scholarly journals Trophic Trait Evolution Explains Variation in Nutrient Excretion Stoichiometry among Panamanian Armored Catfishes (Loricariidae)

Diversity ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 88
Author(s):  
Eric K. Moody ◽  
Fernando Alda ◽  
Krista A. Capps ◽  
Oscar Puebla ◽  
Benjamin L. Turner
Keyword(s):  
Significant Variation ◽  
Trophic Position ◽  
Nutrient Recycling ◽  
Trophic Niche ◽  
Relative Importance ◽  
Closely Related Species ◽  
Trait Evolution ◽  
Nutrient Excretion ◽  
Nutrient Mineralization ◽  
Excretion Rates

Variation in nutrient excretion rates and stoichiometric ratios (e.g., nitrogen to phosphorus) by consumers can have substantial effects on aquatic ecosystem function. While phylogenetic signals within an assemblage often explain variation in nutrient recycling rates and stoichiometry, the phylogenetically conserved traits that underlie this phenomenon remain unclear. In particular, variation in nutrient excretion stoichiometry across a phylogeny might be driven by phylogenetic patterns in either diet or body stoichiometry. We examined the relative importance of these traits in explaining variation in nutrient recycling rates and stoichiometry in a diverse family of Neotropical-armored catfishes, Loricariidae, in Panamanian streams. We found significant variation in nutrient mineralization traits among species and subfamilies, but variation in nutrient excretion stoichiometry among species was best explained by trophic position rather than body stoichiometry. The variation in trophic position among Panamanian species was consistent with variation in the trophic niche of their genera across South America, suggesting that phylogenetic patterns underpin the evolution of trophic and nutrient excretion traits among these species. Such geographical variation in nutrient mineralization patterns among closely related species may be common, given that trophic variation in fish lineages occurs widely. These results suggest that information on trophic trait evolution within lineages will advance our understanding of the functional contribution of animals to biogeochemical cycling.

scholarly journals Consumer-driven nutrient recycling of freshwater decapods: linking ecological theories and application in integrated multi-trophic aquaculture

2022 ◽  
Author(s):  
Gabriela Musin ◽  
María Victoria Torres ◽  
Débora de Azevedo Carvalho
Keyword(s):  
Body Mass ◽  
Nutrient Recycling ◽  
Elemental Content ◽  
Fish Feed ◽  
Nutrient Inputs ◽  
Nutrient Excretion ◽  
Nutrient Mineralization ◽  
Physiological Variables ◽  
Excretion Rates ◽  
Productive Systems

The Metabolic Theory of Ecology (MET) and the Ecological Stoichiometry Theory (EST) are central and complementary in the consumer-driven recycling conceptual basis. The comprehension of physiological processes of organisms at different levels of organizations is essential to explore and predict nutrient recycling behavior in different scenarios, and to design integrated productive systems that efficiently use the nutrient inputs through an adjusted mass balance. We fed with fish-feed three species of decapods from different families and with aquacultural potential to explore the animal-mediated nutrient dynamic and its applicability in productive systems. We tested whether physiological (body mass, body elemental content), ecological (diet), taxonomic and experimental (time of incubation) variables predicts N and P excretion rates and ratios across and within taxa. We also analysed body mass and body elemental content independently as predictors of N and P excretion of decapods across, among and within taxa. Finally, we verified if body content scales allometrically across and within taxa and if differed among taxa. Body mass and taxonomic identity predicted nutrient excretion rates both across and within taxa. When physiological variables were analysed independently, body size best predicted nutrient mineralization in both scales of analyses. Regarding body elemental content, only body P content scaled negatively with body mass across taxa. Results showed higher N-requirements and lower C:N of prawns than anomurans and crabs. The role of crustaceans as nutrient recyclers depends mainly on the species and body mass, and should be considered to select complementary species that efficiently use feed resources. Prawns need more protein in their feed and might be integrated with fish of higher N-requirements, while crabs and anomurans, with fish of lower N-requirements. Our study contributed to the background of MTE and EST through empirical data obtained from decapods and provided useful information to achieve more efficient aquaculture integration systems.

scholarly journals Fish-mediated nutrient recycling and the trophic cascade in lakes

2001 ◽  
Vol 58 (10) ◽  
pp. 1924-1931 ◽  
Author(s):  
José Luiz Attayde ◽  
Lars-Anders Hansson
Keyword(s):  
Phytoplankton Community ◽  
Nutrient Recycling ◽  
Effect Sizes ◽  
Zooplankton Grazing ◽  
Relative Importance ◽  
Phytoplankton Community Structure ◽  
Phytoplankton Assemblages ◽  
Nutrient Excretion ◽  
Positive Effects ◽  
Natural Phytoplankton

The effects of planktivorous fish on phytoplankton through nutrient recycling and zooplankton herbivory were experimentally separated and their relative importance quantified in a eutrophic humic lake. Natural phytoplankton assemblages were incubated in nutrient-permeable chambers placed inside enclosures with or without fish. Outside these chambers, phytoplankton were exposed to zooplankton herbivory and to nutrient recycling by fish and zooplankton, whereas inside the chambers, phytoplankton were exposed only to nutrient recycling by these consumers. Our results show that fish had significant positive effects on cyanobacteria, cryptomonads, and chlorophytes inside the chambers, indicating that fish-mediated nutrient recycling had significant effects on these phytoplankton groups. However, our results also indicate that changes in zooplankton grazing induced by fish were an important mechanism by which fish affected all phytoplankton groups except cyanobacteria. Comparison of effect sizes revealed that the effects on cyanobacteria and chlorophytes through nutrient recycling were stronger than those through zooplankton grazing. Moreover, most of the fish-mediated nutrient recycling effects were due to increased nutrient recycling by zooplankton rather than direct nutrient excretion by fish. In conclusion, we provide experimental evidence supporting the hypothesis that fish-mediated nutrient recycling is an important mechanism affecting phytoplankton community structure and favoring cyanobacteria dominance in lakes.

Direct and indirect effects of fish on pelagic nitrogen and phosphorus availability in oligotrophic Arctic Alaskan lakes

2010 ◽  
Vol 67 (10) ◽  
pp. 1635-1648 ◽  
Author(s):  
Cody R. Johnson ◽  
Chris Luecke ◽  
Stephen C. Whalen ◽  
Mary Anne Evans
Keyword(s):  
Indirect Effects ◽  
Nutrient Recycling ◽  
Zooplankton Biomass ◽  
Trophic Levels ◽  
Arctic Lakes ◽  
Nitrogen And Phosphorus ◽  
Lake Productivity ◽  
Nutrient Excretion ◽  
Significant Difference ◽  
Excretion Rates

The importance of fish nutrient recycling for lake primary production increases with lake productivity. However, fish in low-productivity lakes may have substantial indirect effects on nutrient recycling from lower trophic levels. We measured nutrient excretion rates from fish and zooplankton in oligotrophic Arctic lakes and investigated direct and indirect fish effects on consumer nutrient recycling. Fish nutrient excretion rates were small relative to phytoplankton nutrient demand. Zooplankton excretion, however, supplied 19%–130% and 37%–200% of phytoplankton nitrogen and phosphorus demand, respectively. Fish had a significant effect on zooplankton biomass; in lakes with fish, this was approximately 80% lower than in lakes without fish. The difference in zooplankton biomass was due primarily to a decrease in zooplankton density; no significant difference in average zooplankton size was observed between fish and fishless lakes. Fish also impacted zooplankton community composition; communities in lakes with fish were dominated by copepods compared with cladoceran dominance in lakes without fish. Because of lower zooplankton biomass, lakes with fish showed lower rates of zooplankton nitrogen and phosphorus excretion relative to lakes without fish. Thus, our results support the hypothesis that fish have major indirect effects on lake nutrient cycles, even when direct excretion from fish is minimal.

scholarly journals Comparison of cnidae sizes between the two morphotypes of the giant Caribbean sea anemone Condylactis gigantea (Actiniaria: Actiniidae)

2018 ◽  
Vol 66 (3) ◽  
pp. 1055
Author(s):  
Ricardo Enrique González Muñoz ◽  
Carlos Hernández-Ortiz ◽  
Agustin Garese ◽  
Nuno Simões ◽  
Fabián Horacio Acuña
Keyword(s):  
Coral Reefs ◽  
Gulf Of Mexico ◽  
Related Species ◽  
Significant Variation ◽  
Caribbean Sea ◽  
Sea Anemone ◽  
Tropical Atlantic ◽  
Closely Related Species ◽  
Mexican Caribbean ◽  
Ecological Differences

The sea anemone Condylactis gigantea is an ecologically important member of the benthic community in coral reefs of the tropical Atlantic, and displays two morphotypes with respect to the color in their tentacular tips: the green tip morphotype and the pink/purple tip morphotype. Although some molecular and ecological differences have been found between these morphotypes, no other morphological distinctions have been reported, and currently both are still considered a single taxonomic species. In the present study, we perform an exploration on the variability in the size of cnidae between these two morphotypes and performed statistical analyses to compare the 10 categories of cnidae from specimens hosted in the Cnidarian Collection of Gulf of Mexico and Mexican Caribbean, of the Universidad Nacional Autónoma de México, which were previously collected in several coral reefs localities of the Yucatán Peninsula. Results reveal no significant variation in cnidae size between the two morphotypes, but significant variations were found within each morphotype. In addition, we update the composition of the cnidom of C. gigantea, and the utility of the size of cnidae to distinguish between morphotypes or closely related species is discussed.

Managing Centrarchid Fisheries in Rivers and Streams

2019 ◽  
Keyword(s):  
Community Structure ◽  
Stable Isotope ◽  
Prey Availability ◽  
Prey Selection ◽  
Trophic Position ◽  
Trophic Niche ◽  
Smallmouth Bass ◽  
Spatial Differences ◽  
Stream Size ◽  
Diet Analyses

<em>Abstract.</em>—Prey selection and diet are highly plastic and can vary with temporal and spatial differences in competition or prey availability. This study investigated the possibility that the trophic position of Smallmouth Bass <em> Micropterus dolomieu </em>might change in response to systematic, hierarchical variation in community structure in stream networks. We hypothesized that a shift toward increased insectivory and decreased piscivory would be observed in smaller streams, resulting in a lower trophic position of Smallmouth Bass and reflecting differences in community structure and prey availability. We applied a combination of diet analyses and stable isotope methods to compare prey selection and trophic position of Smallmouth Bass across a range of stream sizes. Stable isotope analyses indicated that Smallmouth Bass trophic position was slightly elevated in smaller watersheds, contradicting our initial hypothesis. However, differences in average trophic position in watershed size categories were small (ranging from 3.6 to 3.8) and of limited ecological significance. Isotopic niche width did not vary among stream size categories, and gut content analyses revealed no differences in frequency of occurrence of fish, crayfish, or insects (larvae and adults). Collectively these results indicate that trophic position, and perhaps trophic niche, of Smallmouth Bass are consistent across hierarchical variation in stream size and habitat.

scholarly journals The relative impact of evolving pleiotropy and mutational correlation on trait divergence

2019 ◽  
Author(s):  
Jobran Chebib ◽  
Frédéric Guillaume
Keyword(s):  
Stochastic Model ◽  
Directional Selection ◽  
Population Variation ◽  
The Other ◽  
Common Mechanism ◽  
Stabilizing Selection ◽  
Relative Impact ◽  
Relative Importance ◽  
Trait Evolution ◽  
Trait Divergence

AbstractBoth pleiotropic connectivity and mutational correlations can restrict the divergence of traits under directional selection, but it is unknown which is more important in trait evolution. In order to address this question, we create a model that permits within-population variation in both pleiotropic connectivity and mutational correlation, and compare their relative importance to trait evolution. Specifically, we developed an individual-based, stochastic model where mutations can affect whether a locus affects a trait and the extent of mutational correlations in a population. We find that traits can diverge whether there is evolution in pleiotropic connectivity or mutational correlation but when both can evolve then evolution in pleiotropic connectivity is more likely to allow for divergence to occur. The most common genotype found in this case is characterized by having one locus that maintains connectivity to all traits and another that loses connectivity to the traits under stabilizing selection (subfunctionalization). This genotype is favoured because it allows the subfunctionalized locus to accumulate greater effect size alleles, contributing to increasingly divergent trait values in the traits under directional selection without changing the trait values of the other traits (genetic modularization). These results provide evidence that partial subfunctionalization of pleiotropic loci may be a common mechanism of trait divergence under regimes of corridor selection.

scholarly journals Régime Alimentaire De Hemichromis Fasciatus (Perciformes, Cichlidae) Dans Le Lac De Barrage Hydroélectrique D’ayamé 2 (Côte D’ivoire)

2017 ◽  
Vol 13 (30) ◽  
pp. 126
Author(s):  
Blahoua Kassi Georges ◽  
Adou Yedehi Euphrasie ◽  
Gogbé Zeré Marius ◽  
N’Douba Valentin
Keyword(s):  
Cote D'ivoire ◽  
Food Habits ◽  
Significant Variation ◽  
Côte D’Ivoire ◽  
Predatory Fish ◽  
Régime Alimentaire ◽  
Relative Importance ◽  
Cote D’Ivoire ◽  
Côte D'ivoire ◽  
Significant Difference

The diet of Hemichromis fasciatus (Perciformes, Cichlidae) was studied in the lake dam of Ayame 2 (Côte d'Ivoire) from September 2015 to August 2016. A total of 141 specimens were captured using gill nets and hawks. The relative importance of food index has been calculated to assess the relative abundance of the preys. The standard length of fish varied between 70 mm and 250 mm. The global percentage of emptiness and intestinal coefficient mean were 23.40 % and 1.35 ± 0.48 respectively. The food spectra constituted of fishes, insects, arachnids and plants debris showing that this species an omnivorous fish with predatory fish tendency. The comparison of the food habits between size ranges (LS ≤ 110 mm and LS ˃ 110 mm) did not show any significant difference. But, a significant variation of the diet according the sexes and seasons was observed.

scholarly journals Sex-specific spatial use of the winter foraging areas by Magellanic penguins and assessment of potential conflicts with fisheries during winter dispersal

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256339
Author(s):  
Samanta Dodino ◽  
Nicolás A. Lois ◽  
Luciana Riccialdelli ◽  
Michael J. Polito ◽  
Klemens Pütz ◽  
...  
Keyword(s):  
Trophic Position ◽  
Isotope Analysis ◽  
Trophic Niche ◽  
Bottom Trawl ◽  
Winter Period ◽  
Shrimp Fishery ◽  
Trawl Fishery ◽  
Magellanic Penguins ◽  
Winter Foraging ◽  
Spatial Use

Magellanic penguins (Spheniscus magellanicus) disperse widely during winter and are a major consumer of marine resources over the Patagonian Shelf. Magellanic penguins were equipped with geolocators at Martillo Island in late February- early March 2017 and recaptured at the beginning of the next breeding season to recover the devices and to collect blood samples for stable carbon (δ13C) and nitrogen (δ15N) isotope analysis. We evaluated their whole winter dispersal and their trophic niche by sex during the last month of the winter dispersal. Also, we evaluated their spatial overlap with bottom trawl and shrimp fisheries using data from satellite fisheries monitoring. Penguins dispersed northwards up to 42°S and showed latitudinal spatial segregation between sexes during May to August (females were located further north than males). In contrast, during the last month of the winter dispersal females were located more southerly and showed lower trophic position than males. Also, females did not dive as deep as males during winter. We found high overlap between both fisheries and penguin’s spatial use in regions with documented interaction. However, no sex-specific statistical differences with fisheries overlap were found. Our results highlight the importance of understanding the spatial domains of each sex and assessment of their potential conflicts with bottom trawl fishery and shrimp fishery during the winter period.

scholarly journals Effects of Drying and Re-Wetting on Litter Decomposition and Nutrient Recycling: A Manipulative Experiment

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 708 ◽  
Author(s):  
Beatrice Palmia ◽  
Marco Bartoli ◽  
Alex Laini ◽  
Rossano Bolpagni ◽  
Claudio Ferrari ◽  
...  
Keyword(s):  
Interactive Effect ◽  
Nutrient Recycling ◽  
Leaf Size ◽  
Leaf Biomass ◽  
Manipulative Experiment ◽  
Water Abstraction ◽  
Nutrient Mineralization ◽  
Stream Drying ◽  
Benthic Environment ◽  
Leaf Disks

Climate change and water abstraction may change stream flow from perennial into intermittent lotic systems, modifying their abiotic and biotic benthic environment and impacting ecosystem processes such as nutrient turnover. We conducted a microcosm experiment to investigate the interactive effect of water intermittency, macrofauna and leaf size (Populus nigra leaves) on nutrient mineralization and recycling. Leaf disks (1 or 5 cm diameter) were incubated for 40 days with or without the leaf-consumer, Potamophylax cingulatus larvae (Trichoptera, Limnephilidae) and with or without an intervening, 10-days simulation of stream drying and subsequent rewetting. Nutrient fluxes, residual leaf biomass and leaf elemental composition were measured to evaluate how intermittency, macrofauna and leaf size affect organic matter mineralization rates and stoichiometry. Results suggest that drying slows decomposition rates, impacting both the microbial and setting to zero macrofauna activities. The presence of macrofauna increases mineralization and nutrient (C, N and P) regeneration rates. Our findings also suggest that leaf disks with higher diameter display higher microbial activity and NH4+ regeneration. During the experiment, the C:N:P ratios of residual litter changed, as the leaf material became enriched with N and P. Our study suggests that increasingly frequent dry events might slow mineralization rates and downstream nutrient transport.

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