Characterization of deep-sea benthic invertebrate megafauna of the Galapagos Islands

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Salinas-de-León, P., Martí-Puig, P., Buglass, S., Arnés-Urgellés, C., Rastoin-Laplane, E., Creemers, M., Cairns, S., Fisher, C., O'Hara, T., Ott, B., Raineault, N. A., Reiswig, H., Rouse, G., Rowley, S., Shank, T. M., Suarez, J., Watling, L., Wicksten, M. K., & Marsh, L. Characterization of deep-sea benthic invertebrate megafauna of the Galapagos Islands. Scientific Reports, 10(1), (2020): 13894, doi:10.1038/s41598-020-70744-1.The deep sea represents the largest and least explored biome on the planet. Despite the iconic status of the Galapagos Islands and being considered one of the most pristine locations on earth, the deep-sea benthic ecosystems of the archipelago are virtually unexplored in comparison to their shallow-water counterparts. In 2015, we embarked on a multi-disciplinary scientific expedition to conduct the first systematic characterization of deep-sea benthic invertebrate communities of the Galapagos, across a range of habitats. We explored seven sites to depths of over 3,300 m using a two-part Remotely Operated Vehicle (ROV) system aboard the E/V Nautilus, and collected 90 biological specimens that were preserved and sent to experts around the world for analysis. Of those, 30 taxa were determined to be undescribed and new to science, including members of five new genera (2 sponges and 3 cnidarians). We also systematically analysed image frame grabs from over 85 h of ROV footage to investigate patterns of species diversity and document the presence of a range of underwater communities between depths of 290 and 3,373 m, including cold-water coral communities, extensive glass sponge and octocoral gardens, and soft-sediment faunal communities. This characterization of Galapagos deep-sea benthic invertebrate megafauna across a range of ecosystems represents a first step to study future changes that may result from anthropogenic impacts to the planet’s climate and oceans, and informed the creation of fully protected deep-water areas in the Galapagos Marine Reserve that may help preserve these unique communities in our changing planet.We are thankful to the Ocean Exploration Trust as well as the pilots and crew aboard the E/V Nautilus during cruise NA064 for their assistance in sample collection and exploration using the Hercules ROV. Thank you to the NOAA Office of Exploration and Research for funding the E/V Nautilus Exploration Program (NA15OAR0110220). Further acknowledgements and thanks go out to the Charles Darwin Foundation and the Galapagos National Park Directorate for their collaboration and assistance in the exploration of the Galapagos Platform conducted under research permits PC-26–15 & PC-45-15. We also gratefully recognize the Government of Ecuador via the Ecuadorian Navy for permission to operate in their territorial waters. This research was supported by a grant from the Helmsley Charitable Trust and the Gordon and Betty Moore Foundation. This publication is contribution number 2354 of the Charles Darwin Foundation for the Galapagos Islands

A study on the recovery of Tobago's coral reefs following the 2010 mass bleaching event

The rise of ocean temperatures globally has become a grave threat to coral reefs, as it is increasing the severity and frequency of mass coral bleaching events and post-bleaching coral mortality. The continued existence of productive coral reefs will rely on corals’ ability to undergo recovery. In 2010, Tobago’s coral reefs were exposed to severe heat stress leading to mass bleaching of up to 29-60% of colonies at observed sites. This study evaluated the impact of coral bleaching and recovery of coral communities across three major reef systems in Tobago that differ in their exposure to terrestrial runoff. Assessments were done on the 1) density and composition of coral juveniles to characterise the levels of recruitment, 2) sedimentation rates and composition to understand its potential impact on recovery, and 3) species’ size frequency distributions in 2010, 2011 and 2013 to examine temporal changes among population size structure. In 2013, low juvenile densities were observed (5.41 ± 6.31 m-²) at most reef sites, which were dominated by brooding genera while broadcasting genera were rare. Sediment material, measured in May and June (end of Tobago’s dry season) was mostly terrigenous and deposited at rates below coral stress threshold levels at most sites. Out of 27 species populations assessed between all sites, 4 populations mean colony size had significantly changed by the bleaching event, and only changed 5 populations over the two following years. The few populations that were significantly altered (mainly S. siderea and M. faveolata) after the bleaching saw a rise in small sized colonies, mostl likely as a result of colony fragmentation. This study highlights that recovery via sexually produced recruits among broadcasting species was limited. While sedimentation rates were low, it is likely they are significantly higher throughout the rainy season, thus a long-term sedimentation study is highly recommended. Most coral populations resisted significant alteration from heat stress in 2010. However, given that future thermal stress is projected to become more intense, this study shows that mass bleaching disturbance could lead to decline coral population’s mean colony size, which could affect coral recovery as smaller colonies are less fecund.Arts, Faculty ofGeography, Department ofGraduat

Arthropoda; Crustacea; Decapoda of deep-sea volcanic habitats of the Galapagos Marine Reserve, Tropical Eastern Pacific

The deep-sea biome (> 200 m depth) is the world's last great wilderness, covering more than 65% of the earth's surface. Due to rapid technological advances, deep-sea environments are becoming more accessible to scientific research and ocean exploration around the world and, in recent years, this is also true for the Galapagos Islands. Deep-sea habitats cover the largest proportion of Galapagos Marine Reserve (GMR), yet to date, no comprehensive baseline exists on the biodiversity of the benthic fauna associated with volcanic seafloor formations within this region. Closing this knowledge gap is essential to provide information for decision-making for the management of marine resources within the GMR and assessing any potential changes in biodiversity resulting from climate-driven alterations that deep-sea environments are expected to experience. In 2015, the Charles Darwin Foundation's Seamounts of the GMR Research Project, together with the Galapagos National Park Directorate (GNPD) and Ocean Exploration Trust (OET), conducted a joint expedition on board the EV Nautilus. Using Remotely operated vehicles (ROVs), the aim of the expedition was to characterise the geological formations and biological communities present on seamounts, lava flows and other deep-sea habitats (> 200 m) within the GMR.We provide the first comprehensive image inventory for the phylum Arthropoda from 260 to 3400 m of depth within the GMR. Past studies on deep-sea macroinvertebrates in the GMR have been limited to voucher samples collected from dredging (restricted to soft bottom environments) or by submersibles (only allowing limited biological sampling). The image inventory, presented here, is based on high-definition video transects conducted by the Hercules ROV on board the EV Nautilus. Images of macroinvertebrate morphospecies were captured, catalogued and identified, thus providing the first known image inventory of in-situ macroinvertebrate species from the deep-sea region of the GMR.We present 32 distinct morphospecies occurrences within the class Malacostraca and order Decapoda. We also report 17 different families, three species that are new records to the GMR, in-situ images of two new species to science recently described and one possible new squat lobster, as well as interesting behavioural observations

Evolution of the Galapagos in the anthropocene

The Galapagos Islands inspired the theory of evolution by means of natural selection; now in the Anthropocene, the Galapagos represent an important natural laboratory to understand ecosystem resilience in the face of climate extremes and enable effective socio-ecological co-evolution under climate change