Niche acclimatization in Red Sea corals is dependent on flexibility of host-symbiont association

Ziegler, Maren; Roder, Cornelia; Büchel, Claudia; Voolstra, Christian R.

doi:10.3354/meps11365

Cited by 56 publications

(57 citation statements)

References 57 publications

(73 reference statements)

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“…The 2‐dimensional plating morphology of this coral species and symbiont photobiological acclimation to reduced irradiance due to increasing depth and/or turbidity help to explain the apparent cryptic nature of P. speciosa in shallow reefs and its greater abundance in reef cavities and lower‐light upper mesophotic reefs of the Maldives (4% of surface irradiance at 30 m; Ciarapica & Passeri, ; Cooper et al, ; Browne, Smithers, & Perry, ). Indeed, P. speciosa symbionts are efficient autotrophs over large depth ranges (i.e., 0–60 m), with the coral host showing a consistent association with one clade of symbionts across shallow to deep mesophotic reefs in different oceans (Bongaerts et al, ; Cooper et al, ; Ziegler, Roder, Büchel, & Voolstra, ). In addition to our findings from the Maldives, a previous study also observed a decreased abundance of P. speciosa colonies in shallow reefs compared to deep reefs of the upper mesophotic zone (Ziegler, Roder, Büchel, & Voolstra, ).…”

Section: Discussionmentioning

confidence: 99%

Upwelling as the major source of nitrogen for shallow and deep reef‐building corals across an oceanic atoll system

et al. 2019

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Oceanographic processes shape coral reefs worldwide by redistributing inorganic nutrients and particulate resources over depth. Deep‐water upwelling occurs frequently in coral reef ecosystems, but its impact on coral nutrition remains unclear. This study investigated the influence of upwelling on the trophic ecology of three common reef‐building corals (Galaxea fascicularis, Pachyseris speciosa and Pocillopora verrucosa) from different reef depths (shallow reef, 10 m, vs. deep reef, 30 m) and reef exposures (oceanic rim vs. Inner Sea) across > 250 km of the Maldives archipelago, Indian Ocean. Carbon and nitrogen stable isotope ratios (δ13C and δ15N) of coral hosts, their symbionts and particulate organic matter (POM) were used to characterize coral trophic strategies. Across the Maldives, consistent mean δ15N values were recorded in hosts (5.5‰) and symbionts (5.2‰) of the three coral species from shallow and deep reefs of oceanic and Inner Sea reef exposures. Coral hosts, symbionts and POM from both depths had δ15N values that were consistent with the isotopic signature of a deep‐water nitrate source transported to surface waters via upwelling. In contrast, a wide range of δ13C values (~10‰) revealed different trophic strategies and isotopic niches among the coral species. Different mean δ13C values of G. fascicularis indicated greater symbiont autotrophy in corals from shallow (‐15.5‰) compared to deep reefs (‐17.6‰). Conversely, the mean δ13C values of P. speciosa (‐15.1‰) and P. verrucosa (‐17.7‰) were not affected by reef depth. These corals maintained consistent trophic strategies over depth, with P. speciosa relying more on autotrophy compared to P. verrucosa. Despite different reef exposure to oceanic waters, coral host and POM δ15N and δ13C values did not differ between oceanic and Inner Sea reef exposures. Nutritional resources appear to be homogenous in the central Maldives due to atoll‐wide water circulation. However, species‐specific trophic strategies resulted in diverse patterns of δ13C values over depth. Because heterotrophic feeding has been linked to coral host survival through coral bleaching events, understanding the trophic ecology of corals within the reef assemblage can provide insight into species resilience under ocean warming conditions. As a member of the typically competitive Pocilloporidae family, the dependence of P. verrucosa on heterotrophy may help this coral be a future “winner” under sustained ocean warming. A plain language summary is available for this article.

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Section: Discussionmentioning

confidence: 99%

Upwelling as the major source of nitrogen for shallow and deep reef‐building corals across an oceanic atoll system

et al. 2019

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“…To report on phosphate, silicate, nitrate & nitrite, and ammonia we used samples from Ziegler et al [75]. More specifically, discrete water samples were collected at each of the monitoring stations from 5 m and 10 m, once in winter (11 and 29 February 2012) and again at the end of summer (10 and 24 September 2012) and filtered over GF/F filters (0.7 μm; Whatman, USA).…”

Section: Methodsmentioning

confidence: 99%

Year-Long Monitoring of Physico-Chemical and Biological Variables Provide a Comparative Baseline of Coral Reef Functioning in the Central Red Sea

et al. 2016

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Coral reefs in the central Red Sea are sparsely studied and in situ data on physico-chemical and key biotic variables that provide an important comparative baseline are missing. To address this gap, we simultaneously monitored three reefs along a cross-shelf gradient for an entire year over four seasons, collecting data on currents, temperature, salinity, dissolved oxygen (DO), chlorophyll-a, turbidity, inorganic nutrients, sedimentation, bacterial communities of reef water, and bacterial and algal composition of epilithic biofilms. Summer temperature (29–33°C) and salinity (39 PSU) exceeded average global maxima for coral reefs, whereas DO concentration was low (2–4 mg L-1). While temperature and salinity differences were most pronounced between seasons, DO, chlorophyll-a, turbidity, and sedimentation varied most between reefs. Similarly, biotic communities were highly dynamic between reefs and seasons. Differences in bacterial biofilms were driven by four abundant families: Rhodobacteraceae, Flavobacteriaceae, Flammeovirgaceae, and Pseudanabaenaceae. In algal biofilms, green crusts, brown crusts, and crustose coralline algae were most abundant and accounted for most of the variability of the communities. Higher bacterial diversity of biofilms coincided with increased algal cover during spring and summer. By employing multivariate matching, we identified temperature, salinity, DO, and chlorophyll-a as the main contributing physico-chemical drivers of biotic community structures. These parameters are forecast to change most with the progression of ocean warming and increased nutrient input, which suggests an effect on the recruitment of Red Sea benthic communities as a result of climate change and anthropogenic influence. In conclusion, our study provides insight into coral reef functioning in the Red Sea and a comparative baseline to support coral reef studies in the region.

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“…Secondly, the extent of bleaching is inevitably affected by the duration (Anthony, Connolly, & Hoegh‐Guldberg, ) and periodicity (Pratchett, McCowan, Maynard, & Heron, ) of SST anomalies relative to historical SST patterns (Heron et al., ). For example, reoccuring thermal events can increase stress tolerance (Armoza‐Zvuloni, Segal, Kramarsky‐Winter, & Loya, ; Palumbi et al., ) particularly in corals with high energy reserves (Grottoli et al., ) and in those hosting phenotypically plastic symbionts (Ziegler, Roder, Büchel, & Voolstra, ). Thirdly, thermal stress is further moderated by other environmental factors such as light intensity, salinity and nutrient concentrations (Baker, Glynn, & Riegl, ; Suggett & Smith, ; Wiedenmann et al., ).…”

Section: Introductionmentioning

confidence: 99%

Thermal refugia against coral bleaching throughout the northern Red Sea

Osman

Smith

Ziegler

et al. 2017

Global Change Biology

186

242

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Tropical reefs have been impacted by thermal anomalies caused by global warming that induced coral bleaching and mortality events globally. However, there have only been very few recordings of bleaching within the Red Sea despite covering a latitudinal range of 15° and consequently it has been considered a region that is less sensitive to thermal anomalies. We therefore examined historical patterns of sea surface temperature (SST) and associated anomalies (1982-2012) and compared warming trends with a unique compilation of corresponding coral bleaching records from throughout the region. These data indicated that the northern Red Sea has not experienced mass bleaching despite intensive Degree Heating Weeks (DHW) of >15°C-weeks. Severe bleaching was restricted to the central and southern Red Sea where DHWs have been more frequent, but far less intense (DHWs <4°C-weeks). A similar pattern was observed during the 2015-2016 El Niño event during which time corals in the northern Red Sea did not bleach despite high thermal stress (i.e. DHWs >8°C-weeks), and bleaching was restricted to the central and southern Red Sea despite the lower thermal stress (DHWs < 8°C-weeks). Heat stress assays carried out in the northern (Hurghada) and central (Thuwal) Red Sea on four key reef-building species confirmed different regional thermal susceptibility, and that central Red Sea corals are more sensitive to thermal anomalies as compared to those from the north. Together, our data demonstrate that corals in the northern Red Sea have a much higher heat tolerance than their prevailing temperature regime would suggest. In contrast, corals from the central Red Sea are close to their thermal limits, which closely match the maximum annual water temperatures. The northern Red Sea harbours reef-building corals that live well below their bleaching thresholds and thus we propose that the region represents a thermal refuge of global importance.

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Niche acclimatization in Red Sea corals is dependent on flexibility of host-symbiont association

Cited by 56 publications

References 57 publications

Upwelling as the major source of nitrogen for shallow and deep reef‐building corals across an oceanic atoll system

Upwelling as the major source of nitrogen for shallow and deep reef‐building corals across an oceanic atoll system

Year-Long Monitoring of Physico-Chemical and Biological Variables Provide a Comparative Baseline of Coral Reef Functioning in the Central Red Sea

Thermal refugia against coral bleaching throughout the northern Red Sea

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