scholarly journals Trophic states regulate assembly processes and network structures of small chromophytic phytoplankton communities in subtropical coastal ecosystem

2020 ◽  
Author(s):  
Xing Chen ◽  
Huaxian Zhao ◽  
Gonglingxia Jiang ◽  
Jinli Tang ◽  
Qiangsheng Xu ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Community Assembly ◽  
Significant Proportion ◽  
Alpha Diversity ◽  
Beibu Gulf ◽  
Coastal Eutrophication ◽  
Nitrogen And Phosphorus ◽  
Ecological Processes ◽  
Phytoplankton Communities ◽  
Estuarine Coastal

Abstract Small chromophytic phytoplankton (SCP) are anticipated to be more important for a significant proportion of primary production in estuarine-coastal ecosystems. However, responses of SCP community to coastal eutrophication are still unclear. In this study, we investigated diversity, co-occurrence and assembly features of SCP communities, as well as their relationship with environmental factors in the subtropical Beibu Gulf. The results exhibited that the alpha diversity (ANOVA, p < 0.001) and beta diversity (ANOSIM, p < 0.001) of SCP communities were significantly different among eutrophic states. Co-occurrence network analysis revealed a complex interaction between SCP community and environmental factors. Most ASVs in modules of the network were specific to trophic states. Further, phylogenetic based β-nearest taxon distance analyses revealed that stochastic processes mainly provided 69.26% contribution to SCP community assembly, whereas deterministic processes dominated community assembly in a heavy eutrophic state. Importantly, increased environmental disturbances, such as nitrogen and phosphorus nutrients, could alter SCP community structure and disrupt ecological processes. Overall, our findings elucidate the mechanism of diversity and assembly in marine SCP community and promote the understanding of SCP ecology related to subtropical coastal eutrophication.

scholarly journals Trophic states regulate assembly processes and network structures of small chromophytic phytoplankton communities in subtropical coastal ecosystem

2020 ◽  
Author(s):  
Xing Chen ◽  
Huaxian Zhao ◽  
Gonglingxia Jiang ◽  
Jinli Tang ◽  
Qiangsheng Xu ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Community Assembly ◽  
Significant Proportion ◽  
Alpha Diversity ◽  
Beibu Gulf ◽  
Coastal Eutrophication ◽  
Nitrogen And Phosphorus ◽  
Ecological Processes ◽  
Phytoplankton Communities ◽  
Estuarine Coastal

Abstract Small chromophytic phytoplankton (SCP) are anticipated to be more important for a significant proportion of primary production in estuarine-coastal ecosystems. However, responses of SCP community to coastal eutrophication are still unclear. In this study, we investigated diversity, co-occurrence and assembly features of SCP communities, as well as their relationship with environmental factors in the subtropical Beibu Gulf. The results exhibited that the alpha diversity (ANOVA, p < 0.001) and beta diversity (ANOSIM, p < 0.001) of SCP communities were significantly different among eutrophic states. Co-occurrence network analysis revealed a complex interaction between SCP community and environmental factors. Most OTUs in modules of the network were specific to trophic states. Further, phylogenetic based β-nearest taxon distance analyses revealed that stochastic processes mainly provided 69.26% contribution to SCP community assembly, whereas deterministic processes dominated community assembly in a heavy eutrophic state. Importantly, increased environmental disturbances, such as nitrogen and phosphorus nutrients, could alter SCP community structure and disrupt ecological processes. Overall, our findings elucidate the mechanism of diversity and assembly in marine SCP community and promote the understanding of SCP ecology related to subtropical coastal eutrophication.

scholarly journals Trophic States Regulate Assembly Processes and Network Structures of Picophytoplankton Communities in Subtropical Coastal Ecosystems

2020 ◽  
Author(s):  
Xing Chen ◽  
Huaxian Zhao ◽  
Gonglingxia Jiang ◽  
Jinli Tang ◽  
Qiangsheng Xu ◽  
...  
Keyword(s):  
Community Assembly ◽  
Anthropogenic Activities ◽  
Alpha Diversity ◽  
Amplicon Sequencing ◽  
Coastal Ecosystems ◽  
Network Structures ◽  
Coastal Eutrophication ◽  
Nitrogen And Phosphorus ◽  
Ecological Processes ◽  
Deterministic Processes

Abstract Background: Long-term coastal eutrophication especially in semi-enclosed marine areas is driven by increased amounts of nutrients derived from anthropogenic activities. Given that accelerating nutrients may constitute a strong environmental filter, understanding the diversity, assembly process and co-occurrence pattern of picophytoplankton communities in response to increasing coastal eutrophication is clearly of great importance. Results: We investigated picophytoplankton community changes using rbcL gene amplicon sequencing. The results exhibited that the alpha diversity (ANOVA, p < 0.001) and beta diversity (ANOSIM, p < 0.001) were significantly different among eutrophic states. Further, phylogenetic based β-nearest taxon distance analyses revealed that stochastic processes mainly provided 69.26% contribution to picophytoplankton community assembly, whereas deterministic processes dominated community assembly in a heavy eutrophic state. Integrated co-occurrence networks modularly responded to eutrophic states and revealed that keystone taxa mainly belonged to the oligo eutrophic group, which may play fundamental roles in network persistence. Importantly, increased environmental disturbances, such as nitrogen and phosphorus nutrients, could alter picophytoplankton community structure and disrupt ecological processes. Conclusion: Stochastic and deterministic processes simultaneously influenced the assembly of picophytoplankton communities in the subtropical coastal ecosystems. Eutrophic disturbances alert the assembly processes and network structures of picophytoplankton community. Our findings promote the understanding of fundamental ecological processes along eutrophic gradients in subtropical coastal ecosystems.

Inferring community assembly processes from trait diversity across environmental gradients

2016 ◽  
Vol 32 (4) ◽  
pp. 290-299 ◽  
Author(s):  
Yong Shen ◽  
Shi-Xiao Yu ◽  
Ju-Yu Lian ◽  
Hao Shen ◽  
Hong-Lin Cao ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Soil Fertility ◽  
Functional Diversity ◽  
Community Assembly ◽  
Environmental Gradients ◽  
Environmental Filtering ◽  
Competitive Interactions ◽  
Dry Matter Content ◽  
Ecological Processes ◽  
Trait Diversity

Abstract:Environmental filtering and competitive interactions are important ecological processes in community assembly. The contribution of the two processes to community assembly can be evaluated by shifts in functional diversity patterns. We examined the correlations between functional diversity of six traits (leaf chlorophyll concentration, dry matter content, size, specific leaf area, thickness and wood density) and environmental gradients (topography and soil) for 92 species in the 20-ha Dinghushan forest plot in China. A partial Mantel test showed that most of the community-weighted mean trait values changed with terrain convexity and soil fertility, which implied that environmental filtering was occurring. Functional diversity of many traits significantly increased with increasing terrain convexity and soil fertility, which was associated with increased light and below-ground resources respectively. These results suggest that co-occurring species are functionally convergent in regions of strong abiotic stress under the environmental filtering, but functionally divergent in more benign environments due to resource partitioning and competitive interactions. Single-trait diversity and multivariate functional diversity had different relationships with environmental factors, indicating that traits were related to different niche axes, and associated with different ecological processes, which demonstrated the importance of focusing niche axes in traits selection. Between 9% and 41% of variation in functional diversity of different traits was explained by environmental factors in stepwise multiple regression models. Terrain convexity and soil fertility were the best predictors of functional diversity, which contributed 30.5% and 29.0% of total R2to the model. These provided essential evidence that different environmental factors had distinguishing impacts on regulating diversity of traits.

Rhinella icterica and Rhinella ornata (Anura: Bufonidae) tadpoles do not recognise siblings

2021 ◽  
pp. 214-220
Author(s):  
Alexandre Polettini Neto
Keyword(s):  
Environmental Factors ◽  
Laboratory Experiments ◽  
Inclusive Fitness ◽  
Costs And Benefits ◽  
Environmental Characteristics ◽  
Ecological Processes ◽  
Aggregation Behaviour ◽  
Rearing Methods

Benefits conferred to animals living in groups may be greater if groups are formed by relatives rather than non-relatives, because cooperating with relatives increases the probability of their own genes being passed on to group offspring (inclusive fitness). Non-social aggregations are formed in response to environmental characteristics, while social aggregations are formed from the attraction among individuals. The attraction or repulsion between individuals is mediated by recognition mechanisms, which mediate important ecological processes and behaviours. Here, we conducted laboratory experiments to test if tadpoles of two sympatric bufonids, Rhinella icterica and R. ornata, are able to recognise siblings. We collected eggs of the two species in the field and raised them in laboratory settings, according to three different methods: siblings and non-siblings reared in separated containers; siblings and non-siblings reared in the same container separated by a plastic net; and eggs from the same spawn reared separately, each one in an individual container. Later, we tested if tadpoles could choose between groups of siblings and non-siblings. The results indicate that tadpoles of neither species were able to discriminate between siblings and non-siblings, regardless of the rearing methods. Therefore, kinship is less important than environmental factors in tadpole aggregation behaviour of these species, and it may be dependent on the balance between costs and benefits. Our results can be used as a start point to better understand tadpole aggregation behaviour and recognition mechanisms in these species.

scholarly journals Phytoplankton community structure in Menjer Lake, Central Java

2021 ◽  
Vol 869 (1) ◽  
pp. 012037
Author(s):  
F Sulawesty ◽  
G P Yoga ◽  
L Subehi ◽  
R Rosidah
Keyword(s):  
Community Structure ◽  
Phytoplankton Community ◽  
Diversity Index ◽  
Nutrient Content ◽  
Cell Counting ◽  
Phytoplankton Community Structure ◽  
Nitrogen And Phosphorus ◽  
Central Java ◽  
Phytoplankton Communities ◽  
Ecological Pressure

Abstract The occurrence of land changes around Lake Menjer, Central Java Province will affect the condition of water quality subsequently will affect biota, including phytoplankton. The purposes of study was to analyze the composition and abundance of phytoplankton in Menjer Lake regarding to nutrient content i.e. nitrogen and phosphorus. Observations on the phytoplankton community were conducted in July and October 2019 at six locations in Menjer Lake. Water samples were taken at the water surface as much as 10 L filtered using plankton net. Identification was carried out under the inverted microscope Diaphot 300. The abundance was calculated using the Sedgwick Rafter cell counting (SRCC) method. Analysis of the phytoplankton community structure was derived by calculating the Diversity Index, Evenness Index, and Simpson Dominance Index. The nutrient content in Menjer Lake influences the structure of phytoplankton communities quantitatively and qualitatively. Observation showed that the diversity of phytoplankton was low and there was one species dominanted, the result explained that the phytoplankton community in Menjer Lake is unstable and there is ecological pressure on the community. It can be concluded that the improvement of environmental conditions around Menjer Lake is the basis for the sustainable management of Menjer Lake.

scholarly journals Dynamics of the cyanobacterial water bloom with focus to Microcystis and its relationship with environmental factors in Brno reservoir

2013 ◽  
Vol 61 (5) ◽  
pp. 1383-1390
Author(s):  
Lucie Straková ◽  
Radovan Kopp ◽  
Eliška Maršálková ◽  
Blahoslav Maršálek
Keyword(s):  
Environmental Factors ◽  
Point Sources ◽  
Water Bloom ◽  
Data Set ◽  
New Information ◽  
Phytoplankton Communities ◽  
Management Effort ◽  
Phosphate Loading ◽  
Treatment Facilities

Our paper brings new information about long-term changes of the phytoplankton communities in the Brno reservoir with the focus on the Microcystis abundance using the semi-monthly monitoring data covering the period 2006–2012. The main aim is to extract from this long-term data set differences in number of Microcystis cells depending on environmental factors. The development of cyanobacteria in Brno reservoir is caused by excessive phosphate loading from wastewater treatment facilities upstream and from non–point sources along the Svratka river. It focuses management effort on upstream controls of reservoir condition. High abundance in millions of cyanobacteria cells in 1ml observed in Brno reservoir before was reduced to values in the order of thousands cells in 1ml in last two years through a combination of measures (liming, precipitation of phosphorus on inflow, aeration and destratification). Phytoplankton composition was also changed and at the expense of cyanobacteria promoted the development of green algae and diatoms.

scholarly journals Genome size mediates the effect of environmental filtering in determining plant β-diversity across temperate grasslands

2021 ◽  
Author(s):  
Hai-Yang Zhang ◽  
Xiaotao Lü ◽  
cunzheng wei ◽  
Jeff Powell ◽  
Xiaobo Wang ◽  
...  
Keyword(s):  
Genome Size ◽  
Community Assembly ◽  
Nuclear Dna ◽  
Environmental Filtering ◽  
Nuclear Dna Content ◽  
Mean Annual Precipitation ◽  
Mean Annual Temperature ◽  
Nitrogen And Phosphorus ◽  
Temperate Grasslands ◽  
Β Diversity

Elucidating mechanisms underlying community assembly and biodiversity patterns is central to ecology and evolution. Genome size (GS, i.e. nuclear DNA content) determines species’ capacity to tolerate environmental stress or to exploit new environments and therefore potentially drive community assembly. However, its role in driving β-diversity (i.e., the site-to-site variability in species composition) remains unclear. We measured GS for 169 plant species and investigated their occurrences within plant communities across 52 sites spanning a 3200-km transect in the temperate grasslands of China. We found environmental factors showed larger effects on β-diversity of large-GS than that of small-GS species. Community weighted mean GS increased with mean annual precipitation, soil total nitrogen and phosphorus concentrations, but decreased with mean annual temperature, suggesting a negative selection against species with large GS in resources-limited or warmer climates. These findings highlight the roles for GS in driving community assembly and predicting species responses to climate change.

Microbial ecological processes in MBBR biofilms for biological phosphorus removal from wastewater

2019 ◽  
Vol 79 (8) ◽  
pp. 1467-1473 ◽  
Author(s):  
Knut Rudi ◽  
Inger Andrea Goa ◽  
Torgeir Saltnes ◽  
Gjermund Sørensen ◽  
Inga Leena Angell ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Alpha Diversity ◽  
Fold Increase ◽  
Environmental Pollutant ◽  
Biofilm Reactor ◽  
Operational Performance ◽  
Biological Phosphorus Removal ◽  
Ecological Processes ◽  
Biological Phosphorus

Abstract Phosphorus is both a major environmental pollutant and a limiting resource. Although enhanced biological phosphorus removal (EBPR) is used worldwide for phosphorus removal, the standard activated sludge-based EBPR process shows limitations with stability and efficiency. Recently, a new EBPR moving bed biofilm reactor (MBBR) process has been developed at HIAS (Hamar, Norway), enabling a phosphorus removal stability above 90% during a whole year cycle. To increase the knowledge of the HIAS (MBBR) process the aim of the current work was to characterize the MBBR microbiota and operational performance weekly for the operational year. Surprisingly, we found a major succession of the microbiota, with a five-fold increase in phosphorus accumulating organisms (PAOs), and major shifts in eukaryote composition, despite a stable phosphorus removal. Temperature was the only factor that significantly affected both phosphorus removal and the microbiota. There was a lower phosphor removal during the winter, coinciding with a higher microbiota alpha diversity, and a lower beta diversity. This differs from what is observed for activated sludge based EBPR. Taken together, the knowledge gained from the current microbiota study supports the efficiency and stability of MBBR-based systems, and that knowledge from activated sludge-based EBPR approaches cannot be translated to MBBR systems.

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