Function and stability of mesophotic coral reefs.

The function and stability of mesophotic coral ecosystems (MCEs) have been extensively studied in recent years. These deep reefs are characterized by local physical processes, particularly the steep gradient in irradiance with increasing depth, and their impact on trophic resources. Mesophotic reefs exhibit distinct zonation patterns that segregate shallow reef biodiversity from ecologically unique deeper communities of endemic species.

Microbiome diversity and metabolic capacity determines the trophic ecology of the holobiont in Caribbean sponges.

Sponges are increasingly recognized as an ecologically important taxon on coral reefs, representing significant biomass and biodiversity where sponges have replaced scleractinian corals. Most sponge species can be divided into two symbiotic states based on symbiont community structure and abundance (i.e.

Cophylogeny and convergence shape holobiont evolution in sponge-microbe symbioses.

Symbiotic microbial communities of sponges serve critical functions that have shaped the evolution of reef ecosystems since their origins. Symbiont abundance varies tremendously among sponges, with many species classified as either low microbial abundance (LMA) or high microbial abundance (HMA), but the evolutionary dynamics of these symbiotic states remain unknown. This study examines the LMA/HMA dichotomy across an exhaustive sampling of Caribbean sponge biodiversity and predicts that the LMA symbiotic state is the ancestral state among sponges.

Incident light and morphology determine coral productivity along a shallow to mesophotic depth gradient.

While the effects of irradiance on coral productivity are well known, corals along a shallow to mesophotic depth gradient (10-100 m) experience incident irradiances determined by the optical properties of the water column, coral morphology, and reef topography.Modeling of productivity (i.e.

Combined and independent effects of hypoxia and tributyltin on mRNA expression and physiology of the Eastern oyster (Crassostrea virginica).

Oyster reefs are vital to estuarine health, but they experience multiple stressors and globally declining populations. This study examined effects of hypoxia and tributyltin (TBT) on adult Eastern oysters (Crassostrea virginica) exposed either in the laboratory or the field following a natural hypoxic event. In the laboratory, oysters were exposed to either hypoxia followed by a recovery period, or to hypoxia combined with TBT.

Will coral reef sponges be winners in the Anthropocene?

Recent observations have shown that increases in climate change-related coral mortality cause changes in shallow coral reef community structure through phase shifts to alternative taxa. As a result, sponges have emerged as a potential candidate taxon to become a "winner," and therefore a numerically and functionally dominant member of many coral reef communities. But, in order for this to occur, there must be sufficient trophic resources to support larger populations of these active filter-feeding organisms.

Annual Thermal Stress Increases a Soft Coral's Susceptibility to Bleaching.

Like scleractinian corals, soft corals contain photosymbionts (Family Symbiodiniaceae) that provide energy for the host. Recent thermal events have resulted in soft coral bleaching in four of five years on Guam, where they dominated back-reef communities. Soft coral bleaching was examined in Sinularia maxima, S.

Allelopathy-mediated competition in microbial mats from Antarctic lakes.

Microbial mats are vertically stratified communities that host a complex consortium of microorganisms, dominated by cyanobacteria, which compete for available nutrients and environmental niches, within these extreme habitats. The Antarctic Dry Valleys near McMurdo Sound include a series of lakes within the drainage basin that are bisected by glacial traverses. These lakes are traditionally independent, but recent increases in glacial melting have allowed two lakes (Chad and Hoare) to become connected by a meltwater stream.

Biochemical Mechanisms for Geographical Adaptations to Novel Toxin Exposures in Butterflyfish.

Some species of butterflyfish have had preyed upon corals for millions of years, yet the mechanism of butterflyfish specialized coral feeding strategy remains poorly understood. Certain butterflyfish have the ability to feed on allelochemically rich soft corals, e.g.

Hard coral (Porites lobata) extracts and homarine on cytochrome P450 expression in Hawaiian butterflyfishes with different feeding strategies.

Dietary specialists tend to be less susceptible to the effects of chemical defenses produced by their prey compared to generalist predators that feed upon a broader range of prey species. While many researchers have investigated the ability of insects to detoxify dietary allelochemicals, little research has been conducted in marine ecosystems. We investigated metabolic detoxification pathways in three species of butterflyfishes: the hard coral specialist feeder, Chaetodon multicinctus, and two generalist feeders, Chaetodon auriga and Chaetodon kleinii.

Allelopathy in the tropical alga Lobophora variegata (Phaeophyceae): mechanistic basis for a phase shift on mesophotic coral reefs?

Macroalgal phase shifts on Caribbean reefs have been reported with increasing frequency, and recent reports of these changes on mesophotic coral reefs have raised questions regarding the mechanistic processes behind algal population expansions to deeper depths. The brown alga Lobophora variegata is a dominant species on many shallow and deep coral reefs of the Caribbean and Pacific, and it increased in percent cover (>50%) up to 61 m on Bahamian reefs following the invasion of the lionfish Pterois volitans. We examined the physiological and ecological constraints contributing to the spread of Lobophora on Bahamian reefs across a mesophotic depth gradient from 30 to 61 m, pre- and post-lionfish invasion.

Chlorinated didemnins from the tunicate Trididemnum solidum.

Chemical investigation of the tunicate Trididemnum solidum resulted in the isolation of two new chlorinated compounds belonging to the didemnin class, along with two known compounds didemnin A and didemnin B. The structural determination of the compounds was based on extensive NMR and mass spectroscopic analysis. The isolated compounds 1-4 were tested for their anti-inflammatory activity using in vitro assays for inhibition of inducible nitric oxide synthase (iNOS) and nuclear factor-kappa B (NF-κB) activity.

Exploring individual- to population-level impacts of disease on coral reef sponges: using spatial analysis to assess the fate, dynamics, and transmission of Aplysina Red Band Syndrome (ARBS).

Background: Marine diseases are of increasing concern for coral reef ecosystems, but often their causes, dynamics and impacts are unknown. The current study investigated the epidemiology of Aplysina Red Band Syndrome (ARBS), a disease affecting the Caribbean sponge Aplysina cauliformis, at both the individual and population levels. The fates of marked healthy and ARBS-infected sponges were examined over the course of a year.

Ecology of Caribbean sponges: are top-down or bottom-up processes more important?

Benthic-pelagic coupling and the role of bottom-up versus top-down processes are recognized as having a major impact on the structure of marine communities. While the roles of bottom-up processes are better appreciated they are still viewed as principally affecting the outcome of top-down processes. Sponges on coral reefs are important members of the benthic community and provide a critically important functional linkage between water-column productivity and the benthos.

Genetic structure in the coral, Montastraea cavernosa: assessing genetic differentiation among and within Mesophotic reefs.

Mesophotic coral reefs (30-150 m) have recently received increased attention as a potential source of larvae (e.g., the refugia hypothesis) to repopulate a select subset of the shallow water (<30 m) coral fauna.

Marine proteomics: a critical assessment of an emerging technology.

The application of proteomics to marine sciences has increased in recent years because the proteome represents the interface between genotypic and phenotypic variability and, thus, corresponds to the broadest possible biomarker for eco-physiological responses and adaptations. Likewise, proteomics can provide important functional information regarding biosynthetic pathways, as well as insights into mechanism of action, of novel marine natural products. The goal of this review is to (1) explore the application of proteomics methodologies to marine systems, (2) assess the technical approaches that have been used, and (3) evaluate the pros and cons of this proteomic research, with the intent of providing a critical analysis of its future roles in marine sciences.

Antibacterial secondary metabolites from the cave sponge Xestospongia sp.

Chemical investigation of the cave sponge Xestospongia sp. resulted in the isolation of three new polyacetylenic long chain compounds along with two known metabolites. The structures of the new metabolites were established by NMR and MS analyses.

Spatial variability in secondary metabolites of the indo-pacific sponge Stylissa massa.

Chemical diversity represents a measure of selective pressures acting on genotypic variability. In order to understand patterns of chemical ecology and biodiversity in the environment, it is necessary to enhance our knowledge of chemical diversity within and among species. Many sponges produce variable levels of secondary metabolites in response to diverse biotic and abiotic environmental factors.

Unique actinomycetes from marine caves and coral reef sediments provide novel PKS and NRPS biosynthetic gene clusters.

In the ever-expanding search for novel bioactive molecules and enzymes, marine actinomycetes have proven to be a productive source. While open reef sediment and sponge-associated actinomycetes have been extensively examined, their marine cave counterparts remain unevaluated. Anchialine cave systems in the Bahamas offered an ideal setting to evaluate the occurrence and variation within sediment-associated actinomycete communities.

Contemporary 14C radiocarbon levels of oxygenated polybrominated diphenyl ethers (O-PBDEs) isolated in sponge-cyanobacteria associations.

Considerable debate surrounds the sources of oxygenated polybrominated diphenyl ethers (O-PBDEs) in wildlife as to whether they are naturally produced or result from anthropogenic industrial activities. Natural radiocarbon ((14)C) abundance has proven to be a powerful tool to address this problem as recently biosynthesized compounds contain contemporary (i.e.

Chemical constituents of the deep reef caribbean sponges Plakortis angulospiculatus and Plakortis halichondrioides and their anti-inflammatory activities.

Chemical investigations of two collections of the deep reef Caribbean sponge Plakortis angulospiculatus resulted in the isolation of a new compound (1) along with the known compound spiculoic acid B (2) belonging to the spiculoic acid class and four other new compounds (3-6) belonging to the zyggomphic acid class. Three new aromatic compounds (7-9) were isolated from the Caribbean sponge Plakortis halichondrioides. The structural determination of the compounds was based on extensive NMR and mass spectroscopic analysis.

Photoacclimatization by the coral Montastraea cavernosa in the mesophotic zone: light, food, and genetics.

Most studies on coral reefs have focused on shallow reef (< 30 m) systems due to the technical limitations of conducting scientific diving deeper than 30 m. Compared to their shallow-water counterparts, these mesophotic coral reefs (30-150 m) are understudied, which has slowed our broader understanding of the biodiversity, ecology, and connectivity of shallow and deep coral reef communities. We know that the light environment is an important component of the productivity, physiology, and ecology of corals, and it restricts the distribution of most species of coral to depths of 60 m or less.

Scalarane sesterterpenoids: semisynthesis and biological activity.

Aiming to improve the potency and selectivity of scalarane sesterterpenoids, a series of natural and semisynthetic analogues, derived from the cytotoxic naturally abundant sesterterpene heteronemin (1), were evaluated for their in vitro antimicrobial and cytotoxic properties. The new sesterterpenes 16-O-methylsesterstatin 4 (6c), 17, 24-dihydroheteronemin (7a), 16, 25-deacetoxy-17, 24-dihydroheteronemin (7b), and 16-deacetoxy-25-methoxy-17, 24-dihydroheteronemin (7c) were structurally defined via physical data analyses. Scalarane sesterterpenes possessing an unsaturated 1,4-dialdehyde moiety showed potent inhibitory activity against methicillin-resistant Staphylococcus aureus at concentrations that are not significantly cytotoxic to mammalian cells.