scholarly journals Holobiont Nitrogen Control and its Potential for Eutrophication Resistance in an Obligate Photosymbiotic Jellyfish

2020 ◽  
Author(s):  
Till Röthig ◽  
Giulia Puntin ◽  
Jane CY Wong ◽  
Alfred Burian ◽  
Wendy McLeod ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
Microbial Community Composition ◽  
Nitrate Assimilation ◽  
Feeding Rates ◽  
Symbiotic Relationships ◽  
Algal Symbionts ◽  
Bacterial Microbiome ◽  
Host Mortality ◽  
C And N ◽  
Reef Decline

Abstract Background: Marine holobionts depend on microbial partners for health and nutrient cycling. This is particularly evident amongst cnidarian-Symbiodiniaceae symbioses, where nutrient acquisition is facilitated. However, the symbiosis is sensitive to environmental change - including eutrophication – that cause dysbiosis and host mortality, which contributes to global coral reef decline. Yet, some holobionts exhibit resistance to dysbiosis in eutrophic environments, including the obligate photosymbiotic scyphomedusa Cassiopea xamachana. Methods: Our aim was to assess the mechanisms in C. xamachana that stabilize symbiotic relationships. We combined labelled bicarbonate (13C) and nitrate (15N) and metabarcoding approaches to evaluate nutrient cycling and microbial community composition in symbiotic and aposymbiotic medusae.Results: We found C-cycling within the C. xamachana holobiont to be essential as aposymbiotic medusae continuously lost weight even at high heterotrophic feeding rates. Heterotrophically acquired C and N were readily shared among host and algae. This was in sharp contrast to nitrate assimilation, which was strongly restricted from Symbiodiniaceae. Instead, the bacterial microbiome seemed to play a major role in the holobiont’s DIN assimilation as uptake rates showed a significant positive relationship with phylogenetic diversity of medusa-associated bacteria. This is corroborated by inferred functional capacity that links the dominant bacterial taxa (~90 %) to nitrogen cycling and particularly denitrification. Observed bacterial community structure differed between apo- and symbiotic C. xamachana putatively highlighting enrichment of ammonium oxidizers and denitrifiers and depletion of nitrogen-fixators in symbiotic medusae. Conclusion: Host, algal symbionts, and bacterial associates contribute to regulated nutrient assimilation and cycling in C. xamachana. We found that the bacterial microbiome of symbiotic medusae was seemingly structured to increase DIN removal and enforce algal N-limitation - a mechanism that would help to stabilize algae-host relationship even under eutrophic conditions.

scholarly journals Holobiont nitrogen control and its potential for eutrophication resistance in an obligate photosymbiotic jellyfish

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Till Röthig ◽  
Giulia Puntin ◽  
Jane C. Y. Wong ◽  
Alfred Burian ◽  
Wendy McLeod ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
Microbial Community Composition ◽  
Nitrate Assimilation ◽  
Feeding Rates ◽  
Symbiotic Relationships ◽  
Algal Symbionts ◽  
Nitrogen Fixers ◽  
Bacterial Microbiome ◽  
C And N ◽  
Reef Decline

Abstract Background Marine holobionts depend on microbial members for health and nutrient cycling. This is particularly evident in cnidarian-algae symbioses that facilitate energy and nutrient acquisition. However, this partnership is highly sensitive to environmental change—including eutrophication—that causes dysbiosis and contributes to global coral reef decline. Yet, some holobionts exhibit resistance to dysbiosis in eutrophic environments, including the obligate photosymbiotic scyphomedusa Cassiopea xamachana. Methods Our aim was to assess the mechanisms in C. xamachana that stabilize symbiotic relationships. We combined labelled bicarbonate (13C) and nitrate (15N) with metabarcoding approaches to evaluate nutrient cycling and microbial community composition in symbiotic and aposymbiotic medusae. Results C-fixation and cycling by algal Symbiodiniaceae was essential for C. xamachana as even at high heterotrophic feeding rates aposymbiotic medusae continuously lost weight. Heterotrophically acquired C and N were readily shared among host and algae. This was in sharp contrast to nitrate assimilation by Symbiodiniaceae, which appeared to be strongly restricted. Instead, the bacterial microbiome seemed to play a major role in the holobiont’s DIN assimilation as uptake rates showed a significant positive relationship with phylogenetic diversity of medusa-associated bacteria. This is corroborated by inferred functional capacity that links the dominant bacterial taxa (~90 %) to nitrogen cycling. Observed bacterial community structure differed between apo- and symbiotic C. xamachana putatively highlighting enrichment of ammonium oxidizers and nitrite reducers and depletion of nitrogen-fixers in symbiotic medusae. Conclusion Host, algal symbionts, and bacterial associates contribute to regulated nutrient assimilation and cycling in C. xamachana. We found that the bacterial microbiome of symbiotic medusae was seemingly structured to increase DIN removal and enforce algal N-limitation—a mechanism that would help to stabilize the host-algae relationship even under eutrophic conditions.

scholarly journals Diversity and Distribution of Bracket Fungi in Mt. Kilakiron, Bukidnon, Philippines

2021 ◽  
Vol 13 (1) ◽  
pp. 41-50
Author(s):  
Mc Arthur Lequin Cababan ◽  
Aprille Kake Ora Jaranilla ◽  
Mariane Catayas Bastatas ◽  
Chazzel Feel Comonong Salvane ◽  
Uzziel Campuso Toldo
Keyword(s):  
Low Temperature ◽  
Nutrient Cycling ◽  
High Altitude ◽  
Environmental Factor ◽  
Trametes Versicolor ◽  
Diversity Index ◽  
Large Contribution ◽  
Floristic Survey ◽  
Symbiotic Relationships ◽  
Total Species

Fungi have a lot of important function in the bionetwork resembling to decomposition and even nutrient cycling with respect to its symbiotic relationships with trees and other plants. This study aimed to assess the diversity and distribution of bracket fungi in Mt. Kilakiron, Portulin, Pangantucan, Bukidnon. Thus, floristic survey was conducted in one of the mountain of Mindanao to provide information as to what and how many species of bracket fungi are present in Mt. Kilakioron, Bukidnon, Philippines.  40 total species belonging to 17 genera and 5 family was collected and assessed. 12 individuals of Trametes versicolor were observe which favors dwellings with low temperature and high altitude are. Additionally, study revealed that most types of bracket fungi initiate in the site are decomposers and saprophytic in nature which contributes a lot in the process of putrefaction. The species of bracket fungi in Mt. Kilakiron clearly shows abundant and provides a large contribution to the ecosystem having high Shannon diversity index. The significance of each environmental factor is discussed in relationship to the ecology of the species. Bracket fungi are reliant on the climatic and conservational settings which makes them as excellent natural pointers of ecosystem in the forests of Mindanao Island, Philippines.

scholarly journals Using Canopy Hyperspectral Reflectance to Predict Root Biomass Carbon and Nitrogen Content

2018 ◽  
Vol 8 (1) ◽  
pp. 84
Author(s):  
Brekke L. Peterson ◽  
Patrick J. Starks ◽  
Cooper Sadowsky ◽  
Trey Scott
Keyword(s):  
Nutrient Cycling ◽  
Tallgrass Prairie ◽  
Plant Root ◽  
Combustion Method ◽  
The United States ◽  
United States Department ◽  
Canopy Reflectance ◽  
Improve Model ◽  
C And N ◽  
Carbon And Nitrogen Content

Full assessment of soil carbon (C) and nitrogen (N) pools is necessary for long-term sustainability of agricultural production and provides information on plant health and nutrient cycling. A major component of nutrient cycling is plant root C and N. Although root C and N contribute to nutrient cycling, determination of these quantities is laborious and tedious and is, therefore, not commonly done. In this study we attempt to determine the feasibility of using remotely sensed canopy reflectance as a proxy to determine root C and N data of live, standing forages. The study site was the United States Department of Agriculture-Grazinglands Research Laboratory located in El Reno, Oklahoma. Twelve plots in each of two sites (a native, tallgrass prairie and an improved, Old World Bluestem pasture) were used for collection and measurement of root C and root N and measurement of canopy reflectance using a field portable hyperspectral spectroradiometer. Root and soil samples were then taken from under the remote sensed area for total C and N analysis using the combustion method. The results of this study indicated that it is feasible to predict root C and N, but further study is required to improve model accuracy.

Bioenergetics Model and Foraging Hypothesis for Sea Lamprey (Petromyzon marinus)

1980 ◽  
Vol 37 (11) ◽  
pp. 2159-2168 ◽  
Author(s):  
James F. Kitchell ◽  
James E. Breck
Keyword(s):  
Great Lakes ◽  
Petromyzon Marinus ◽  
Sea Lamprey ◽  
Fish Mortality ◽  
Feeding Rates ◽  
Mortality Pattern ◽  
Bioenergetics Model ◽  
Host Mortality ◽  
Host Fishes ◽  
The Impact

A bioenergetics model for growth of lamprey during the parasitic phase was used to estimate food consumption by lampreys and the impact of lamprey feeding on host fishes. Estimates are evaluated by application to several Great Lakes case histories. Temperature and size-dependence of feeding and respiration were sufficient to account for growth dynamics. The model demonstrates that distribution of host fishes, by determining the thermal history of the lamprey, has important effects on lamprey life history and host mortality. Modeled lamprey growth and feeding rates, relative to size of the host, predict a strongly seasonal host mortality rate peaking in autumn. The predicted mortality pattern corresponds with that of independently derived data. Principles of optimal foraging theory applied to lamprey yield a hypothesis that predicts highest wounding and scarring frequencies at intermediate lamprey: host abundance ratios. A second component of the hypothesis predicts seasonal changes in these frequencies as lamprey size increases. Growth rates of lamprey and their host species plus wounding and scarring frequencies are more sensitive indicators of changing abundance ratios and lamprey effects than population changes resulting from predation by lamprey.Key words: sea lamprey, Petromyzon marinus; model, bioenergetics, growth, consumption, fish mortality, Great Lakes

scholarly journals Host Habitat Is the Major Determinant of the Gut Microbiome of Fish

2021 ◽  
Author(s):  
Pil Soo Kim ◽  
Na-Ri Shin ◽  
Jae-Bong Lee ◽  
Min-Soo Kim ◽  
Tae Woong Whon ◽  
...  
Keyword(s):  
Microbial Community ◽  
Gut Microbiota ◽  
Gut Microbiome ◽  
Microbial Community Composition ◽  
Terrestrial Vertebrates ◽  
Symbiotic Relationships ◽  
Machine Learning Approach ◽  
Host Habitat ◽  
Functional Profiles ◽  
Gut Microbial Community

Abstract Background: Our understanding of the gut microbiota of animals is largely based on studies of mammals. To better understand the evolutionary basis of symbiotic relationships between animal hosts and indigenous microbes, it is necessary to investigate the gut microbiota of non-mammalian vertebrate species. In particular, fish have the highest species diversity among groups of vertebrates, with approximately 33,000 species. In this study, we comprehensively characterized gut bacterial communities in fish.Results: We analyzed 227 individual fish representing 14 orders, 42 families, 79 genera, and 85 species. The fish gut microbiota was dominated by Proteobacteria (51.7%) and Firmicutes (13.5%), different from the dominant taxa reported in terrestrial vertebrates (Firmicutes and Bacteroidetes). The gut microbial community in fish was more strongly shaped by host habitat than by host taxonomy or trophic level. Using a machine learning approach trained on the microbial community composition or predicted functional profiles, we found that the host habitat exhibited the highest classification accuracy. Principal coordinate analysis revealed that the gut bacterial community of fish differs significantly from those of other vertebrate classes (reptiles, birds, and mammals).Conclusions: Collectively, these data provide a reference for future studies of the gut microbiome of aquatic animals as well as insights into the relationship between fish and their gut bacteria, including the key role of host habitat and the distinct compositions in comparison with those of mammals, reptiles, and birds.

scholarly journals Carbon and nitrogen recycling during cyanoHABs in dreissenid-invaded and non-invaded US midwestern lakes and reservoirs

Hydrobiologia ◽  
2019 ◽  
Vol 847 (3) ◽  
pp. 939-965 ◽  
Author(s):  
Trinity L. Hamilton ◽  
Jessica R. Corman ◽  
Jeff R. Havig
Keyword(s):  
Nutrient Cycling ◽  
Nitrogen Cycling ◽  
Carbon Cycling ◽  
Microbial Community Composition ◽  
Freshwater Ecosystems ◽  
Rrna Gene ◽  
Eutrophic Lakes ◽  
Carbon And Nitrogen ◽  
Carbon And Nitrogen Cycling ◽  
Lakes And Reservoirs

AbstractLakes and reservoirs play key roles in global carbon cycling, especially as a carbon sink. Enrichment of nutrients in lakes and reservoirs (eutrophication) and rising global temperatures favors the proliferation of bloom-forming cyanobacteria. Harmful blooms of cyanobacteria (cyanoHABs) alter carbon and nutrient cycling in freshwater ecosystems. Some evidence suggests the introduction or establishment of invasive mussel species (i.e., Dreissena spp.) also favor cyanoHAB formation through selective filter feeding, a process through which they may also impact biogeochemical processes including carbon cycling and sequestration. However, few studies have considered the combined effects of invasive mussels and cyanoHABs on carbon and nitrogen cycling in freshwater ecosystems. Here, we examined microbial community composition and biogeochemical attributes (including carbon and nitrogen stable isotopes) in eutrophic lakes, reservoirs, and rivers in western Ohio, eastern Indiana, and northern Kentucky during the cyanobacterial bloom period of the summer of 2015. Our samples include both sites impacted by invasive mussels and those where invasive mussels have not yet been observed. Based on 16S and 18S rRNA gene sequence analysis, we found that cyanobacterial and algal communities varied across sites and were most closely related to habitat (sediment or water column sample) and site, regardless of the presence of invasive mussels or other environmental factors. However, we did find evidence that invasive mussels may influence both carbon and nitrogen cycling. While the results are based on a single time point sampling, they highlight the interactions of multiple environmental stressors in aquatic ecosystems and the critical need for more temporally intensive studies of carbon and nutrient cycling in bloom- and mussel-impacted waters.

scholarly journals Host habitat is the major determinant of the gut microbiome of fish

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Pil Soo Kim ◽  
Na-Ri Shin ◽  
Jae-Bong Lee ◽  
Min-Soo Kim ◽  
Tae Woong Whon ◽  
...  
Keyword(s):  
Microbial Community ◽  
Gut Microbiota ◽  
Gut Microbiome ◽  
Microbial Community Composition ◽  
Terrestrial Vertebrates ◽  
Symbiotic Relationships ◽  
Machine Learning Approach ◽  
Host Habitat ◽  
Functional Profiles ◽  
Gut Microbial Community

Abstract Background Our understanding of the gut microbiota of animals is largely based on studies of mammals. To better understand the evolutionary basis of symbiotic relationships between animal hosts and indigenous microbes, it is necessary to investigate the gut microbiota of non-mammalian vertebrate species. In particular, fish have the highest species diversity among groups of vertebrates, with approximately 33,000 species. In this study, we comprehensively characterized gut bacterial communities in fish. Results We analyzed 227 individual fish representing 14 orders, 42 families, 79 genera, and 85 species. The fish gut microbiota was dominated by Proteobacteria (51.7%) and Firmicutes (13.5%), different from the dominant taxa reported in terrestrial vertebrates (Firmicutes and Bacteroidetes). The gut microbial community in fish was more strongly shaped by host habitat than by host taxonomy or trophic level. Using a machine learning approach trained on the microbial community composition or predicted functional profiles, we found that the host habitat exhibited the highest classification accuracy. Principal coordinate analysis revealed that the gut bacterial community of fish differs significantly from those of other vertebrate classes (reptiles, birds, and mammals). Conclusions Collectively, these data provide a reference for future studies of the gut microbiome of aquatic animals as well as insights into the relationship between fish and their gut bacteria, including the key role of host habitat and the distinct compositions in comparison with those of mammals, reptiles, and birds.

scholarly journals Heat stress reduces the contribution of diazotrophs to coral holobiont nitrogen cycling

2021 ◽  
Author(s):  
Nils Rädecker ◽  
Claudia Pogoreutz ◽  
Hagen M. Gegner ◽  
Anny Cárdenas ◽  
Gabriela Perna ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Heat Stress ◽  
Nutrient Cycling ◽  
Environmental Conditions ◽  
Nitrogen Availability ◽  
Coral Tissue ◽  
Stylophora Pistillata ◽  
Algal Symbionts ◽  
Coral Holobiont ◽  
Algal Symbiosis

AbstractEfficient nutrient cycling in the coral-algal symbiosis requires constant but limited nitrogen availability. Coral-associated diazotrophs, i.e., prokaryotes capable of fixing dinitrogen, may thus support productivity in a stable coral-algal symbiosis but could contribute to its breakdown when overstimulated. However, the effects of environmental conditions on diazotroph communities and their interaction with other members of the coral holobiont remain poorly understood. Here we assessed the effects of heat stress on diazotroph diversity and their contribution to holobiont nutrient cycling in the reef-building coral Stylophora pistillata from the central Red Sea. In a stable symbiotic state, we found that nitrogen fixation by coral-associated diazotrophs constitutes a source of nitrogen to the algal symbionts. Heat stress caused an increase in nitrogen fixation concomitant with a change in diazotroph communities. Yet, this additional fixed nitrogen was not assimilated by the coral tissue or the algal symbionts. We conclude that although diazotrophs may support coral holobiont functioning under low nitrogen availability, altered nutrient cycling during heat stress abates the dependence of the coral host and its algal symbionts on diazotroph-derived nitrogen. Consequently, the role of nitrogen fixation in the coral holobiont is strongly dependent on its nutritional status and varies dynamically with environmental conditions.

scholarly journals Salinity-Conveyed Thermotolerance in the Coral Model Aiptasia Is Accompanied by Distinct Changes of the Bacterial Microbiome

2020 ◽  
Vol 7 ◽  
Author(s):  
Janna L. Randle ◽  
Anny Cárdenas ◽  
Hagen M. Gegner ◽  
Maren Ziegler ◽  
Christian R. Voolstra
Keyword(s):  
Heat Stress ◽  
Bacterial Community ◽  
Community Composition ◽  
Bacterial Communities ◽  
Thermal Tolerance ◽  
High Salinity ◽  
Bacterial Community Composition ◽  
Algal Symbiont ◽  
Bacterial Microbiome ◽  
Reef Decline

Coral bleaching, i.e., the loss of photosynthetic algal endosymbionts, caused by ocean warming is now among the main factors driving global reef decline, making the elucidation of factors that contribute to thermotolerance important. Recent studies implicate high salinity as a contributing factor in cnidarians, potentially explaining the high thermotolerance of corals from the Arabian Seas. Here we characterized bacterial community composition under heat stress at different salinities using the coral model Aiptasia. Exposure of two Aiptasia host-algal symbiont pairings (H2-SSB01 and CC7-SSA01) to ambient (25°C) and heat stress (34°C) temperatures at low (36 PSU), intermediate (39 PSU), and high (42 PSU) salinities showed that bacterial community composition at high salinity was significantly different, concomitant with reduced bleaching susceptibility in H2-SSB01, not observed in CC7-SSA01. Elucidation of bacteria that showed increased relative abundance at high salinity, irrespective of heat stress, revealed candidate taxa that could potentially contribute to the observed increased thermotolerance. We identified 4 (H2-SSB01) and 3 (CC7-SSA01) bacterial taxa belonging to the orders Alteromonadales (1 OTU), Oligoflexales (1 OTU), Rhizobiales (2 OTUs), and Rhodobacterales (2 OTUs), suggesting that only few bacterial taxa are potential contributors to an increase in thermal tolerance at high salinities. These taxa have previously been implicated in nitrogen and DMSP cycling, processes that are considered to affect thermotolerance. Our study demonstrates microbiome restructuring in symbiotic cnidarians under heat stress at different salinities. As such, it underlines how host-associated bacterial communities adapt to prevailing environmental conditions with putative consequences for the environmental stress tolerance of the emergent metaorganism.

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