1,720,999 research outputs found
Corals and global warming: the Mediterranean versus the Red Sea (CoralWarm)
No full textCoralWarm will generate for the first time projections of temperate and subtropical coral survival by integrating sublethal temperature increase effects on metabolic and skeletal processes in Mediterranean and Red Sea key species.
CoralWarm unique approach is from the nano- to the macro-scale, correlating molecular events to environmental processes. This will show new pathways to future investigations on cellular mechanisms linking environmental factors to final phenotype, potentially improving prediction powers and paleoclimatological interpretation.
Biological and chemical expertise will merge, producing new interdisciplinary approaches for ecophysiology and biomineralization.
Field transplantations will be combined with controlled experiments under IPCC scenarios. Corals will be grown in aquaria, exposing the Mediterranean species native to cooler waters to higher temperatures, and the Red Sea ones to gradually increasing above ambient warming seawater. Virtually all state-of-the-art methods will be used, by uniquely combining the investigators’ expertise.
Expected results include responses of algal symbionts’ photosynthesis, host, symbiont and holobiont respiratioIMG_0743n, biomineralization rates and patterns, including colony architecture, and reproduction to temperature and pH gradients and combinations.
Integration of molecular aspects of potential replacement of symbiont clades, changes in skeletal crystallography, with biochemical and physiological aspects of temperature response, will lead to a novel mechanistic model predicting changes in coral ecology and survival prospect.
High-temperature tolerant clades and species will be revealed, allowing future bioremediation actions and establishment of coral refuges, saving corals and coral reefs for future generations
Analytical pyrolysis-based study on intra-skeletal organic matrices from Mediterranean corals
No full textOff-line analytical pyrolysis combined with gas chromatography–mass spectroscopy (GC–MS), directly or after trimethylsilylation, along with infrared spectroscopy and amino acid analysis was applied for the first time to the characterization of the intra-skeletal organic matrix (OM) extracted from four Mediterranean hard corals. They were diverse in growth form and trophic strategy namely Balanophyllia europaea and Leptopsammia pruvoti—solitary
corals, only the first having zooxanthelle—and Cladocora caespitosa and Astroides calycularis—colonial corals, only the first with zooxanthelle. Pyrolysis products evolved from
OM could be assigned to lipid (e.g. fatty acids, fatty alcohols, monoacylglicerols), protein (e.g. 2,5-diketopiperazines,
DKPs) and polysaccharide (e.g. anhydrosugars) precursors. Their quantitative distribution showed for all the species a low
protein content with respect to lipids and polysaccharides. A chemometric approach using principal component analysis
(PCA) and clustering analysis was applied on OM mean amino acidic compositions. The small compositional diversity
across coral species was tentatively related with coral growth form. The presence of N-acetyl glucosamine markers suggested
a functional link with other calcified tissues containing chitin. The protein fraction was further investigated using novel DKP markers tentatively identified from analytical pyrolysis of model polar linear dipeptides. Again, no correlation was observed in relation to coral ecology. These analytical results revealed that the bulk structure and composition of OMs among studied corals are similar, as it is the textural organization of the skeletonmineralized units. Therefore, they suggest that coral’s biomineralization is governed by similar macromolecules, and probably mechanisms, independently from their ecology
Temperature-dependent photoregulation in oceanic picophytoplankton during excessive irradiance exposure
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Photosynthesis
No full textAmong the myriads of volumes dedicated to various aspects of photosynthesis, the current one is singular in integrating an update of the most recent insights on this most important biological process in the biosphere. While photosynthesis fuels all the life supporting processes and activities of all living creatures on Earth, from bacteria though mankind, it also created in the first place, our life supporting oxygenic atmosphere, and keeps maintaining it. This volume is organized in four sections: I) Mechanisms, II) Stress effects, III) Methods, and IV) Applications
Coral research: past efforts and future horizons
No full textModern coral reefs had their origins in the Triassic Period, and over the past 65 million years, have expanded and contracted due to a variety of extrinsic factors such as sea level and climatic changes. As humans evolved, so did a new era for coral reefs: that of exposure to anthropogenic stressors on top of the already persistent natural events such as hurricanes/typhoons, volcanic eruptions and Acanthaster plancii outbreaks. Early studies of corals and coral reefs focused on taxonomy, ecology and physiology. The establishment of reef-based marine laboratories and technological advances in SCUBA enabled a rapid expansion of in situ studies and the ability to compare reef processes and changes over both space and time. The documented declines in the state of coral reefs worldwide have shifted the focus of many research programs from basic to applied and management-directed research. Expanded studies of reproductive processes, animal-algal symbioses, molecular genetics, ecotoxicology, connectivity, ecological modelling, calcification, cellular biology and biochemistry have allowed researchers to better understand how coral reefs function and how best to respond to a variety of stressors. Coral reef research has necessarily become multidisciplinary in nature, embracing the social and economic as well as the biophysical sciences. In the face of increasing effects of stressors tied to local activities such as poor land-use practices, and mounting concerns tied to global climate change, the bridging of science to policy development, management and conservation is critical if there is to be a legacy of vital reefs left for future generations to enjoy
Photosynthesis
No full textAmong the myriads of volumes dedicated to various aspects of photosynthesis, the current one is singular in integrating an update of the most recent insights on this most important biological process in the biosphere. While photosynthesis fuels all the life supporting processes and activities of all living creatures on Earth, from bacteria though mankind, it also created in the first place, our life supporting oxygenic atmosphere, and keeps maintaining it. This volume is organized in four sections: I) Mechanisms, II) Stress effects, III) Methods, and IV) Applications
Photosynthesis
Full text linkAmong the myriads of volumes dedicated to various aspects of photosynthesis, the current one is singular in integrating an update of the most recent insights on this most important biological process in the biosphere. While photosynthesis fuels all the life supporting processes and activities of all living creatures on Earth, from bacteria though mankind, it also created in the first place, our life supporting oxygenic atmosphere, and keeps maintaining it. This volume is organized in four sections: I) Mechanisms, II) Stress effects, III) Methods, and IV) Applications
Advances in Predicting the Impacts of Global Warming on the Mussels Mytilus galloprovincialis in the Mediterranean Sea
No full textMussels Mytilus galloprovincialis have been used as model bivalves to study the impacts of global warming on their physiological performance in Themaikos Gulf, North Greece. The studies have been conducted under laboratory and field conditions for more than 6 years and focused on the biochemical, metabolic, physiological and energetic responses of M. galloprovincialis to increases in the ambient temperature. Here we summarize the findings concerning the responses of mussels to environmental temperature, present an integrated model of their physiological performance during thermal stress and discuss these findings in the light of the predicted temperature changes in the Thermaikos Gulf from the regional climate trends and the mean global temperature projections for the period 1990–2100 based on IS92 emission scenarios of the Intergovernmental Panel for Climate Change (IPCC). Our findings indicate that mussels in Themaikos Gulf currently face the temperatures close to their upper thermal limits, especially during the summer, and thus are likely vulnerably to any further increase in the temperature such as expected during the global warmin
The role of plankton in coral trophodynamics
No full textHistorically, reef-building corals have been considered to be photoautotrophs due to their symbiosis with dinoflagellates that transfer photosynthetically fixed carbon to the animal tissue. Nevertheless, corals also obtain carbon heterotrophically through capture of plankton, ingestion of suspended particulate matter, and uptake of dissolved organic compounds. This review assesses the effects of heterotrophy on coral physiology, and how strongly feeding on all of these food sources contributes to coral energy budgets. Evidence in the literature demonstrates that feeding has a positive effect on coral tissue, enhancing the growth of both partners of the symbiosis. Nevertheless, the effects of feeding are light dependent: in general, tissue quality (lipid and protein composition) is enhanced in the presence of an adequate food source only under low-light conditions or in bleached corals. On the other hand, growth rates are typically highest under conditions of high light and food availability. However, under low-light conditions, feeding can provide a mechanism to maintain skeletal growth rates even though photosynthesis is reduced. Overall, a strong interaction between autotrophy and heterotrophy is apparent for scleractinian corals. Feeding can play a central role in maintaining physiological function when autotrophy is reduced. Moreover, taking all food sources into account, heterotrophy contributes more strongly to coral energy budgets than was previously thought. Nevertheless, not all symbiotic corals can sufficiently upregulate heterotrophic feeding to compensate for reduced photosynthesis, and identifying which coral species are facultative heterotrophs should be a focus of future research
Cold-water corals in an era of rapid global change: Are these the deep ocean’s most vulnerable ecosystems?
No full textCold-water corals create highly complex biogenic habitats that promote and sustain high biological diversity in the deep sea and play critical roles in deep-water ecosystem functioning across the globe. However, these often out of sight and out of mind ecosystems are increasingly under pressure both from human activities in the deep sea such as fishing and mineral extraction, and from a rapidly changing climate. This chapter gives an overview of the importance of cold-water coral habitats, the threats they face and how recent advances in understanding of both past and present cold-water coral ecosystems helps us to understand how well they may be able to adapt to current and future climate change. We address key knowledge gaps and the ongoing efforts at national and international scales to promote and protect these important yet vulnerable ecosystems
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