Ocean acidification-decreasing oceanic pH resulting from the uptake of excess atmospheric CO2-has the potential to affect marine life in the future. Among the possible consequences, a series of ...studies on coral reef fish suggested that the direct effects of acidification on fish behavior may be extreme and have broad ecological ramifications. Recent studies documenting a lack of effect of experimental ocean acidification on fish behavior, however, call this prediction into question. Indeed, the phenomenon of decreasing effect sizes over time is not uncommon and is typically referred to as the "decline effect." Here, we explore the consistency and robustness of scientific evidence over the past decade regarding direct effects of ocean acidification on fish behavior. Using a systematic review and meta-analysis of 91 studies empirically testing effects of ocean acidification on fish behavior, we provide quantitative evidence that the research to date on this topic is characterized by a decline effect, where large effects in initial studies have all but disappeared in subsequent studies over a decade. The decline effect in this field cannot be explained by 3 likely biological explanations, including increasing proportions of studies examining (1) cold-water species; (2) nonolfactory-associated behaviors; and (3) nonlarval life stages. Furthermore, the vast majority of studies with large effect sizes in this field tend to be characterized by low sample sizes, yet are published in high-impact journals and have a disproportionate influence on the field in terms of citations. We contend that ocean acidification has a negligible direct impact on fish behavior, and we advocate for improved approaches to minimize the potential for a decline effect in future avenues of research.
Keeping science honest Sundin, Josefin; Jutfelt, Fredrik
Science (American Association for the Advancement of Science),
03/2018, Letnik:
359, Številka:
6383
Journal Article
Recenzirano
Odprti dostop
We are the whistle-blowers. Our ethical obligations as scientists made it impossible for us to accept a publication of fabricated results, even though it could have cost us our scientific careers. ...The process was slow and arduous, but worked nevertheless. Would we do it again? Yes. It was something we had to do to retain our trust in science.
•The Swedish index VIX is used for classification of ecological status of rivers.•The endangered European eel has a negative influence on the Swedish river index VIX.•The negative effect is due to ...eel being classified as a tolerant species.•Using VIX, mere presence of eel can influence status classification negatively, all else equal.•Improved eel population has negative effects on Swedish river status classification.
Biological indicators are important quality elements for classification of ecological status of water bodies according to the European Water Framework Directive. Multimetric indices are commonly regarded as robust and reliable indicators of human impact and are often used as quality elements. In fish-based indices, species are often grouped into guilds based on general tolerance to common anthropogenic pressures, with higher proportion of tolerant species being indicative of degraded systems. Within the Swedish electrofishing index VIX, the critically endangered European eel Anguilla anguilla (L.) is classified as a tolerant indicator species, and it therefore has a negative effect on classified ecological status. The scientific literature, however, suggests that eels are not generally tolerant and they benefit from similar environmental conditions as many insensitive species. VIX has been criticized for being too sensitive to the presence of eel in catch data, leading to low status classifications when eels are caught in the monitoring surveys. In a case study using manipulations of historical electrofishing data, we assessed the influence of eel presence and abundance on the ecological status classification as determined by VIX. We demonstrate that reduction of eels in survey data have positive effects on the classified status, in many cases substantial effects. An increase of eels in the data had the reverse effect. Mere presence of eel had a strong negative effect, which is problematic if the aim is to increase the endangered eel population. Given the Swedish classification system where the quality element indicating the worst status is decisive, the classified ecological status of Swedish rivers can theoretically be improved by management actions disfavouring eel, unless the results from VIX are carefully evaluated by experts. Along the same lines, measures implemented with an aim to increase the endangered eel population will lead to a decrease in assessed ecological status of Swedish rivers. Our conclusion is that the usage of VIX within Swedish water management is problematic and needs revision. From a broader perspective, the classification of species as generally tolerant need to be approached with great caution when developing new indices for assessing ecological status and integrity.
Theoretical models predict that ocean acidification, caused by increased dissolved CO
, will reduce the maximum thermal limits of fishes, thereby increasing their vulnerability to rising ocean ...temperatures and transient heatwaves. Here, we tested this prediction in three species of damselfishes on the Great Barrier Reef, Australia. Maximum thermal limits were quantified using critical thermal maxima (CT
) tests following acclimation to either present-day or end-of-century levels of CO
for coral reef environments (∼500 or ∼1000 µatm, respectively). While species differed significantly in their thermal limits, whereby
exhibited greater CT
(37.88±0.03°C;
=47) than
(37.68±0.02°C;
=85) and
(36.58±0.02°C;
=63), end-of-century CO
had no effect (
) or a slightly positive effect (increase in CT
of 0.16°C in
and 0.21°C in
) on CT
Contrary to expectations, early-stage juveniles were equally as resilient to CO
as larger conspecifics, and CT
was higher at smaller body sizes in two species. These findings suggest that ocean acidification will not impair the maximum thermal limits of reef fishes, and they highlight the critical role of experimental biology in testing predictions of theoretical models forecasting the consequences of environmental change.
The effects of increased levels of carbon dioxide (CO
) on the Earth's temperature have been known since the end of the 19th century. It was long believed that the oceans' buffering capacity would ...counteract any effects of dissolved CO
in marine environments, but during recent decades, many studies have reported detrimental effects of ocean acidification on aquatic organisms. The most prominent effects can be found within the field of behavioural ecology, e.g., complete reversal of predator avoidance behaviour in CO
-exposed coral reef fish. Some of the studies have been very influential, receiving hundreds of citations over recent years. The results have also been conveyed to policymakers and publicized in prominent media outlets for the general public. Those extreme effects of ocean acidification on fish behaviour have, however, spurred controversy, given that more than a century of research suggests that there are few or no negative effects of elevated CO
on fish physiology. This is due to sophisticated acid-base regulatory mechanisms that should enable their resilience to near-future increases in CO
. In addition, an extreme "decline effect" has recently been shown in the literature regarding ocean acidification and fish behaviour, and independent research groups have been unable to replicate some of the most profound effects. Here, the author presents a brief historical overview on the effects of elevated CO
and ocean acidification on fishes. This historical recap is warranted because earlier work, prior to a recent (c. 10 year) explosion in interest, is often overlooked in today's ocean acidification studies, despite its value to the field. Based on the historical data and the current knowledge status, the author suggests future strategies with the aim to improve research rigour and clarify the understanding of the effects of ocean acidification on fishes.
Clements et al. respond to Munday's claim that his "reanalysis shows there is not an extreme decline effect in fish ocean acidification studies". They contend that extreme data reported in early ...studies authored by Dixson and Munday indeed result in an "extreme" decline effect in this field, and conclude that the decline effect is primarily driven by papers by particular authors.
Summary Background Concerns have been raised about the psychological effect of continued combat exposure and of repeated deployments. We examined the consequences of deployment to Iraq and ...Afghanistan on the mental health of UK armed forces from 2003 to 2009, the effect of multiple deployments, and time since return from deployment. Methods We reassessed the prevalence of probable mental disorders in participants of our previous study (2003–05). We also studied two new randomly chosen samples: those with recent deployment to Afghanistan, and those who had joined the UK armed forces since April, 2003, to ensure that the final sample continued to be representative of the UK armed forces. Between November, 2007, and September, 2009, participants completed a questionnaire about their deployment experiences and health outcomes. Findings 9990 (56%) participants completed the study questionnaire (8278 regulars, 1712 reservists). The prevalence of probable post-traumatic stress disorder was 4·0% (95% CI 3·5–4·5; n=376), 19·7% (18·7–20·6; n=1908) for symptoms of common mental disorders, and 13·0% (12·2–13·8; n=1323) for alcohol misuse. Deployment to Iraq or Afghanistan was significantly associated with alcohol misuse for regulars (odds ratio 1·22, 95% CI 1·02–1·46) and with probable post-traumatic stress disorder for reservists (2·83, 1·23–6·51). Regular personnel in combat roles were more likely than were those in support roles to report probable post-traumatic stress disorder (1·87, 1·26–2·78). There was no association with number of deployments for any outcome. There was some evidence for a small increase in the reporting of probable post-traumatic stress disorder with time since return from deployment in regulars (1·13, 1·03–1·24). Interpretation Symptoms of common mental disorders and alcohol misuse remain the most frequently reported mental disorders in UK armed forces personnel, whereas the prevalence of probable post-traumatic stress disorder was low. These findings show the importance of continued health surveillance of UK military personnel. Funding UK Ministry of Defence.
Behavioural abnormality in fishes has been proposed as a significant consequence of the increasing levels of carbon dioxide occurring in the oceans. Negative effects of elevated CO2 have been ...reported for behaviours such as predator–prey interactions, foraging, hearing and behavioural lateralization. Importantly, the effects vary greatly both within and between species, and some recent studies have shown minimal effects of CO2 on behaviour. Whether the effect of CO2 also varies between males and females is, however, virtually unexplored. According to resource allocation theory, females are expected to be more sensitive to elevated CO2, meaning that non-sex-specific studies may overlook ecologically important differences between the sexes. In this study, we investigated the possible differences between males and females in their response to elevated CO2 by performing behavioural lateralization tests in adult temperate two-spotted gobies, Gobiusculus flavescens. We found that the strength of the side bias (absolute lateralization) was unaffected by the CO2 treatment, and there was no difference between males and females. The control fish were slightly right-biased in their behavioural asymmetry (mean relative lateralization of 14). Exposure to high CO2 affected this pattern, such that treated fish were slightly left-biased (mean relative lateralization of −10), regardless of their sex. The same results were obtained yet again when the study was repeated during a second year. We discuss our results in light of the great variation in lateralization that has been reported to depend on variables such as species, ecological settings and environmental factors.
The incidence of cutaneous malignant melanoma, which is mostly attributable (86%) to UV radiation exposure, has been steadily increasing over the past four decades in predominantly fair-skinned ...populations. Although public health campaigns are increasing sun-protective behaviour in England, their effect on melanoma incidence is largely unknown. We conducted a retrospective population-based cohort study to examine whether there have been changes in the epidemiology of melanoma in England during the past four decades.
Individual level data for patients diagnosed with melanoma in England during 1981–2018 were obtained from the Office for National Statistics/Public Health England. Average annual incidence rates were calculated by three age categories (0–34, 35–64, 65+ years), gender and anatomical site during the seven five-year time periods (1981–85 to 2011–15) and the recent three-year period (2016–18). The percentage change in incidence was calculated as change in the average incidence rate from the first (1981–85) to the last time period (2016–18). The Average Annual Percentage Change (AAPC) was estimated using the slope of the linear trend line fitted to the incidence rates by year of diagnosis.
During the 38-year period (1981–2018), a total of 265,302 cases of melanoma (45.7% males, 54.3% females) were registered in England. The average annual number of cases increased from 837/year in 1981–85 to 6963/year in 2016–18 in males (+732%), and from 1609/year in 1981–85 to 6952/year in 2016–18 in females (+332%). In the young age-group (0–34 years), the average annual incidence rates initially increased from 1981–85 to 2001–05 and then stabilised during the recent period (2006–18). In the middle age group (35–64 years), the rates increased by +332% (AAPC, 10.4%) in males (from 5.6/100,000 in 1981–85 to 24.2/100,000 in 2016–18) and +185% (AAPC, 5.7%) in females (from 10.2/100,000 in 1981–85 to 29.1/100,000 in 2016–18); and in the old age-group (65+ years) the rates increased by +842% (AAPC, 25.7%) in males (from 9.6/100,000 in 1981–85 to 90.4/100,000 in 2016–18) and +381% (AAPC, 11.2%) in females (from 12.5/100,000 in 1981–85 to 60.1/100,000 in 2016–18). The largest increase in incidence in both males and females was observed for melanoma of the trunk (+817%, AAPC, 24.8% in males and +613%, AAPC, 18.3% in females), followed by melanoma of upper limb (+750%, AAPC, 22.9% in males and 518%, AAPC, 15.5% in females).
It appears that the incidence of melanoma among young people in England has stabilised (or levelled off) in recent decades, whereas it continues to increase substantially in older population. These findings suggest that public health campaigns targeted at children/adolescents/parents may be favourably influencing melanoma incidence. The steeper increase in incidence in males is consistent with their relatively greater sun exposure and poor sun-protective behaviour. All the available evidence suggests that the enormous increase in the melanoma of the trunk and upper limb, since the 1980s, is most likely due to increasing trend in intermittent high intensity recreational UV radiation exposure (e.g. sunbathing, holidaying in places with strong sunlight, indoor tanning).
This work was supported by Brighton and Sussex Medical School (BSMS).
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