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Antarctica, benthic communities, disturbance, GIS, landscape ecology, succession, underwater photography. - In this study, I introduce the use of methods borrowed from landscape ecology to analyse quantitatively spatial patterns in Antarctic mega-epibenthic communities. This discipline focuses on the notion that communities can be observed as a patch mosaic at any scale. From this perspective I investigated spatial patterns based on landscape indices in an undisturbed benthic assemblage across different stations; and through successional stages after iceberg disturbance. The present study i) characterizes coverage and abundance of sessile benthic fauna, ii) describes faunal heterogeneity using ordination techniques and identifies "structural species" from each successional stage, iii) analyses changes of ...

Disease, storms, ocean warming, and pollution have caused the mass mortality of reef-building corals across the Caribbean over the last four decades. Subsequently, stony corals have been replaced by macroalgae, bacterial mats, and invertebrates including soft corals and sponges, causing changes to the functioning of Caribbean reef ecosystems. Here we describe changes in the absolute cover of benthic reef taxa, including corals, gorgonians, sponges, and algae, at 15 fore-reef sites (12–15m depth) across the Belizean Barrier Reef (BBR) from 1997 to 2016. We also tested whether Marine Protected Areas (MPAs), in which fishing was prohibited but likely still occurred, mitigated these changes. Additionally, we determined whether ocean-temperature anomalies (measured via satellite) or local human impacts (estimated using the Human Influence Index, HII) were related to changes in benthic community structure. We observed a reduction in the cover of reef-building corals, including the long-lived, massive corals Orbicella spp. (from 13 to 2%), and an increase in fleshy and corticated macroalgae across most sites. These and other changes to the benthic communities were unaffected by local protection. The covers of hard-coral taxa, including Acropora spp., Montastraea cavernosa, Orbicella spp., and Porites spp., were negatively related to the frequency of ocean-temperature anomalies. Only gorgonian cover was related, negatively, to our metric of the magnitude of local impacts (HII). Our results suggest that benthic communities along the BBR have experienced disturbances that are beyond the capacity of the current management structure to mitigate. We recommend that managers devote greater resources and capacity to enforcing and expanding existing marine protected areas and to mitigating local stressors, and most importantly, that government, industry, and the public act immediately to reduce global carbon emissions.

8 páginas, 5 figuras, 3 tablas ; The structural parameters of sponge-dominated benthic communities from two Mediterranean caves in two seasons, autumn (November) and spring (June) were compared. The percentage of species in common between communities in each cave was calculated as a rough estimate of the capacity of species dispersion in each cave. The Shannon diversity index and Kulczynski similarity index were calculated for each community. Moreover, we studied the spatial distribution, patchiness and interspecies contacts of the most abundant species. The value of a-diversity was quite constant among communities of the Cabrera cave but decreased from the external to the innermost community in the Medes cave. The Kulczynski similarity index was generally lower among samples of the Cabrera cave. The most abundant sponge species showed a predominantly clumped distribution, especially in the most internal communities of the two caves. The innermost community of the Medes cave had the highest number of patches. Finally, the study of contacts among species that were non-random (meaning species that were in contact with a given species signicantly more or less frequently than expected) showed that they were very common in the two seasons and in all communities, indicating the importance of biotic associations among benthic species in cave assemblages. ; This research was supported by a postgraduate fellowship from the Catalan Government and a post-doctoral fellowship from the Spanish Government to R.M., and by the project REN2001-2312 of the Spanish Government, the bilateral project CSIC/ CNR2001-2002, and by the INTERREG IIIA-1-72-E project of the European Union. ; Peer reviewed

This work was developed within the BLUEBIO (CTM 2016-78901-R), POSVOLDEC (CTM 2016-79617-P) (AEI/FEDER-UE), CRONOANTAR (CTM 2016-77878-P), and VOLCLIMA (CGL 2015-72629-EXP/AEI) projects funded by the Spanish Government, altogether with IHM (Navy Hydrographic Spanish Institute), and IEO (Spanish Oceano-graphic Institute) support. C. A-P has been funded by the fundacion Ramon Areces. A.G. is grateful for her Ramon y Cajal contract (RYC-2012-11024). A-V, A.G. and G.K. also thank the assistance of the VOL-GASDEC project (PGC 2018-095693-B-I00) (AEI/FEDER-UE).

ABSTRACT. Thriving benthic communities were observed in the oxygen minimum zones along the southwestern African margin. On the Namibian margin, fossil cold-water coral mounds were overgrown by sponges and bryozoans, while the Angolan margin was characterized by cold-water coral mounds covered by a living coral reef. To explore why benthic communities differ in both areas, present-day environmental conditions were assessed, using conductivity–temperature–depth (CTD) transects and bottom landers to investigate spatial and temporal variations of environmental properties. Near-bottom measurements recorded low dissolved oxygen concentrations on the Namibian margin of 0–0.15 mL L−1 (≜0 %–9 % saturation) and on the Angolan margin of 0.5–1.5 mL L−1 (≜7 %–18 % saturation), which were associated with relatively high temperatures (11.8–13.2 ∘C and 6.4–12.6 ∘C, respectively). Semidiurnal barotropic tides were found to interact with the margin topography producing internal waves. These tidal movements deliver water with more suitable characteristics to the benthic communities from below and above the zone of low oxygen. Concurrently, the delivery of a high quantity and quality of organic matter was observed, being an important food source for the benthic fauna. On the Namibian margin, organic matter originated directly from the surface productive zone, whereas on the Angolan margin the geochemical signature of organic matter suggested an additional mechanism of food supply. A nepheloid layer observed above the cold-water corals may constitute a reservoir of organic matter, facilitating a constant supply of food particles by tidal mixing. Our data suggest that the benthic fauna on the Namibian margin, as well as the cold-water coral communities on the Angolan margin, may compensate for unfavorable conditions of low oxygen levels and high temperatures with enhanced availability of food, while anoxic conditions on the Namibian margin are at present a limiting factor for cold-water coral growth. This study provides an example of ...

In a world of declining biodiversity, monitoring is becoming crucial. Molecular methods, such as metabarcoding, have the potential to rapidly expand our knowledge of biodiversity, supporting assessment, management, and conservation. In the marine environment, where hard substrata are more difficult to access than soft bottoms for quantitative ecological studies, Artificial Substrate Units (ASUs) allow for standardized sampling. We deployed ASUs within five regional seas (Baltic Sea, Northeast Atlantic Ocean, Mediterranean Sea, Black Sea, and Red Sea) for 12–26 months to measure the diversity and community composition of macroinvertebrates. We identified invertebrates using a traditional approach based on morphological characters, and by metabarcoding of the mitochondrial cytochrome oxidase I (COI) gene. We compared community composition and diversity metrics obtained using the two methods. Diversity was significantly correlated between data types. Metabarcoding of ASUs allowed for robust comparisons of community composition and diversity, but not all groups were successfully sequenced. All locations were significantly different in taxonomic composition as measured with both kinds of data. We recovered previously known regional biogeographical patterns in both datasets (e.g., low species diversity in the Black and Baltic Seas, affinity between the Bay of Biscay and the Mediterranean). We conclude that the two approaches provide complementary information and that metabarcoding shows great promise for marine monitoring. However, until its pitfalls are addressed, the use of metabarcoding in monitoring of rocky benthic assemblages should be used in addition to classical approaches rather than instead of them. ; This manuscript is a result of the DEVOTES (DEVelopment Of innovative Tools for understanding marine biodiversity and assessing good Environmental Status) project, funded by the European Union under the 7th Framework Programme, "The Ocean of Tomorrow" Theme (grant agreement no. 308392), www.devotes-project.eu. S Carvalho and JK Pearman were funded through the Saudi Aramco—KAUST Center for Marine Environmental Observations (SAKMEO). MC Uyarra was partially funded through the Spanish programme for Talent and Employability in R+D+I "Torres Quevedo." Funding for publication was provided to AEC by Albion College. We thank the ICM-Brain and Spine Institute in Paris, France (especially Y Marie and D Bouteiller) for sequencing, U Langner for Figure 1, and everyone who helped with the deployment and recovery of the ASUs and initial laboratory processing. We thank the editor and reviewers for their revisions, which improved earlier versions of the manuscript.