scholarly journals Nutrient Enrichment Predominantly Affects Low Diversity Microbiomes in a Marine Trophic Symbiosis between Algal Farming Fish and Corals

2021 ◽  
Vol 9 (9) ◽  
pp. 1873
Author(s):  
Adriana Messyasz ◽  
Rebecca L. Maher ◽  
Sonora S. Meiling ◽  
Rebecca Vega Thurber
Keyword(s):  
Species Richness ◽  
Trophic Interactions ◽  
Nutrient Enrichment ◽  
Nutrient Pollution ◽  
Sequence Variants ◽  
Porites Lobata ◽  
Low Diversity ◽  
Single Genus ◽  
Community Variability

While studies show that nutrient pollution shifts reef trophic interactions between fish, macroalgae, and corals, we know less about how the microbiomes associated with these organisms react to such disturbances. To investigate how microbiome dynamics are affected during nutrient pollution, we exposed replicate Porites lobata corals colonized by the fish Stegastes nigricans, which farm an algal matrix on the coral, to a pulse of nutrient enrichment over a two-month period and examined the microbiome of each partner using 16S amplicon analysis. We found 51 amplicon sequence variants (ASVs) shared among the three hosts. Coral microbiomes had the lowest diversity with over 98% of the microbiome dominated by a single genus, Endozoicomonas. Fish and algal matrix microbiomes were ~20 to 70× more diverse and had higher evenness compared to the corals. The addition of nutrients significantly increased species richness and community variability between samples of coral microbiomes but not the fish or algal matrix microbiomes, demonstrating that coral microbiomes are less resistant to nutrient pollution than their trophic partners. Furthermore, the 51 common ASVs within the 3 hosts indicate microbes that may be shared or transmitted between these closely associated organisms, including Vibrionaceae bacteria, many of which can be pathogenic to corals.

Macroalgal fouling communities as indicators of environmental change: potential applications for water quality monitoring

2017 ◽  
Vol 98 (7) ◽  
pp. 1581-1588 ◽  
Author(s):  
Veronica Farrugia Drakard ◽  
Sandro Lanfranco ◽  
Patrick J. Schembri
Keyword(s):  
Water Quality ◽  
Species Richness ◽  
Community Structure ◽  
Environmental Change ◽  
Environmental Monitoring ◽  
Environmental Conditions ◽  
Nutrient Enrichment ◽  
Water Quality Monitoring ◽  
Environmental Data ◽  
Fouling Communities

Macroalgal fouling communities are potentially useful as bioindicators in environmental monitoring as they are considered to be sensitive to changes in environmental conditions and the use of artificial substrata facilitates the implementation of standardized sampling strategies. The response of macroalgal fouling communities on buoys to changes in water quality was investigated with a view to the possible utilization of these assemblages in environmental monitoring programmes. Seven study sites were selected based on previously collected environmental data and Principal Components Analysis (PCA) was used to order sites according to beam attenuation coefficient (BAC) and concentration of dissolved nitrates and phosphates, relative to a minimally impacted reference site. At each site, all fouling macroalgae were collected from 10 buoys of standard shape and size, and were identified to the lowest possible taxonomic level. Species composition and species dominance were highly variable among impacted sites, indicating that qualitative aspects of community structure may not be useful as indicators of changes in water quality. However, higher levels of nutrient enrichment and turbidity were associated with lower macroalgal species richness, lower overall abundances, and decreased diversities, and therefore these quantitative aspects of community structure are potentially useful as indicators of environmental change. Intermediate levels of turbidity and nutrient enrichment were associated with lower evenness, but did not influence species richness, suggesting that macroalgal abundances respond to changes in environmental conditions before species replacement occurs.

scholarly journals How habitat-modifying organisms structure the food web of two coastal ecosystems

2016 ◽  
Vol 283 (1826) ◽  
pp. 20152326 ◽  
Author(s):  
Els M. van der Zee ◽  
Christine Angelini ◽  
Laura L. Govers ◽  
Marjolijn J. A. Christianen ◽  
Andrew H. Altieri ◽  
...  
Keyword(s):  
Species Richness ◽  
Food Web ◽  
Food Webs ◽  
Trophic Interactions ◽  
Trophic Levels ◽  
Interaction Networks ◽  
Habitat Modification ◽  
Seagrass Meadows ◽  
Link Density ◽  
Trophic Role

The diversity and structure of ecosystems has been found to depend both on trophic interactions in food webs and on other species interactions such as habitat modification and mutualism that form non-trophic interaction networks. However, quantification of the dependencies between these two main interaction networks has remained elusive. In this study, we assessed how habitat-modifying organisms affect basic food web properties by conducting in-depth empirical investigations of two ecosystems: North American temperate fringing marshes and West African tropical seagrass meadows. Results reveal that habitat-modifying species, through non-trophic facilitation rather than their trophic role, enhance species richness across multiple trophic levels, increase the number of interactions per species (link density), but decrease the realized fraction of all possible links within the food web (connectance). Compared to the trophic role of the most highly connected species, we found this non-trophic effects to be more important for species richness and of more or similar importance for link density and connectance. Our findings demonstrate that food webs can be fundamentally shaped by interactions outside the trophic network, yet intrinsic to the species participating in it. Better integration of non-trophic interactions in food web analyses may therefore strongly contribute to their explanatory and predictive capacity.

Nutrient enrichment increased species richness of leaf litter fungal assemblages in a tropical forest

2013 ◽  
Vol 22 (10) ◽  
pp. 2827-2838 ◽  
Author(s):  
Jennifer Kerekes ◽  
Michael Kaspari ◽  
Bradley Stevenson ◽  
R. Henrik Nilsson ◽  
Martin Hartmann ◽  
...  
Keyword(s):  
Species Richness ◽  
Tropical Forest ◽  
Leaf Litter ◽  
Nutrient Enrichment ◽  
Fungal Assemblages

scholarly journals DINÁMICA DEL FITOPLANCTON DE LA CIÉNAGA GRANDE DE SANTA MARTA, CARIBE COLOMBIANO

2016 ◽  
Vol 33 ◽  
Author(s):  
María Virginia De La Hoz Aristizbal
Keyword(s):  
Species Richness ◽  
Environmental Factors ◽  
Seasonal Changes ◽  
Dominant Species ◽  
General Trend ◽  
Meteorological Conditions ◽  
Phytoplankton Dynamics ◽  
Four Seasons ◽  
Low Diversity

In order to assess phytoplankton dynamics in the Ciénaga Grande de Santa Marta, bimonthly sampling was done at six stations from March 1996 to February 1997. Salinity showed wide ranges so the year could be divided in four seasons. Higher salinities were related to higher phytoplankton density, while lower salinities were related to lower phytoplankton densities and increased species richness. 224 taxa were recorded, and the general trend was towards a low diversity with a few dominant species, and most of them rare. Cyanophytes showed the highest abundances all year. Salinity, turbidity and orthophosphates were the environmental factors best related to the biotic data. Seasonal changes in phytoplankton concerning to meteorological conditions, fresh and tidal floods and dredging of Clarín canal are discussed.

scholarly journals Species-area and network-area relationships in host–helminth interactions

2021 ◽  
Vol 288 (1947) ◽  
Author(s):  
Tad A. Dallas ◽  
Pedro Jordano
Keyword(s):  
Species Richness ◽  
Trophic Interactions ◽  
Species Interactions ◽  
Geographical Area ◽  
Species Interaction ◽  
Helminth Parasites ◽  
Scaling Relationship ◽  
Theoretical Predictions ◽  
Species Area ◽  
Network Area

The scaling relationship observed between species richness and the geographical area sampled (i.e. the species-area relationship (SAR)) is a widely recognized macroecological relationship. Recently, this theory has been extended to trophic interactions, suggesting that geographical area may influence the structure of species interaction networks (i.e. network-area relationships (NARs)). Here, we use a global dataset of host–helminth parasite interactions to test existing predictions from macroecological theory. Scaling between single locations to the global host–helminth network by sequentially adding networks together, we find support that geographical area influences species richness and the number of species interactions in host–helminth networks. However, species-area slopes were larger for host species relative to their helminth parasites, counter to theoretical predictions. Lastly, host–helminth network modularity—capturing the tendency of the network to form into separate subcommunities—decreased with increasing area, also counter to theoretical predictions. Reconciling this disconnect between existing theory and observed SAR and NAR will provide insight into the spatial structuring of ecological networks, and help to refine theory to highlight the effects of network type, species distributional overlap, and the specificity of trophic interactions on NARs.

scholarly journals Climate modifies response of non-native and native species richness to nutrient enrichment

2016 ◽  
Vol 371 (1694) ◽  
pp. 20150273 ◽  
Author(s):  
Habacuc Flores-Moreno ◽  
Peter B. Reich ◽  
Eric M. Lind ◽  
Lauren L. Sullivan ◽  
Eric W. Seabloom ◽  
...  
Keyword(s):  
Species Richness ◽  
Nutrient Enrichment ◽  
Time Scale ◽  
Native Species ◽  
Niche Partitioning ◽  
Climatic Conditions ◽  
Nutrient Addition ◽  
Interactive Effects ◽  
Native Plant ◽  
Native Species Richness

Ecosystem eutrophication often increases domination by non-natives and causes displacement of native taxa. However, variation in environmental conditions may affect the outcome of interactions between native and non-native taxa in environments where nutrient supply is elevated. We examined the interactive effects of eutrophication, climate variability and climate average conditions on the success of native and non-native plant species using experimental nutrient manipulations replicated at 32 grassland sites on four continents. We hypothesized that effects of nutrient addition would be greatest where climate was stable and benign, owing to reduced niche partitioning. We found that the abundance of non-native species increased with nutrient addition independent of climate; however, nutrient addition increased non-native species richness and decreased native species richness, with these effects dampened in warmer or wetter sites. Eutrophication also altered the time scale in which grassland invasion responded to climate, decreasing the importance of long-term climate and increasing that of annual climate. Thus, climatic conditions mediate the responses of native and non-native flora to nutrient enrichment. Our results suggest that the negative effect of nutrient addition on native abundance is decoupled from its effect on richness, and reduces the time scale of the links between climate and compositional change.

Nutrient enrichment increases size of Zostera marina shoots and enriches for sulfur and nitrogen cycling bacteria in root-associated microbiomes

2020 ◽  
Vol 96 (8) ◽  
Author(s):  
Lu Wang ◽  
Fiona Tomas ◽  
Ryan S Mueller
Keyword(s):  
Nutrient Enrichment ◽  
Zostera Marina ◽  
Amplicon Sequencing ◽  
Nutrient Pollution ◽  
Bulk Sediment ◽  
Ambient Conditions ◽  
Seagrass Meadows ◽  
16S Rrna Amplicon Sequencing ◽  
Sulfide Toxicity ◽  
Number Of Leaves

ABSTRACT Seagrasses are vital coastal ecosystem engineers, which are mutualistically associated with microbial communities that contribute to the ecosystem services provided by meadows. The seagrass microbiome and sediment microbiota play vital roles in belowground biogeochemical and carbon cycling. These activities are influenced by nutrient, carbon and oxygen availability, all of which are modulated by environmental factors and plant physiology. Seagrass meadows are increasingly threatened by nutrient pollution, and it is unknown how the seagrass microbiome will respond to this stressor. We investigated the effects of fertilization on the physiology, morphology and microbiome of eelgrass (Zostera marina) cultivated over 4 weeks in mesocosms. We analyzed the community structure associated with eelgrass leaf, root and rhizosphere microbiomes, and of communities from water column and bulk sediment using 16S rRNA amplicon sequencing. Fertilization led to a higher number of leaves compared with that of eelgrass kept under ambient conditions. Additionally, fertilization led to enrichment of sulfur and nitrogen bacteria in belowground communities. These results suggest nutrient enrichment can stimulate belowground biogeochemical cycling, potentially exacerbating sulfide toxicity in sediments and decreasing future carbon sequestration stocks.

Grassland species response to soil disturbance and nutrient enrichment on the Northern Tablelands of New South Wales

2005 ◽  
Vol 53 (6) ◽  
pp. 485 ◽  
Author(s):  
A. Chalmers ◽  
S. McIntyre ◽  
R. D. B. Whalley ◽  
N. Reid
Keyword(s):  
Species Richness ◽  
Exotic Species ◽  
Nutrient Enrichment ◽  
New South ◽  
Soil Disturbance ◽  
Species Response ◽  
High Soil ◽  
South Wales ◽  
Total Species Richness ◽  
Total Species

An experiment was established in an area of long-grazed temperate grassland on the Northern Tablelands of New South Wales to investigate individual species response to mechanical soil disturbance and nutrient enrichment. Grazing was excluded for the duration of the experiment. The total species pool available in the experiment included 56 native and 24 exotic species recorded in the plots, as well as seven exotic species that were artificially introduced (i.e. sowing treatment). Eighteen months after treatment, total species richness was significantly lower under high soil disturbance (mean of 14.7 ± 0.85 species m–2) than under low (21.1 ± 0.67 species m–2) and moderately (21.7 ± 0.77 species m–2) disturbed conditions. Total species richness was not significantly affected by nutrient enrichment or sowing. Most of the annuals analysed were exotic and their relative cover increased with nutrient enrichment (Aira cupaniana Guss., Briza minor L. and Vulpia spp.), but was unresponsive to soil disturbance. Perennials showed varied responses, with the abundance of most decreasing with high soil disturbance and being unaffected by moderate soil disturbance levels. All four perennials favoured by high soil disturbance were exotic (Dactylis glomerata L., Lolium perenne L., Hypochaeris radicata L. and Sanguisorba minor Scop.); three of these were sown. Most perennials showed no significant response to nutrient enrichment, although the occurrence of a small number was either reduced (Aristida ramosa R.Br., A. warburgii Mez., H. radicata and S. minor) or increased (Carex inversa R.Br., D. glomerata, Fimbristylis dichotoma (L.) Vahl., Sporobolus creber De Nardi and Tricoryne elatior R.Br.). Most interactions (i.e. species response to one experimental factor depends on another experimental factor) occurred because few individuals survived on the severely soil-disturbed plots to respond to nutrient enrichment. However, in this particular grassland, the short-term response of most species to soil disturbance was independent of the level of nutrient enrichment.

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