Microbial and nutrient dynamics in mangrove, reef, and seagrass waters over tidal and diurnal time scales

Becker, CC; Weber, Laura; Suca, JJ; Llopiz, JK; Mooney, T. Aran; Apprill, Amy

doi:10.3354/ame01944

Cited by 22 publications

(45 citation statements)

References 80 publications

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“…This resulted in the higher growth rates and significant reductions in FALS and fluorescence values recorded during post-sunset incubations (Table 1, Supp tables 3-4). For Prochlorococcus, the high division rates early in the evening resulted in higher cell abundance during the pre-sunrise incubation period, similar to diel patterns of cyanobacterial cell abundance observed across reef sites in the U.S. Virgin Islands (8,9). However, significant reductions in Prochlorococcus cell abundance due to predation by all three corals only occurs during the post-sunset incubation period, suggesting that predation is not driven by prey availability alone (Fig 4a-c).…”

Section: Discussionsupporting

confidence: 61%

“…The microbial communities found in the water column surrounding and overlying coral reef systems are largely comprised of small phytoplankton such as picoeukaryotes, Prochlorococcus, Synechococcus, and heterotrophic bacteria (6)(7)(8)(9)(10). Reductions in particulate organic material (POM), as measured by carbon isotope ratios and carbon to nitrogen ratios, suggest that water column phytoplankton concentrations decrease across the reef crest in fringing reef systems (11).…”

Section: Introductionmentioning

confidence: 99%

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Selective Uptake of Pelagic Microbial Community Members by Caribbean Reef Corals

Hoadley

Hamilton

Poirier

et al. 2021

Appl Environ Microbiol

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Coral reefs are possible ‘sinks’ for microbes, however the removal mechanisms at play are not well understood. Here, we characterize pelagic microbial groups at CARMABI reef (Curaçao) and examine microbial consumption by three coral species: Madracis mirabilis, Porites astreoides, and Stephanocoenia intersepta. Flow cytometry analyses of water samples collected from a depth of 10 meters identified 6 microbial groups: Prochlorococcus, three groups of Synechococcus, photosynthetic eukaryotes, and heterotrophic bacteria. Minimum growth rates for Prochlorococcus, all Synechococcus, and photosynthetic eukaryotes were 0.55, 0.29, and 0.45 μ d−1, respectively and suggest relatively high rates of productivity despite low nutrient conditions on the reef. During a series of 5-hr incubations with reef corals performed just after sunset or prior to sunrise, reductions in the abundance of photosynthetic picoeukaryotes, Prochlorococcus and Synechococcus cells were observed. Of the three Synechococcus groups, one decreased significantly during incubations with each coral and the other two only with M. mirabilis. Removal of carbon from the water column is based on coral consumption rates of phytoplankton and averaged between 138 ng hr−1 to 387 ng hr−1, depending on the coral species. A lack of coral-dependent reduction in heterotrophic bacteria, differences in Synechococcus reductions, and diurnal variation in reductions of Synechococcus and Prochlorococcus, coinciding with peak cell division, point to selective feeding by corals. Our study indicates that bentho-pelagic coupling via selective grazing of microbial groups influences carbon flow and supports heterogeneity of microbial communities overlying coral reefs. Importance: We identify interactions between coral grazing behavior and the growth rates and cell abundances of pelagic microbial groups found surrounding a Caribbean reef. During incubation experiments with three reef corals, reductions in microbial cell abundance differed according to coral species and suggest specific coral or microbial mechanisms are at play. Peaks in removal rates of Prochlorococcus and Synechococcus cyanobacteria appear highest during post-sunset incubations and coincide with microbial cell division. Grazing rates and effort vary across coral species and picoplankton groups, possibly influencing overall microbial composition and abundance over coral reefs. For reef corals, use of such a numerically abundant source of nutrition may be advantageous especially during environmentally-stressful conditions when symbioses with dinoflagellate algae - break down.

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Section: Discussionsupporting

confidence: 61%

Section: Introductionmentioning

confidence: 99%

Selective Uptake of Pelagic Microbial Community Members by Caribbean Reef Corals

Hoadley

Hamilton

Poirier

et al. 2021

Appl Environ Microbiol

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“…However, the picophytoplankton, Synechococcus and picoeukaryotes showed significant population growth during daytime (31.5  9.1 and 15.0  7.8 % cells mL -1 h -1 , respectively), but a low mortality rate during the dark incubations (2.4  0.8 and 5.3  2.8 % cells mL -1 h -1 , respectively). My observations of autotrophic picoplankton confirm the findings of Becker et al (2020), who also observed variability in these groups related to diurnal cycles in seagrass beds. However, while Becker et al (2020) found heterotrophic bacteria had a consistent abundance throughout the day (24 h) at their study sites, I found that the abundance of heterotrophic bacteria at my studied seagrass beds showed variation related to diurnal cycles.…”

Section: Picoplankton In the Seagrass Meadowsupporting

confidence: 88%

Sponge nutritional modes in an Indo-Pacific seagrass ecosystem

Bachtiar¹

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Life on earth depends on the constant cycle of nutrients that keep ecosystems in equilibrium and maintain ecosystem functioning, which might be disrupted due to the major and rapid environmental changes we are currently facing. Sponges are a major component of benthic communities in many marine ecosystems worldwide. Most sponges are heterotrophic and gain their nutritional needs from filter feeding dissolved organic carbon and particulate organic carbon from the water column. However, some sponges also form symbioses with photosynthetic symbionts and are autotrophic under some circumstances. These two different nutritional modes may play different roles in the movement of energy flow through benthic systems. Here I studied the sponge assemblages in a seagrass meadow at two spatially separated sites at three tidal zones, located in the Wakatobi National Park, Indonesia, which is representative of shallow-water seagrass ecosystems in the Southeast Asian Indo-Pacific bioregion. My thesis aims to increase our understanding of the importance of these two different sponge nutritional modes in seagrass ecosystems to better understand how environmental change might impact sponge assemblages. In my first data chapter, I conducted sponge and seagrass surveys to investigate the seagrass and sponge community structure and the potential drivers of the observed distribution patterns. For the identification of the sponges, I combined morphological and molecular techniques, using four DNA markers (18S, 28S, ITS, and CO1-ext). I identified ten sponge species: Spongia sp., Spheciospongia sp, Phyllospongia foliascens, Haliclona koremella, Amphimedon sp., Dactylospongia elegans, Axinella sp., Clathria reinwardti, Rhopaloeides sp., and Siphonodictyon mucosum. Sponges were found in all tidal zones of the studied seagrass meadow, including at the high-shore zone that regularly experiences aerial exposure during low tide. I propose that sponge morphological adaptation is important for sponge survival in the different seagrass zones. My second data chapter determined the dominant nutritional mode of seagrass sponges by measuring in situ gross primary production (GPP) to dark respiration (P:R) ratios. I measured the P:R ratios for eight sponges out of the ten found in the studied seagrass meadow. I found that six sponges were autotrophic and net oxygen producers over a full 24 hour period. Based on their high biomass, autotrophic sponges contributed considerably to the total sponge assemblage biomass at all tidal zones and sites. While the high-shore and middle-shore zones had more similar abundances of heterotrophic and autotrophic sponges, autotrophic sponges dominated the sponge assemblage in the near-reef-flat zone of the seagrass meadow by contributing up to 98% of the total sponge biomass. In my third data chapter, I measured the sponge-mediated organic carbon flux in situ to investigate the influence of sponges on the carbon flow from the water column to benthos. The five most abundant sponge species, comprising two heterotrophic sponges and three autotrophic sponges, representing 75.1–99.8% of the total sponge biomass at my studied seagrass meadow, were investigated. I found that in dark incubations (representing night-time), the heterotrophic and autotrophic sponges did not show significant differences in sponge-mediated carbon flux (p > 0.05). However, in light incubations (representing daytime), autotrophic sponges released organic carbon to the water column, while heterotrophic sponges removed organic carbon from the water column. Overall, at the seagrass meadow level, the sponge assemblage was still a net remover of organic carbon over a 24-hour cycle at all tidal zones, including where autotrophic sponges contributed 98% of the total sponge biomass (the near-reef-flat zone). In my fourth data chapter, I measured the sponge-mediated picoplankton flux of the six most abundant sponges (representing 75.1–99.8% of the total sponge biomass) in situ to investigate the influence of sponge assemblages on picoplankton abundance. I found diel variability in all picoplankton observed and for the sponge-mediated fluxes. I found that heterotrophic sponges removed significantly more picoplankton-derived organic carbon than the autotrophic sponges, removing 40–60 times more carbon than the autotrophic sponges over 24 hours. This chapter supports the hypothesis that autotrophic sponges are gaining supplementary nutrition from their hosted photosynthetic symbionts, reducing their need to suspension feed for their nutritional needs. In summary, autotrophic sponges dominated the sponge assemblages in the seagrass ecosystem I studied in the Southeast Asian Indo-Pacific bioregion. This thesis has shown that autotrophic sponges can be net oxygen producers, releasing organic carbon to the water column (during daytime) and thus are not so dependent on picoplankton feeding. Variation in bentho-pelagic interactions due to autotrophic sponges compared to heterotrophic sponges will influence the impact of any increase or decline in sponges as a result of changing environmental conditions.

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“…Even though they are located within the same bay, Donkey Bight and West Lameshur differ in coral cover [30]. Additionally, a mangrove swamp empties out near West Lameshur site, and therefore water quality parameters and reef communities are likely to vary among our sites [53], leading to differences in sh microbial consortia. In fact, several studies have shown that sh skin microbiota respond to changes in the physicochemical composition of the water [11,13].…”

Section: Goby Cleaning Activity Impacts Skin Microbial Diversitymentioning

confidence: 99%

Habitat and Client Diversity Influence the Skin Microbiome of the Caribbean Cleaner Goby Elacatinus Evelynae

Pereira

Soares

Santos

et al. 2021

Preprint

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Fish associated microorganisms are known to be affected by the environment and other external factors, such as microbial transfer between interacting partners. One of the most iconic mutualistic interactions on coral reefs are the cleaning interactions between cleanerfishes and their clients, during which direct physical contact occurs. Here, we characterized the skin bacteria of the Caribbean cleaner sharknose goby, Elacatinus evelynae, in four coral reefs of the US Virgin Islands using sequencing of the V4 region of the 16S rRNA gene. We specifically tested the relationship between gobies’ level of interaction with clients and skin microbiota diversity and composition. Our results showed differences in microbial alpha- and beta-diversity in the skin of gobies from different reef habitats and high inter-individual variation in microbiota diversity and structure. Overall, the results showed that fish-to-fish direct contact and specifically, access to a diverse clientele, influences the bacterial diversity and structure of cleaner gobies’ skin. Because of their frequent contact with clients, and therefore, high potential for microbial exchange, cleanerfish may serve as models in future studies aiming to understand the role of social microbial transfer in reef fish communities.

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Microbial and nutrient dynamics in mangrove, reef, and seagrass waters over tidal and diurnal time scales

Cited by 22 publications

References 80 publications

Selective Uptake of Pelagic Microbial Community Members by Caribbean Reef Corals

Selective Uptake of Pelagic Microbial Community Members by Caribbean Reef Corals

Sponge nutritional modes in an Indo-Pacific seagrass ecosystem

Habitat and Client Diversity Influence the Skin Microbiome of the Caribbean Cleaner Goby Elacatinus Evelynae

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