Mesophotic Ecosystems: The Link between Shallow and Deep-Sea Habitats

Mesophotic ecosystems (MEs) are characterized by the presence of light-dependent organisms, found at depths ranging from ~30 to 150 m in temperate, subtropical and tropical regions. These communities occasionally create massive reef structures with diverse but characteristic morphologies, which serve as the framework builders of those ecosystems. In many localities, MEs are physically linked with shallow and deep-sea habitats, and while taxa from both environments share this space, a unique and endemic biodiversity is also found. The main MEs studied to date are the mesophotic coral ecosystems (MCEs) and the temperate mesophotic ecosystems (TMEs), which have received increased attention during the last decade. As shallow coral reef ecosystems are among the most threatened habitats on Earth, the potential of MEs to act as refugia and contribute to the resilience of the whole ecosystem has been a subject of scrutiny. New technologies and methods have become more available to study these deeper parts of the reef ecosystems, yielding many new discoveries. However, basic gaps in knowledge remain in our scientific understanding of the global diversity of MEs, limiting our ability to recognize biogeographic patterns and to make educated decisions for the management and conservation of these ecosystems.

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Extracellular Reef Metabolites Across the Protected Jardines de la Reina, Cuba Reef System

Frontiers in Marine Science ◽

10.3389/fmars.2020.582161 ◽

2020 ◽

Vol 7 ◽

Author(s):

Laura Weber ◽

Maickel Armenteros ◽

Melissa Kido Soule ◽

Krista Longnecker ◽

Elizabeth B. Kujawinski ◽

...

Keyword(s):

Coral Reef ◽

Nutrient Cycling ◽

Photochemical Oxidation ◽

Surface Seawater ◽

High Productivity ◽

Sources And Sinks ◽

Biogeographic Patterns ◽

Extracellular Metabolites ◽

Coral Reef Ecosystems ◽

Benthic Pelagic Coupling

Coral reef ecosystems are incredibly diverse marine biomes that rely on nutrient cycling by microorganisms to sustain high productivity in generally oligotrophic regions of the ocean. Understanding the composition of extracellular reef metabolites in seawater, the small organic molecules that serve as the currency for microorganisms, may provide insight into benthic-pelagic coupling as well as the complexity of nutrient cycling in coral reef ecosystems. Jardines de la Reina (JR), Cuba is an ideal environment to examine extracellular metabolites across protected and high-quality reefs. Here, we used liquid chromatography mass spectrometry (LC-MS) to quantify specific known metabolites of interest (targeted metabolomics approach) and to survey trends in metabolite feature composition (untargeted metabolomics approach) from surface and reef depth (6 – 14 m) seawater overlying nine forereef sites in JR. We found that untargeted metabolite feature composition was surprisingly similar between reef depth and surface seawater, corresponding with other biogeochemical and physicochemical measurements and suggesting that environmental conditions were largely homogenous across forereefs within JR. Additionally, we quantified 32 of 53 detected metabolites using the targeted approach, including amino acids, nucleosides, vitamins, and other metabolic intermediates. Two of the quantified metabolites, riboflavin and xanthosine, displayed interesting trends by depth. Riboflavin concentrations were higher in reef depth compared to surface seawater, suggesting that riboflavin may be produced by reef organisms at depth and degraded in the surface through photochemical oxidation. Xanthosine concentrations were significantly higher in surface reef seawater. 5′-methylthioadenosine (MTA) concentrations increased significantly within the central region of the archipelago, displaying biogeographic patterns that warrant further investigation. Here we lay the groundwork for future investigations of variations in metabolite composition across reefs, sources and sinks of reef metabolites, and changes in metabolites over environmental, temporal, and reef health gradients.

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Using resilience assessments to inform the management and conservation of coral reef ecosystems

Journal of Environmental Management ◽

10.1016/j.jenvman.2020.111384 ◽

2021 ◽

Vol 277 ◽

pp. 111384

Author(s):

Elizabeth McLeod ◽

Elizabeth C. Shaver ◽

Maria Beger ◽

Jennifer Koss ◽

Gabriel Grimsditch

Keyword(s):

Coral Reef ◽

Coral Reef Ecosystems ◽

Management And Conservation

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Cryptic Species from Biodiversity Hotspot: Estimation of Decapoda on Dead Coral Head Pocillopora in Raja Ampat Papua

ILMU KELAUTAN Indonesian Journal of Marine Sciences ◽

10.14710/ik.ijms.25.1.1-6 ◽

2019 ◽

Vol 25 (1) ◽

pp. 1-6

Author(s):

Eka Maya Kurniasih ◽

Andrianus Sembiring ◽

Ni Putu Dian Pertiwi ◽

Aji Wahyu Anggoro ◽

Ni Kadek Dita Cahyani ◽

...

Keyword(s):

Species Richness ◽

Coral Reef ◽

Wiener Index ◽

Sample Collection ◽

Dead Coral ◽

Coral Reef Ecosystems ◽

Cryptic Biodiversity ◽

Management And Conservation ◽

Additional Sample ◽

Coral Head

Cryptic organisms that live within the interstices of reef habitats contribute significantly to coral reef biodiversity. One example of this cryptic biodiversity is the high abundance of decapods in dead coral heads that associated with various biota. However, this diversity poorly studied especially species identification and species richness. This study aims to estimate the decapods diversity in Raja Ampat, Papua, using Pocillopora dead coral head method as semi-quantitative sampling approach. Raja Ampat in Papua is chosen because it situated in the center of Coral Triangle marine hotspot. Data were collected from 10 dead coral heads of genus Pocillopora from 10-meter depth near the islands of Kri and Misool. This study observed a total of 205 individuals Decapoda from Kri Island and 672 Individual from Misool Islands. Species richness observation (Chao1 and ACE) of the total samples reports only 11 families of decapoda detected in this study. Rarefaction curve reach an asymptote after all after all ten dead coral were analyzed; indicating that additional sample collection would not change estimates of diversity found in this study. The Shannon-Wiener index diversity on the Kri Island showed lower diversity value (2.09) compared to Misool Island (2.18). In the future, this research can be used as a basis for understanding the diversity of coral reefs as well as for management and conservation of coral reef ecosystems.

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Mesophotic Coral Ecosystems of the Great Barrier Reef Are Understudied and Underexplored

Frontiers in Marine Science ◽

10.3389/fmars.2021.622856 ◽

2021 ◽

Vol 8 ◽

Author(s):

Gal Eyal ◽

Jack H. Laverick ◽

Pim Bongaerts ◽

Oren Levy ◽

John M. Pandolfi

Keyword(s):

Coral Reef ◽

Great Barrier Reef ◽

Fishery Management ◽

Research Effort ◽

Decision Makers ◽

Barrier Reef ◽

Mesophotic Coral Ecosystems ◽

Deep Reef ◽

The World ◽

Coral Reef Ecosystems

Mesophotic coral ecosystems (MCEs) are characterized by the presence of photosynthetically active organisms such as corals and algae, and associated communities at depths ranging from 30 to 150 m in tropical and subtropical regions. Due to the increased awareness of the potential importance of these reefs as an integral part of coral reef ecosystems (i.e., deep reef refuge, specialized biodiversity, transition zone between shallow and deep-sea environments, and recreational and intrinsic values), interest from the scientific community has grown around the world over the last two decades. Several nations have already made management declarations and started to extend marine protected areas and fishery management to MCEs. The estimated area of Australian MCEs is likely equivalent to that of shallow reef ecosystems down to 30 m; however, Australian MCEs attract limited research effort compared to other major coral reef regions around the world. In this perspective, we briefly explore the reasons for this scarcity of research on mesophotic ecosystems of the Great Barrier Reef (GBR) of Australia (e.g., strict diving regulations, new researchers’ involvement, and logistics and cost). At present, research efforts on the mesophotic ecosystems of the GBR are in decline and if this trajectory is maintained, the global disparity in knowledge between MCEs near Australia and those from the other main coral reef regions worldwide will sharpen deeply. We call for action from the research community, grant agencies, and decision-makers toward a wider understanding of these important ecosystems in Australia.

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Documentation et gestion du patrimoine archéologique de la chaîne montagneuse tuniso-libyenne via l'utilisation des nouvelles technologies : résultats préliminaires

Libyan Studies ◽

10.1017/lis.2020.17 ◽

2021 ◽

pp. 1-16

Author(s):

Héla Mekki

Keyword(s):

New Technologies ◽

Management Plan ◽

Archaeological Sites ◽

Mountain Range ◽

Direct Evaluation ◽

Nouvelles Technologies ◽

Data Assessment ◽

Conservation Plan ◽

Indirect Evaluation ◽

Management And Conservation

Abstract The mountain range formed by Jebels Matmata, Demmer and Nefoussa which links the two countries, Tunisia and Libya, is strewn with archaeological remains that are little known today, due in part to the rugged terrain which makes it difficult to see them. This issue has been helped by the use of new technologies, in this case remote sensing and QGIS software. Archaeological evidence has been uncovered and more than 3,900 sites and monuments have been detected on the sides of these mountains. In addition to the inventory of unknown archaeological sites, the main aim of the work was to draw up a management and conservation plan to provide, with an order of priority, a strategy for the safeguard and conservation of the mountain heritage. This management plan was only possible through a correlation of three data: assessment of values, identification of threats, and study of the state of conservation. These components were studied using an indirect evaluation based on satellite imagery and direct evaluation through field visits.

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