Nitrogen fixation (acetylene reduction) in stony corals: evidence for coral-bacteria interactions

Shashar, Nadav; Cohen, Yossi; Loya, Yossi; Sar, Nechemia

doi:10.3354/meps111259

Cited by 164 publications

(169 citation statements)

References 26 publications

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“…Direct evidence suggests that like the production of vitamin B12 occurring inside the coral itself, the high gross productivity of the zooxanthellae may also be due to internal recycling of nutrients and micronutrients rather than uptake from the surrounding reef water. A similar conclusion concerning endolithic organisms as part of the symbiotic complex throughout nitrogen fixation was reported (Shashar et al 1994). …”

Section: Vitamin B12 In Coral Reef Surface Watersupporting

confidence: 52%

“…In order to study the relationships among the bacteria, coral host, and zooxanthellae, a biological approach alone is not sufficient-the biochemical processes involved must also be described. The only notable quantitative study of the relationship between coral and bacteria highlighted the importance of endolithic bacteria in the coral skeleton as a nitrogen fixer, thus providing assimilable fixed nitrogen to the coral (Shashar et al 1994).…”

Section: Introductionmentioning

confidence: 99%

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Coral symbiotic complex: Hypothesis through vitamin B12 for a new evaluation

Agostini

Suzuki

Casareto

et al. 2009

Galaxea, Journal of Coral Reef Studies

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Historically, hermatypic corals are defined as a symbiotic system composed of an animal host, corals belonging to the taxa Cnidarian, and a photosynthetic organism, the dinoflagellate Symbiodinium spp., also known as zooxanthellae. The high gross productivity and stability of coral reefs have been explained by the effi ciency of the coral algal symbiotic system in using the low nutrient concentrations found in the surrounding water and their rapid recycling in the water. Although several studies have reported the presence of bacteria closely associated with corals, the mechanisms of the relationships among them, the host and the zooxanthellae, remain to be shown. In this study, evidence for the im portance of coelenteric bacteria in corals as a component of the coral symbiotic complex was shown by using a new approach. Vitamin B12, which is produced only by pro karyotes, was chosen as a chemical tool to clarify the symbiotic relationships among bacteria, coral, and zoo xanthellae, which require vitamin B12. High vitamin B12 concentrations (up to 700 pmol l −1 compared with max.20 pmol l −1 in the surrounding water) and high bacteria abundances (100 times higher than surrounding water) were found in the coelenteron of live corals using a new sampling method. The results led to the hypothesis that prokaryotes are the drivers of internal processes, such as vitamin B12 production, occurring directly inside the coral, forming a semi closed system. Furthermore, most main tenance of the symbiotic complex is due to internal pro cesses rather than the supply from outside the coral.

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Section: Vitamin B12 In Coral Reef Surface Watersupporting

confidence: 52%

Section: Introductionmentioning

confidence: 99%

Coral symbiotic complex: Hypothesis through vitamin B12 for a new evaluation

Agostini

Suzuki

Casareto

et al. 2009

Galaxea, Journal of Coral Reef Studies

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“…However, as the reef ecosystem is a nutrient-limited environment (Muscatine and Porter, 1977), bacteria-driven nitrogen fixation can compensate for any deficiency of nitrogen source for coral holobiont (Shashar et al, 1994;Lesser et al, 2004). Nitrogen-fixing bacteria have been detected elsewhere in coral (Shashar et al, 1994;Lesser et al, 2004). In this study, we also detected several potential nitrogen fixers, including Cyanobacteria (Meeks, 1998;Berman-Frank et al, 2003), Clostridia (Chen et al, 2001), Chlorobia (Wahlund and Madigan, 1993) and Chloroflexi (Seshadri et al, 2005;Kneip et al, 2007).…”

Section: Potential Nitrogen Fixer Groupsmentioning

confidence: 50%

Section: Potential Nitrogen Fixer Groupsmentioning

confidence: 99%

The dynamics of microbial partnerships in the coral Isopora palifera

et al. 2010

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Both bacteria and algal symbionts (genus Symbiodinium), the two major microbial partners in the coral holobiont, respond to fluctuations in the environment, according to current reports; however, little evidence yet indicates that both populations have any direct interaction with each other in seasonal fluctuation. In this study, we present field observations of a compositional change in bacteria and Symbiodinium in the coral Isopora palifera in three separate coral colonies following monthly sampling from February to November in 2008. Using massively parallel pyrosequencing, over 200 000 bacterial V6 sequences were classified to build the bacterial community profile; in addition, the relative composition and quantity of Symbiodinium clades C and D were determined by real-time PCR. The results showed that coral-associated bacterial and Symbiodinium communities were highly dynamic and dissimilar among the tagged coral colonies, suggesting that the effect of host specificity was insignificant. The coral-associated bacterial community was more diverse (Shannon index up to 6.71) than previous estimates in other corals and showed rapid seasonal changes. The population ratios between clade C and D groups of Symbiodinium varied in the tagged coral colonies through the different seasons; clade D dominated in most of the samples. Although significant association between bacteria and symbiont was not detected, this study presents a more detailed picture of changes in these two major microbial associates of the coral at the same time, using the latest molecular approaches.

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“…Consequently, symbioses with nitrogen-fixing organisms (diazotrophs) that convert the abundant gas dinitrogen (N 2 ) into more usable forms like ammonium (NH 4 + ) provide important supplemental sources of nitrogen. Although evidence is mounting that nitrogen-fixing bacteria are associated with corals (Shashar et al, 1994;Lesser et al, 2004Lesser et al, , 2007Kvennefors and Roff 2009;Olson et al, 2009;Kimes et al, 2010;Lema et al, 2012;Santos et al, 2014;Lema et al, 2014a,b), to date the location of nitrogen-fixing bacteria within coral tissues and evidence that fixed nitrogen is available to corals or their endosymbiotic algae, Symbiodinium, remains elusive. Techniques such as nanoscale secondary ion mass spectrometry (NanoSIMS), which is able to map enriched stable isotope (for example, 13 C, 15 N and so on) tracers at the cellular scale, provides a powerful tool for co-locating diazotrophs within coral tissues.…”

Section: Introductionmentioning

confidence: 99%

Imaging the uptake of nitrogen-fixing bacteria into larvae of the coral Acropora millepora

et al. 2015

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Diazotrophic bacteria are instrumental in generating biologically usable forms of nitrogen by converting abundant dinitrogen gas (N2) into available forms, such as ammonium. Although nitrogen is crucial for coral growth, direct observation of associations between diazotrophs and corals has previously been elusive. We applied fluorescence in situ hybridization (FISH) and nanoscale secondary ion mass spectrometry to observe the uptake of 15N-enriched diazotrophic Vibrio sp. isolated from Acropora millepora into conspecific coral larvae. Incorporation of Vibrio sp. cells was observed in coral larvae after 4-h incubation with enriched bacteria. Uptake was restricted to the aboral epidermis of larvae, where Vibrio cells clustered in elongated aggregations. Other bacterial associates were also observed in epidermal areas in FISH analyses. Although the fate and role of these bacteria requires additional investigation, this study describes a powerful approach to further explore cell associations and nutritional pathways in the early life stages of the coral holobiont.

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Nitrogen fixation (acetylene reduction) in stony corals: evidence for coral-bacteria interactions

Cited by 164 publications

References 26 publications

Coral symbiotic complex: Hypothesis through vitamin B12 for a new evaluation

Coral symbiotic complex: Hypothesis through vitamin B12 for a new evaluation

The dynamics of microbial partnerships in the coral Isopora palifera

Imaging the uptake of nitrogen-fixing bacteria into larvae of the coral Acropora millepora

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