Effects of Ocean Acidification on the phenotypic plasticity and functional properties of European sea bass (Dicentrarchus labrax) haemoglobin

Due to anthropogenic emissions, sea water pH has decreased about 0.1 units since preindustrial times, and will continue to decline up to 0.4 units by the end of this century. The acclimation capacity of marine life to ocean acidification is a subject of rising interest and importance, still studies on animals with well-developed ion- regulating capacities, such as fish, are comparatively scarce. In this study, acclimation capacities of European sea bass (Dicentrarchus labrax) haemoglobin (Hb) on a functional and molecular level have been researched, by means of oxygen equilibrium curves and qPCR. Fish were reared under three different environmental relevant CO2 partial pressures, with a total incubation time of 33 months. Results show that neither oxygen tension at 50% protein saturation (P50) and cooperativity (n50), nor haematocrit and isoform expression levels change under environmental hypercapnia. The pH dependant O2 affinity (pH50) was found to significantly decrease in both high CO2 treatments. Since molecular analyses suggest that changes in pH sensitivity are not caused by a shift in Hb isoforms to more pH sensitive proteins, an over-compensatory blood alkalosis, followed by chronically elevated erythrocytic organic phosphate levels (GTP and ATP) are assumed. Data indicate that sea bass Hb is adapted to changes in sea water pH, which can be linked to its ecological niche in coastal and estuarine habitats, where fluctuations in abiotic parameters, such as pH, are frequent. Nevertheless, if ocean acidification causes a chronic elevation in organic phosphate levels, sea bass would be facing an energetically costly regulation to maintain respiratory homeostasis, and it would consequently reduce the overall fitness of the animal

Impacts of 1.5°C Global Warming on Natural and Human Systems

An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate povert

Investigating the gill-oxygen limitation hypothesis in fishes: intraspecific scaling relationships of metabolic rate and gill surface area

Abstract Many ectotherms have shown a reduction in maximum body size in the past decades in parallel with climate warming. Indeed, some models forecast a maximum body size decline of 14%&ndash;24% by 2050 for numerous fish species. The gill-oxygen limitation (GOL) hypothesis is perhaps the most prominent concept regarding the physiological mechanisms underlying the observed trends, implicating oxygen uptake limitations in driving the decline in fish body size with warming. Current scientific debates, however, demonstrate a clear need for a synthesis of existing empirical evidence to test the fundamental assumptions of the GOL hypothesis. Here, we perform a systematic literature review of the intraspecific allometry of gill surface area (GSA) and metabolic rate. Additionally, we introduce a new parameter, the ratio S, which provides a measure of GSA in relation to the metabolic requirements for maintenance (SSMR) and maximum activity (SAMR). Support for the GOL hypothesis would be evidenced by a universal decline in S with increasing body mass within each species, such that gills become less equipped to supply metabolic requirements as fish grow. In contrast to the predictions of the GOL hypothesis, we show that the scaling exponents for SSMR and SAMR are consistently close to zero, with only a few exceptions where S either increased or decreased. These findings suggest that the GSA of each species is sufficient to meet its oxygen requirements throughout life, and that growth is not universally restricted by oxygen uptake limitations across the gills. We identify the need to investigate hypotheses other than the GOL hypothesis to help explain the observed declines in maximum fish body sizes concurrent with climate warming, in order to facilitate accurate predictions of fish community structure and manage fisheries in the face of climate change.</jats:p

Dementia Care Competency Model for Higher Education: A Pilot Study

A statewide landscape analysis was initiated to identify workforce development and educational needs concerning the support of persons with Alzheimer’s Disease and Related Dementias (ADRD). Educational programs preparing healthcare professionals were targeted since people with ADRD, and their families/caregivers, often have frequent, ongoing contact with healthcare providers. A literature review and thematic analysis discovered a dearth of research and a lack of consistent competency identification for healthcare education. A crosswalk comparison of various competency models led to the development of a five factor model. A survey based on this model was sent to educators statewide evaluating confidence in ADRD-specific competency attainment in graduates. Descriptive statistics and factor analysis led to a revision of the original five factor model to a three factor model, including competencies in Global Dementia knowledge, Communication, and Safety, each with various sub-competencies. Identifying ADRD-specific competencies for graduating healthcare students is essential. This three factor competency framework will support educational programs in examining curricular offerings and increasing awareness concerning the needs of the ADRD population. Furthermore, using a robust competency model for healthcare education can assist in preparing graduates to address the needs of those with ADRD as well as the needs of the family/caregiving system and environment

Behavioural temperature regulation is a low priority in a coral reef fish (Plectropomus leopardus): insights from a novel behavioural thermoregulation system

Current understanding of behavioural thermoregulation in aquatic ectotherms largely stems from systems such as ‘shuttle boxes’, which are generally limited in their capacity to test large-bodied species. Here, we introduce a controlled system that allows large aquatic ectotherms to roam freely in a tank at sub-optimal temperatures, using thermal refuges to increase body temperature to their thermal optimum as desired. Of the 10 coral grouper (Plectropomus leopardus; length ∼400 mm) implanted with thermal loggers, three fish maintained themselves at the ambient tank temperature of 17.5–20.5°C for the entire 2–4 days of the trial. Of the other seven fish, body temperature never exceeded ∼21.5°C, which was well below the temperature available in the thermal refuges (∼31°C) and below the species' optimal temperature of ∼27°C. This study adds to a growing literature documenting an unexpected lack of behavioural thermoregulation in aquatic ectotherms in controlled, heterothermal environments

Paths towards greater consensus building in experimental biology

ABSTRACT In a recent editorial, the Editors-in-Chief of Journal of Experimental Biology argued that consensus building, data sharing, and better integration across disciplines are needed to address the urgent scientific challenges posed by climate change. We agree and expand on the importance of cross-disciplinary integration and transparency to improve consensus building and advance climate change research in experimental biology. We investigated reproducible research practices in experimental biology through a review of open data and analysis code associated with empirical studies on three debated paradigms and for unrelated studies published in leading journals in comparative physiology and behavioural ecology over the last 10 years. Nineteen per cent of studies on the three paradigms had open data, and 3.2% had open code. Similarly, 12.1% of studies in the journals we examined had open data, and 3.1% had open code. Previous research indicates that only 50% of shared datasets are complete and re-usable, suggesting that fewer than 10% of studies in experimental biology have usable open data. Encouragingly, our results indicate that reproducible research practices are increasing over time, with data sharing rates in some journals reaching 75% in recent years. Rigorous empirical research in experimental biology is key to understanding the mechanisms by which climate change affects organisms, and ultimately promotes evidence-based conservation policy and practice. We argue that a greater adoption of open science practices, with a particular focus on FAIR (Findable, Accessible, Interoperable, Re-usable) data and code, represents a much-needed paradigm shift towards improved transparency, cross-disciplinary integration, and consensus building to maximize the contributions of experimental biologists in addressing the impacts of environmental change on living organisms.</jats:p