Colonies of Acropora formosa with greater survival potential show conservative calcification rates

AbstractCoral reefs are facing increasingly devasting impacts from ocean warming and acidification due to anthropogenic climate change. In addition to reducing greenhouse gas emissions, potential solutions have focused either on reducing light stress during heating, or the potential for identifying or engineering “super corals”. These studies, however, have tended to focus primarily on the bleaching response of corals, and assume that corals that bleach earlier in a thermal event are more likely to die. Here, we explore how survival, potential bleaching, and coral skeletal growth (as branch extension and densification) varies for conspecifics collected from distinctive reef zones at Heron Island on the Southern Great Barrier Reef. A series of reciprocal transplantation experiments were undertaken using the dominant reef building coral (Acropora formosa) between the highly variable ‘reef flat’ and the less variable ‘reef slope’ environments. Coral colonies originating from the reef flat had higher rates of survival and thicker tissues but reduced rates of calcification than conspecifics originating from the reef slope. The energetics of both populations however benefited from greater light intensity offered in the shallows. Reef flat origin corals moved to the lower light intensity of reef slope reduced protein density and calcification rates. For A. formosa, genetic difference, or long-term entrainment to a highly variable environment, appeared to promote coral survival at the expense of calcification. The response divorces coral resilience from carbonate coral reef resilience, a response that was further exacerbated by reductions in irradiance. As we begin to discuss interventions necessitated by the CO2 that has already been released to the atmosphere, we need to prioritise our focus on the properties that maintain valuable carbonate ecosystems. Rapid and dense calcification by corals such as branching Acropora is essential to the ability of carbonate coral reefs to rebound following disturbances events, but may be the first property that is sacrificed to enable coral genet survival under stress.

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The coral communities of Yongle atoll: status, threats and conservation significance for coral reefs in South China Sea

Marine and Freshwater Research ◽

10.1071/mf15110 ◽

2016 ◽

Vol 67 (12) ◽

pp. 1888 ◽

Cited By ~ 17

Author(s):

Meixia Zhao ◽

Kefu Yu ◽

Qi Shi ◽

Hongqiang Yang ◽

Bernhard Riegl ◽

...

Keyword(s):

South China Sea ◽

Coral Reefs ◽

South China ◽

Reef Flat ◽

Coral Cover ◽

Reef Slope ◽

Xisha Islands ◽

China Sea ◽

Marine Habitats ◽

Coral Communities

Xisha Islands are in the central South China Sea and form one of the four large island groups in this region. They include more than 40 islands, reefs and cays, and have considerable ecological and biodiversity value, both intrinsically and as a source of larvae for coastal ecosystems throughout the South China Sea. Yongle atoll is the biggest and one of the most important atolls in the Xisha Islands. The detailed surveys of the marine habitats in the Yongle atoll were conducted from June to July 2013. This baseline survey revealed coral communities in a relatively healthy condition. Mean coral cover of different geomorphic habitats varied from 2 to 29%. Branching corals were most important, followed by encrusting and massive growth forms (48, 29 and 17% of coral cover). Pocillopora (29% of total cover in line transects), Porites (19%), Acropora (17%) and Montipora (16%) were the four dominant genera. Communities differentiated into four clusters, namely, lower reef slope, upper reef slope, outer reef flat, and inner reef flat and lagoon slope. This baseline investigation highlighted the ecological value of these reefs. Destructive fishing and overfishing are presently the most serious threats for these coral reefs. They should receive much more scientific and conservation attention.

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Fossil molluscan fauna reflects zonation of a Late Pleistocene reef of the Red Sea

10.5194/egusphere-egu21-16060 ◽

2021 ◽

Author(s):

Anna Haider ◽

Angelina Ivkić ◽

Andreas Kroh ◽

Abbas Mansour ◽

Martin Zuschin

Keyword(s):

Coral Reefs ◽

Red Sea ◽

Late Pleistocene ◽

Reef Flat ◽

Patch Reef ◽

Alpha Diversity ◽

Reef Slope ◽

Soft Bottom ◽

Last Interglacial ◽

Gastropod Species

Many studies focus on modern coral reefs and their associated invertebrate fauna, but not much is known about the paleoecology and diversity of molluscs of Late Pleistocene coral reefs, which were formed during the last interglacial MIS5e. This study is investigating the molluscan assemblage of a Late Pleistocene coral reef in southern Egypt, at the locality Sharm El Luli, in the area of Marsa Alam. The locality is characterized by a variety of reef- and reef associated habitats, including a reef flat, reef slope, a patch reef, and soft bottoms of a lagoon and in the backreef area. We quantitatively and qualitatively sampled 10 sites with a total of 79 samples and collected 2126 shells, which belong to 177 taxa, mostly identified to the species level.&#160;&#160; Most taxa were found with the qualitative sampling approach. The most abundant bivalves taxon was the epifaunal, encrusting Chama spp., the most abundant gastropod species was the cerithiid Rhinoclavis vertagus. Regarding the life habitats most bivalve species are infaunal filter feeders, while most gastropods are epifaunal carnivores.&#160;&#160;&#160; Alpha diversity is highest in the coral patch and in the upper reef region, which implies the reef slope, the reef flat as well as the transition between reef slope and the lagoon. Preliminary statistical results suggest a division in coral-patch, lagoon and backreef as well as a cluster of upper-reef habitats. From these two broad environments can be distinguished: hard bottoms associated to reefs and reef-associated soft bottom environments. The former are best characterized by encrusting taxa such as Chama spp. and Spondylus spp., and by Tridacna maxima and Perigylypta spp., which are well-known reef associates. Gastropods in this environment are predatory conids and cypraeids. All of these species live on - or occur cryptically in - structured hard bottoms. Reef associated-soft bottom environments are best characterized by infauna, such as the tellinid Quidinipagus palatam and the lucinids Anodontia kora and Pillucina vietnamica. Furthermore, many soft bottom gastropod species such as the strombid Gibberulus gibberulus albus, the cerithiid Rhinoclavis vertagus, both with an herbivorous diet, and the nassariid Nassarius fenistratus, a scavenger, can be found here.&#160; A comparison with modern datasets from the Red Sea indicates strong similarities in faunal composition and habitat diversity between fossil and recent reefs.&#160; Furthermore, our preliminary results suggest that Late Pleistocene molluscan assemblages can aid in reconstruction of associated fossil reef habitats.&#160;

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Plant buffering against the high-light stress-induced accumulation of CsGA2ox8 transcripts via alternative splicing to finely tune gibberellin levels and maintain hypocotyl elongation

Horticulture Research ◽

10.1038/s41438-020-00430-w ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Bin Liu ◽

Shuo Zhao ◽

Pengli Li ◽

Yilu Yin ◽

Qingliang Niu ◽

...

Keyword(s):

Alternative Splicing ◽

Light Intensity ◽

Intron Retention ◽

Light Stress ◽

Photosynthetic Photon Flux Density ◽

Photon Flux ◽

Photon Flux Density ◽

Rna Seq ◽

Multiple Transcripts ◽

Novel Transcript

AbstractIn plants, alternative splicing (AS) is markedly induced in response to environmental stresses, but it is unclear why plants generate multiple transcripts under stress conditions. In this study, RNA-seq was performed to identify AS events in cucumber seedlings grown under different light intensities. We identified a novel transcript of the gibberellin (GA)-deactivating enzyme Gibberellin 2-beta-dioxygenase 8 (CsGA2ox8). Compared with canonical CsGA2ox8.1, the CsGA2ox8.2 isoform presented intron retention between the second and third exons. Functional analysis proved that the transcript of CsGA2ox8.1 but not CsGA2ox8.2 played a role in the deactivation of bioactive GAs. Moreover, expression analysis demonstrated that both transcripts were upregulated by increased light intensity, but the expression level of CsGA2ox8.1 increased slowly when the light intensity was >400 µmol·m−2·s−1 PPFD (photosynthetic photon flux density), while the CsGA2ox8.2 transcript levels increased rapidly when the light intensity was >200 µmol·m−2·s−1 PPFD. Our findings provide evidence that plants might finely tune their GA levels by buffering against the normal transcripts of CsGA2ox8 through AS.

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Pair formation, home range, and spatial variation in density, size and social status in blotched foxfaceSiganus unimaculatuson an Okinawan coral reef

PeerJ ◽

10.7717/peerj.1280 ◽

2015 ◽

Vol 3 ◽

pp. e1280 ◽

Cited By ~ 5

Author(s):

Atsushi Nanami

Keyword(s):

Coral Reef ◽

Home Range ◽

Spatial Variation ◽

Reef Flat ◽

Pair Formation ◽

Size Class ◽

Reef Slope ◽

Rocky Reef ◽

Seagrass Bed ◽

Agonistic Display

The present study examined pair formation, spatial pattern of home range and spatial variation in density, size and social status of blotched foxfaceSiganus unimaculatus(family Siganidae) on an Okinawan coral reef. Of 32 pairs sampled for sexing, 31 (96.9%) were heterosexual and showed size-assortative pairing. Developed ovaries were found in April and July, whereas oocytes were immature in August, September and February. Heterosexual pairing was found in both reproductive and non-reproductive periods. Home range size tended to be positively related to fork length (FL). The degree of home range overlap for same size class pairs was smaller than that for different size class pairs. The intraspecific behavior when two pairs approached each other was categorized as ‘attack,’ ‘agonistic display’ and ‘no interactions,’ and the frequency of agonistic behaviors (“attack” or “agonistic display”) was significantly greater than “no interactions.” Underwater observations at a seagrass bed, a rocky reef flat and a sheltered reef slope revealed that the mean FL was significantly smaller at the sheltered reef slope (4–13 cm) than at the rocky reef flat (>13 cm). No individuals were found in the seagrass bed. Most individuals less than 6 cm FL were solitary, whereas most individuals over 7 cm FL were paired. Density was significantly greater on the sheltered reef slope than on the rocky reef flat.

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UNDULAR BORE DEVELOPMENT OVER A LABORATORY FRINGING REEF

Coastal Engineering Proceedings ◽

10.9753/icce.v36.currents.53 ◽

2018 ◽

pp. 53 ◽

Cited By ~ 1

Author(s):

Marion Tissier ◽

Jochem Dekkers ◽

Ad Reniers ◽

Stuart Pearson ◽

Ap Van Dongeren

Keyword(s):

Coral Reefs ◽

Wave Field ◽

Reef Flat ◽

Wave Transformation ◽

Undular Bore ◽

Fringing Reef ◽

Long Wave ◽

Reef Type ◽

Run Up ◽

Infragravity Wave

Several studies have reported the development of undular bores over fringing coral reefs (e.g, Gallagher, 1976; Nwogu and Demirbilek, 2010) but the importance of this phenomenon for reef hydrodynamics has never been studied. Yet, the transformation of a long wave (e.g., swell or infragravity wave) into an undular bore leads to significant modifications of the wave field. The formation of undulations is for example associated to a significant increase of the leading bore height. Moreover, if the undulations have enough time to develop (i.e. if the reef flat is wide enough), the initial long wave will ultimately split into a series of solitons (e.g., Grue et al., 2008). All this is likely to affect wave run-up. As reeffronted coastlines are particularly vulnerable to flooding, a good understanding of long wave transformation over the reef flat, including their possible transformation into undular bores, is crucial. In this study, we investigate undular bore development over reef-type profiles based on a series of laboratory experiments. More specifically, we aim to characterize the conditions under which undular bores develop, and analyse how their development affect the hydrodynamics at the toe of the reef-lined beach and the resulting wave run-up.

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Spatial distribution of chaetodontid fish in coral reefs of the Ryukyu Islands, southern Japan

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315498000873 ◽

1999 ◽

Vol 79 (4) ◽

pp. 725-735 ◽

Cited By ~ 26

Author(s):

L. Cadoret ◽

M. Adjeroud ◽

M. Tsuchiya

Keyword(s):

Species Richness ◽

Coral Reefs ◽

Reef Slope ◽

Data Matrix ◽

Ryukyu Islands ◽

Southern Japan ◽

The Ryukyu Islands ◽

The World ◽

Species Richness And Abundance ◽

Reef Edge

The spatial patterns of butterflyfish assemblages (Chaetodontidae) were examined within and between five islands of the Ryukyu Archipelago, southern Japan. Despite being the northernmost reef communities in the world and despite the severe natural and human-induced disturbances that have affected them since the 1970s, the coral reefs of the Ryukyu Islands have one of the most diversified assemblages of chaetodontids in the world. A total of 30 species were identified, and species richness per island ranged from 20 to 25 species. On each of the 45 stations prospected, between four and 17 species were recorded, and between 0.75 and 21.75 ind 250 m−2 were counted. Variation in species composition, species richness and abundance between islands was less pronounced than the variation within islands, where assemblages of the major reef environments (i.e. the reef flat, the reef edge, and the reef slope) were distinguished. The highest species richness and abundance were found on the reef slope and the reef edge. Canonical correspondence analysis revealed that depth, substrate complexity, and live coral cover influenced the distribution of chaetodontid fishes. These factors accounted for 20% of the variation in the species data matrix.

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Coral mortality induced by the 2015–2016 El-Niño in Indonesia: the effect of rapid sea level fall

Biogeosciences ◽

10.5194/bg-14-817-2017 ◽

2017 ◽

Vol 14 (4) ◽

pp. 817-826 ◽

Cited By ~ 34

Author(s):

Eghbert Elvan Ampou ◽

Ofri Johan ◽

Christophe E. Menkes ◽

Fernando Niño ◽

Florence Birol ◽

...

Keyword(s):

Coral Reefs ◽

Sea Level ◽

El Niño ◽

Reef Flat ◽

El Nino ◽

Differential Mortality ◽

Altimetry Data ◽

Bathymetric Range ◽

The Past ◽

Coral Genus

Abstract. The 2015–2016 El-Niño and related ocean warming has generated significant coral bleaching and mortality worldwide. In Indonesia, the first signs of bleaching were reported in April 2016. However, this El Niño has impacted Indonesian coral reefs since 2015 through a different process than temperature-induced bleaching. In September 2015, altimetry data show that sea level was at its lowest in the past 12 years, affecting corals living in the bathymetric range exposed to unusual emersion. In March 2016, Bunaken Island (North Sulawesi) displayed up to 85 % mortality on reef flats dominated by Porites, Heliopora and Goniastrea corals with differential mortality rates by coral genus. Almost all reef flats showed evidence of mortality, representing 30 % of Bunaken reefs. For reef flat communities which were living at a depth close to the pre-El Niño mean low sea level, the fall induced substantial mortality likely by higher daily aerial exposure, at least during low tide periods. Altimetry data were used to map sea level fall throughout Indonesia, suggesting that similar mortality could be widespread for shallow reef flat communities, which accounts for a vast percent of the total extent of coral reefs in Indonesia. The altimetry historical records also suggest that such an event was not unique in the past two decades, therefore rapid sea level fall could be more important in the dynamics and resilience of Indonesian reef flat communities than previously thought. The clear link between mortality and sea level fall also calls for a refinement of the hierarchy of El Niño impacts and their consequences on coral reefs.

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Does Astaxanthin Protect Haematococcus against Light Damage?

Zeitschrift für Naturforschung C ◽

10.1515/znc-1998-1-217 ◽

1998 ◽

Vol 53 (1-2) ◽

pp. 93-100 ◽

Cited By ~ 48

Author(s):

Lu Fan ◽

Avigad Vonshak ◽

Aliza Zarka ◽

Sammy Boussiba

Keyword(s):

Light Intensity ◽

Light Stress ◽

Phosphate Starvation ◽

High Light Intensity ◽

High Irradiance ◽

High Light ◽

Protective Agent ◽

Light Damage ◽

Low Light ◽

Very High

Abstract The photoprotective function of the ketocarotenoid astaxanthin in Haematococcus was questioned. When exposed to high irradiance and/or nutritional stress, green Haematococcus cells turned red due to accumulation of an immense quantity of the red pigment astaxanthin. Our results demonstrate that: 1) The addition of diphenylamine, an inhibitor of astaxanthin biosynthesis, causes cell death under high light intensity; 2) Red cells are susceptible to high light stress to the same extent or even higher then green ones upon exposure to a very high light intensity (4000 μmol photon m-2 s-1); 3) Addition of 1O2 generators (methylene blue, rose bengal) under noninductive conditions (low light of 100 (μmol photon m-2 s-1) induced astaxanthin accumulation. This can be reversed by an exogenous 1O2 quencher (histidine); 4) Histidine can prevent the accumulation of astaxanthin induced by phosphate starvation. We suggest that: 1) Astaxanthin is the result of the photoprotection process rather than the protective agent; 2) 1O2 is involved indirectly in astaxanthin accumulation process.

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Physiological response of Monimopetalum chinense to light stress under habitat fragmentation

Plant Soil and Environment ◽

10.17221/41/2009-pse ◽

2010 ◽

Vol 56 (No. 12) ◽

pp. 551-556 ◽

Cited By ~ 1

Author(s):

C. Hao ◽

R. Fan ◽

X. Zhang ◽

L. Wang ◽

W. Chen ◽

...

Keyword(s):

Antioxidant Enzymes ◽

Habitat Fragmentation ◽

Light Intensity ◽

Physiological Responses ◽

Light Stress ◽

Strong Light ◽

Malondialdehyde Content ◽

Antioxidant Enzymes Activities ◽

Intense Light ◽

Effect Of Light

To determine the effect of light stress under fragmental habitat on the physiology, this paper investigated the physiological responses of Monimopetalum chinense with different light intensities in the Xianyu Mountains (Anhui, China). The study showed that both weak and intense light brought about by habitat fragmentation could improve antioxidant enzymes activities, and promote electrical conductivity and malondialdehyde content of M. chinense leaves. However, too strong light could inhibit photosynthesis rates, superoxide dismutase, catalase, and ascorbate peroxidase activities. In addition, the characteristics of leaves were affected by light intensity at the fragmental habitat. Specifically, intense light was disadvantageous to photosynthesis and antioxidant enzymes of the species. Our results suggest that the biodiversity conservation of M. chinense is necessary, and that light intensity should be considered carefully when implementing conservation efforts.  

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Growth performance of Alexandrium catenella from the Chilean fjords under different environmental drivers: plasticity as a response to a highly variable environment

Journal of Plankton Research ◽

10.1093/plankt/fbaa011 ◽

2020 ◽

Vol 42 (2) ◽

pp. 119-134 ◽

Cited By ~ 1

Author(s):

Javier Paredes-Mella ◽

Daniel Varela ◽

Pamela Fernández ◽

Oscar Espinoza-González

Keyword(s):

Light Intensity ◽

Growth Performance ◽

Harmful Algal Blooms ◽

Algal Blooms ◽

Optimal Growth ◽

N:P Ratio ◽

Environmental Drivers ◽

Growth Responses ◽

Variable Environment ◽

Alexandrium Catenella

Abstract Alexandrium catenella, the main species associated with harmful algal blooms, has progressively increased its distribution through one of the most extensive and highly variable fjord systems in the world. In order to understand this successful expansion, we evaluated the effects of different salinities, light intensity, temperatures, nitrogen (N) forms and nitrogen/phosphate (N:P) ratio levels on the growth performance, using clones isolated from different locations across its wide geographic distribution. Results showed that the growth responses were plastic and, in some cases, different reaction norms among clones were observed. Despite plasticity, the optimal growth of A. catenella (i.e. highest growth rate and highest maximal cells density) was reached within a narrow thermal range (12–15°C), while salinity (20–30 PSU) and light intensity (20–120 μmol m−2 s−1) ranges were wider. These results are partially consistent with the highest cell densities recorded in the field. Furthermore, optimal growth was reached using reduced forms of nitrogen (i.e. urea and NH4+) and in unbalanced N:P ratios (18:1 and 30:1). These characteristics likely allow A. catenella to grow in highly variable environmental conditions and might partly explain the recent expansion of this species.

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