Coral Community Composition Linked to Hypoxia Exposure.

Tropical reef ecosystems are strongly influenced by the composition of coral species, but the factors influencing coral diversity and distributions are not fully understood. Here we demonstrate that large variations in the relative abundance of three major coral species across adjacent Caribbean reef sites are strongly related to their different low O tolerances. In laboratory experiments designed to mimic reef conditions, the cumulative effect of repeated nightly low O drove coral bleaching and mortality, with limited modulation by temperature.

Compound Extreme Events Induce Rapid Mortality in a Tropical Sea Urchin.

AbstractThe frequency, magnitude, and duration of marine heatwaves and deoxygenation events are increasing globally. Recent research suggests that their co-occurrence is more common than previously thought and that their combination can have rapid, dire biological impacts. We used the sea urchin to determine whether mortality occurs faster when deoxygenation events are combined with extreme heating (compound events), compared to deoxygenation events alone.

Rapid ecosystem-scale consequences of acute deoxygenation on a Caribbean coral reef.

Loss of oxygen in the global ocean is accelerating due to climate change and eutrophication, but how acute deoxygenation events affect tropical marine ecosystems remains poorly understood. Here we integrate analyses of coral reef benthic communities with microbial community sequencing to show how a deoxygenation event rapidly altered benthic community composition and microbial assemblages in a shallow tropical reef ecosystem. Conditions associated with the event precipitated coral bleaching and mass mortality, causing a 50% loss of live coral and a shift in the benthic community that persisted a year later.

Oxygen-mediated plasticity confers hypoxia tolerance in a corallivorous polychaete.

There is mounting evidence that the deoxygenation of coastal marine ecosystems has been underestimated, particularly in the tropics. These physical conditions appear to have far-reaching consequences for marine communities and have been associated with mass mortalities. Yet little is known about hypoxia in tropical habitats or about the effects it has on reef-associated benthic organisms.

An assessment of local adaptation in a calcifying polychaete from a shallow CO vent system.

Ocean acidification (OA) is likely to exert selective pressure on natural populations. Our ability to predict which marine species will adapt to OA and what underlies this adaptive potential is of high conservation and resource management priority. Using a naturally low-pH vent site in the Mediterranean Sea (Castello Aragonese, Ischia) mirroring projected future OA conditions, we carried out a reciprocal transplant experiment to investigate the relative importance of phenotypic plasticity and local adaptation in two populations of the sessile, calcifying polychaete sp.

To brood or not to brood: Are marine invertebrates that protect their offspring more resilient to ocean acidification?

Anthropogenic atmospheric carbon dioxide (CO2) is being absorbed by seawater resulting in increasingly acidic oceans, a process known as ocean acidification (OA). OA is thought to have largely deleterious effects on marine invertebrates, primarily impacting early life stages and consequently, their recruitment and species' survival. Most research in this field has been limited to short-term, single-species and single-life stage studies, making it difficult to determine which taxa will be evolutionarily successful under OA conditions.