Interpreting the sign of coral bleaching as friend vs. foe

Coral bleaching is a major concern to researchers, conservationists and the general public worldwide. To date, much of the high profile attention for bleaching has coincided with major environmental impacts and for many the term coral bleaching is synonymously associated with coral mortality (so‐called ‘lethal’ bleaching episodes). While this synonymous association has undoubtedly been key in raising public support, it carries unfair representation: nonlethal bleaching is, and always has been, a phenomenon that effectively occurs regularly in nature as corals acclimatize to regular periodic changes in growth environment (days, seasons etc). In addition, corals can exhibit sublethal bleaching during extreme environmental conditions whereby mortality does not occur and corals can potentially subsequently recover once ambient environmental conditions return. Perhaps not surprisingly it is the frequency and extent of these non and sublethal processes that yield key evidence as to how coral species and reef systems will likely withstand environmental and thus climatic change. Observations of non and sublethal bleaching (and subsequent recovery) are arguably not as readily reported as those of lethal bleaching since (1) the convenient tools used to quantify bleaching yield major ambiguity (and hence high potential for misidentification) as to the severity of bleaching; and (2) lethal bleaching events inevitably receive higher profile (media) attention and so are more readily reported. Under‐representation of non and sublethal bleaching signs may over‐classify the severity of bleaching, under‐estimate the potential resilience of reefs against environmental change, and thus ultimately limit (if not depreciate) the validity and effectiveness of reef management policies and practices. While bleaching induced coral mortality must remain our key concern it must be better placed within the context of bleaching signs that do not result in a long‐term loss of reef viability.     

A major fish stranding caused by a natural hypoxic event in a shallow bay of the eastern South Pacific Ocean

A massive beaching and mortality of fishes occurred in Coliumo Bay, a shallow bay located along the coast of the eastern South Pacific Ocean on 3 January 2008. This stranding was a consequence of an abrupt decrease in the dissolved oxygen concentration throughout the whole water column, due to the effect of intense upwelling along the coast off central‐southern Chile. The main objectives of this study were: (1) to characterize taxonomically and biologically the fish species assemblage present in this beaching; (2) to evaluate several physiological indicators for the condition of the beached species at the time of their death; and (3) to assess the possible cause–effect mechanisms involved in the fishes death and the changes that took place in the fish community throughout the time. In this beaching, 26 fish species were identified: 23 teleosts, one myxiniform and two elasmobranchs. Most beached specimens were juveniles. Haematological and histological evidence indicate that severe hypoxia that lasted for at least 48 h was the most plausible cause of death. The main conclusion of this study is that the presence of oxygen‐poor equatorial sub‐surface water in the shallow coastal zone due to intense regional‐scale upwelling caused the fish stranding. Although the effect of the hypoxic event was severe for the fish assemblage of Coliumo Bay, the rapid recuperation observed suggests that hypoxic events at the local spatial scale can be buffered by migration processes from the fish community inhabiting close by areas non‐affected by low oxygen conditions. The effect that severe hypoxic events may have on larger spatial scales remains unknown.     

Correlation of Hemoglobin A1C and Outcomes in Patients Hospitalized With COVID-19

ObjectiveDiabetes is a known risk factor for severe coronavirus disease 2019 (COVID-19). We conducted this study to determine if there is a correlation between hemoglobin A1C (HbA1C) level and poor outcomes in hospitalized patients with diabetes and COVID-19.MethodsThis is a retrospective, single-center, observational study of patients with diabetes (defined by an HbA1C level of ≥6.5% or known medical history of diabetes) who had a confirmed case of COVID-19 and required hospitalization. All patients were admitted to our institution between March 3, 2020, and May 5, 2020. HbA1C results for each patient were divided into quartiles: 5.1% to 6.7% (32-50 mmol/mol), 6.8% to 7.5% (51-58 mmol/mol), 7.6% to 8.9% (60-74 mmol/mol), and >9% (>75 mmol/mol). The primary outcome was in-hospital mortality. Secondary outcomes included admission to an intensive care unit, invasive mechanical ventilation, acute kidney injury, acute thrombosis, and length of hospital stay.ResultsA total of 506 patients were included. The number of deaths within quartiles 1 through 4 were 30 (25%), 37 (27%), 34 (27%), and 24 (19%), respectively. There was no statistical difference in the primary or secondary outcomes among the quartiles, except that acute kidney injury was less frequent in quartile 4.ConclusionThere was no significant association between HbA1C level and adverse clinical outcomes in patients with diabetes who are hospitalized with COVID-19. HbA1C levels should not be used for risk stratification in these patients.     

Cause of egg mortality in azuki bean weevils (Callosobruchus chinensis): physical or chemical?

The cause of high egg mortality at high adult density in azuki bean weevil is still controversial. It may be physical, as a result of adult trampling, or chemical, as a result of substance(s) secreted by adults and coated on the bean surface. In this study, I first constructed simple mathematical models based on each mechanism, which could predict the change of egg hatchability oviposited on different dates at different adult densities. I then devised an experimental method that could identify the fate of eggs oviposited on different dates. The experimental results showed that egg mortality was most likely caused by adult trampling. An erratum to this article can be found at     

Poor Performance of Corals Transplanted onto Substrates of Short Durability

Worldwide, coral reefs are degrading due to increasing anthropogenic pressures. Yet, management of reefs still falls short of effectively addressing these threats, and active restoration methods are increasingly being called for. Coral transplantation is frequently advocated as a possible means of coral reef rehabilitation. Fragments produced in coral nurseries or farms have been proposed as a potential source for transplantation, and culture media (inexpensive but non‐durable materials such as wood or bamboo) may serve as transplantation substrate if placed directly in the reef. However, the performance of coral transplants attached to such substrates has not been examined yet. Here, the long‐term survival of transplants attached to bamboo substrates is reported. A total of 6,164 fragments of 4 coral species (Acroporids and Pocilloporids) were monitored for up to 20 months at three sites in North Sulawesi/Indonesia. Bamboo failed as a suitable inexpensive substrate in at least two of the three sites examined. Mortality of transplants 2 years after transplantation was high in three of the four species (67–95%) and was partially linked to substrate disintegration. The results show that, in places were currents or waves threaten to dislocate transplants, a higher effort needs to be directed at a strong and durable attachment of transplanted corals.