1,721,051 research outputs found
Exploring the relationship between macrofaunal biodiversity and ecosystem functioning in the deep sea
No full textThe global scale of the biodiversity crisis has stimulated research into the relationship
between biodiversity and ecosystem functioning (BEF). Even though the deep sea is
the largest biome on Earth, BEF studies in deep-sea benthic ecosystems are scant.
Moreover, the small number of recent studies, which mostly focus on meiobenthic
nematodes, report conflicting results that range from a very clear positive relationship
to none at all. In this BEF study, the deep-sea macrofauna were used as a model to
investigate the structural and functional diversity of macrofauna assemblages at three
depths (1,200, 1,900, and 3,000 m) in seven open-slope systems from the North-Eastern
Atlantic Ocean to the Central-Eastern Mediterranean Sea. The presence and nature
of BEF relationships were studied considering two spatial scales, the large and the
basin scale, in different environmental settings. Total benthic biomass and macrofaunal
predator biomass were used as proxies to assess ecosystem functioning. Ecosystem
efficiency was expressed as macrofaunal biomass to biopolymeric carbon content ratio,
macrofaunal biomass to prokaryotic biomass ratio, macrofaunal biomass to meiofaunal
biomass ratio, and meiofaunal biomass to prokaryotic biomass ratio. On both large and
basin spatial scales, some significant relationships between macrofaunal diversity and
ecosystem functioning and efficiency were reported. When significant, the nature of BEF
relations was positive and exponential or linear supporting the general idea that a higher
diversity can enhance ecosystem functioning. Other BEF relationships were explained
by the effect of environmental variables. More data from different deep-sea systems are
needed, to better elucidate the consequences of biodiversity loss on the ocean floor
Last snails standing since the Early Pleistocene, a tale of Calliostomatidae (Gastropoda) living in deep-water coral habitats in the north-eastern Atlantic
No full textHoffman, Leon, Beuck, Lydia, Heugten, Bart Van, Lavaleye, Marc, Freiwald, André (2019): Last snails standing since the Early Pleistocene, a tale of Calliostomatidae (Gastropoda) living in deep-water coral habitats in the north-eastern Atlantic. Zootaxa 4613 (1): 93-110, DOI: https://doi.org/10.11646/zootaxa.4613.1.
FIGURE 1 in Last snails standing since the Early Pleistocene, a tale of Calliostomatidae (Gastropoda) living in deep-water coral habitats in the north-eastern Atlantic
No full textFIGURE 1. Distribution maps of Calliostoma bullatum and Calliostoma leptophyma (left) and of Calliostoma maurolici (right). In the left map, empty shells of Calliostoma bullatum as red diagonal crosses, live observations as yellow triangles, empty shells of Calliostoma leptophyma as red normal crosses, live observations in this study as green triangles, live observations from literature as green diamonds. In the right map, empty shells of Calliostoma maurolici as red normal crosses, live observations as yellow triangles, live observations from literature as green diamonds. Bathymetry data source: GEBCO, depth contour intervals 500 m.Published as part of Hoffman, Leon, Beuck, Lydia, Heugten, Bart Van, Lavaleye, Marc & Freiwald, André, 2019, Last snails standing since the Early Pleistocene, a tale of Calliostomatidae (Gastropoda) living in deep-water coral habitats in the north-eastern Atlantic, pp. 93-110 in Zootaxa 4613 (1) on page 95, DOI: 10.11646/zootaxa.4613.1.4, http://zenodo.org/record/323809
FIGURES 15–20 in Last snails standing since the Early Pleistocene, a tale of Calliostomatidae (Gastropoda) living in deep-water coral habitats in the north-eastern Atlantic
No full textFIGURES 15–20. Calliostoma bullatum on substrates. 15. MSM16-3/GeoB 14871 (ROV5). Grazing on carnivorous sponge Cladorhiza corallophila; arrow indicating grazing effect. 16. MSM16-3/GeoB 14902 (ROV10). On framework encrusting sponge. 17. MSM16-3/GeoB 14902 (ROV10). Grazing on a valve of live Acesta excavata, which is colonised by epibionts; the two laser points are at a distance of 6 cm. 18. MSM16-3/GeoB 14902 (ROV10). Grazing on a valve of dead Acesta excavata (note in direct surrounding the free portions of epibionts on the valve and the white framework portions of Lophelia pertusa lacking any tissue). 19. MSM16-3/GeoB 14902 (ROV10). Grazing on a gastropod shell (Ranella olearium). 20. MSM16-3/ GeoB 14891 (ROV9). Grazing on dead hydroid axis in close vicinity to a Solenogastres.Published as part of Hoffman, Leon, Beuck, Lydia, Heugten, Bart Van, Lavaleye, Marc & Freiwald, André, 2019, Last snails standing since the Early Pleistocene, a tale of Calliostomatidae (Gastropoda) living in deep-water coral habitats in the north-eastern Atlantic, pp. 93-110 in Zootaxa 4613 (1) on page 100, DOI: 10.11646/zootaxa.4613.1.4, http://zenodo.org/record/323809
FIGURES 29–34 in Last snails standing since the Early Pleistocene, a tale of Calliostomatidae (Gastropoda) living in deep-water coral habitats in the north-eastern Atlantic
No full textFIGURES 29–34. Calliostoma maurolici on various substrates. 29. Caracole/PL129-7 (ROV). Grazing on dead Lophelia pertusa framework. 30. M61-3/632 (GeoB 9285, ROV). Grazing on dead Lophelia pertusa framework portions. 31. POS 400/GeoB 14544 (ROV 3). Grazing on a Madrepora oculata colony. 32. POS400/GeoB 14548 (ROV5). Two specimens of different age grazing in close vicinity on dead coral framework. 33. POS400/GeoB 14543 (ROV2). Grazing on deep-sea anemone Phelliactis hertwigii. 34. POS400/GeoB 14548 (ROV5). Grazing on epiliths, grown on a hardground. [Fig. 29 was taken by ROV "VIC- TOR 6000", IFREMER, France. Fig. 30 was taken by ROV "QUEST 4000" and Figs 31–34 were taken via ROV "Cherokee", MARUM, Bremen University, Germany.]Published as part of Hoffman, Leon, Beuck, Lydia, Heugten, Bart Van, Lavaleye, Marc & Freiwald, André, 2019, Last snails standing since the Early Pleistocene, a tale of Calliostomatidae (Gastropoda) living in deep-water coral habitats in the north-eastern Atlantic, pp. 93-110 in Zootaxa 4613 (1) on page 103, DOI: 10.11646/zootaxa.4613.1.4, http://zenodo.org/record/323809
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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