Nuevos registros de crinoideos (Echinodermata: crinoidea) en el talud continental de chile

Indexación: Scopus.The presence of Solanometra antarctica has been reported in the continental slope of central Chile, however, some studies suggest that this species could have been confused with Florometra magellanica. In this study, 11 crinoid specimens obtained in the continental slope of Central Chile were analyzed and compared with other specimens previously collected in that same region and catalogued as Florometra magellanica. The morphological and meristic characteristics confirm that the crinoids collected in Central Chile, off Concepción and Los Vilos, correspond to Florometra magellanica.https://revistas.uv.cl/index.php/rbmo/article/view/239

Man and the Last Great Wilderness: Human Impact on the Deep Sea

The deep sea, the largest ecosystem on Earth and one of the least studied, harbours high biodiversity and provides a wealth of resources. Although humans have used the oceans for millennia, technological developments now allow exploitation of fisheries resources, hydrocarbons and minerals below 2000 m depth. The remoteness of the deep seafloor has promoted the disposal of residues and litter. Ocean acidification and climate change now bring a new dimension of global effects. Thus the challenges facing the deep sea are large and accelerating, providing a new imperative for the science community, industry and national and international organizations to work together to develop successful exploitation management and conservation of the deep-sea ecosystem. This paper provides scientific expert judgement and a semi-quantitative analysis of past, present and future impacts of human-related activities on global deep-sea habitats within three categories: disposal, exploitation and climate change. The analysis is the result of a Census of Marine Life – SYNDEEP workshop (September 2008). A detailed review of known impacts and their effects is provided. The analysis shows how, in recent decades, the most significant anthropogenic activities that affect the deep sea have evolved from mainly disposal (past) to exploitation (present). We predict that from now and into the future, increases in atmospheric CO2 and facets and consequences of climate change will have the most impact on deep-sea habitats and their fauna. Synergies between different anthropogenic pressures and associated effects are discussed, indicating that most synergies are related to increased atmospheric CO2 and climate change effects. We identify deep-sea ecosystems we believe are at higher risk from human impacts in the near future: benthic communities on sedimentary upper slopes, cold-water corals, canyon benthic communities and seamount pelagic and benthic communities. We finalise this review with a short discussion on protection and management methods

A blueprint for an inclusive, global deep-sea Ocean Decade field programme

The ocean plays a crucial role in the functioning of the Earth System and in the provision of vital goods and services. The United Nations (UN) declared 2021–2030 as the UN Decade of Ocean Science for Sustainable Development. The Roadmap for the Ocean Decade aims to achieve six critical societal outcomes (SOs) by 2030, through the pursuit of four objectives (Os). It specifically recognizes the scarcity of biological data for deep-sea biomes, and challenges the global scientific community to conduct research to advance understanding of deep-sea ecosystems to inform sustainable management. In this paper, we map four key scientific questions identified by the academic community to the Ocean Decade SOs: (i) What is the diversity of life in the deep ocean? (ii) How are populations and habitats connected? (iii) What is the role of living organisms in ecosystem function and service provision? and (iv) How do species, communities, and ecosystems respond to disturbance? We then consider the design of a global-scale program to address these questions by reviewing key drivers of ecological pattern and process. We recommend using the following criteria to stratify a global survey design: biogeographic region, depth, horizontal distance, substrate type, high and low climate hazard, fished/unfished, near/far from sources of pollution, licensed/protected from industry activities. We consider both spatial and temporal surveys, and emphasize new biological data collection that prioritizes southern and polar latitudes, deeper (> 2000 m) depths, and midwater environments. We provide guidance on observational, experimental, and monitoring needs for different benthic and pelagic ecosystems. We then review recent efforts to standardize biological data and specimen collection and archiving, making “sampling design to knowledge application” recommendations in the context of a new global program. We also review and comment on needs, and recommend actions, to develop capacity in deep-sea research; and the role of inclusivity - from accessing indigenous and local knowledge to the sharing of technologies - as part of such a global program. We discuss the concept of a new global deep-sea biological research program ‘Challenger 150,’ highlighting what it could deliver for the Ocean Decade and UN Sustainable Development Goal 14

Diversity patterns along and across the Chilean margin: A continental slope encompassing oxygen gradients and methane seep benthic habitats

14 páginas, 4 tablas,5 figuras.In the present study we review datasets available for the Chilean margin to assess the relationship between environmental (or habitat) heterogeneity and benthic diversity. Several factors, such as the presence of different water masses, including the oxygen-deficient Equatorial Sub-surface Waters (ESSW) at the continental shelf and upper slope, and the Antarctic Intermediate Waters (AIW) at mid slope depths appear to control the bathymetric distribution of benthic communities. The presence of methane seeps and an extended oxygen minimum zone (OMZ) add complexity to the benthic distribution patterns observed. All these factors generate environmental heterogeneity, which is predicted to affect the diversity patterns both along and across the Chilean continental margin. The response to these factors differs among different faunal size groups: meio-, macro-, and megafauna. Physiological adaptations to oxygen deficiency and constraints related to body size of each group seem to explain the larger-scale patterns observed, while sediment⁄ habitat heterogeneity (e.g. at water mass boundaries, hardgrounds, biogeochemical patchiness, sediment organic content, grain size) may influence the local fauna diversity patterns.The expedition was funded by the German BMBF (grant No. 03G0156A). We also thank the captain and crew of the Chilean Navy’s R⁄V Vidal Gorma´z for support at sea during the SeepOx cruise, funded by FONDECYT project #1061217 to J.S.Peer reviewe

Meiofaunal distributions on the Peru margin: relationship to oxygen and organic matter availability.

A quantitative study of metazoan meiofauna was carried out on bathyal sediments (305, 562, 830 and 1210m) along a transect within and beneath the oxygen minimum zone (OMZ) in the southeastern Pacific off Callao, Peru (128S). Meiobenthos densities ranged from 1517 (upper slope, middle of OMZ) to 440– 548 ind. 10 cm2 (lower slope stations, beneath the OMZ). Nematodes were the numerically dominant meiofaunal taxon at every station, followed by copepods and nauplii. Increasing bottom-water oxygen concentration and decreasing organic matter availability downslope were correlated with observed changes in meiofaunal abundance. The 300-m site, located in the middle of the OMZ, differed significantly in meiofaunal abundance, dominance, and in vertical distribution pattern from the deeper sites. At 305m, nematodes amounted to over 99 % of total meiofauna; about 70 % of nematodes were found in the 2–5 cm interval. At the deeper sites, about 50 % were restricted to the top 1 cm. The importance of copepods and nauplii increased consistently with depth, reaching 12 % of the total meiofauna at the deepest site. The observation of high nematode abundances at oxygen concentrations 50.02ml l1 supports the hypothesis that densities are enhanced by an indirect positive effect of low oxygen involving (a) reduction of predators and competitors and (b) preservation of organic matter leading to high food availability and quality. Foo

Meiofauna and sedimentary organic matter off Central Chile: response to changes caused by the 1997-1998 El Nino

Quantitative surveys of metazoan meiofauna were carried out in an upwelling region off Central Chile (36 degreesS). During May 1997 and May 1998, coinciding with the onset and end of Fl Nino, five benthic stations (respectively 27, 34, 64, 88, and 120 m depth), from the middle of Concepcion Bay to the edge of the adjacent continental shelf, were sampled. The sedimentary organic matter biopolymeric fraction (proteins, carbohydrates and lipids) and chloroplastic pigments were also assessed. Total meiofauna abundance and biomass increased significantly between sampling dates at the mid-bay and inner shelf sites, from 1474 +/- 354 to 5035 +/- 291 individuals 10 cm(-2) and from 2618 +/- 332 to 5241 +/- 903 individuals 10 cm(-2), respectively. The relative importance of copepods in the top 2 cm increased at all sites (except in the bay mouth). During May 1998, meiofauna, especially nematodes, penetrated deeper in the bay, as well as in the inner and middle shelf sediments. Changes observed in meiobenthos structure among sites and periods were attributed to the higher oxygenation of bottom waters during the summer of 1998 (i.e. El Nino conditions). This was most evident at sites such as the mid bay, where during non-EI Nino years, oxygen-deficient conditions prevail. A decrease of organic matter quantity and quality, related to low primary productivity conditions in 1998 (El Nino), apparently caused few changes in meiofauna structure. A positive correlation between Thioploca and the meiofauna biomass was observed in May 1997, whereas in May 1998 no relationship was found.Des mesures quantitatives de la méiofaune ont été réalisées dans une région côtière du Chili central (36°S). Pendant les périodes de mai 1997 et de mai 1998, qui coïncident avec l'apparition et la disparition d’El Niño, cinq stations (27, 34, 64, 88, 120 m de profondeur), comprises entre le milieu de la baie de Concepción et le bord du plateau continental, ont été examinées. La fraction de matières organiques sédimentaires (protéines, hydrates de carbone et lipides) ainsi que les pigments chloroplastiques ont été déterminés. Lˈabondance de la méiofaune et sa biomasse augmentent significativement : dans le milieu de la baie, de 1474 ± 354 à 5035 ± 291 individus pour 10 cm–2, dans les sites intérieurs du plateau, de 2618 ± 332 à 5241 ± 903 individus pour 10 cm–2. L’importance relative des copépodes dans les 2 cm supérieurs augmente dans presque tous les sites, à l’exception de l’entrée de la baie. En mai 1998, la méiofaune, en particulier les nématodes, pénètre plus profondément dans les sédiments de la baie que dans ceux de l'intérieur et du centre du plateau. Les changements de la structure du méiobenthos, sont attribués à la haute oxygénation de l'été 1998 (El Niño). Ceci est plus évident dans les sites où, pendant les années sans El Niño, des conditions de déficience en oxygène ont prévalu, c'est-à-dire dans le milieu de la baie. La décroissance de la qualité et de la quantité de la matière organique révèle que les conditions de basse productivité en 1998 (El Niño) jouent un rôle mineur dans les changements de la structure de la méiofaune. Une correlation positive a été observée entre Thioploca et la biomasse de la méiofaune en mai 1997, tandis quˈaucune nˈa été trouvée en mai 1998

Meiofaunal distributions on the Peru margin: relationship to oxygen and organic matter availability

A quantitative study of metazoan meiofauna was carried out on bathyal sediments (305, 562, 830 and 1210 m) along a transect within and beneath the oxygen minimum zone (OMZ) in the southeastern Pacific off Callao, Peru (128S). Meiobenthos densities ranged from 1517 (upper slope, middle of OMZ) to 440– 548 ind. 10 cm 2 (lower slope stations, beneath the OMZ). Nematodes were the numerically dominant meiofaunal taxon at every station, followed by copepods and nauplii. Increasing bottom-water oxygen concentration and decreasing organic matter availability downslope were correlated with observed changes in meiofaunal abundance. The 300-m site, located in the middle of the OMZ, differed significantly in meiofaunal abundance, dominance, and in vertical distribution pattern from the deeper sites. At 305 m, nematodes amounted to over 99 % of total meiofauna; about 70 % of nematodes were found in the 2–5 cm interval. At the deeper sites, about 50 % were restricted to the top 1 cm. The importance of copepods and nauplii increased consistently with depth, reaching 12 % of the total meiofauna at the deepest site. The observation of high nematode abundances at oxygen concentrations 50.02 ml l 1 supports the hypothesis that densities are enhanced by an indirect positive effect of low oxygen involving (a) reduction of predators and competitors and (b) preservation of organic matter leading to high food availability and quality. Foo

No reef-associated gradient in the infaunal communities of Rapa Nui (Easter Island) – Are oceanic waves more important than reef predators?

Reef-associated predators are thought to influence the distribution of invertebrates of surrounding sediment habitats. In this study, we analyzed the predation pressure and the distributional patterns of macro- and meiofaunal assemblages in soft sediments surrounding two coral reef sites at Rapa Nui (Easter Island), in the central South Pacific. We tested the hypothesis that reef-associated predators negatively affect sediment-dwelling invertebrates, causing macro- and meiofauna to be less abundant and diverse in soft sediments near the reefs. As expected, predation intensity was greater nearer the reef than farther away, but macro- and meiofaunal assemblages did not differ significantly with distance from the reef. Taxon richness of macro- and meiofaunal assemblages were similar irrespective of distance from the reef. Only meiofauna showed significant variation in total abundance with distance from the reef, but this trend was not consistent between the two study sites. No gradient in sediment texture was observed with distance from the reef. Underwater video recordings at one study site also revealed that local hydrodynamics cause frequent disturbance and resuspension of the upper sediment layers. Our results suggest that soft-sediment assemblages are constantly reshuffled by oceanic waves, thereby blurring the potential effects of predation on invertebrate assemblages closer to the reef