Group items tagged

A new study of the World Heritage-listed Ningaloo Marine Park has found that further protection may be needed to shield the reef against the impacts of climate change.

A new study of the World Heritage-listed Ningaloo Marine Park has found that further protection may be needed to shield the reef against the impacts of climate change.

Arctic ice melt could trigger uncontrollable climate change at global level.

These resilient corals can handle conditions that would decimate other species.

These resilient corals can handle conditions that would decimate other species.

Marine microworlds: the private life of plankton.

In the Maldives, one of the world's lowest-lying countries, new and urgent solutions are needed to protect the islands from the impacts of climate change. Tourist resort owners and local communities are joining government authorities in efforts to make the islands more resilient.

Groundwater pumped from the depths of the coastal Bengal Basin supporting more than 80 million people is largely secure from contamination, according to new research by UCL and the British Geological Survey.

Study shows severe loss of central Indian Ocean coral reefs between 2015 and 2017.

Study shows dramatic loss of central Indian Ocean coral reefs between 2015 and 2017.

Tough species of corals can go mobile and lay the foundations for new reefs in otherwise inhospitable areas, a study shows.

Two severe heat waves triggered coral bleaching and mass mortality in the Maldives in 1998 and 2016. Analysis of live coral cover data from 1997 to 2019 in shallow (5 m depth) reefs of the Maldives showed that the 1998 heat wave caused more than 90% of coral mortality leaving only 6.8 ± 0.3% of survived corals in all the shallow reefs investigated. No significant difference in coral mortality was observed among atolls with different levels of human pressure. Maldivian reefs needed 16 years to recover to the pre-bleaching hard coral cover values. The 2016 heat wave affected all reefs investigated, but reefs in atolls with higher human pressure showed greater coral mortality than reefs in atolls with lower human pressure. Additionally, exposed (ocean) reefs showed lower coral mortality than those in sheltered (lagoon) reefs. The reduced coral mortality in 2016 as compared to 1998 may provide some support to the Adaptive Bleaching Hypothesis (ABH) in shallow Maldivian reefs, but intensity and duration of the two heat waves were different. Analysis of coral cover data collected along depth profiles on the ocean sides of atolls, from 10 to 50 m, allowed the comparison of coral mortality at different depths to discuss the Deep Refuge Hypothesis (DRH). In the upper mesophotic zone (i.e., between 30 and 50 m), coral mortality after bleaching was negligible. However, live coral cover did not exceed 15%, a value lower than coral survival in shallow reefs. Low cover values of corals surviving in the mesophotic reefs suggest that their role as refuge or seed banks for the future recovery of some species in shallow-water reefs of the Maldives may be small. The repeatedly high coral mortality after bleaching events and the long recovery period, especially in sites with human pressure, suggest that the foreseen increased frequency of bleaching events would jeopardize the future of Maldivian reefs, and ask for reducing local pressures to improve their resilience.

* Construction of Asset Wealth Index for Tanzanian Small-Scale Fisheries based on a Multiple Correspondence Approach. * Less wealthy fishers target fewer species and are less able to absorb changes in management measures such as closures. * Wealthier fishers with high adaptive capacity are able to better absorb the short-term losses of fisheries closures.

Genetic diversity can influence resilience and adaptative capacity of organisms to environmental change. Genetic diversity within populations is largely structured by reproduction, with the prevalence of asexual versus sexual reproduction often underpinning important diversity metrics that determine selection efficacy. Asexual or clonal reproduction is expected to reduce genotypic diversity and slow down adaptation through reduced selection efficacy, yet the evolutionary consequences of clonal reproduction remain unclear for many natural populations. Here, we examine the genomic consequences of sympatric sexual (haplodiplontic) and clonal morphs of the kelp Ecklonia radiata that occur interspersed on reefs in Hamelin Bay, Western Australia. Using genome-wide single nucleotide polymorphisms, we confirm significant asexual reproduction for the clonal populations, indicated by a significantly lower number of multi-locus lineages and higher intra-individual diversity patterns (individual multi-locus heterozygosity, MLH). Nevertheless, co-ancestry analysis and breeding experiments confirmed that sexual reproduction by the clonal morph and interbreeding between the two morphs is still possible, but varies among populations. One clonal population with long-term asexuality showed trends of decreased selection efficacy (increased ratio non- vs. synonymous gene diversities). Yet, all clonal populations showed distinct patterns of putative local adaptation relative to the sexual morph, possibly indicating maladaptation to local environmental conditions and high vulnerability of this unique clonal morph to environmental stress.

Deep reefs below 30 m provide essential ecosystem services for ocean health and human well-being such as food security and climate change resilience. Yet, deep reefs remain poorly researched and largely unprotected, including in the Western Indian Ocean (WIO). Here, we assessed current conservation approaches in the WIO focusing on deep reefs, using a combination of online surveys and semi-structured interviews. Results indicated that deep-reef data are sparse and commonly stemming from non-peer-reviewed or non-publicly available sources, and are often not used to inform conservation of WIO marine protected areas. Based on those findings, we co-developed a framework with WIO stakeholders comprising recommendations linked to specific actions to be undertaken by regional actors to improve the capacity of the region to collect and share deep-reef information. We hope this framework will enhance deep-reef stewardship and management throughout the WIO and thus aid sustainable blue economic growth in the region.