82 research outputs found
A roadmap for Antarctic and Southern Ocean science for the next two decades and beyond
Antarctic and Southern Ocean science is vital to understanding natural variability, the processes
that govern global change and the role of humans in the Earth and climate system. The potential for new
knowledge to be gained from future Antarctic science is substantial. Therefore, the international Antarctic
community came together to âscan the horizonâ to identify the highest priority scientific questions that
researchers should aspire to answer in the next two decades and beyond. Wide consultation was a
fundamental principle for the development of a collective, international view of the most important future
directions in Antarctic science. From the many possibilities, the horizon scan identified 80 key scientific
questions through structured debate, discussion, revision and voting. Questions were clustered into seven
topics: i)Antarctic atmosphere and global connections, ii) Southern Ocean and sea ice in a warming world,
iii) ice sheet and sea level, iv) the dynamic Earth, v) life on the precipice, vi) near-Earth space and beyond,
and vii) human presence in Antarctica. Answering the questions identified by the horizon scan will require
innovative experimental designs, novel applications of technology, invention of next-generation field and
laboratory approaches, and expanded observing systems and networks. Unbiased, non-contaminating
procedures will be required to retrieve the requisite air, biota, sediment, rock, ice and water samples.
Sustained year-round access toAntarctica and the Southern Ocean will be essential to increase winter-time
measurements. Improved models are needed that represent Antarctica and the Southern Ocean in the
Earth System, and provide predictions at spatial and temporal resolutions useful for decision making.
A co-ordinated portfolio of cross-disciplinary science, based on new models of international collaboration,
will be essential as no scientist, programme or nation can realize these aspirations alone.Tinker Foundation, Antarctica New Zealand, The New Zealand
Antarctic Research Institute, the Scientific Committee on
Antarctic Research (SCAR), the Council of Managers of
National Antarctic Programs (COMNAP), the Alfred
Wegner Institut, Helmholtz Zentrum fĂŒr Polar und
Meeresforschung (Germany), and the British Antarctic
Survey (UK).http://journals.cambridge.org/action/displayJournal?jid=ANShb201
Growth and tissue mass cycles in the infaunal bivalve Yoldia eightsi at Signy Island, Antarctica
Shell growth in Yoldia eightsi was measured over an austral summer and winter in 1992. In specimens 27âmm length did not increase in length. Tissue dry and ash-free dry mass (AFDM) cycles were assessed at monthly intervals between December 1988 and January 1991. ANCOVA indicated significant interannual and seasonal effects on this cycle. Tissue mass increased in the summer, coinciding with the phytoplankton bloom and the period of maximum sedimentation of organic material from the water column. A standard 20-mm-length animal reached a maximum AFDM of 114âmg in February 1990. The minimum value (68âmg AFDM) throughout the 2âyears of measurements was in early December 1988, at the end of the austral winter. Periods of tissue mass increase were, therefore, decoupled from shell growth, at least in juveniles. Tissue mass was significantly higher in 1990 than 1989, which was mainly due to high organic contents in the summer (January to May). This was not consistent with the pattern of organic content in the sediments at the study site, but was in phase with the cycle in sediment chlorophyll a content. Tissue mass increase depended on major resource input during the summer, but Y. eightsi was capable of maintaining winter condition from stocks of benthic microalgae in years of poor ice cover. Tissue mass declined between April and July each year. This was accompanied by large falls in tissue ash content, and coincided with the spawning period in early June. These are the first monthly tissue mass data collected over a 2-year period for an Antarctic mollusc. They are the first such data indicating seasonal variation in tissue mass and showing a decoupling of shell and tissue growth in a polar bivalve. The P/B ratio calculated from these data was 0.106, which is slightly lower than previous values found for this species, but is in line with general values for Antarctic marine benthos
On the edge of death: Rates of decline and lower thresholds of biochemical condition in food-deprived fish larvae and juveniles
Gaining reliable estimates of how long fish early life stages can survive without feeding and how starvation rate
and time until death are influenced by body size, temperature and species is critical to understanding processes
controlling mortality in the sea. The present study is an across-species analysis of starvation-induced changes in
biochemical condition in early life stages of ninemarine and freshwater fishes. Datawere compiled on changes in
body size (dry weight, DW) and biochemical condition (standardized RNAâDNA ratio, sRD) throughout the
course of starvation of yolk-sac and feeding larvae and juveniles in the laboratory. In all cases, themean biochemical
condition of groups decreased exponentially with starvation time, regardless of initial condition and endogenous
yolk reserves. A starvation rate for individuals was estimated from discrete 75th percentiles of sampled
populations versus time (degree-days, Dd). The 10th percentile of sRD successfully approximated the lowest,
life-stage-specific biochemical condition (the edge of death). Temperature could explain 59% of the variability
in time to death whereas DW had no effect. Species and life-stage-specific differences in starvation parameters
suggest selective adaptation to food deprivation. Previously published, interspecific functions predicting the relationship
between growth rate and sRD in feeding fish larvae do not apply to individuals experiencing prolonged
food deprivation. Starvation rate, edge of death, and time to death are viable proxies for the physiological processes
under food deprivation of individual fish pre-recruits in the laboratory and provide useful metrics for research
on the role of starvation in the sea
The Eco-Costs of Material Scarcity, a Resource Indicator for LCA, Derived from a Statistical Analysis on Excessive Price Peaks
The availability of resources is crucial for the socio-economic stability of our society. For more than two decades, there was a debate on how to structure this issue within the context of life-Cycle assessment (LCA). The classical approach with LCA is to describe "scarcity" for future generations (100-1000 years) in terms of absolute depletion. The problem, however, is that the long-term availability is simply not known (within a factor of 100-1000). Outside the LCA community, the short-term supply risks (10-30 years) were predicted, resulting in the list of critical raw materials (CRM) of the European Union (EU), and the British risk list. The methodology used, however, cannot easily be transposed and applied into LCA calculations. This paper presents a new approach to the issue of short-term material supply shortages, based on subsequent sudden price jumps, which can lead to socio-economic instability. The basic approach is that each resource is characterized by its own specific supply chain with its specific price volatility. The eco-costs of material scarcity are derived from the so-called value at risk (VAR), a well-known statistical risk indicator in the financial world. This paper provides a list of indicators for 42 metals. An advantage of the system is that it is directly related to business risks, and is relatively easy to understand. A disadvantage is that "statistics of the past" might not be replicated in the future (e.g., when changing from structural oversupply to overdemand, or vice versa, which appeared an issue for two companion metals over the last 30 years). Further research is recommended to improve the statistics.Marketing and Consumer ResearchClimate Design and SustainabilityApplied Probabilit
Combined analyses of costs, market value and eco-costs in circular business models: eco-efficient value creation in remanufacturing
Eco-efficient Value Creation is a method to analyse innovative product and service design together with circular business strategies. The method is based on combined analyses of the costs, market value (perceived customer value) and eco-costs. This provides a prevention-based single indicator for âexternal environmental costsâ in LCA. The remanufacturing of products is an environmental and sustainable approach, in the circular economy, and can deliver lower eco-costs of materials depletion and pollution. From a business point of view, however, remanufacturing seems to be viable in B2B niche markets only. In consumer markets, remanufacturing is less common. The question is how can remanufacturing become a viable business solution for mainstream consumer markets. Traditional âgreenâ marketing approaches are not enough: green has a positive, but also negative connotations, so marketing approaches are complex. By using the Eco-efficient Value Creation method, marketing strategies for the roll-out of remanufacturing in mainstream consumer markets, can be revealed. This approach has led to the development of five aspects, which are key to innovative circular business models, for remanufacturing: (1) buyers differ from the buyers of the ânew productâ (2) quality must be emphasised in all communications (3) risk must be taken away from the buyer (4) top level service is required to convince the buyer (5) a âgreenâ brand may support the remanufactured product image.Publisher Correction: Jnl Remanufactur (2017) 7(1):1â17 https://doi.org/10.1007/s13243-017-0031-9 Due to technical error, the original HTML version of this article unfortunately contained a mistake. The copyright information should be â© The Author(s) 2017â, not â© Springer Science+Business Media Dordrecht 2017â. The original article has been corrected.Marketing and Consumer ResearchCircular Product DesignClimate Design and Sustainabilit
Role of protozooplankton in the diet of North Sea autumn spawning herring (Clupea harengus) larvae
The role of small prey (< 200 ”m) in larval marine fish nutrition is largely understudied. Here, we explore the contribution of protozooplankton (PZP 20â200 ”m) to larval fish diets, compared to metazoan microzooplankton (MZP 55â200 ”m). More specifically, we tested whether the contribution of PZP increased during the low productivity season and decreased as larvae grow. We used North Sea autumn spawning herring (Clupea harengus) as a case study, as it is a key species with high commercial and ecological importance. In autumn and winter, the potential PZP and MZP prey was dominated by cells < 50 ”m (mainly Gymnodiniales, Pronoctiluca pelagica,Tripos spp. and Strombidium spp.), while copepod nauplii and copepodites where more abundant in autumn than in winter. Based on their trophic enrichment (â15 N), larvae preferentially grazed on small MZP < 50 ”m rather than PZP both in autumn and winter. Larvae of different body size (range 8â14 mm standard length) fed at the same trophic level but on different prey (similar ÎŽ15N but different ÎŽ13C). Growth rates (based on RNA/DNA estimates) were similar in autumn and winter, suggesting that growth was not affected by station-specific differences in the composition of the prey field. Our results not only underscore the important role of MZP on larval herring diets both in autumn and wintertime, but also emphasize the limitations of bulk stable isotope analysis. Given the current low recruitment in North Sea herring, these results provide significant information for future monitoring approaches relevant to stock assessment of this species
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