Benthic N₂ fixation in coral reefs and the potential effects of human‐induced environmental change

Ecology and Evolution, Год журнала: 2014, Номер 4(9), С. 1706 - 1727

Опубликована: Март 31, 2014

Abstract Tropical coral reefs are among the most productive and diverse ecosystems, despite being surrounded by ocean waters where nutrients in short supply. Benthic dinitrogen (N 2 ) fixation is a significant internal source of “new” nitrogen (N) reef but related information appears to be sparse. Here, we review current state (and gaps) knowledge on N associated with organisms their ecosystems. By summarizing existing literature, show that benthic an omnipresent process tropical environments. Highest rates detected reef‐associated cyanobacterial mats sea grass meadows, clearly showing significance these functional groups, if present, input new Nonetheless, key such as hard corals also importantly contribute reef. Given usually high coverage healthy systems, results indicate symbiotic associations may more important than previously thought. In fact, mutualisms between carbon (C) fixers have likely evolved enable communities mitigate limitation. We then explore potential effects increasing human interferences via changes diazotrophic populations, enzymatic activities, or availability substrates favorable microorganisms. Current indicates positive acidification, warming, deoxygenation negative increased ultraviolet radiation amount fixed reefs. Eutrophication either boost suppress fixation, depending nutrient becoming limiting. As play fundamental role nutrient‐limited assumptions need expanded confirmed future research efforts addressing gaps identified this review.

Язык: Английский

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Biogeography rather than association with cyanobacteria structures symbiotic microbial communities in the marine sponge Petrosia ficiformis

Frontiers in Microbiology, Год журнала: 2014, Номер 5

Опубликована: Окт. 10, 2014

The sponge Petrosia ficiformis is ubiquitous in the Mediterranean Sea and Eastern Atlantic Ocean hosting a diverse assembly of bacteria, including, illuminated sites, cyanobacteria. Two closely related color morphs have been described, one inside caves at their entrance (white/pink), on rocky cliffs (violet). presence different ubiquity (from North-West to South-East) provides an opportunity examine which factors mostly affect associated microbial communities this species: (i) phototrophic symbionts or (ii) biogeography. 16S rRNA gene tag pyrosequencing data revealed that Chloroflexi, Gammaproteobacteria Acidobacteria dominated bacterial all sponges analyzed. Chlorophyll content, TEM observations DNA sequence confirmed cyanobacterium Synechococcus feldmannii violet pink P. absence white morphs. Rather than cyanobacterial (i.e. morphs) accounting for variability symbiont communities, biogeographic trend was observed between collected Israel Italy. Analyses partial 18S mitochondrial cytochrome c oxidase subunit I (COX1) sequences consistent genetic divergence pink-white morphotypes ficiformis. Overall, indicated were more similar genetically distinct from same location, distant locations.

Язык: Английский

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Host rules: spatial stability of bacterial communities associated with marine sponges (Irciniaspp.) in the Western Mediterranean Sea

FEMS Microbiology Ecology, Год журнала: 2013, Номер 86(2), С. 268 - 276

Опубликована: Июнь 12, 2013

Dispersal limitation and environmental selection are the main processes shaping free-living microbial communities, but host-related factors may also play a major role in structuring symbiotic communities. Here, we aimed to determine effects of isolation-by-distance host species on spatial structure sponge-associated bacterial communities using as model abundant demosponge genus Ircinia. We targeted three co-occurring Ircinia used terminal restriction fragment length polymorphism (T-RFLP) analysis 16S rRNA gene sequences explore differentiation their across scale hundreds kilometres Western Mediterranean Sea. Multivariate nonmetric multidimensional scaling plots T-RFLP profiles showed that sponges were structured by remained stable sampling locations, despite geographic distances (80–800 km) diverse local conditions. While significant differences among some locations observed variabilis-derived no correlation between distance community similarity was consistently detected for bacteria any sponge species. Our results indicate mostly shaped species-specific suggest evolutionary acting long-term relationships have favored stability

Язык: Английский

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Elevated seawater temperature disrupts the microbiome of an ecologically important bioeroding sponge

Molecular Ecology, Год журнала: 2018, Номер 27(8), С. 2124 - 2137

Опубликована: Фев. 23, 2018

Bioeroding sponges break down calcium carbonate substratum, including coral skeleton, and their capacity for reef erosion is expected to increase in warmer more acidic oceans. However, elevated temperature can disrupt the functionally important microbial symbionts of some sponge species, often with adverse consequences host health. Here, we provide first detailed description community bioeroding Cliona orientalis assess how responds seawater temperatures incrementally increasing from 23°C 32°C. The microbiome, identified using 16S rRNA gene sequencing, was dominated by Alphaproteobacteria, a single operational taxonomic unit (OTU; Rhodothalassium sp.) that represented 21% all sequences. "core" (taxa present >80% samples) included putative nitrogen fixers ammonia oxidizers, suggesting symbiotic metabolism may be key function C. holobiont. microbiome generally stable at up 27°C; however, shift occurred 29°C, changes relative abundance turnover OTUs. Notably, this lower than 32°C threshold induced bleaching, indicating play role destabilization failed regain Symbiodinium or restore its baseline following has limited ability recover extreme thermal exposure, least under aquarium conditions.

Язык: Английский

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In four shallow and mesophotic tropical reef sponges from Guam the microbial community largely depends on host identity

PeerJ, Год журнала: 2016, Номер 4, С. e1936 - e1936

Опубликована: Апрель 18, 2016

Sponges (phylum Porifera) are important members of almost all aquatic ecosystems, and renowned for hosting often dense diverse microbial communities. While the specificity sponge microbiota seems to be closely related host phylogeny, environmental factors that could shape differences within local sponge-specific communities remain less understood. On tropical coral reefs, habitats can span from shallow areas deeper, mesophotic sites. These differ in terms such as light, temperature, food availability, well anthropogenic impact. In order study potential influence varying on a area, four reef sponges, Rhabdastrella globostellata , Callyspongia sp., Rhaphoxya Acanthella cavernosa were collected exposed slopes deep drop-off. Based 16S rRNA gene pyrosequencing profiles, beta diversity analyses revealed each species possessed specific was significantly different those other exhibited attributes characteristic high- and/or low-microbial-abundance sponges. findings emphasize identity associated microbiota. Dominant sponge- seawater-associated bacterial phyla Chloroflexi, Cyanobacteria, Proteobacteria. Comparison individual taxa seawater samples between sites no significant variation alpha estimates, while (variation community composition) sp. sponges samples. Overall, sponge-associated is shaped by across samples, effect habitat differentiation predominant

Язык: Английский

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