Ongoing and Upcoming Cold-Water Coral Multi Stressor Experiments

Comunicación escrita (póster) a Congresos• Cold-water corals (CWC) form complex 3-D structures that are biodiversity hotspots. However, the knowledge about their ecophysiological response to global change stressors (i.e. warming, acidification, decrease of dissolved oxygen concentration) is still very limited, as well as their possible interactions with local stressors such as the impacts from mining and fishing activities. • Three long-term, multi stressor experiments will explore the combined impact of several environmental and local stressors based on the IPCC projections on different CWC species across the North Atlantic. • Further experiments will include the addition of particles from mining or sediment from trawling activities to all treatments after long-term experiments finish to study the potential physical damage and ecotoxicological effects. • The results from these studies will increase our knowledge on the potential consequences of global change and local stressors and their possible interactions on CWC species and ecosystems that they form. • The results will contribute to support science-based marine spatial planning for the North Atlantic.European Union Commission Horizon 2020 Programa (grant agreement 818123), FEDER ((ACORES-01-0145-FEDER-000140), Ayuntamiento de A Coruña (Spain) and Deep-Sea Biology Societ

Embryo and larval biology of the deepsea octocoral Dentomuricea aff. meteor under different temperature regimes

Deep-sea octocorals are common habitat-formers in deep-sea ecosystems, however, our knowledge on their early life history stages is extremely limited. The present study focuses on the early life history of the species Dentomuricea aff. meteor, a common deep-sea octocoral in the Azores. The objective was to describe the embryo and larval biology of the target species under two temperature regimes, corresponding to the minimum and maximum temperatures in its natural environment during the spawning season. At temperature of 13 ±0.5 °C, embryos of the species reached the planula stage after 96h and displayed a median survival of 11 days. Planulae displayed swimming only after stimulation, swimming speed was 0.24 ±0.16 mm s−1 and increased slightly but significantly with time. Under a higher temperature (15 °C ±0.5 °C) embryos reached the planula stage 24 h earlier (after 72 h), displayed a median survival of 16 days and had significantly higher swimming speed (0.3 ±0.27 mm s−1). Although the differences in survival were not statistically significant, our results highlight how small changes in temperature can affect embryo and larval characteristics with potential cascading effects in larval dispersal and success. In both temperatures, settlement rates were low and metamorphosis occurred even without settlement. Such information is rarely available for deep-sea corals, although essential to achieve a better understanding of dispersal, connectivity and biogeographical patterns of benthic species.S

Peeping through the deep: Insights to the reproductive strategies of cold water gorgonians in the Azores Archipelago

<p>Cold-water coral (CWC) habitats in the Azores Archipelago are formed mainly by octocoral species which form dense aggregations known as coral gardens, occurring over a bathymetric range of approximately 200 and 2200 m of depth. Due to their relevant role as habitat-forming species for a variety of marine organisms and high vulnerability to anthropogenic activities, coral gardens are considered in many cases as Vulnerable Marine Ecosystems (VMEs). The effective conservation and management of these CWC species and the ecosystems they form requires in-depth knowledge about their ecology, population biology, and connectivity, including their reproductive strategies and life history traits. Current knowledge on reproduction of CWCs is fairly scarce and limited to some species. The objective of this study is to gather information on the reproductive biology and ecology of some important habitat forming octocorals in the Azores, including <em>Viminella flagellum</em>, <em>Dentomuricea aff. meteor</em>, <em>Acanella arbuscula</em> and <em>Acanthogorgia armata</em>. By using a variety of methods, such as the collection of specimens through by-catch from deep long-line fisheries and scientific cruises, histological processing and opportunistic observations of specimens kept in aquaria, we attempt a first insight to their sexual reproduction, including sexuality, reproductive mode and reproductive seasonality, as well as to strategies of asexual reproduction such as fragmentation and polyp bail-out.</p

Feeding biology of a habitat-forming antipatharian in the Azores Archipelago

Benthic suspension feeders have developed a variety of feeding strategies and food availability has often proven to be a key factor explaining their occurrence and distribution. The feeding biology of coral species has been the target of an increasing number of studies, however most of them focus on Scleractinia and Octocorallia, while information for Antipatharia is very scarce. The present study focused on Antipathella wollastoni, a common habitat-forming antipatharian in the Azores Archipelago, forming dense black coral forests between 20 and 150 m. The objective of the study was to investigate the food preferences of the target species upon availability of different isotopically enriched food substrates and determine its ability to capture zooplankton prey under different flow speeds. The species was able to utilize different food sources including live phytoplankton, live zooplankton and dissolved organic matter (DOM), indicating the ability to exploit seasonally available food sources. However, ingestion of zooplankton enhanced carbon (C) and nitrogen (N) incorporation in coral tissue and metabolic activity, highlighting the importance of zooplankton prey for vital physiological processes such as growth and reproduction. Maximum zooplankton capture rates occurred under 4 cm−1, however the species displayed high capacity to capture zooplankton prey over different flow rates highlighting the ability of A. wollastoni to exploit high quantities of shortly available prey

Feeding biology of a habitat-forming antipatharian in the Azores Archipelago

Benthic suspension feeders have developed a variety of feeding strategies and food availability has often proven to be a key factor explaining their occurrence and distribution. The feeding biology of coral species has been the target of an increasing number of studies, however most of them focus on Scleractinia and Octocorallia, while information for Antipatharia is very scarce. The present study focused on Antipathella wollastoni, a common habitat-forming antipatharian in the Azores Archipelago, forming dense black coral forests between 20 and 150 m. The objective of the study was to investigate the food preferences of the target species upon availability of different isotopically enriched food substrates and determine its ability to capture zooplankton prey under different flow speeds. The species was able to utilize different food sources including live phytoplankton, live zooplankton and dissolved organic matter (DOM), indicating the ability to exploit seasonally available food sources. However, ingestion of zooplankton enhanced carbon (C) and nitrogen (N) incorporation in coral tissue and metabolic activity, highlighting the importance of zooplankton prey for vital physiological processes such as growth and reproduction. Maximum zooplankton capture rates occurred under 4 cm−1, however the species displayed high capacity to capture zooplankton prey over different flow rates highlighting the ability of A. wollastoni to exploit high quantities of shortly available prey

First description of polyp bailout in cold-water octocorals

Cnidarians, characterized by high levels of plasticity, exhibit remarkable mechanisms to withstand or escape unfavourable conditions including reverse development which describes processes of transformation of adult stages into early developmental stages with higher mobility. Polyp bailout is a stress-escape response common among scleractinian species, consisting of massive detachment of live polyps and subsequent death of the mother colony. Here, we describe two cases of polyp bailout in the cold-water octocoral species Acanthogorgia armata and Acanella arbuscula. During maintenance in aquaria, specimens of both species presented coenosarc withdrawal and loss of sclerites, followed by detachment of intact polyps. This is a strong indication of reverse development which can be a very important strategy under stress conditions and has not been reported before in cold-water octocorals

Ecophysiology of Lophelia pertusa and Madrepora oculata from Formigas seamount (Azores): the influence of different water masses

Water masses have been identified as potential important drivers of cold-water corals (CWC) distribution. It has been hypothesized that Mediterranean Outflow Water (MOW) driven the CWC colonization of North-East Atlantic after the last glacial period, promoting transport of coral larvae and fenerating suitable environmental conditions enhancing croal growth. Several seamounts inhabited by the CWC Lophelia pertusa and Madrepora oculata are directly influenced by the MOW along its way west to Azores Islands. To advance in the exploration of the possible influence of MOW on the past and current distribution of Atlantic CWC, this study experimentally assessed the respiration rates of L. pertusa and M. oculata, under the influence of Mediterranean and Atlantic waters