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Marine heatwaves are increasing in frequency and intensity as climate change progresses, especially in the highly productive Arctic regions. Although their effects on primary producers will largely determine the impacts on ecosystem services, mechanistic understanding on phytoplankton responses to these extreme events is still very limited. We experimentally exposed Arctic phytoplankton assemblages to stable warming, as well as to repeated heatwaves, and measured temporally resolved productivity, physiology, and composition. Our results show that even extreme stable warming increases productivity, while the response to heatwaves depends on the specific scenario applied and is not predictable from stable warming responses. This appears to be largely due to the underestimated impact of the cool phase following a heatwave, which can be at least as important as the warm phase for the overall response. We show that physiological and compositional adjustments to both warm and cool phases drive overall phytoplankton productivity and need to be considered mechanistically to predict overall ecosystem impacts.

Growth rates and other biomass traits of phytoplankton are strongly affected by temperature. We hypothesized that resulting phenotypes originate from deviating temperature sensitivities of underlying physiological processes. We used membrane-inlet mass spectrometry to assess photosynthetic and respiratory O 2 and CO 2 fluxes in response to abrupt temperature changes as well as after acclimation periods in the diatom Phaeodactylum tricornutum. Abrupt temperature changes caused immediate over- or undershoots in most physiological processes, that is, photosynthetic oxygen release ( PS O 2 ), photosynthetic carbon uptake ( PS CO 2 ), and respiratory oxygen release ( R O 2 ). Over acclimation timescales, cells were, however, able to re-adjust their physiology and revert to phenotypic 'sweet spots'. Respiratory CO 2 release ( R CO 2 ) was generally inhibited under high temperature and stimulated under low-temperature settings, on abrupt as well as acclimation timescales. Such behavior may help mitochondria to stabilize plastidial ATP : NADPH ratios and thus maximize photosynthetic carbon assimilation., (© 2023 The Authors. New Phytologist © 2023 New Phytologist Foundation.)

With increasing mpox cases in Maricopa County, Arizona, the county's health department launched a survey on July 11, 2022, to gather eligibility and contact data and provide clinic information to those interested in JYNNEOS as postexposure prophylaxis (PEP) or expanded postexposure prophylaxis(PEP++). Survey data were matched to case and vaccination data. Overall, 343 of the 513 respondents (66.9%) who reported close contact with an mpox case patient received PEP and 1712 of the 3379 respondents (50.7%) who were unsure of their contact status received PEP++. This outreach intervention connected potential close contacts unknown to MCDPH with PEP or PEP++. ( Am J Public Health. 2023;113(5):504-508. https://doi.org/10.2105/AJPH.2023.307224).

High-entropy perovskite oxides have already been studied in various fields owing to their high-entropy-induced properties. Partial substitution of an element by a lower valence element usually improves the oxygen permeability of perovskite oxides, but high substitution amounts may lead to structural instability. In this work, pure high-entropy perovskites Pr 1- x Sr x (Cr,Mn,Fe,Co,Ni)O 3-δ with high amounts Sr up to x = 0.5 were synthesized via a sol-gel method. Several characterization methods prove that the solubility of Sr increases with higher temperatures of the heating treatment. The ceramic with x  = 0.5 shows a transition from semi-conductive to metallic behavior when the temperature reaches 873K. Its oxygen flux is comparable to the low-entropy counterpart La 0.6 Sr 0.4 Co 0.5 Fe 0.5 O 3-δ . A stable run of ca. 46.2 h was documented for oxygen permeation under an air/CO 2 gradient.