1,721,470 research outputs found
Seawater carbonate chemistry and behavioural trait expression of polar invertebrates
No full textThis dataset is included in the OA-ICC data compilation maintained in the framework of the IAEA Ocean Acidification International Coordination Centre (see https://oa-icc.ipsl.fr). Original data were downloaded from Polar Data Centre (see associated paper) by the OA-ICC data curator. In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Gattuso et al, 2024) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). In this dataset the original values were archived in addition with the recalculated parameters (see related PI). The date of carbonate chemistry calculation by seacarb is 2024-07-11.</span
Ecological consequences of climatic forcing in the Arctic marine benthos
No full textClimate change is causing unprecedented changes in high-latitude environments, which have widespread implications for the underlying ecology and global climate and ocean systems. Of particular concern is the Arctic seafloor, an integral component of sympagic-pelagic-benthic food-webs, biogeochemical cycling and a variety of ecosystem services. Arctic climate change studies often overlook changes in the physiological, behavioural, and life-history traits of organisms, instead focusing on observable, macro-level responses such as range shifts and biomass turnovers. However, alterations of trait expression are crucial in determining an organism's capacity to adapt and influence the environment, preceding population and community-level responses. Substantial variability of trait expression is already observed across different spatiotemporal scales, between co-existing species and within conspecifics. As a result of these complexities, accurately assessing the impact of climate change on Arctic benthic biodiversity and ecosystem functioning is challenging. Here, I use laboratory-based mesocosm experiments, geochemical tracer analyses and simulative ecological extinction scenarios of Arctic benthic model systems to evaluate the consequences of organism responses to climate-driven environmental changes for benthic ecosystem functioning. Overall, my results demonstrate that organism responses are not generic, and can fundamentally alter their ability to persist and mediate aspects of ecosystem functioning. Specifically, I find that the capacity of species to endure climate-induced environmental change does not always equate to sustained contributions towards functional processes such as nutrient cycling and incurs inter- and intra-specific shifts in behaviour and physiological costs within metabolic pathways. Diverse responses to climate change are also reflected in the paleorecords, where intra-specific variability within long-lived cold-water corals influences their reliability in reconstructing deep-water temperature and seawater barium concentrations. Upscaling from organism responses to species turnover and community-level ecosystem functioning requires an appropriate acknowledgement of species interactions. By factoring in species co-dependencies during the “borealisation” of benthic assemblages, I demonstrate that co-extinctions can intensify the loss of community functioning, while concurrently observing a larger compensation effect from local and surrounding species pools. As such, I provide evidence that incorporating connections between taxa into predictions of biodiversity change enables more realistic assessments of systemic responses to climate-driven environmental change. Collectively, my findings highlight the influence of context on biodiversity responses and their repercussions on ecosystem functioning. In particular, I show that both individual organisms and entire assemblages from south of the Polar Front exhibit different responses to climatic forcing compared to north of the Polar Front and at its transition. In doing so, I draw attention to the importance of incorporating gradients of environmental variability into climate change assessments. I conclude that both environmental and biological variability shape the responses of Arctic benthic invertebrates to climatic forcing and the repercussions on ecosystem functioning. Rather than continuing to generalise responses at the macro-level, climate assessments should move towards incorporating the environmental context, interactions between organisms as well as intra- and inter-specific trait variability to accurately assess cascading effects on ecosystems. Integrating these components enhances our understanding of ecological responses to environmental change and improves predictions of future ecosystem dynamics. This knowledge is crucial for informing the most effective policy and management decisions aimed at mitigating stressor impacts
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Co-extinctions and co-compensatory species responses to climate change moderate ecosystem futures
No full textConsensus has been reached that the sequential loss of biodiversity leads to a non-linear and accelerating decline in ecosystem properties. The form of this relationship, however, is based on theory and empirically derived observations that do not include species co-extinctions. Here, we use data from marine benthic invertebrate communities to parameterise trait-based extinction models that adjust the probability of species extirpation and compensation by including the dependencies between different spe- cies across a gradient of climate-driven environmental change. Our simulations reveal that the inclusion of static co-extinctions leads to more pronounced declines in the trajectories of sediment bioturbation—a process of great importance to the functioning of marine ecosystems—than those observed with sequential losses of single species. Compensatory mechanisms and the allow- ance of the formation of new interactions derived from local and regional species pools moderate the compounding influence of co-extinction but introduce additional variability in community response depending on the composition and functional role of incoming and outgoing species. Our observations emphasise the importance of accounting for local and regional community dynamics, especially in highly connected systems that are prone to extinction cascades when projecting the ecosystem conse- quences of altered biodiversity
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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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