Mixoplankton and mixotrophy: future research priorities.

Phago-mixotrophy, the combination of photoautotrophy and phagotrophy in mixoplankton, organisms that can combine both trophic strategies, have gained increasing attention over the past decade. It is now recognized that a substantial number of protistan plankton species engage in phago-mixotrophy to obtain nutrients for growth and reproduction under a range of environmental conditions. Unfortunately, our current understanding of mixoplankton in aquatic systems significantly lags behind our understanding of zooplankton and phytoplankton, limiting our ability to fully comprehend the role of mixoplankton (and phago-mixotrophy) in the plankton food web and biogeochemical cycling. Here, we put forward five research directions that we believe will lead to major advancement in the field: (i) evolution: understanding mixotrophy in the context of the evolutionary transition from phagotrophy to photoautotrophy; (ii) traits and trade-offs: identifying the key traits and trade-offs constraining mixotrophic metabolisms; (iii) biogeography: large-scale patterns of mixoplankton distribution; (iv) biogeochemistry and trophic transfer: understanding mixoplankton as conduits of nutrients and energy; and (v) in situ methods: improving the identification of in situ mixoplankton and their phago-mixotrophic activity.

Snapshot of suspected acute coronary syndrome assessment processes in the emergency department: A national cross-sectional survey.

OBJECTIVE: The Snapshot of Suspected ACS Assessment (SSAASY) study aims to describe the assessment processes for patients with suspected acute coronary syndrome (ACS) in Australian EDs, and to compare these processes with the National Heart Foundation of Australia and Cardiac Society of Australia and New Zealand (NHFA/CSANZ) guidelines. METHODS: Between March and May 2021, a cross-sectional survey of Australian EDs was undertaken to investigate the assessment strategies used within the ED. All public and private hospitals identified as having dedicated EDs were invited to participate. Respondents provided data on hospital, ED and cardiac service characteristics. They also provided data on the risk stratification process recommended within their department (risk scores, troponin testing, objective testing for coronary artery disease). Awareness of the NHFA/CSANZ guidelines was assessed. RESULTS: Responses were received from 109/162 departments (67%). Most sites (n = 100, 92%) reported using dedicated protocols developed by ED clinicians that included risk stratification scores. Highly sensitive troponin assays were used at 103 (94%) sites. Serial troponin testing was performed over 2 h for low-risk patients in 53 (49%) sites and 2-3 h for intermediate and high-risk patients in 74 (68%) sites. Further investigations included exercise stress tests (48%) and stress echocardiography (38%), with 45% of sites ordering outpatient investigations. CONCLUSIONS: The SSAASY study reported the strategies used to assess suspected ACS. In line with current NHFA/CSANZ guidelines, highly sensitive troponin assays are widely utilised. However, serial sampling intervals were longer than guideline recommendations, suggesting a translational gap between guidelines and clinical practice.

Massive phytoplankton blooms under Arctic sea ice.

Phytoplankton blooms over Arctic Ocean continental shelves are thought to be restricted to waters free of sea ice. Here, we document a massive phytoplankton bloom beneath fully consolidated pack ice far from the ice edge in the Chukchi Sea, where light transmission has increased in recent decades because of thinning ice cover and proliferation of melt ponds. The bloom was characterized by high diatom biomass and rates of growth and primary production. Evidence suggests that under-ice phytoplankton blooms may be more widespread over nutrient-rich Arctic continental shelves and that satellite-based estimates of annual primary production in these waters may be underestimated by up to 10-fold.