Bright
Monika
Bright
Monika
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ArticleTubeworm-associated permanent meiobenthic communities from two chemically different hydrothermal vent sites on the East Pacific Rise(Inter-Research, 2007-05-14) Gollner, Sabine ; Zekely, Julia ; Govenar, Breea ; Le Bris, Nadine ; Nemeschkal, Hans L. ; Fisher, Charles R. ; Bright, MonikaThe permanent meiobenthic community associated with aggregations of the tubeworm Riftia pachyptila was characterized at 2 different hydrothermal vent sites, Tica and Riftia Field, on the East Pacific Rise near 9°50’N. The maximum effluent temperatures were similar at both sites, but the chemistry of the hydrothermal fluids differed between sites. The abundance of meiobenthos was very low in 5 out of 6 samples (<61 ind. 10 cm–2) and was higher at Tica (20 to 976 ind. 10 cm–2) than at Riftia Field (<1 to 12 ind. 10 cm–2). Meiobenthos abundance was positively correlated with the volume of sediment within the tubeworm aggregations. Sediment consisted mainly of particulate organic material and contained only a few mineral grains. A total of 33 meiobenthic species (15 of them new to science) was identified, comprising nematodes, copepods, ostracods, tanaidaceans, and foraminiferans. The meiobenthic fauna contributed a third to the total species richness in the benthic community associated with these tubeworm aggregations. There were 19 meiobenthic species shared between the 2 sites. The majority of meiobenthic species were first-order primary consumers. The most abundant taxa were nematodes and copepods, and other taxa were rare at both sites. Nematodes numerically dominated the community at Tica, while no clear dominance of a higher taxon could be detected at Riftia Field. Species richness was similar at both sites, whereas Shannon-Wiener diversity index and Pielou’s evenness index were higher at Riftia Field. Due to the differences in the relative abundance of some species and unique occurrence of others at each site, the meiobenthic communities from the 2 different sites had an average Bray-Curtis dissimilarity of almost 70%.
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ArticleExploring the ecology of deep-sea hydrothermal vents in a metacommunity framework(Frontiers Media, 2018-02-21) Mullineaux, Lauren S. ; Metaxas, Anna ; Beaulieu, Stace E. ; Bright, Monika ; Gollner, Sabine ; Grupe, Benjamin ; Herrera, Santiago ; Kellner, Julie B. ; Levin, Lisa A. ; Mitarai, Satoshi ; Neubert, Michael G. ; Thurnherr, Andreas M. ; Tunnicliffe, Verena ; Watanabe, Hiromi K. ; Won, Yong-JinSpecies inhabiting deep-sea hydrothermal vents are strongly influenced by the geological setting, as it provides the chemical-rich fluids supporting the food web, creates the patchwork of seafloor habitat, and generates catastrophic disturbances that can eradicate entire communities. The patches of vent habitat host a network of communities (a metacommunity) connected by dispersal of planktonic larvae. The dynamics of the metacommunity are influenced not only by birth rates, death rates and interactions of populations at the local site, but also by regional influences on dispersal from different sites. The connections to other communities provide a mechanism for dynamics at a local site to affect features of the regional biota. In this paper, we explore the challenges and potential benefits of applying metacommunity theory to vent communities, with a particular focus on effects of disturbance. We synthesize field observations to inform models and identify data gaps that need to be addressed to answer key questions including: (1) what is the influence of the magnitude and rate of disturbance on ecological attributes, such as time to extinction or resilience in a metacommunity; (2) what interactions between local and regional processes control species diversity, and (3) which communities are “hot spots” of key ecological significance. We conclude by assessing our ability to evaluate resilience of vent metacommunities to human disturbance (e.g., deep-sea mining). Although the resilience of a few highly disturbed vent systems in the eastern Pacific has been quantified, these values cannot be generalized to remote locales in the western Pacific or mid Atlantic where disturbance rates are different and information on local controls is missing.
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ArticleAnimal community dynamics at senescent and active vents at the 9° N East Pacific Rise after a volcanic eruption(Frontiers Media, 2020-01-24) Gollner, Sabine ; Govenar, Breea ; Arbizu, P. Martinez ; Mullineaux, Lauren S. ; Mills, Susan W. ; Le Bris, Nadine ; Weinbauer, Markus ; Shank, Timothy M. ; Bright, MonikaIn 2005/2006, a major volcanic eruption buried faunal communities over a large area of the 9°N East Pacific Rise (EPR) vent field. In late 2006, we initiated colonization studies at several types of post eruption vent communities including those that either survived the eruption, re-established after the eruption, or arisen at new sites. Some of these vents were active whereas others appeared senescent. Although the spatial scale of non-paved (surviving) vent communities was small (several m2 compared to several km2 of total paved area), the remnant individuals at surviving active and senescent vent sites may be important for recolonization. A total of 46 meio- and macrofauna species were encountered at non-paved areas with 33 of those species detected were also present at new sites in 2006. The animals living at non-paved areas represent refuge populations that could act as source populations for new vent sites directly after disturbance. Remnants may be especially important for the meiofauna, where many taxa have limited or no larval dispersal. Meiofauna may reach new vent sites predominantly via migration from local refuge areas, where a reproductive and abundant meiofauna is thriving. These findings are important to consider in any potential future deep-sea mining scenario at deep-sea hydrothermal vents. Within our 4-year study period, we regularly observed vent habitats with tubeworm assemblages that became senescent and died, as vent fluid emissions locally stopped at patches within active vent sites. Senescent vents harbored a species rich mix of typical vent species as well as rare yet undescribed species. The senescent vents contributed significantly to diversity at the 9°N EPR with 55 macrofaunal species (11 singletons) and 74 meiofaunal species (19 singletons). Of these 129 species associated with senescent vents, 60 have not been reported from active vents. Tubeworms and other vent megafauna not only act as foundation species when alive but provide habitat also when dead, sustaining abundant and diverse small sized fauna.
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ArticleComparative genomics of a vertically transmitted thiotrophic bacterial ectosymbiont and its close free-living relative(Wiley, 2023-11-27) Espada-Hinojosa, Salvador ; Karthauser, Clarissa ; Srivastava, Abhishek ; Schuster, Lukas ; Winter, Teresa ; de Oliveira, Andre Luiz ; Schulz, Frederik ; Horn, Matthias ; Sievert, Stefan ; Bright, MonikaThiotrophic symbioses between sulphur-oxidizing bacteria and various unicellular and metazoan eukaryotes are widespread in reducing marine environments. The giant colonial ciliate Zoothamnium niveum, however, is the only host of thioautotrophic symbionts that has been cultivated along with its symbiont, the vertically transmitted ectosymbiont Candidatus Thiobius zoothamnicola (short Thiobius). Because theoretical predictions posit a smaller genome in vertically transmitted endosymbionts compared to free-living relatives, we investigated whether this is true also for an ectosymbiont. We used metagenomics to recover the high-quality draft genome of this bacterial symbiont. For comparison we have also sequenced a closely related free-living cultured but not formally described strain Milos ODIII6 (short ODIII6). We then performed comparative genomics to assess the functional capabilities at gene, metabolic pathway and trait level. 16S rRNA gene trees and average amino acid identity confirmed the close phylogenetic relationship of both bacteria. Indeed, Thiobius has about a third smaller genome than its free-living relative ODIII6, with reduced metabolic capabilities and fewer functional traits. The functional capabilities of Thiobius were a subset of those of the more versatile ODIII6, which possessed additional genes for oxygen, sulphur and hydrogen utilization and for the acquisition of phosphorus illustrating features that may be adaptive for the unstable environmental conditions at hydrothermal vents. In contrast, Thiobius possesses genes potentially enabling it to utilize lactate and acetate heterotrophically, compounds that may be provided as byproducts by the host. The present study illustrates the effect of strict host-dependence of a bacterial ectosymbiont on genome evolution and host adaptation.