Selective nutrient incorporation may underestimate heterotrophy of a mixotrophic reef-building coral.

Mixotrophic reef-building corals acquire nutrition via photosynthate translocation from endosymbiotic microalgae and by heterotrophic prey/particle capture. Heterotrophy promotes resistance to, and recovery from, environmental stress, but quantifying coral heterotrophy remains difficult due to complex resource exchanges within the coral holobiont. We interrogated the response of multiple biomarkers to coral heterotrophy using fatty acid profiling and stable isotope analysis of Stylophora pistillata grown along a controlled feeding gradient from pure autotrophy to pure heterotrophy.

First reference genomes for two mesophotic, reef-building coral species: Leptoseris cf. scabra and Montipora cf. grisea.

Coral mortality is occurring worldwide at an alarming rate. Despite the immense and underestimated biodiversity of reef-building corals, very few genomes are available. Further, almost all genomic resources originate from shallow water corals even though photosynthetic, symbiotic corals occur at mesophotic depths deeper than 30 m and even >100 m.

Heterotrophy in marine animal forests in an era of climate change.

Marine animal forests (MAFs) are benthic ecosystems characterised by biogenic three-dimensional structures formed by suspension feeders such as corals, gorgonians, sponges and bivalves. They comprise highly diversified communities among the most productive in the world's oceans. However, MAFs are in decline due to global and local stressors that threaten the survival and growth of their foundational species and associated biodiversity.

Marine heatwaves modulate the genotypic and physiological responses of reef-building corals to subsequent heat stress.

Back-to-back marine heatwaves in 2016 and 2017 resulted in severe coral bleaching and mortality across the Great Barrier Reef (GBR). Encouragingly, some corals that survived these events exhibit increased bleaching resistance and may represent thermally tolerant populations that can better cope with ocean warming. Using the GBR as a natural laboratory, we investigated whether a history of minimal (Heron Island) or severe (Lizard Island) coral bleaching in 2016 and 2017 equates to stress tolerance in a successive heatwave (2020).

Complex dynamics of coral gene expression responses to low pH across species.

Coral capacity to tolerate low pH affects coral community composition and, ultimately, reef ecosystem function. Low pH submarine discharges ('Ojo'; Yucatán, México) represent a natural laboratory to study plasticity and acclimatization to low pH in relation to ocean acidification. A previous >2-year coral transplant experiment to ambient and low pH common garden sites revealed differential survivorship across species and sites, providing a framework to compare mechanistic responses to differential pH exposures.

Linking isotopic signatures of nitrogen in nearshore coral skeletons with sources in catchment runoff.

We use a multi-tracer approach to identify catchment sources of nitrogen (N) in the skeletons of nearshore Porites corals within the Great Barrier Reef. We measured δN, δC and C:N ratios of particulate organic matter (POM) sampled from the Pioneer River catchment and identified five distinct end-members: (1) marine planktonic and algal-dominated matter with higher δN values from the river mouth and coastal waters; (2) estuarine planktonic and algal matter with lower δN values associated with estuarine mixing; (3) lower river freshwater phytoplankton and algal-dominated matter in stratified reservoirs adjacent to catchment weirs, with the N-enriched source likely caused by microbial remineralization and denitrification; (4) upper river low δN terrigenous soil matter eroded from cane fields bordering waterways; and (5) terrestrial plant detrital matter in forest streams, representing a low δN fixed atmospheric nitrogen source. The δN values of adjacent, nearshore Porites coral skeletons is reflective of POM composition in coastal waters, with N-enriched values reflective of transformed N during flood pulses from the Pioneer River.

A contemporary baseline record of the world's coral reefs.

Addressing the global decline of coral reefs requires effective actions from managers, policymakers and society as a whole. Coral reef scientists are therefore challenged with the task of providing prompt and relevant inputs for science-based decision-making. Here, we provide a baseline dataset, covering 1300 km of tropical coral reef habitats globally, and comprised of over one million geo-referenced, high-resolution photo-quadrats analysed using artificial intelligence to automatically estimate the proportional cover of benthic components.

Evolutionary biogeography of the reef-building coral genus Galaxea across the Indo-Pacific ocean.

Stony corals (Scleractinia) form the basis for some of the most diverse ecosytems on Earth, but we have much to learn about their evolutionary history and systematic relationships. In order to improve our understanding of species in corals we here investigated phylogenetic relationships between morphologically defined species and genetic lineages in the genus Galaxea (Euphyllidae) using a combined phylogenomic and phylogeographic approach. Previous studies revealed the nominal species G.

Mesophotic.org: a repository for scientific information on mesophotic ecosystems.

Mesophotic coral ecosystems (MCEs) and temperate mesophotic ecosystems (TMEs) occur at depths of roughly 30-150 m depth and are characterized by the presence of photosynthetic organisms despite reduced light availability. Exploration of these ecosystems dates back several decades, but our knowledge remained extremely limited until about a decade ago, when a renewed interest resulted in the establishment of a rapidly growing research community. Here, we present the 'mesophotic.

Evaluating coral trophic strategies using fatty acid composition and indices.

The ecological success of shallow water reef-building corals has been linked to the symbiosis between the coral host and its dinoflagellate symbionts (herein 'symbionts'). As mixotrophs, symbiotic corals depend on nutrients 1) transferred from their photosynthetic symbionts (autotrophy) and 2) acquired by host feeding on particulate organic resources (heterotrophy). However, coral species differ in the extent to which they depend on heterotrophy for nutrition and these differences are typically poorly defined.

Gradients in Primary Production Predict Trophic Strategies of Mixotrophic Corals across Spatial Scales.

Mixotrophy is among the most successful nutritional strategies in terrestrial and marine ecosystems. The ability of organisms to supplement primary nutritional modes along continua of autotrophy and heterotrophy fosters trophic flexibility that can sustain metabolic demands under variable or stressful conditions. Symbiotic, reef-building corals are among the most broadly distributed and ecologically important mixotrophs, yet we lack a basic understanding of how they modify their use of autotrophy and heterotrophy across gradients of food availability.