A genomic view of the reef-building coral Porites lutea and its microbial symbionts

Corals and the reef ecosystems that they support are in global decline due to increasing anthropogenic pressures such as climate change1. However, effective reef conservation strategies are hampered by a limited mechanistic understanding of coral biology and the functional roles of the diverse microbial communities that underpin coral health2,3. Here, we present an integrated genomic characterization of the coral species Porites lutea and its microbial partners. High-quality genomes were recovered from P. lutea, as well as a metagenome-assembled Cladocopium C15 (the dinoflagellate symbiont) and 52 bacterial and archaeal populations. Comparative genomic analysis revealed that many of the bacterial and archaeal genomes encode motifs that may be involved in maintaining association with the coral host and in supplying fixed carbon, B-vitamins and amino acids to their eukaryotic partners. Furthermore, mechanisms for ammonia, urea, nitrate, dimethylsulfoniopropionate and taurine transformation were identified that interlink members of the holobiont and may be important for nutrient acquisition and retention in oligotrophic waters. Our findings demonstrate the critical and diverse roles that microorganisms play within the coral holobiont and underscore the need to consider all of the components of the holobiont if we are to effectively inform reef conservation strategies.</p

Social and political barriers to the use of Marine Protected Areas for conservation and fishery management in Melanesia

In this paper we examine the strengths and weaknesses of state-supported Customary Marine Tenure (CMT) systems in two independent Melanesian states (Solomon Islands and Papua New Guinea) in the context of the management of rapidly intensifying commercial and subsistence fisheries. We focus particularly on the proposed use of permanent no-take Marine Protected Areas (MPAs), which are at present strongly favoured by scientists and environmentalists around the world, as the most versatile marine fishery management tool, especially in poor developing countries. We argue that, with some exceptions, typical Melanesian CMT regimes make MPAs difficult to establish, primarily due to issues of scale. We look closely at the ecological rationale for no-take MPAs, for different coral-reef based species, and assess the likelihood that populations of these species are self-replacing on the same scale as CMT territories for most of coastal PNG and Solomon Islands. We argue that with some exceptions (mainly species with short-lived larvae), the dynamics and scale of population replacement processes for most fished species make no-take permanent closures largely incompatible with traditional CMT systems, and therefore unlikely to prove a successful management tool in this socio-political context