scholarly journals Community Assembly Processes as a Mechanistic Explanation of the Predator-Prey Diversity Relationship in Marine Microbes

2021 ◽  
Vol 8 ◽  
Author(s):  
Feng-Hsun Chang ◽  
Jinny Wu Yang ◽  
Ariana Chih-Hsien Liu ◽  
Hsiao-Pei Lu ◽  
Gwo-Ching Gong ◽  
...  
Keyword(s):  
Community Assembly ◽  
Mechanistic Explanation ◽  
Trophic Levels ◽  
Heterotrophic Nanoflagellates ◽  
Similar Species ◽  
Marine Microbes ◽  
Predator Prey ◽  
Shannon Diversity ◽  
Α Diversity ◽  
Underlying Mechanisms

Predator and prey α-diversities are often positively associated; yet, understandings of the underlying mechanisms require manipulative experiments and thus remain unclear. We attempt to address this issue by deciphering how α-diversity of predator and prey influences each other’s community assembly processes, which subsequently determine their α-diversity. The occurrence of assembly processes was indicated by the mean pairwise taxonomic index within a community (αMPTI), assuming assembly processes left traceable imprints on species’ phylogeny. Specifically, αMPTI quantifies deviations of observed phylogenetic distances from that of random, so that it can be used to hint at the occurrence of non-random/deterministic assembly processes. Larger αMPTI of a community implies the occurrence of weaker homogenizing deterministic assembly processes, which suggests that this community might be comprised of less similar species and thus has higher α-diversity. We hypothesize that higher predator and prey α-diversity would be positively associated with each other’s αMPTI, which would then be positively associated with their α-diversity. To test the hypothesis, we calculated Shannon diversity and αMPTI for heterotrophic nanoflagellates (HNF; predator) and bacteria (prey) communities in the East China Sea (ECS). The HNF Shannon diversity was found to be positively associated with αMPTI of bacteria, which was then positively associated with bacterial Shannon diversity. In contrast, bacterial Shannon diversity did not correlate with HNF’s αMPTI. We argue that top-down control is one of the explanations to the positive α-diversity association among trophic levels in microbes of the ECS.

scholarly journals Community assembly processes as a mechanistic explanation of the predator-prey diversity relationship in marine microbes

2020 ◽  
Author(s):  
Feng-Hsun Chang ◽  
Jinny Yang ◽  
Ariana Chih-Hsien Liu ◽  
Hsiao-Pei Lu ◽  
Gwo-Ching Gong ◽  
...  
Keyword(s):  
Community Assembly ◽  
Mechanistic Explanation ◽  
Marine Microbes ◽  
Predator Prey ◽  
Prey Diversity

scholarly journals Match-mismatch dynamics in the Norwegian-Barents Sea system

2020 ◽  
Vol 650 ◽  
pp. 81-94
Author(s):  
ASA Ferreira ◽  
LC Stige ◽  
AB Neuheimer ◽  
B Bogstad ◽  
N Yaragina ◽  
...  
Keyword(s):  
Early Life ◽  
Barents Sea ◽  
Mechanistic Explanation ◽  
Trophic Levels ◽  
Calanus Finmarchicus ◽  
Life Stages ◽  
Early Life Stages ◽  
Predator Prey ◽  
Spatio Temporal ◽  
Prey Overlap

A key process affecting variation in the recruitment of fish into fisheries is the spatio-temporal overlap between prey and predator (match-mismatch hypothesis, MMH). The Northeast Arctic cod Gadus morhua and its dominant prey, the copepod Calanus finmarchicus, have long been studied in the Norwegian-Barents Sea system. However, the mechanistic explanation of how cod survival is affected by MMH dynamics remains unclear. Most MMH studies have focused on either the time synchrony or the spatial overlap between trophic levels. Here, we used G. morhua larvae and C. finmarchicus data collected in the Norwegian-Barents Sea via ichthyoplankton surveys from 1959-1992 to assess the effect of the predator-prey relationship on predator recruitment to the fisheries at age 3 (as a measure of survival) and to develop a metric of predator-prey overlap using spatio-temporal statistical models. We then compared the interannual variability of the predator-prey overlap with the predator’s abundance at recruitment to assess how MMH dynamics explain the survival of cod during its early life stages. We found that the amount of overlap between cod larvae (length: 11-15 mm) and their prey explained 29% of cod recruitment variability. Positive correlations between predator-prey overlap and subsequent recruitment were also found for predators of 6-10 and 16-20 mm, but not for 21+ mm. This improved predator-prey overlap metric is thus (1) useful to better understand how predator-prey dynamics at early life stages of fish impact the survival of later stages; and (2) a valuable tool for assessing the state of an ecosystem.

scholarly journals Ocean acidification reduces growth and grazing of Antarctic heterotrophic nanoflagellates

2019 ◽  
Author(s):  
Stacy Deppeler ◽  
Kai G. Schulz ◽  
Alyce Hancock ◽  
Penelope Pascoe ◽  
John McKinlay ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Food Web ◽  
Heterotrophic Nanoflagellates ◽  
Marine Microbes ◽  
Predator Prey ◽  
Marine Food Web ◽  
Antarctic Marine ◽  
Growth Changes ◽  
Organic Matter Recycling ◽  
Marine Microbial Communities

Abstract. High-latitude oceans have been identified as particularly vulnerable to ocean acidification if anthropogenic CO2 emissions continue. Marine microbes are an essential part of the marine food web and are a critical link in biogeochemical processes in the ocean, such as the cycling of nutrients and carbon. Despite this, the response of Antarctic marine microbial communities to ocean acidification is poorly understood. We investigated the effect of increasing fCO2 on the growth of heterotrophic nanoflagellates (HNF), nano- and picophytoplankton, and prokaryotes in a natural coastal Antarctic marine microbial community from Prydz Bay, East Antarctica. At CO2 levels ≥ 634 μatm, HNF abundance was reduced, coinciding with significantly increased abundance of picophytoplankton and prokaryotes. This increase in picophytoplankton and prokaryote abundance was likely due to a reduction in top-down control of grazing HNF. Nanophytoplankton abundance was significantly elevated in the 634 and 953 μatm treatments, suggesting that moderate increases in CO2 may stimulate growth. Changes in predator-prey interactions with ocean acidification could have a significant effect on the food web and biogeochemistry in the Southern Ocean. Based on these results, it is likely that the phytoplankton community composition in these waters will shift to communities dominated by prokaryotes, nano- and picophytoplankton. This may intensify organic matter recycling in surface waters, leading to a decline in carbon flux, as well as a reducing the quality and quantity of food available to higher trophic organisms.

scholarly journals Skin Microbiome in Patients with Hand Eczema and Healthy Controls: A Three-week Prospective Study

2021 ◽  
Author(s):  
Line Brok Nørreslet ◽  
Berit Lilje ◽  
Anna Cäcilia Ingham ◽  
Sofie Marie Edslev ◽  
Maja-Lisa Clausen ◽  
...  
Keyword(s):  
Prospective Study ◽  
Disease Severity ◽  
Amplicon Sequencing ◽  
Hand Eczema ◽  
Skin Microbiome ◽  
Healthy Controls ◽  
16S Rrna Amplicon Sequencing ◽  
Chronic Hand Eczema ◽  
Α Diversity ◽  
Underlying Mechanisms

The pathogenesis of chronic hand eczema remains unclear. Insights into the skin microbiome in hand eczema and its potential relevance to disease severity may help to elucidate the underlying mechanisms of hand eczema. The aim of this study was to characterize the microbiome in patients with hand eczema and healthy controls. A 5-visit prospective study was conducted over a period of 3 weeks. At each visit, bacterial swabs were taken from the hands of patients with hand eczema and controls. The microbiome was examined using DNA extraction and 16S rRNA amplicon sequencing (V3–V4 regions). Fifty patients with hand eczema and 50 controls were included (follow-up rate=100%). The baseline bacterial α-diversity was reduced on the hands of patients with hand eczema compared with controls (effect size=–0.31; 95% confidence interval (95% CI) –0.50; –0.11; p = 0.003). The dysbiosis on the patients’ hands was stable over the study period, was associated with disease severity, and was characterized by reduced bacterial diversity and different bacterial community compositions.

scholarly journals Articulatory motor planning and timbral idiosyncrasies as underlying mechanisms of instrument-specific absolute pitch in expert musicians

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247136
Author(s):  
Niels Chr. Hansen ◽  
Lindsey Reymore
Keyword(s):  
Motor Planning ◽  
Mechanistic Explanation ◽  
Absolute Pitch ◽  
Musical Instrument ◽  
Professional Musicians ◽  
Instrument Type ◽  
External Reference ◽  
Intense Training ◽  
Underlying Mechanisms

The study of musical expertise illustrates how intense training in a specialized domain may instigate development of implicit skills. While absolute pitch, or the ability to identify musical pitches without external reference, is rare even in professional musicians and is understood to have a genetic component, anecdotal evidence and pilot data suggest that some musicians without traditional absolute pitch are nonetheless better able to name notes played on their musical instrument of expertise than notes played on less familiar instruments. We have previously termed this particular gain in absolute pitch identification ability “instrument-specific absolute pitch” (ISAP) and have proposed that this skill is related to learned instrument type-specific timbral and intonational idiosyncrasies and articulatory motor planning activated by the timbre of the instrument. In this Registered Report Protocol, we describe two experiments designed to investigate ISAP in professional oboists. Experiment 1 tests for ISAP ability by comparing oboists’ pitch identification accuracies for notes played on the oboe and on the piano. A subset of the participants from Experiment 1 who demonstrate this ability will be recruited for Experiment 2; the purpose of Experiment 2 is to test hypotheses concerning a mechanistic explanation for ISAP. The outcome of these experiments may provide support for the theory that some individuals have ISAP and that the underlying mechanisms of this ability may rely on the perception of subtle timbral/intonational idiosyncrasies and on articulatory motor planning developed through intensive long-term training. In general, this work will contribute to the understanding of specialized expertise, specifically of implicit abilities and biases that are not addressed directly in training, but that may yet develop through practice of a related skill set.

Microbiota community assembly in wild rice (Oryza longistaminata) in response to drought stress shows phylogenetic conservation, stochasticity, and aboveground-belowground patterns

2020 ◽  
Author(s):  
xia ding ◽  
Xiaojue Peng ◽  
Zhichao Chen ◽  
Yingjie Li ◽  
Lihui Mao ◽  
...  
Keyword(s):  
Microbial Community ◽  
Drought Stress ◽  
Microbial Communities ◽  
Community Assembly ◽  
Wild Rice ◽  
Microbial Community Composition ◽  
Α Diversity ◽  
Oryza Longistaminata ◽  
Network Properties ◽  
Microbiome Assembly

Abstract Background Drought is a global environmental stress that limits crop yields. Microbial communities control many biogeochemical processes, and a predictive understanding of how crop microbial communities assemble in response to drought stress is central to addressing the challenges caused by drought. Little is known about the microbiome assembly processes in rice-ecosystems, particularly with regard to their environmental adaptation. Wild rice may serve as a source of superior drought tolerance candidate for rice breeding. There is an urgent need to explore wild rice resistance mechanisms to drought stress. Here, we evaluated the effect of drought stress on the microbial community recruitment and assembly in the endosphere (leaf, stem, and root) and rhizosphere of Oryza longistaminata. Results Species replacement was the dominant process shaping microbial community composition under drought stress. O. longistaminata recruited the phyla Actinobacteria and Fusobacteria, the genus Streptomyces, and phototrophic prokaryotes to improve its fitness. The host exerted strong effects on microbiome assembly, and the responses of the microbial community structure to the drought environment showed above- and belowground patterns. Drought reduced taxonomic α-diversity and destabilized co-occurrence network properties in the leaves and stems, but not in the roots and rhizosphere. Drought promoted the restructuring and strengthening of belowground network links to more strongly interconnect network properties. The drought response of the microbiome was phylogenetically conserved. Stochastic (neutral) processes acted on microbial community reassembly in response to drought stress across all four compartments. Conclusions Our results provide new insight into the mechanisms through which drought alters microbial community assembly in drought-tolerant wild rice and reveal a potential strategy for manipulating plant microbiomes to improve crop fitness.

Predator–prey interactions and climate change

2019 ◽  
pp. 199-220 ◽  
Author(s):  
Vincent Bretagnolle ◽  
Julien Terraube
Keyword(s):  
Climate Change ◽  
Species Interactions ◽  
Experimental Studies ◽  
Trophic Levels ◽  
Generalist Predators ◽  
Top Down ◽  
Predator Prey ◽  
Key Topics ◽  
Available Information

Climate change is likely to impact all trophic levels, although the response of communities and ecosystems to it has only recently received considerable attention. Further, it is expected to affect the magnitude of species interactions themselves. In this chapter, we summarize why and how climate change could affect predator–prey interactions, then review the literature about its impact on predator–prey relationships in birds, and provide prospects for future studies. Expected effects on prey or predators may include changes in the following: distribution, phenology, population density, behaviour, morphology, or physiology. We review the currently available information concerning particular key topics: top-down versus bottom-up control, specialist versus generalist predators, functional versus numerical responses, trophic cascades and regime shifts, and lastly adaptation and selection. Finally, we focus our review on two well-studied bird examples: seabirds and raptors. Key future topics include long-term studies, modelling and experimental studies, evolutionary questions, and conservation issues.

scholarly journals Examining predator–prey body size, trophic level and body mass across marine and terrestrial mammals

2014 ◽  
Vol 281 (1797) ◽  
pp. 20142103 ◽  
Author(s):  
Marlee A. Tucker ◽  
Tracey L. Rogers
Keyword(s):  
Community Structure ◽  
Body Size ◽  
Body Mass ◽  
Marine Environment ◽  
Trophic Level ◽  
Marine Mammals ◽  
Trophic Position ◽  
Trophic Levels ◽  
Predator Prey ◽  
Terrestrial Mammals

Predator–prey relationships and trophic levels are indicators of community structure, and are important for monitoring ecosystem changes. Mammals colonized the marine environment on seven separate occasions, which resulted in differences in species' physiology, morphology and behaviour. It is likely that these changes have had a major effect upon predator–prey relationships and trophic position; however, the effect of environment is yet to be clarified. We compiled a dataset, based on the literature, to explore the relationship between body mass, trophic level and predator–prey ratio across terrestrial ( n = 51) and marine ( n = 56) mammals. We did not find the expected positive relationship between trophic level and body mass, but we did find that marine carnivores sit 1.3 trophic levels higher than terrestrial carnivores. Also, marine mammals are largely carnivorous and have significantly larger predator–prey ratios compared with their terrestrial counterparts. We propose that primary productivity, and its availability, is important for mammalian trophic structure and body size. Also, energy flow and community structure in the marine environment are influenced by differences in energy efficiency and increased food web stability. Enhancing our knowledge of feeding ecology in mammals has the potential to provide insights into the structure and functioning of marine and terrestrial communities.

Coexistence of morphologically similar bats (Vespertilionidae) on Madagascar: stable isotopes reveal fine-grained niche differentiation among cryptic species

2014 ◽  
Vol 31 (2) ◽  
pp. 153-164 ◽  
Author(s):  
Melanie Dammhahn ◽  
Claude Fabienne Rakotondramanana ◽  
Steven M. Goodman
Keyword(s):  
Stable Isotopes ◽  
Deciduous Forest ◽  
Niche Differentiation ◽  
Sympatric Species ◽  
Trophic Niche ◽  
Trophic Levels ◽  
Seasonal Migration ◽  
Similar Species ◽  
Fine Grained ◽  
Hair Samples

Abstract:Based on niche theory, closely related and morphologically similar species are not predicted to coexist due to overlap in resource and habitat use. Local assemblages of bats often contain cryptic taxa, which co-occur despite notable similarities in morphology and ecology. We measured in two different habitat types on Madagascar levels of stable carbon and nitrogen isotopes in hair (n = 103) and faeces (n = 57) of cryptic Vespertilionidae taxa to indirectly examine whether fine-grained trophic niche differentiation explains their coexistence. In the dry deciduous forest (Kirindy), six sympatric species ranged over 6.0‰ in δ15N, i.e. two trophic levels, and 4.2‰ in δ13C with a community mean of 11.3‰ in δ15N and −21.0‰ in δ13C. In the mesic forest (Antsahabe), three sympatric species ranged over one trophic level (δ15N: 2.4‰, δ13C: 1.0‰) with a community mean of 8.0‰ δ15N and −21.7‰ in δ13C. Multivariate analyses and residual permutation of Euclidian distances in δ13C–δ15N bi-plots revealed in both communities distinct stable isotope signatures and species separation for the hair samples among coexisting Vespertilionidae. Intraspecific variation in faecal and hair stable isotopes did not indicate that seasonal migration might relax competition and thereby facilitate the local co-occurrence of sympatric taxa.

scholarly journals Trophic cascades alter eco-evolutionary dynamics and body size evolution

2020 ◽  
Vol 287 (1938) ◽  
pp. 20200526
Author(s):  
Thomas M. Luhring ◽  
John P. DeLong
Keyword(s):  
Body Mass ◽  
Trophic Level ◽  
Evolutionary Dynamics ◽  
Trophic Cascades ◽  
Trophic Levels ◽  
Chain Model ◽  
Top Predator ◽  
Predator Prey ◽  
Top Predators ◽  
Time Changes

Trait evolution in predator–prey systems can feed back to the dynamics of interacting species as well as cascade to impact the dynamics of indirectly linked species (eco-evolutionary trophic cascades; EETCs). A key mediator of trophic cascades is body mass, as it both strongly influences and evolves in response to predator–prey interactions. Here, we use Gillespie eco-evolutionary models to explore EETCs resulting from top predator loss and mediated by body mass evolution. Our four-trophic-level food chain model uses allometric scaling to link body mass to different functions (ecological pleiotropy) and is realistically parameterized from the FORAGE database to mimic the parameter space of a typical freshwater system. To track real-time changes in selective pressures, we also calculated fitness gradients for each trophic level. As predicted, top predator loss generated alternating shifts in abundance across trophic levels, and, depending on the nature and strength in changes to fitness gradients, also altered trajectories of body mass evolution. Although more distantly linked, changes in the abundance of top predators still affected the eco-evolutionary dynamics of the basal producers, in part because of their relatively short generation times. Overall, our results suggest that impacts on top predators can set off transient EETCs with the potential for widespread indirect impacts on food webs.

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