Dataset Information

Particle-Associated Microbial Community in a Subtropical Lake During Thermal Mixing and Phytoplankton Succession.

ABSTRACT: Ecosystem dynamics in monomictic lakes are characterized by seasonal thermal mixing and stratification. These physical processes bring about seasonal variations in nutrients and organic matter fluxes, affecting the biogeochemical processes that occur in the water column. Physical and chemical dynamics are generally reflected in seasonal structural changes in the phytoplankton and bacterio-plankton community. In this study, we analyzed, using 16S rRNA amplicon sequencing, the structure of the bacterial community associated with large particles (>20 ?m) in Lake Kinneret (Sea of Galilee, Israel), and its associations to phytoplankton populations. The study was carried out during late winter and early spring, a highly dynamic period in terms of thermal mixing, nutrient availability, and shifts in phytoplankton composition. Structural changes in the bacterioplankton population corresponded with limnological variations in the lake. In terms of the entire heterotrophic community, the structural patterns of particle-associated bacteria were mainly correlated with abiotic factors such as pH, ammonia, water temperature and nitrate. However, analysis of microbial taxon-specific correlations with phytoplankton species revealed a strong potential link between specific bacterial populations and the presence of different phytoplankton species, such as the cyanobacterium Microcystis, as well as the dinoflagellates Peridinium and Peridiniopsis. We found that Brevundimonas, a common freshwater genus, and Bdellovibrio, a well-known Gram-negative bacteria predator, were positively associated to Microcystis, suggesting a potentially important role of these three taxa in the microbial ecology of the lake. Our results show that the dynamics of environmental abiotic conditions, rather than specific phytoplankton assemblages, are the main factors positively correlated with changes in the community structure as a whole. Nevertheless, some specific bacteria may interact and be linked with specific phytoplankton, which may potentially control the dynamic patterns of the microbial community.

SUBMITTER: Schweitzer-Natan O

PROVIDER: S-EPMC6753980 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Particle-Associated Microbial Community in a Subtropical Lake During Thermal Mixing and Phytoplankton Succession.

Schweitzer-Natan Orna O Ofek-Lalzar Maya M Sher Daniel D Sukenik Assaf A

Frontiers in microbiology 20190913

Ecosystem dynamics in monomictic lakes are characterized by seasonal thermal mixing and stratification. These physical processes bring about seasonal variations in nutrients and organic matter fluxes, affecting the biogeochemical processes that occur in the water column. Physical and chemical dynamics are generally reflected in seasonal structural changes in the phytoplankton and bacterio-plankton community. In this study, we analyzed, using 16S rRNA amplicon sequencing, the structure of the bac ...[more]

PMID: 31572346

Similar Datasets

Project description:Lake Cajititlán is a small, shallow, subtropical lake located in an endorheic basin in western Mexico. It is characterized by a strong seasonality of climate with pronounced wet and dry seasons and has been classified as a hypereutrophic lake. This eutrophication was driven by improperly treated sewage discharges from four municipal wastewater treatment plants (WWTPs) and by excessive agricultural activities, including the overuse of fertilizers that reach the lake through surface runoff during the rainy season. This nutrient rich runoff has caused algal blooms, which have led to anoxic or hypoxic conditions, resulting in large-scale fish deaths that have occurred during or immediately after the rainy season. This study investigated the changes in the phytoplankton community in Lake Cajititlán during the rainy season and the association between these changes and the physicochemical water quality and environmental parameters measured in the lake's basin. Planktothrix and Cylindrospermopsis were the dominant genera of the cyanobacterial community, while the Chlorophyceae, Chrysophyceae, and Trebouxiophyceae classes dominated the microalgae community. However, the results showed a significant temporal shift in the phytoplankton communities in Lake Cajititlán induced by the rainy season. The findings of this study suggest that significant climatic variations cause high seasonal surface runoff and rapid changes in the water quality (Chlorophyll-a, DO, NH4 +, and NO3 -) and in variations in the composition of the phytoplankton community. Finally, an alternation between phosphorus and nitrogen limitation was observed in Lake Cajititlán during the rainy season, clearly correlating to the presence of Planktothrix when the lake was limited by phosphorus and to the presence of Cylindrospermopsis when the lake was limited by nitrogen. The evidence presented in this study supports the idea that the death of fish in Lake Cajititlán could be mainly caused by anoxia, caused by rapid changes in water quality during the rainy season. Based on our review of the literature, this is the first study on the phytoplankton community in a subtropical lake during the rainy season using high throughput 16S rRNA and 18S rRNA amplicon sequencing.

Project description:Ectomycorrhizal fungi (EMF) can form symbiotic relationships with plants, aiding in plant growth by providing access to nutrients and defense against phytopathogenic fungi. In this context, factors such as plant assemblages and soil properties can impact the interaction between EMF and phytopathogenic fungi in forest soil. However, there is little understanding of how these fungal interactions evolve as forests move through succession stages. In this study, we used high-throughput sequencing to investigate fungal communities in young, intermediate, and old subtropical forests. At the genus level, EMF communities were dominated by Sebacina, Russula, and Lactarius, while Mycena was the most abundant genus in pathogenic fungal communities. The relative abundances of EMF and phytopathogenic fungi in different stages showed no significant difference with the regulation of different factors. We discovered that interactions between phytopathogenic fungi and EMF maintained a dynamic balance under the influence of the differences in soil quality attributed to each forest successional stage. The community composition of phytopathogenic fungi is one of the strong drivers in shaping EMF communities over successions. In addition, the EMF diversity was significantly related to plant diversity, and these relationships varied among successional stages. Despite the regulation of various factors, the positive relationship between the diversity of phytopathogenic fungi and EMF remained unchanged. However, there is no significant difference in the ratio of the abundance of EMF and phytopathogenic fungi over the course of successions. These results will advance our understanding of the biodiversity-ecosystem functioning during forest succession. KEY POINTS: •Community composition of both EMF and phytopathogenic fungi changed significantly over forest succession. •Phytopathogenic fungi is a key driver in shaping EMF community. •The effect of plant Shannon's diversity on EMF communities changed during the forest aging process.

Project description:Pseudo-nitzschia blooms often occur in coastal and open ocean environments, sometimes leading to the production of the neurotoxin domoic acid that can cause severe negative impacts to higher trophic levels. Increasing evidence suggests a close relationship between phytoplankton bloom and bacterial assemblages, however, the microbial composition and succession during a bloom process is unknown. Here, we investigate the bacterial assemblages before, during and after toxic and non-toxic Pseudo-nitzschia blooms to determine the patterns of bacterial succession in a natural bloom setting. Opportunistic sampling of bacterial community profiles were determined weekly at Santa Cruz Municipal Wharf by 454 pyrosequencing and analyzed together with domoic acid levels, phytoplankton community and biomass, nutrients and temperature. We asked if the bacterial communities are similar between bloom and non-bloom events and if domoic acid or the presence of toxic algal species acts as a driving force that can significantly structure phytoplankton-associated bacterial communities. We found that bacterial diversity generally increases when Pseudo-nitzschia numbers decline. Furthermore, bacterial diversity is higher when the low-DA producing P. fraudulenta dominates the algal bloom while bacterial diversity is lower when high-DA producing P. australis dominates the algal bloom, suggesting that the presence of algal toxin can structure bacterial community. We also found bloom-related succession patterns among associated bacterial groups; Gamma-proteobacteria, were dominant during low toxic P. fraudulenta blooms comprising mostly of Vibrio spp., which increased in relative abundance (6-65%) as the bloom progresses. On the other hand, Firmicutes bacteria comprising mostly of Planococcus spp. (12-86%) dominate during high toxic P. australis blooms, with the bacterial assemblage showing the same bloom-related successional patterns in three independent bloom events. Other environmental variables such as nitrate and phosphate and temperature appear to influence some low abundant bacterial groups as well. Our results suggest that phytoplankton-associated bacterial communities are strongly affected not just by phytoplankton bloom in general, but also by the type of algal species that dominates in the natural bloom.

Dataset Information

Particle-Associated Microbial Community in a Subtropical Lake During Thermal Mixing and Phytoplankton Succession.

Publications

Particle-Associated Microbial Community in a Subtropical Lake During Thermal Mixing and Phytoplankton Succession.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets