Nekton

BackgroundDuring the 2022 Nekton Maldives Mission, we deployed a variety of platforms (snorkelling, remotely-operated vehicles and manned submersibles) to conduct video surveys of the biodiversity and composition of shallow (< 30 m), mesophotic (30-150 m) and deep-sea (> 150 m) benthos found in the Maldives’ central and southern atolls. In total, ~ 80 hrs of stereo-video footage were collected during the benthic transect surveys, which were subsequently processed using annotation software in order to evaluate benthic biodiversity and community composition. Here, we present a photographic guide for the visual, in situ identification of reef benthos encountered, including corals, sponges and other invertebrates that inhabit Maldives’ nearshore habitats. We hope that this identification guide will aid future imagery-based surveys or observations of organisms during fieldwork.New informationA total of 283 morphotypes were identified, including those belonging to Octocorallia (61), Scleractinia (57), Porifera (38), Asteroidea (22), Antipatharia (15), Decapoda (13), Hydrozoa (12), Holothuroidea (10), Actiniaria (9), Echinoidea (8), Annelida (6), Chlorophyta (5), Gastropoda (4), Bivalvia (4), Ascidiacea (3), Crinoidea (3), Bryozoa (2), Cyanobacteria (2), Zoantharia (2), Cephalopoda (1), Ceriantharia (1), Corallimorpharia (1), Ctenophora (1), Ophiuroidea (1), Rhodophyta (1) and to an unknown category (1). Out of these, we identified 40 to species level, 120 to genus, 47 to family, 14 to order and suborder, 58 to class and subclass, two to phylum and one was of unknown phylum. This represents the first attempt to catalogue the mesophotic and deep-sea benthic megafaunal diversity in the Maldives using underwater imagery.

Abstract Of all the interconnected threats facing the planet, the top two are the climate and the biodiversity crises. Neither problem will be solved if we ignore the ocean. To turn the tide in favour of humanity and a habitable planet, we need to recognize and better value the fundamental role that the ocean plays in the earth system, and prioritize the urgent action needed to heal and protect the ocean at the ‘Earthscape’ level – the planetary scale at which processes to support life operate. The countries gathering at COP26 have unparalleled political capacity and leadership to make this happen. COP26 could be the turning point, but there must be commitment to united action for the ocean, as well as planning to meet those commitments, based on science‐led solutions that address the interconnectivity of the ocean, climate, and biodiversity. Key ways in which the ocean both contributes to and acts as the major buffer for climate change are summarized, focusing on temperature, but not forgetting the role of storing carbon. It is noted with ‘high confidence’ that the ocean has stored 91% of the excess heat from global warming, with land, melting ice, and the atmosphere only taking up approximately 5, 3, and 1%, respectively. We also highlight the impact of the recent large release of heat from the ocean to the atmosphere during the 2015–2016 El Niño. We then present six science‐based policy actions that form a recovery stimulus package for people, climate, nature, and the planet. Our proposals highlight what is needed to view, value, and treat the planet, including the ocean, for the benefit and future of all life.

Public health and safety concerns around the SARS-CoV-2 novel coronavirus and the COVID-19 pandemic have greatly changed human behaviour. Such shifts in behaviours, including travel patterns, consumerism, and energy use, are variously impacting biodiversity during the human-dominated geological epoch known as the Anthropocene. Indeed, the dramatic reduction in human mobility and activity has been termed the “Anthropause”. COVID-19 has highlighted the current environmental and biodiversity crisis and has provided an opportunity to redefine our relationship with nature. Here we share 10 considerations for conservation policy makers to support and rethink the development of impactful and effective policies in light of the COVID-19 pandemic. There are opportunities to leverage societal changes as a result of COVID-19, focus on the need for collaboration and engagement, and address lessons learned through the development of policies (including those related to public health) during the pandemic. The pandemic has had devastating impacts on humanity that should not be understated, but it is also a warning that we need to redefine our relationship with nature and restore biodiversity. The considerations presented here will support the development of robust, evidence-based, and transformative policies for biodiversity conservation in a post-COVID-19 world.

We present here our experiences with using the spectral element methodology to solve convection-dominated problems. Different polynomial approximations are used inside the spectral elements and both conforming and non-conforming interface conditions are investigated. The three spectral element methods that we explore can all be considered to be special cases of the more general mortar element method. We compare the methods for solving incompressible fluid flow and heat transfer problems. Particular attention is given to the convection treatment. The numerical results can be strongly dependent upon whether a conforming or a non-conforming method is used as well as the particular form of the discrete convection operator (convective form versus skew-symmetric form).