scholarly journals Dangerous demographics in post-bleach corals reveal boom-bust versus protracted declines

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Juliano Morais ◽  
Renato A. Morais ◽  
Sterling B. Tebbett ◽  
Morgan S. Pratchett ◽  
David R. Bellwood
Keyword(s):  
Thermal Stress ◽  
Coral Reefs ◽  
Fast Growth ◽  
Genus Level ◽  
Boom And Bust ◽  
Demographic Response ◽  
Local Recruitment ◽  
Almost All

AbstractThermal-stress events have changed the structure, biodiversity, and functioning of coral reefs. But how these disturbances affect the dynamics of individual coral colonies remains unclear. By tracking the fate of 1069 individual Acropora and massive Porites coral colonies for up to 5 years, spanning three bleaching events, we reveal striking genus-level differences in their demographic response to bleaching (mortality, growth, and recruitment). Although Acropora colonies were locally extirpated, substantial local recruitment and fast growth revealed a marked capacity for apparent recovery. By contrast, almost all massive Porites colonies survived and the majority grew in area; yet no new colonies were detected over the 5 years. Our results highlight contrasting dynamics of boom-and-bust vs. protracted declines in two major coral groups. These dangerous demographics emphasise the need for caution when documenting the susceptibility and perceived resistance or recovery of corals to disturbances.

scholarly journals Early Miocene coral reef-associated bryozoans from Colombia. Part I: Cyclostomata, “Anasca” and Cribrilinoidea Cheilostomata

2021 ◽  
pp. 1-26
Author(s):  
Paola Flórez ◽  
Emanuela Di Martino ◽  
Laís V. Ramalho
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Early Miocene ◽  
Remote Region ◽  
Bryozoan Species ◽  
Patch Reefs ◽  
Genus Level ◽  
Southern Caribbean ◽  
Barrier Reefs

Abstract This is the first of two comprehensive taxonomic works on the early Miocene (ca. 23–20 Ma) bryozoan fauna associated with coral reefs from the Siamaná Formation, in the remote region of Cocinetas Basin in the La Guajira Peninsula, northern Colombia, southern Caribbean. Fifteen bryozoan species in 11 families are described, comprising two cyclostomes and 13 cheilostomes. Two cheilostome genera and seven species are new: Antropora guajirensis n. sp., Calpensia caribensis n. sp., Atoichos magnus n. gen. n. sp., Gymnophorella hadra n. gen. n. sp., Cribrilaria multicostata n. sp., Cribrilaria nixor n. sp., and Figularia bragai n. sp. Eight species are identified only at genus level and remain in open nomenclature. Of the species found, 27% have erect colonies and 73% encrusting colonies. Both types contributed to the reef framework and produced sediment. The observed bryozoan diversity was higher in the barrier reefs than in the lagoonal patch reefs. UUID: http://zoobank.org/5c8468ef-31b0-4e7e-ba93-60a2e2f30b76.

scholarly journals 1997-98: Unprecedented thermal stress to coral reefs?

2000 ◽  
Vol 27 (23) ◽  
pp. 3901-3904 ◽  
Author(s):  
J. M. Lough
Keyword(s):  
Thermal Stress ◽  
Coral Reefs

scholarly journals Climate change and tropical sponges: The effect of elevated pCO₂ and temperature on the sponge holobiont

2021 ◽  
Author(s):  
◽  
Holly Bennett
Keyword(s):  
Climate Change ◽  
Thermal Stress ◽  
Coral Reef ◽  
Cell Membrane ◽  
Coral Reefs ◽  
Climate Change Scenarios ◽  
Holistic View ◽  
Biochemical Constituents ◽  
Functional Components

<p>As atmospheric CO₂ concentrations rise, associated ocean warming (OW) and ocean acidification (OA) are predicted to cause declines in reef-building corals globally, shifting reefs from coral-dominated systems to those dominated by less sensitive species. Sponges are important structural and functional components of coral reef ecosystems, but despite increasing field-based evidence that sponges may be ‘winners’ in response to environmental degradation, our understanding of how they respond to the combined effects of OW and OA is limited. This PhD thesis explores the response of four abundant Great Barrier Reef species – the phototrophic Carteriospongia foliascens and Cymbastela coralliophila and the heterotrophic Stylissa flabelliformis and Rhopaloeides odorabile to OW and OA levels predicted for 2100, under two CO₂ Representative Concentration Pathways (RCPs). The overall aim of this research is to bridge gaps in our understanding of how these important coral reef organisms will respond to projected climate change, to begin to explore whether a sponge dominated state is a possible future trajectory for coral reefs.  To determine the tolerance of adult sponges to climate change, these four species were exposed to OW and OA in the Australian Institute of Marine Science’s (AIMS) National Sea Simulator (SeaSim) in a 3-month experimental study. The first data chapter explores the physiological responses of these sponges to OW and OA to gain a broad understanding of sponge holobiont survival and functioning under these conditions. In this chapter I also address the hypothesis that phototrophic and heterotrophic sponges will exhibit differential responses to climate change. In the second and third data chapters I explore the cellular lipid and fatty acid composition of sponges, and how these biochemical constituents vary with OW and OA. Lipids and fatty acids are not only vital energy stores, they form the major components of cell membranes, and the structure and composition of these biochemical constituents ultimately determines the integrity and physiological competency of a cell. Therefore through these analyses I aimed to determine how OW and OA affects the metabolic balance of sponges, and to understand mechanisms underpinning observed systemic sponge responses. Finally, to provide greater insight into the population level impacts of climate change on tropical sponges, in the last data chapter I explore the response of the phototrophic species Carteriospongia foliascens to OW/OA throughout its developmental stages.   I found that while sponges can generally tolerate climate change scenarios predicted under the RCP6.0 conditions for 2100 (30ºC/ pH 7.8), environmental projections for the end of this century under the RCP8.5 (31.5ºC/ pH 7.6) will have significant implications for their survival. Temperature effects were much stronger than OA effects for all species; however, phototrophic and heterotrophic species responded differently to OA. Elevated pCO₂ exacerbated temperature stress in heterotrophic sponges but somewhat ameliorated thermal stress in phototrophic species. Furthermore, sponges with siliceous spiculated skeletons resisted the RCP 8.5 conditions for longer than the aspiculate species. Biochemical analysis revealed that spiculated species also have greater cell membrane support features, which is likely to contribute to the observed stress tolerance. I also found that the additional energy available to phototrophic sponges under OA conditions may be used for investment into cell membrane support, providing protection against thermal stress. Finally, larval survival and settlement success of C. foliascens was unaffected by OW and OA treatments, and juvenile sponges exhibited greater tolerance than their adult counterparts, again with evidence that OA reduces OW stress for some of these life stages.   Based on the species studied here, this thesis confirms that sponges are better able to deal with OW and OA levels predicted for 2100 under RCP6.0, compared to many corals for which survival in a high CO₂ world requires OW to remain below 1.5°C. This suggests sponges may be future ‘winners’ on coral reefs under global climate change. However, if CO₂ atm concentrations reach levels predicted under RCP8.5, the prognosis for sponge survival by the end of this century changes as inter-species sponge tolerances to OW and OA differ. Under this projection it is likely we will also start to see a shift in sponge populations to those dominated by phototrophic sponges with siliceous spiculated skeletons. Overall, this thesis gives a holistic view of OW and OA impacts on tropical sponges and provides the basis from which to explore the potential for a sponge-coral regime shift in a high CO₂ world.</p>

scholarly journals Climate Change Induced Thermal Stress Caused Recurrent Coral Bleaching over Gulf of Kachchh and Malvan Marine Sanctuary, West Coast of India

2021 ◽  
Author(s):  
Mohit Arora ◽  
Kalyan De ◽  
Nandini Ray Chaudhury ◽  
Mandar Nanajkar ◽  
Prakash Chauhan ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Coral Reef ◽  
Coral Reefs ◽  
Coral Bleaching ◽  
Large Scale ◽  
Heat Waves ◽  
Southern Oscillation ◽  
Coral Cover ◽  
Imminent Threat ◽  
Marginal Reefs

Coral reefs are one of the most sensitive, productive, and invaluable biological resources on the earth. However, coral reefs are facing unprecedented stress due to ongoing climate changes and intensified anthropogenic disturbances globally. Elevated Sea Surface Temperature (SST) has emerged as the most imminent threat to the thermos-sensitive reef-building corals. The 2010–2014-2016 El Niño Southern Oscillation (ENSO) caused prolonged marine heat waves (MHWs) that led to the most widespread coral bleaching and mortality in the tropical Indi-Pacific regions. Coral bleaching prediction is vital for the management of the reef biodiversity, ecosystem functioning, and services. Recent decades, satellite remote sensing has emerged as a convenient tool for large-scale coral reef monitoring programs. As thermal stress is a critical physical attribute for coral bleaching hence, the present study examines the effectiveness of the elevated SSTs as a proxy to predict coral bleaching in shallow water marginal reefs. Advanced Very High-Resolution Radiometer (AVHRR) satellite data from the NOAA Coral Reef Watch’s (CRW) platform has been used for this study. Coral bleaching indices like Bleaching Threshold (BT), Positive SST Anomaly (PA), and Degree Heating Weeks (DHW) are computed to analyze the thermal stress on the coral reefs. The computed thermal stress from satellite-derived SST data over regions concurrence with the mass coral bleaching (MCB) events. This study concludes that in the last decades (2010 to 2019) the coral cover around these regions has dramatically declined due to higher SST, which indicates that the thermal stress induced recurrent bleaching events attributed to the coral loss.

scholarly journals Optimising cool-water injections to reduce thermal stress on coral reefs of the Great Barrier Reef

PLoS ONE ◽  
2020 ◽  
Vol 15 (10) ◽  
pp. e0239978
Author(s):  
Mark Edward Baird ◽  
Rebecca Green ◽  
Ryan Lowe ◽  
Mathieu Mongin ◽  
Elodie Bougeot
Keyword(s):  
Thermal Stress ◽  
Coral Reefs ◽  
Great Barrier Reef ◽  
Barrier Reef ◽  
Cool Water

scholarly journals Thermal stress jeopardizes carbonate production of coral reefs across the western and central Pacific Ocean

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0249008
Author(s):  
Robert van Woesik ◽  
Christopher William Cacciapaglia
Keyword(s):  
Thermal Stress ◽  
Pacific Ocean ◽  
Coral Reefs ◽  
Stress Gradient ◽  
Tropical Pacific ◽  
Tropical Pacific Ocean ◽  
Central Pacific ◽  
Carbonate Production ◽  
Building Capacity ◽  
Habitat Differences

Coral reefs protect islands, coastal areas, and their inhabitants from storm waves and provide essential goods and services to millions of people worldwide. Yet contemporary rates of ocean warming and local disturbances are jeopardizing the reef-building capacity of coral reefs to keep up with rapid rates of sea-level rise. This study compared the reef-building capacity of shallow-water habitats at 142 sites across a potential thermal-stress gradient in the tropical Pacific Ocean. We sought to determine the extent to which habitat differences and environmental variables potentially affect rates of net carbonate production. In general, outer-exposed reefs and lagoonal-patch reefs had higher rates of net carbonate production than nearshore reefs. The study found that thermal anomalies, particularly the intensity of thermal-stress events, play a significant role in reducing net carbonate production—evident as a diminishing trend of net carbonate production from the western to the central tropical Pacific Ocean. The results also showed a latent spatial effect along the same gradient, not explained by thermal stress, suggesting that reefs in the western tropical Pacific Ocean are potentially enhanced by the proximity of reefs in the Coral Triangle—an effect that diminishes with increasing distance and isolation.

scholarly journals Thermal Stress and Bleaching in the Cnidarian-Dinoflagellate Symbiosis: The Application of Metabolomics

2021 ◽  
Author(s):  
◽  
Katie E. Hillyer
Keyword(s):  
Thermal Stress ◽  
Coral Reefs ◽  
Metabolite Profiling ◽  
Alternative Energy ◽  
Metabolic Networks ◽  
Elevated Temperatures ◽  
Central Metabolism ◽  
Diverse Range ◽  
Thermally Induced ◽  
Profiling Techniques

<p>Reef-building corals form critical ecosystems, which provide a diverse range of goods and services. Their success is based on a complex symbiosis between cnidarian host, dinoflagellate algae (genus Symbiodinium) and associated microorganisms (together termed the holobiont). Under functional conditions nutrients are efficiently recycled within the holobiont; however, under conditions of thermal stress, this dynamic relationship can dysfunction, resulting in the loss of symbionts (bleaching). Mass coral bleaching associated with elevated temperatures is a major threat to the long-term persistence of coral reefs. Further study is therefore necessary in order to elucidate the cellular and metabolic networks associated with function in the symbiosis and to determine change elicited by exposure to thermal stress. Metabolomics is the study of small compounds (metabolites) in a cell, tissue or whole organism. The metabolome comprises thousands of components, which will respond rapidly to change, reflecting a combination of genotype, phenotype and the environment. As a result, the study of these metabolic networks serves as a sensitive tool for the detection and elucidation of cellular responses to abiotic stress in complex systems.  This thesis presents outputs of gas chromatography-mass spectrometry-based metabolite profiling techniques, which have been applied to the study of thermal stress and bleaching in the cnidarian-dinoflagellate symbiosis. In Chapter 2 these techniques were developed and applied to the model symbiotic cnidarian Aiptasia sp., and its homologous symbiont (Symbiodinium ITS 2 type B1), to characterise both ambient and thermally-induced metabolite profiles (amino and non-amino organic acids) in both partners. Thermal stress, symbiont photodamage and associated bleaching, resulted in characteristic modifications to the free metabolite pools of both partners. These changes differed between partners and were associated with modifications to central metabolism, biosynthesis, catabolism of stores and homeostatic responses to thermal and oxidative stress.  In Chapter 3 metabolite profiling techniques (focussing this time on carbohydrate pools) were once again applied to the study of thermally-induced changes to the free pools of the coral Acropora aspera and its symbionts (dominant Symbiodinium ITS 2 type C3) at differing stages of symbiont photodamage and thermal stress. Additionally, targeted analysis was employed to quantify these changes in terms of absolute amounts. Once again exposure to elevated temperatures resulted in symbiont photodamage, bleaching and characteristic modifications to the free metabolite pools of symbiont and host, which differed between partners and with the duration of thermal stress. These changes were associated with increased turnover of a number of networks including: energy-generating pathways, antioxidant networks, ROS-associated damage and damage signalling, and were also indicative of potential alterations to the composition of the associated microbial holobiont.  Finally in Chapter 4, metabolite profiling techniques optimized in Chapter 2 and 3 were coupled to 13C labelling in both Aiptasia sp. and A. aspera, in order to further investigate the questions raised in these preceding studies. Once again changes were observed to central metabolism, biosynthesis and alternative energy-generation modes in symbiont and host, in both symbioses. Interestingly however, in all cases there was continued fixation of carbon, production- and translocation of mobile products by the remaining symbionts in hospite. This suggests that even during the later stages of bleaching, symbionts are, at least in part, metabolically functional in terms of photosynthate provision.  This study therefore serves as an important first step in developing the application of metabolomics-based techniques to the study of thermal stress in the cnidarian-dinoflagellate symbiosis. The power of these techniques lies in the capacity to simultaneously assess rapid and often post-translational change in a highly repeatable and quantitative manner. With the use of these methods, this study has shown how metabolic, homeostatic and acclimatory networks interact to elicit change in each partner of the symbiosis during thermal stress and how these responses vary between symbiotic partners. Further understanding of these networks, individual sensitivities- and enhanced resistance to thermal stress are essential if we are to better understand the capacity of coral reefs to acclimate and persist in the face of climate change.</p>

scholarly journals Lingkungan Terumbu Karang sepanjang pantai gugusan Pulau-Pulau terluar di Perairan Kepulauan Aruah, Kabupaten Rokan Hilir Provinsi Riau. Coral reef environment along coastal outer, in Aruah Archipelgo Waters area, Rokan Hilir District Riau Province

2018 ◽  
Vol 9 (1) ◽  
pp. 21
Author(s):  
Deny Setiady ◽  
Ediar Usman
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
High Tide ◽  
Small Island ◽  
Small Islands ◽  
Marine Geology ◽  
Reef Environment ◽  
Sea Bottom ◽  
Coral Reef Environment ◽  
Almost All

Abstrak Secara geografis, Kepulauan Aruah merupakan gugusan pulau-pulau kecil terluar yang  terletak di perairan Selat Malaka, yang berbatasan dengan Malaysia. Metoda penelitian geologi kelautan terdiri dari, Pemetaan geologi pantai dan lepas pantai, penentuan posisi, pengukuran pasang surut, pengukuran kedalaman dasar laut dan pengukuran luas terumbu karang. Hasil pengukuran luas gugusan  Terumbu karang di sekitar Kepulauan Aruah pada waktu pasang yaitu: Pulau Jemur (31.3800 ha), Pulau Kalironggo (39.0229 ha), Pulau Sarong Alang (0.5081 ha), Pulau Pandan (3.5940 ha), Pulau Labuhan Bilik (15.5340 ha), Pulau Tukong Mas (19.4271), Pulau Pasir (25.853), Pulau Batu Adang (43.1740), Pulau Batu Berlayar (70.9140), dan Pulau Batu Mandi (9.0770 ha). Pulau Tukong Simbang terdapat 7 gugusan pulau kecil, dimana  pada saat air laut mengalami surut terendah membentuk satu kesatuan pulau dengan luas mencapai 104,9 ha. Kedalaman dasar laut di daerah penelitian maksimum 80 meter, dengan perbedaan pasang surut maksimum dan surut minimum adalah 5,9 meter di daerah penelitian. Keberadaan batuan Tersier di pantai dan terumbu karang menjadi penyangga keberadaan dan ketahanan gugusan pulau-pulau kecil. Pantai dan lepas pantai Kepulauan Aruah. Hampir seluruh bagian pinggir dari pulau-pulau kecil di sekitar Pulau Jemur dikelilingi oleh lingkungan terumbu karang, sehingga menambah pesona keindahan perairan dan pantai kepuauan Aruah.  Kata Kunci: Kepulauan Aruah, Lingkungan Terumbu Karang, Pulau terluar, dan geologi kelautan Abstract Aruah Islands located in the  Malacca Strait waters is outer islands cluster and the border Malaysia. Study method consits of coastal geology mapping positioning Low – high Tide measurenment, sea bottom measurenment and Coral reef wide measurenment. High tide coral reef cluster measurenment in Aruah archipelago are:  Jemur Island(31.3800 ha), Kalironggo (39.0229 ha), Sarong Alang  Island (0.5081 ha),  Pandan Island (3.5940 ha),  Labuhan Bilik Island (15.5340 ha), Tukong Mas Island (19.4271), Pasir Island (25.853), Batu Adang Island (43.1740), Batu Berlayar Island(70.9140), dan Batu Mandi Isand (9.0770) ha). There are seven small island Tukong Simbang Island, when low tide forming one island with 104.9 ha square. Maximum depth of seawater is 80 meter dept and differences between low tide and high tide is 5,9 meter in  study area. The existence of Tertiary rocks on the beach and coral reefs into existence and resistance as a buffer of small islands cluster. Almost all of the edges of small islands around the Jemur island is surrounded by coral reefs environment, that adding to the charm and beauty of coastal and waters Aruah Islands  Keywords. Aruah archipelago, Coral reef environment, outer island, and marine geology,

Sign in / Sign up

Export Citation Format

Share Document