigeneity. Here we report the application of this method for determining the origin(s) of amino acids in fossils and extraterrestrial samples. Further, nitrogen isotope compositions of fossil materials should reflect trophic order, with increasing enrichment in 515N with progression up the food chain. Establishment of the trophic position of a fossil would further reinforce the appraisal of indigeneity based on the isotopic composition of its residual organic matter. Results of initial studies on Cretaceous age vertebrates which are consistent with the suggested feeding morphologies of these organisms are also presented.

Changes in the crustacean communities of Lakes Michigan, Huron, and Erie following the invasion of the predatory cladoceran Bythotrephes longimanus

2004 ◽  
Vol 61 (11) ◽  
pp. 2111-2125 ◽  
Author(s):  
Richard P Barbiero ◽  
Marc L Tuchman
Keyword(s):  
Zooplankton Community ◽  
Crustacean Zooplankton ◽  
Bythotrephes Longimanus ◽  
Zooplankton Community Structure ◽  
Cladoceran Species ◽  
Invertebrate Predators ◽  
Predatory Cladoceran ◽  
Leptodora Kindti ◽  
Escape Responses ◽  
Zooplankton Communities

The crustacean zooplankton communities in Lakes Michigan and Huron and the central and eastern basins of Lake Erie have shown substantial, persistent changes since the invasion of the predatory cladoceran Bythotrephes in the mid-1980s. A number of cladoceran species have declined dramatically since the invasion, including Eubosmina coregoni, Holopedium gibberum, Daphnia retrocurva, Daphnia pulicaria, and Leptodora kindti, and overall species richness has decreased as a result. Copepods have been relatively unaffected, with the notable exception of Meso cyclops edax, which has virtually disappeared from the lakes. These species shifts have for the most part been consistent and equally pronounced across all three lakes. Responses of crustacean species to the Bythotrephes invasion do not appear to be solely a consequence of size, and it is likely that other factors, e.g., morphology, vertical distribution, or escape responses, are important determinants of vulnerability to predation. Our results indicate that invertebrate predators in general, and invasive ones in particular, can have pronounced, lasting effects on zooplankton community structure.

scholarly journals Preliminary study into the trophic position of symbiotic palaemonid shrimps (Decapoda, Palaemonidae) using stable isotopes

Crustaceana ◽  
2021 ◽  
Vol 94 (9) ◽  
pp. 1145-1153
Author(s):  
Sammy De Grave ◽  
Ulrich Struck ◽  
Magnus L. Johnson
Keyword(s):  
Stable Isotopes ◽  
Trophic Position ◽  
Preliminary Study

Determination of food sources and trophic position in Malaysian tropical highland streams using carbon and nitrogen stable isotopes

2017 ◽  
Vol 37 (2) ◽  
pp. 97-104 ◽  
Author(s):  
Dhiya Shafiqah Ridzuan ◽  
Che Salmah Md. Rawi ◽  
Suhaila Abdul Hamid ◽  
Salman Abdo Al-Shami
Keyword(s):  
Stable Isotopes ◽  
Trophic Position ◽  
Food Sources ◽  
Nitrogen Stable Isotopes ◽  
Carbon And Nitrogen ◽  
Highland Streams

scholarly journals Copepods act as omnivores in a (sub)tropical reservoir: Implication for the top-down effect on phytoplankton

2018 ◽  
Vol 77 (2) ◽  
Author(s):  
Qiuqi Lin ◽  
Liang Peng ◽  
Yang Yang ◽  
Bo-Ping Han
Keyword(s):  
Organic Matter ◽  
Trophic Position ◽  
Zooplankton Community ◽  
Nitrogen Isotope ◽  
Terrestrial Organic Matter ◽  
Tropical Reservoir ◽  
Cascading Effect ◽  
Cladoceran Species ◽  
Grazing Effect ◽  
One Year

Tropical reservoirs in China receive a high input of organic matter from surrounding watersheds and this represents a significant resource for zooplankton consumers. Copepods are often the dominant zooplankton group in the tropical systems. Whether copepods tend to be omnivorous and their potential cascading effect on phytoplankton are subjects of debate. We used stable carbon and nitrogen isotope analyses to elucidate the allochthony and trophic positions of two copepod species (Phyllodiaptomus tunguidus and Mesocyclops thermocyclopoides) and one cladoceran species (Diaphanosoma orghidani) over a one-year period in a tropical oligo-mesotrophic reservoir in China. We assumed the filter-feeding D. orghidani was herbivorous and we used it as a baseline indicator of δ15N to estimate the trophic position of the two copepods. P. tunguidus and M. thermocyclopoides had an average trophic level that was 0.7 and 0.5 higher, respectively, than that of D. orghidani. M. thermocyclopoides showed seasonal differences in trophic position and an increase in trophic position with rising temperatures, whereas P. tunguidus remained omnivorous throughout the year. All three zooplankton species had a much higher degree of allochthony in the flood season than in the dry season, and their allochthony was positively related to the allochthony of the particulate organic matter input. The two copepods’ omnivorous behavior suggests their allochthony was primarily linked to microbial food web based on the input of terrestrial organic matter. The chlorophyll a to total phosphorus ratio was much higher when P. tunguidus dominated the zooplankton community than when D. orghidani dominated. The ratio was positively related to the ratio of omnivorous adult copepods to cladoceran biomass but not to the zooplankton:phytoplankton biomass ratio. Our results suggest that copepods tended to be omnivorous and relied heavily on allochthonous material in the study reservoir. The indirect cascading effect is likely to be stronger than the direct grazing effect, resulting in a positive effect of copepods on the phytoplankton.

Leaves as “crackers”, biofilm as “peanut butter”: Exploratory use of stable isotopes as evidence for microbial pathways in detrital food webs

2011 ◽  
Vol 40 (4) ◽  
Author(s):  
Robert France
Keyword(s):  
Energy Source ◽  
Stable Isotopes ◽  
Food Webs ◽  
Laboratory Experiments ◽  
Peanut Butter ◽  
Field Measurements ◽  
Nitrogen Isotope ◽  
Allochthonous Organic Matter ◽  
Stable Nitrogen Isotope ◽  
Microbial Biofilms

AbstractLaboratory experiments have shown benthic macroinvertebrates to be capable of consuming heterotrophic organisms which develop on decomposing terrestrial leaves. Questions remain, however, as to whether these microbial biofilms represent a significant energy source to macroinvertebrates within the natural environment compared to that supplied by leaf substrates themselves. A compilation of literature data on field measurements of stable nitrogen isotope ratios for herbivorous macroinvertebrates suggests that assimilation of microbial biofilms may be the principle means by which allochthonous organic matter enters freshwater detrital food webs.

Levels of stored energy but not marine foraging patterns differentiate seasonal ecotypes of wild and hatchery steelhead (Oncorhynchus mykiss) returning to the Kalama River, Washington

2017 ◽  
Vol 74 (2) ◽  
pp. 157-167 ◽  
Author(s):  
James S. Lamperth ◽  
Thomas P. Quinn ◽  
Mara S. Zimmerman
Keyword(s):  
Stable Isotopes ◽  
Oncorhynchus Mykiss ◽  
Trophic Position ◽  
Stored Energy ◽  
Arrival Date ◽  
Migration Distance ◽  
Foraging Patterns ◽  
Hatchery Fish ◽  
Foraging Area ◽  
Sufficient Energy

Anadromous fishes need to store sufficient energy at sea to migrate and reproduce, but the energetic demands of freshwater migration distance have been difficult to distinguish from the demands of fasting in fresh water prior to spawning. In addition, differences in stored energy may result from differences in metabolic storage or marine diet. We estimated somatic lipids (SL) and stable isotopes of N and C (as indices of marine trophic position and feeding location) in adult wild and hatchery steelhead (Oncorhynchus mykiss) of summer (stream-maturing) and winter (ocean-maturing) runs that migrate similar distances to spawn. We found that SL at return depended on several factors. Summer steelhead had twice the SL as winter steelhead, and within each run SL decreased with arrival date, converging on about 1% SL. In summer steelhead, females had 19% more SL than males, and wild fish had 21% more SL than hatchery fish. In winter steelhead, females had 27% less SL than males, and there was no difference between rearing origins. No differences were detected in δ15N or δ13C between ecotypes or rearing origins. Taken together, the results indicated different patterns of energy storage among and within ecotypes despite no apparent differences in marine trophic position or foraging area.

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