Evaluating the effects of catch-and-release angling on Cape stumpnose Rhabdosargus holubi in a South African estuary

Fisheries managers are increasingly promoting catch-and-release (C&R) to manage recreationally angled fish stocks. Despite this, there is a scarcity of information on the effects of C&R on estuarine-dependent species. Cape stumpnose Rhabdosargus holubi dominates the recreational fisheries catch and provides an important source of food for subsistence fishers in some temperate South African estuaries. The health and survival of R. holubi exposed to a C&R event was investigated by examining their physiological stress response (blood glucose and lactate), reflex impairment (reflex action mortality predictors [RAMP]) and short-term (12-hour) survival. Fish were captured and exposed to one of three air-exposure treatments: 0 s, 30 s or 90 s. Stress and health were measured either immediately (immediate) or one hour after (delayed) the C&R event. There was no significant difference in blood glucose between air-exposure treatments, but there was a significant difference between the mean immediate and delayed glucose levels within each treatment (F_(2,143) = 81.8, p < 0.01). In contrast, blood lactate level was significantly higher in the 90-s treatment (p < 0.05). Immediate blood lactate levels were significantly lower than the delayed samples for each treatment (F = 4.29, p = 0.02; n = 169). Although all fish exhibited at least one reflex impairment, the RAMP score was significantly higher in the 90-s air-exposure treatment (H_(2,86) = 9.73, p = 0.007). Also, RAMP scores were significantly lower in the delayed samples (p < 0.01). Although short-term mortality was relatively low (2.3%) for this species, it was highest in the 90-s treatment (7%). These results suggest that physiological stress is higher when R. holubi are exposed to longer periods of air exposure and that the physiological stress of fish subject to a C&R event is best measured after a delay.     

Experimental impact cratering: A summary of the major results of the MEMIN research unit

This paper reviews major findings of the Multidisciplinary Experimental and Modeling Impact Crater Research Network (MEMIN). MEMIN is a consortium, funded from 2009 till 2017 by the German Research Foundation, and is aimed at investigating impact cratering processes by experimental and modeling approaches. The vision of this network has been to comprehensively quantify impact processes by conducting a strictly controlled experimental campaign at the laboratory scale, together with a multidisciplinary analytical approach. Central to MEMIN has been the use of powerful two-stage light-gas accelerators capable of producing impact craters in the decimeter size range in solid rocks that allowed detailed spatial analyses of petrophysical, structural, and geochemical changes in target rocks and ejecta. In addition, explosive setups, membrane-driven diamond anvil cells, as well as laser irradiation and split Hopkinson pressure bar technologies have been used to study the response of minerals and rocks to shock and dynamic loading as well as high-temperature conditions. We used Seeberger sandstone, Taunus quartzite, Carrara marble, and Weibern tuff as major target rock types. In concert with the experiments we conducted mesoscale numerical simulations of shock wave propagation in heterogeneous rocks resolving the complex response of grains and pores to compressive, shear, and tensile loading and macroscale modeling of crater formation and fracturing. Major results comprise (1) projectile–target interaction, (2) various aspects of shock metamorphism with special focus on low shock pressures and effects of target porosity and water saturation, (3) crater morphologies and cratering efficiencies in various nonporous and porous lithologies, (4) in situ target damage, (5) ejecta dynamics, and (6) geophysical survey of experimental craters.     

Effects of forestry on summertime low flows and physical fish habitat in snowmelt‐dominant headwater catchments of the Pacific Northwest

Periods of summertime low flows are often critical for fish. This study quantified the impacts of forest clear‐cutting on summertime low flows and fish habitat and how they evolved through time in two snowmelt‐dominant headwater catchments in the southern interior of British Columbia, Canada. A paired‐catchment analysis was applied to July–September water yield, the number of days each year with flow less than 10% of mean annual discharge, and daily streamflow for each calendar day. The postharvest time series were divided into treatment periods of approximately 6–10 years, which were analysed independently to evaluate how the effects of forestry changed through time. An instream flow assessment using a physical habitat simulation‐style approach was used to relate streamflow to the availability of physical habitat for resident rainbow trout. About two decades after the onset of logging and as the extent of logging increased to approximately 50% of the catchments, reductions in daily summertime low flows became more significant for the July–September yield (43%) and for the analysis by calendar day (11–68%). Reductions in summertime low flows were most pronounced in the catchment with the longest postharvest time series. On the basis of the temporal patterns of response, we hypothesize that the delayed reductions in late‐summer flow represent the combined effects of a persistent advance in snowmelt timing in combination with at least a partial recovery of transpiration and interception loss from the regenerating forests. These results indicate that asymptotic hydrological recovery as time progresses following logging is not suitable for understanding the impacts of forest harvesting on summertime low flows. Additionally, these reductions in streamflow corresponded to persistent decreases in modelled fish habitat availability that typically ranged from 20% to 50% during the summer low‐flow period in one of the catchments, suggesting that forest harvest may have substantial delayed effects on rearing salmonids in headwater streams.     

Geochemistry of magnesites and dolomites at the Oberdorf/Laming (Austria) deposit and implications for their origin

The major and trace element geochemistry of magnesite and dolomite samples from alternating rock masses at the Oberdorf/Laming (Styria, Austria) mineralization has been studied. The rare earth elements (REE) are considered to be of importance for the discussion of the origin of sparry magnesite deposits. The Al and REE contents are positively correlated, indicating a clay component as the main source for REE in the magnesites and their precursor rocks. Our data support the view that the Oberdorf and probably other magnesite mineralizations in the Eastern Alps have been formed by metasomatism. Through this process calcite (which was deposited by sedimentation in a marine environment) underwent dolomitization. Subsequently, Mg-rich solutions circulating through the rock masses formed the magnesite bodies.During the formation of the dolomites and the conversion to magnesites, the REE patterns of the original carbonates remained unchanged. The magnesites exhibit patterns that are very similar to sedimentary carbonates (which contain a REE-bearing clay component). Magnesites of purely sedimentary origin, formed in a predominantly evaporitic environment, should have lower total REE contents and different patterns due to the short residence times of these elements in seawater. Analyses of talc pseduomorphs after magnesite indicate as well that the REE patterns are not significantly altered during the talcification. The Mg-rich solutions that led to the formation of the magnesites have probably been derived from serpentinites below the gneiss complexes of eastern Styria and the South Penninic units of the Tauern window.

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Zusammenfassung Die Haupt- und Spurenelementgeochemie von Magnesit- und Dolomitproben, die aus alternierenden Gesteinsstöcken in der Magnesitmine von Oberdorf/Laming (Steiermark, Österreich) stammen, wurde untersucht. Besonderes Augenmerk wurde dabei auf die Geochemie der Seltenen Erdelemente (REE) gelegt, da diese für Aussagen über die Entstehung der Magnesitlagerstätten von besonderer Bedeutung sind. Eine positive Korrelation zwischen den Al und REE-Gehalten deutet darauf hin, daß der Hauptteil der REE einer Tonkomponente entstammt. Die Daten unterstützen eine metasomatische Entstehung der Spatmagnesite der Oberdorfer Lagerstätte und anderer Ostalpiner Lagerstätten. Sedimentär angelegter Kalzit wird dabei über Dolomit mit Mg-reichen Lösungen in Magnesit umgewandelt.Während der Metasomatose bleiben die chondritnormierten REE-Verteilungen der Ausgangskarbonate relativ unverändert erhalten. Die so entstandenen Spatmagnesite weisen Verteilungsmuster auf, die jenen der sedimentären Karbonate, aus denen sie entstanden sind, entsprechen. Rein sedimentär entstandene Magnesite werden praktisch nur in evaporitischem Milieu gebildet und sollten infolge der kurzen Verweilzeit dieser Elemente im Meerwasser wesentlich niedrigere REE-Gehalte und andere Verteilungsmuster aufweisen. Analysen einer Talkpseudomorphose zeigen, daß sich die REE-Verteilungsmuster auch bei der metasomatischen Talk-bildung nicht wesentlich ändern. Die Mg-reichen Lösungen, die zur Bildung der Magnesite notwendig waren, entstammen vermutlich tiefliegenden Sepentiniten, auf die es Hinweise im Untergrund der oststeirischen Gneisskomplexe und des südpenninischen Tauernfensters gibt.

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Résumé Cette note présente les résultats d'une étude géochimique des éléments majeurs et en trace d'échantillons de magnésite et de dolomite qui se présentent en masses alternées dans la mine de magnésite de Oberdorf/Laming (Steiermark, Autriche). Une attention particulière a été apportée aux terres rares, considérées comme fournissant des arguments importants dans la discussion de l'origine des gisements. Les teneurs en Al et en terres rares montrent une corrélation positive, ce qui permet de rapporter à un composant argileux la source principale des terres rares. Les résultats obtenus plaident en faveur d'une origine métasomatique des minéralisations en magnésite d'Oberdorf et d'autres endroits des Alpes orientales. Au cours de ce processus, la calcite, d'origine sédimentaire marine, a été le siège d'une dolomitisation avec, subséquemment, formation de corps de magnésite grâce à la circulation de solutions riches en Mg.Au cours de la métasomatose, la distribution des terres rares des carbonates originels n'est pas modifiée: les magnésites montrent des répartitions très semblables à celles des carbonates sédimentaires (lesquels renferment un constituant argileux porteur des terres rares). Des magnésites d'origine purement sédimentaires, formées en milieu évoporitique, doivent présenter un contenu total en terres rares moins élevé et une distribution différente de ces éléments, eu égard à la brièveté de leur séjour dans l'eau de mer. Des analyses de pseudomorphoses de magnésite en talc montrent de même que la distribution des terres rares n'est pas modifiée de manière significative au cours de la talcification. Les solutions riches en Mg responsables de la formation de la magnésite sont probablement dérivées de serpentines situées sous les complexes gneissiques de Styrie et les unités penniques méridionales de la fenêtre des Tauern.

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Potential impacts of climate change on storage conditions for commercial agriculture: an example for potato production in Michigan

Climate change is anticipated to influence all parts of agricultural production systems. However, the potential impacts on crop storage have rarely been assessed, even though storage is an important component of a grower’s marketing strategy and is essential for the continuous supply of a commodity for processors, exporters, and consumers. The Michigan chip-processing potato industry provides an example of the importance of crop storage. Michigan is the largest producer of chip-processing potatoes in the USA, and potatoes are stored on farms from September to June. We use an ensemble of climate projections developed for three future time slices (early, mid, and late century) from 16 climate models forced by three greenhouse gas concentration pathways to assess future changes in potato storage conditions. Our findings indicate an increased future demand for ventilation and/or refrigeration immediately after harvest and again in spring and early summer, even for the early-century time slice. Furthermore, the period of reliably cold storage temperatures during winter is anticipated, when averaged across all models, to shorten by 11–17 days in Michigan’s primary production area and 14–20 days in the more southern secondary area by mid-century, and by 15–29 days and 31–35 days, respectively, for the northern and southern production areas by late century. The level of uncertainty, as indicated by the ensemble range, is large, although the sign of the projected changes in storage parameters is consistent. This case study provides an example of the potentially large effects of climate change on the storage conditions for agricultural commodities.     

Regional Patterns of the Diurnal Properties of Heavy Hourly Precipitation*

Heavy precipitation is one of the most significant natural hazards in the United States today. Knowledge of the climatography, including the temporal characteristics, of this phenomenon is necessary in order to better plan, design for, and predict this hazard. In this study, cluster analysis is used to simplify and clarify the spatial patterns in the time of day heavy precipitation most frequently occurs. Regions with similar diurnal properties are delineated, and the substantial seasonal fluctuations in the regional patterns are traced. Of particular interest is the expansion during the cool season and contraction during the warm season of the nocturnal precipitation regime in the central United States.     

Who determines transformational change in development and climate finance?

The language of transformational change is increasingly applied to climate policy, and particularly in climate finance. Transformational change in this context is used with respect to low-carbon development futures, with the emphasis on mitigation and GHG metrics. But, for many developing countries, climate policy is embedded in a larger context of sustainable development objectives, defined through a national process. Viewed thus, there is a potential tension between mitigation-focused transformation and nationally driven sustainable development. We explore this tension in the context of operationalizing the Green Climate Fund (GCF), which has to deal with the fundamental tension between country ownership and transformational change. In relation to climate finance, acceptance of diverse interpretations of transformation are essential conditions for avoiding risk of transformational change becoming a conditionality on development. We further draw lessons from climate governance and the development aid literature. The article examines how in the case of both the Clean Development Mechanism and Nationally Appropriate Mitigation Actions, there has been limited success in achieving both development objectives and ‘nationally appropriate’ mitigation. The development aid literature points to process-based approaches as a possible alternative, but there are limitations to this approach.

Policy relevance

The concept of transformational change has gained prominence in climate finance. The conundrum facing the GCF is that it seeks to support transformational change in the climate realm, in a context where countries may have competing priorities. Balancing or even transcending this tension is a fundamental design challenge for the GCF. A primary focus on mitigation, particularly if metrics of performance are tied exclusively to GHG reduction, raise concerns about diluting ownership by recipient countries and evokes concerns of conditionality or worse. The literature on development assistance has explored options notably conditions on process and adequate capacity, and suggests that there are no short cuts to building domestic ownership. Actors on climate change need to avoid the risk that transformational change is perceived as, and becomes, an imposed condition. The risk that transformation change, operationalized in the context of unequal power relations, becomes an imposition on development, needs to be avoided.