The Role of Abiotic Environmental Conditions and Herbivory in Shaping Bacterial Community Composition in Floral Nectar

AbstractSpecies interactions, environmental conditions, and stochastic processes work in concert to bring about changes in community structure. However, the relative importance of specific factors and how their combined influence affects community composition remain largely unclear. We conducted a multi-factorial experiment to 1) disentangle the direct and interaction-mediated effects of environmental conditions and 2) augment our understanding of how environmental context modulates species interactions. We focus on a planktonic system where interactions with phytoplankton effect changes in the composition of bacterial communities, and light and temperature conditions can influence bacteria directly as well as through their interactions with phytoplankton. Epilimnetic bacteria from two humic lakes were combined with phytoplankton assemblages from each lake (“home” or “away”) or a no-phytoplankton control and incubated for 5 days under all combinations of light (surface, ∼25% surface irradiance) and temperature (5 levels from 10°C to 25°C). Observed light effects were primarily direct while phytoplankton and temperature effects on bacterial community composition were highly interdependent. The influence of temperature on aquatic bacteria was consistently mediated by phytoplankton and most pronounced for bacteria incubated with “away” phytoplankton treatments, likely due to the availability of novel phytoplankton-derived resources. The effects of phytoplankton on bacterial community composition were generally increased at higher temperatures. Incorporating mechanisms underlying the observed interdependent effects of species interactions and environmental conditions into modeling frameworks may improve our ability to forecast ecological responses to environmental change.

Download Full-text

Metagenomics reveals diet-specific specialization of bacterial communities in fungus gardens of grass- and dicot-cutter ants

10.1101/250993 ◽

2018 ◽

Cited By ~ 1

Author(s):

Lily Khadempour ◽

Huan Fan ◽

Ken Keefover-Ring ◽

Camila Carlos ◽

Nilson S. Nagamoto ◽

...

Keyword(s):

Bacterial Community ◽

Community Composition ◽

Bacterial Communities ◽

Potential Role ◽

Sequence Data ◽

Bacterial Community Composition ◽

Fungus Garden ◽

Functional Profiles ◽

Ant Fungus

AbstractLeaf-cutter ants in the genusAttaare dominant herbivores in the Neotropics. While most species ofAttacut dicots to incorporate into their fungus gardens, some species specialize on grasses. Here we examine the bacterial community associated with the fungus gardens of grass- and dicot-cutter ants to examine how changes in substrate input affect the bacterial community. We sequenced the metagenomes of 12Attafungus gardens, across four species of ants, with a total of 5.316 Gbp of sequence data. We show significant differences in the fungus garden bacterial community composition between dicot- and grass-cutter ants, with grass-cutter ants having lower diversity. Reflecting this difference in community composition, the bacterial functional profiles between the fungus gardens are significantly different. Specifically, grass-cutter ant fungus garden metagenomes are particularly enriched for genes responsible for amino acid, siderophore, and terpenoid biosynthesis while dicot-cutter ant fungus gardens metagenomes are enriched in genes involved in membrane transport. These differences in bacterial community composition and functional capacity show that different substrate inputs matter for fungus garden bacteria, and sheds light on the potential role of bacteria in mediating the ants’ transition to the use of a novel substrate.

Download Full-text

Key role of selective viral-induced mortality in determining marine bacterial community composition

Environmental Microbiology ◽

10.1111/j.1462-2920.2006.01137.x ◽

2007 ◽

Vol 9 (2) ◽

pp. 287-297 ◽

Cited By ~ 139

Author(s):

T. Bouvier ◽

P. A. del Giorgio

Keyword(s):

Bacterial Community ◽

Community Composition ◽

Bacterial Community Composition

Download Full-text

Bacterial community composition associated with freshwater algae: species specificity vs. dependency on environmental conditions and source community

FEMS Microbiology Ecology ◽

10.1111/1574-6941.12022 ◽

2012 ◽

Vol 83 (3) ◽

pp. 650-663 ◽

Cited By ~ 40

Author(s):

Falk Eigemann ◽

Sabine Hilt ◽

Ivette Salka ◽

Hans-Peter Grossart

Keyword(s):

Bacterial Community ◽

Community Composition ◽

Environmental Conditions ◽

Bacterial Community Composition ◽

Species Specificity ◽

Freshwater Algae

Download Full-text

The total and active bacterial community of the chlorolichen Cetraria islandica and its response to long-term warming in sub-Arctic tundra

10.1101/2020.03.04.976944 ◽

2020 ◽

Author(s):

Ingeborg J. Klarenberg ◽

Christoph Keuschnig ◽

Denis Warshan ◽

Ingibjörg Svala Jónsdóttir ◽

Oddur Vilhelmsson

Keyword(s):

Bacterial Community ◽

Community Composition ◽

Relative Abundance ◽

Environmental Conditions ◽

Bacterial Community Composition ◽

Arctic Tundra ◽

Amplicon Sequencing ◽

Total Community ◽

First Time

AbstractLichens are traditionally defined as a symbiosis between a fungus and a green alga and or a cyanobacterium. This idea has been challenged by the discovery of bacterial communities inhabiting the lichen thalli. These bacteria are thought to contribute to the survival of lichens under extreme and changing environmental conditions. How these changing environmental conditions affect the lichen-associated bacterial community composition remains unclear.We describe the total (rDNA-based) and potentially metabolically active (rRNA-based) bacterial community of the lichen Cetaria islandica and its response to long-term warming using a 20-year warming experiment in an Icelandic sub-Arctic tundra. 16S rRNA and rDNA amplicon sequencing showed that the orders Acetobacterales (of the class Alphaproteobacteria) and Acidobacteriales (of the phylum Acidobacteria) dominated the bacterial community. Numerous ASVs (amplicon sequence variants) taxa could only be detected in the potentially active community but not in the total community. Long-term warming led to increases in relative abundance on class, order and ASV level. Warming altered the relative abundance of ASVs of the most common bacterial genera, such as Granulicella and Endobacter. The potentially metabolically active bacterial community was also more responsive to warming than the total community.Our results suggest that the bacterial community of the lichen C. islandica is dominated by acidophilic taxa and harbors disproportionally active rare taxa. We also show for the first time that climate warming can lead to shifts in lichen-associated bacterial community composition.

Download Full-text

Spatial scale structure soil bacterial communities across an Arctic landscape

Applied and Environmental Microbiology ◽

10.1128/aem.02220-20 ◽

2020 ◽

Author(s):

Lucie A Malard ◽

Muhammad Zohaib Anwar ◽

Carsten S Jacobsen ◽

David A Pearce

Keyword(s):

Bacterial Community ◽

Spatial Scale ◽

Community Composition ◽

Bacterial Communities ◽

Bacterial Community Composition ◽

Arctic Region ◽

Dispersal Limitation ◽

Sampling Strategies ◽

Autocorrelation Distance

Bacterial community composition is largely influenced by environmental factors, and this applies to the Arctic region. However, little is known about the role of spatial factors in structuring such communities. In this study, we evaluated the influence of spatial scale on bacterial community structure across an Arctic landscape. Our results showed that spatial factors accounted for approximately 10% of the variation at the landscape scale, equivalent to observations across the whole Arctic region, suggesting that while the role and magnitude of other processes involved in community structure may vary, the role of dispersal may be stable globally in the region. We assessed dispersal limitation by identifying the spatial autocorrelation distance, standing at approximately 60 m, which would be required in order to obtain fully independent samples and may inform future sampling strategies in the region. Finally, indicator taxa with strong statistical correlations with environment variables were identified. However, we showed that these strong taxa-environment associations may not always be reflected in the geographical distribution of these taxa. IMPORTANCE The significance of this study is threefold. It investigated the influence of spatial scale on the soil bacterial community composition across a typical Arctic landscape and demonstrated that conclusions reached when examining the influence of specific environmental variables on bacterial community composition are dependent upon the spatial scales over which they are investigated. This study identified a dispersal limitation (spatial autocorrelation) distance of approximately 60 m, required to obtain samples with fully independent bacterial communities, and therefore, should serve to inform future sampling strategies in the region and potentially elsewhere. The work also showed that strong taxa-environment statistical associations may not be reflected in the observed landscape distribution of the indicator taxa.

Download Full-text