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  • 1
    Publication Date: 2019-07-17
    Description: It has been hypothesized that endolithic photo- autotrophs inside the skeleton of cold-water corals may have a mutualistic relationship with the coral host posi- tively affecting coral calcification. This study investigated the effect of endolithic photo-autotrophs on the apical septal extension of the cold-water coral Desmophyllum dianthus at Fjord Comau, southern Chile (42.41°–42.15°S, 72.5°W). The fluorescent staining agent calcein was used to document the linear apical extension of septae for a period of one and a half years between 2006 and 2007. The results showed a severe reduction in extension rates asso- ciated with the presence of endolithic photo-autotrophs. Infested individuals grew about half as fast as non-infested polyps with a median value of 1.18 lm day-1 compared to 2.76 lm day-1. Contrary to the initial hypothesis, these results point toward a parasitic relationship between D. dianthus and its endolithic photo-autotrophs potentially impairing coral fitness. However, further data on physio- logical parameters and other aspects of the calcification process are necessary to confirm these findings.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 2
    Publication Date: 2018-12-12
    Description: The feeding behavior of the cosmopolitan cold-water coral (CWC) Desmophyllum dianthus (Cnidaria: Scleractinia) is still poorly known. Its usual deep distribution restricts direct observations, and manipulative experiments are so far limited to prey that do not occur in CWC natural habitat. During a series of replicated incubations, we assessed the functional response of this coral feeding on a medium-sized copepod (Calanoides patagoniensis) and a large euphausiid (Euphausia vallentini). Corals showed a Type I functional response, where feeding rate increased linearly with prey abundance, as predicted for a tentaculate passive suspension feeder. No significant differences in feeding were found between prey items, and corals were able to attain a maximum feeding rate of 10.99 mg C h-1, which represents an ingestion of the 11.4% of the coral carbon biomass per hour. These findings suggest that D. dianthus is a generalist zooplankton predator capable of exploiting dense aggregations of zooplankton over a wide prey size-range.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 3
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    Springer
    In:  EPIC3Marine Animal Forests, Marine Animal Forests, Switzerland, Springer, 35 p., ISBN: 978-3-319-17001-5
    Publication Date: 2017-09-26
    Description: The Chilean fjord region, situated between 42 and 56 °S, forms one of the most ragged shorelines and belongs to the ecologically and biogeographically least understood marine regions of the world. A labyrinth of fjords, channels, and islands extends over 240,000 km2 and creates a coastline of more than 80,000 km. Due to strong abiotic gradients, numerous habitats are created, which are further diversified by temporal dynamics (tidal cycle, seasonal changes in precipitation, temperature, radiation, etc.). The region is a biodiversity hotspot hosting unique and fragile ecosystems. Among the species living here, several are species forming habitats in the ecosystem. These organisms can reach high densities conforming the so-called marine animal forests. Examples are marine animal forests dominated by cold-water stony corals, gorgonians, hydrocorals, brachiopods, polychaetes, giant barnacles, sponges, and ascidians. Many of these communities have been discov- ered only recently. There is also a singular characteristic in this area: exceptionally low pH levels of the waters of Patagonian fjords provide the opportunity to study calcifying organisms in an environment with pH conditions in the same range as the ones predicted by the IPCC for the world oceans in 2100. Despite the scarce ecological and biogeographical knowledge of this area, it encounters an unparalleled economic development including high-impact industry-scale salmonid farming, ambitious infrastructure and industrialization projects, and increasing extractive activities. Baseline research on the abiotic and biotic environment of the region is needed to reach sustainability in the use of the marine resources. Management plans including the establishment of marine protected areas to preserve benthic diversity and ecosystem services are urgently needed.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Inbook , peerRev
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  • 4
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    In:  EPIC3YOUMARES, Session 10 "Coral reefs -Recent approaches in coral reef research: traditional and novel applications towards building resilience", Bremen, Germany, 2015-09-16-2015-09-18
    Publication Date: 2016-03-01
    Description: The recently discovered scleractinian coral Tethocyathus endesa (Cairns, Häussermann and Försterra, 2005) is a cold-water coral, thriving in the fjord Comau (Chile). It exhibits horizontal and vertical pH gradients resembling values forecasted for the end of this century by the recent IPCC-report (IPCC, 2014). Ongoing ocean acidification and global ocean warming might have harmful impacts on all calcifying organisms such as scleractinians. This study aims for a better understanding of the metabolic response of T. endesa in a changing ocean. Measured parameters were in situ growth rates and respiration rates as being two of the main factors that can be influenced by ocean acidification. In 2014, test corals were placed at two study sites (inside the fjord with low pH of 7.67 ± 0.05 and outside the fjord with higher pH of 7.87 ± 0.06). For each study site, ten specimens of T. endesa stayed at their place of origin to determine the general in situ long-term growth rates (one year) as well as to serve as a control for a cross- transplantation experiment. For the latter, additional ten specimens of T. endesa were exchanged to the other study site in 2014. One year later, growth rates were determined via buoyant weighing and respiration rates measured with the aid of optodes. So far there is only little knowledge about the in situ long-term growth rates and the respiration rates of cold-water corals. To the best of our knowledge this is the first study on the reaction of T. endesa towards a changing seawater pH. The findings of this study are therefore crucial to rate the ecological importance of T. endesa and its response to future conditions
    Repository Name: EPIC Alfred Wegener Institut
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  • 5
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    In:  EPIC3Turning back the past - New views from proxies for early earth history and evolution of life on Earth, Graz, 2017-10-02-2017-10-07
    Publication Date: 2018-05-03
    Repository Name: EPIC Alfred Wegener Institut
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  • 6
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    Ledizioni
    In:  EPIC3Rivista Italiana di Paleontologia e Stratigrafia (Research in Paleontology and Stratigraphy), Ledizioni, 124(2), pp. 343-359
    Publication Date: 2018-06-05
    Description: Recent and fossil brachiopod shells have a long record as biomineral archives for (palaeo)climatic and (palaeo)environmental reconstructions, as they lack or exhibit limited vital effects in their calcite shell and generally are quite resistant to diagenetic alteration. Despite this, only few studies address the issue of identifying the best or optimal part of the shell for geochemical analyses. We investigated the link between ontogeny and geochemical signatures recorded in different parts of the shell. To reach this aim, we analysed the elemental (Ca, Mg, Sr, Na) and stable isotope (δ18O, δ13C) compositions of five recent brachiopod species (Magellania venosa, Liothyrella uva, Aerothyris kerguelensis, Liothyrella neozelanica and Gryphus vitreus), spanning broad geographical and environmental ranges (Chile, Antarctica, Indian Ocean, New Zealand and Italy) and having different shell layer successions (two-layer and three-layer shells). We observed similar patterns in the ventral and dorsal valves of these two groups, but different ontogenetic trends by the two- and three-layer shells in their trace element and stable isotope records. Our investigation led us to conclude that the optimal region to sample for geochemical and isotope analyses is the middle part of the mid-section of the shell, avoiding the primary layer, posterior and anterior parts as well as the outermost part of the secondary layer in recent brachiopods. Also, the outermost and innermost rims of shells should be avoided due to diagenetic impacts on fossil brachiopods.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
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  • 7
    Publication Date: 2017-10-20
    Description: El fiordo Comau en la Patagonia chilena norte se caracteriza por presentar un marcado gradiente de pH, de 7.4 a 8.1. Bajo estas condiciones, las cuales corresponden al pH pronosticado para los océanos en el año 2100, están prosperando bancos de mitílidos, bancos de braquiópodos, acumulaciones de picorocos, praderas de gorgonias y bancos de corales de aguas frías. Estos “bosques” de animales marinos forman la base estructural y funcional de un ecosistema bentónico marino muy diverso. La comunidad que domina principalmente en paredes rocosas desde los 80 m son los bancos de corales, con la especie matriz Desmophyllum dianthus. Interesantemente, D. dianthus crece en aguas de alto (sobresaturadas de aragonita) y bajo pH (insaturadas de aragonita), así como en aguas someras y profundas (desde aprox. 15 m hasta más de 400 m). Esto indica que el coral es capaz de regular y controlar su calcificación. Se incubó D. dianthus simulando futuros escenarios de acidificación oceánica y en dichas incubaciones se midió la composición isotópica del boro en su esqueleto (11B). D. dianthus presentó incrementos del pH interno de calcificación (pHcf) como respuesta reguladora frente a pH externos (pHsw) más bajos. Todavía falta una explicación fisiológica del pHcf en corales bajo diferentes pHsw. Utilizando microsensores para pH, calcio y oxígeno medimos el pHcf en D. dianthus en relación a la dinámica del calcio y la respiración a lo largo del pólipo del coral bajo diferentes pHsw. Encontramos que el pHcf y el pHsw están relacionados, pero no de forma directa debido a la gran heterogeneidad del pHcf. Esto sugiere una regulación del pHcf altamente compleja e inconsistente con los modelos anteriores, indicando que D. dianthus incrementa probablemente el pool interno de carbono y no el pH para facilitar la calcificación.
    Repository Name: EPIC Alfred Wegener Institut
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  • 8
    Publication Date: 2019-07-17
    Description: In Patagonia, Chile, an extensive Fjord system can be found. The Comau Fjord is located in the northern part and is characterized by steep walls, a high tidal range and is approximately 500 m deep. Along its course from mouth to head (horizontally, along isobaths) and with decreasing depth (vertically) it shows gradual changes in water parameters including pH and the associated carbonate chemistry. Desmophyllum dianthus is a cosmopolite coral usually found in deeper water (〉 200 m). In the Comau Fjord it thrives in shallow depth up to 15 m and is distributed in a broad variety of water parameters, including a pH range of at least 0.5 units – likely more. This demonstrates the high adaptation ability of cold water corals to a relatively wide spectrum of pH values.
    Repository Name: EPIC Alfred Wegener Institut
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  • 9
    Publication Date: 2019-07-17
    Description: In Patagonia, Chile, an extensive Fjord system can be found. The Comau Fjord is located in the northern part and is characterized by steep walls, a high tidal range and is approximately 500 m deep. Along its course from mouth to head (horizontally, along isobaths) and with decreasing depth (vertically) it shows gradual changes in water parameters including pH and the associated carbonate chemistry. Desmophyllum dianthus is a cosmopolite coral usually found in deeper water (〉 200 m). In the Comau Fjord it thrives in shallow depth up to 15 m and is distributed in a broad variety of water parameters, including a pH range of at least 0.5 units – likely more. This demonstrates the high adaptation ability of cold water corals to a relatively wide spectrum of pH values.
    Repository Name: EPIC Alfred Wegener Institut
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  • 10
    Publication Date: 2019-07-17
    Description: Increasing dissolution of anthropogenic-released carbon dioxide into the world’s oceans is causing ocean acidification (OA). OA is thought to negatively affect most marine-calcifying organisms, notably cold-water corals (CWC), which may be especially sensitive due to the deep and cold waters they normally thrive in. However, the impact of OA on CWC is difficult to predict. Recorded distributions of CWC are rarely linked to in situ water chemistry, and the boundaries of their distributions are not clearly defined. The fjord Comau in Chilean Patagonia features pronounced pH gradients, and up to 0.5 pH units have been recorded both vertically (at some sites within 50 m depth) and less distinct horizontally (from head to mouth). The cosmopolite coral Desmophyllum dianthus grows along the course of the fjord and of the entire pH range. It occurs in shallow depths (below 12 m, pH 8.1) as part of a deep-water emergence community, but also in 225 m depth at a pH of 7.4. Based on pH and totalalkalinity, data calculations of the associated carbonate chemistry revealed that this CWC thrives commonly close the aragonite (the orthogonal crystal form of calcium carbonate, the mineral structure of coral skeletons) saturation horizon and even below. This suggests a high adaptation potential of D. dianthus to adjust its calcification performance to conditions thermodynamically unfavourable for the precipitation of aragonite.
    Repository Name: EPIC Alfred Wegener Institut
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