The temporal pattern and rate of release of zooxanthellae from the reef coral Pocillopora damicornis (Linnaeus) under nitrogen-enrichment and control conditions

Stimson, John; Kinzie, Robert A.

doi:10.1016/s0022-0981(05)80006-1

Cited by 429 publications

(302 citation statements)

References 24 publications

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“…Finally, protein concentration (water-soluble) of the host was measured in a UV spectrophotometer (at 280 and 235 nm) (51). Symbiont cell density and protein content were expressed per surface area obtained by the wax weight method (52).…”

Section: Methodsmentioning

confidence: 99%

Bleaching susceptibility and mortality of corals are determined by fine-scale differences in symbiont type

Sampayo

Ridgway

Bongaerts

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

409

434

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Coral bleaching has been identified as one of the major contributors to coral reef decline, and the occurrence of different symbionts determined by broad genetic groupings (clades A-H) is commonly used to explain thermal responses of reef-building corals. By using Stylophora pistillata as a model, we monitored individual tagged colonies in situ over a two-year period and show that fine level genetic variability within clade C is correlated to differences in bleaching susceptibility. Based on denaturing gradient gel electrophoresis of the internal transcribed spacer region 2, visual bleaching assessments, symbiont densities, host protein, and pulse amplitude modulated fluorometry, we show that subcladal types C78 and C8/a are more thermally tolerant than C79 and C35/a, which suffered significant bleaching and postbleaching mortality. Although additional symbiont types were detected during bleaching in colonies harboring types C79 and C35/a, all colonies reverted back to their original symbionts postbleaching. Most importantly, the data propose that the differential mortality of hosts harboring thermally sensitive versus resistant symbionts rather than symbiont shuffling/switching within a single host is responsible for the observed symbiont composition changes of coral communities after bleaching. This study therefore highlights that the use of broad cladal designations may not be suitable to describe differences in bleaching susceptibility, and that differential mortality results in a loss of both symbiont and host genetic diversity and therefore represents an important mechanism in explaining how coral reef communities may respond to changing conditions. climate change ͉ coral reefs ͉ Symbiodinium ͉ zooxanthellae ͉ Stylophora

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Section: Methodsmentioning

confidence: 99%

Bleaching susceptibility and mortality of corals are determined by fine-scale differences in symbiont type

Sampayo

Ridgway

Bongaerts

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

409

434

View full text Add to dashboard Cite

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“…The rest of the pellet containing Symbiodinium cells was used for further analysis of the content in total nitrogen, glutamine and glutamate. Dinoflagellate density was then normalized to the skeletal surface area (cm 2 ) of each coral branch by using the melted paraffin technique modified from Stimson and Kinzie (1991).…”

Section: Physiological Measurementmentioning

confidence: 99%

A single-cell view of ammonium assimilation in coral–dinoflagellate symbiosis

et al. 2012

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Assimilation of inorganic nitrogen from nutrient-poor tropical seas is an essential challenge for the endosymbiosis between reef-building corals and dinoflagellates. Despite the clear evidence that reef-building corals can use ammonium as inorganic nitrogen source, the dynamics and precise roles of host and symbionts in this fundamental process remain unclear. Here, we combine high spatial resolution ion microprobe imaging (NanoSIMS) and pulse-chase isotopic labeling in order to track the dynamics of ammonium incorporation within the intact symbiosis between the reefbuilding coral Acropora aspera and its dinoflagellate symbionts. We demonstrate that both dinoflagellate and animal cells have the capacity to rapidly fix nitrogen from seawater enriched in ammonium (in less than one hour). Further, by establishing the relative strengths of the capability to assimilate nitrogen for each cell compartment, we infer that dinoflagellate symbionts can fix 14 to 23 times more nitrogen than their coral host cells in response to a sudden pulse of ammoniumenriched seawater. Given the importance of nitrogen in cell maintenance, growth and functioning, the capability to fix ammonium from seawater into the symbiotic system may be a key component of coral nutrition. Interestingly, this metabolic response appears to be triggered rapidly by episodic nitrogen availability. The methods and results presented in this study open up for the exploration of dynamics and spatial patterns associated with metabolic activities and nutritional interactions in a multitude of organisms that live in symbiotic relationships.

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“…Total densities of algal symbionts (healthy and degenerate combined) were calculated from the average of eight replicate counts per coral. Counts were corrected for subsample and total volume and normalized to coral surface area determined using paraffin wax (Stimson and Kinzie, 1991). Counts of degenerate cells were summed across eight replicate haemocytometer counts and divided by the total number of cells counted to estimate the proportion of degenerate cells.…”

Section: Bleaching Assessmentmentioning

confidence: 99%

Changes in coral-associated microbial communities during a bleaching event

et al. 2007

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Environmental stressors such as increased sea surface temperatures are well-known for contributing to coral bleaching; however, the effect of increased temperatures and subsequent bleaching on coral-associated microbial communities is poorly understood. Colonies of the hard coral Acropora millepora were tagged on a reef flat off Magnetic Island (Great Barrier Reef) and surveyed over 2.5 years, which included a severe bleaching event in January/February 2002. Daily average water temperatures exceeded the previous 10-year average by more than 1 1C for extended periods with field-based visual surveys recording all tagged colonies displaying signs of bleaching. During the bleaching period, direct counts of coral zooxanthellae densities decreased by B64%, before recovery to pre-bleaching levels after the thermal stress event. A subset of three tagged coral colonies were sampled through the bleaching event and changes in the microbial community elucidated. Denaturing gradient gel electrophoresis (DGGE) analysis demonstrated conserved bacterial banding profiles between the three coral colonies, confirming previous studies highlighting specific microbial associations. As coral colonies bleached, the microbial community shifted and redundancy analysis (RDA) of DGGE banding patterns revealed a correlation of increasing temperature with the appearance of Vibrio-affiliated sequences. Interestingly, this shift to a Vibrio-dominated community commenced prior to visual signs of bleaching. Clone libraries hybridized with Vibrio-specific oligonucleotide probes confirmed an increase in the fraction of Vibrio-affiliated clones during the bleaching period. Post bleaching, the coral microbial associations again shifted, returning to a profile similar to the fingerprints prior to bleaching. This provided further evidence for corals selecting and shaping their microbial partners. For non-bleached samples, a close association with Spongiobacter-related sequences were revealed by both clone libraries and DGGE profiling. Despite Vibrio species being previously implicated in bleaching of specific coral species, it is unsure if the relative increase in retrieved Vibrio sequences is due to bacterial infection or an opportunistic response to compromised health and changing environmental parameters of the coral host. This study provides the first molecular-based study demonstrating changes in coral-associated bacterial assemblages during a bleaching event on a natural reef system.

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The temporal pattern and rate of release of zooxanthellae from the reef coral Pocillopora damicornis (Linnaeus) under nitrogen-enrichment and control conditions

Cited by 429 publications

References 24 publications

Bleaching susceptibility and mortality of corals are determined by fine-scale differences in symbiont type

Bleaching susceptibility and mortality of corals are determined by fine-scale differences in symbiont type

A single-cell view of ammonium assimilation in coral–dinoflagellate symbiosis

Changes in coral-associated microbial communities during a bleaching event

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