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An unprecedented devastating forest fire occurred in Australia from September 2019 to March 2020. Satellite observations revealed that this rare fire event in Australia destroyed a record amount of more than 202,387 km 2 of forest, including 56,471 km 2 in eastern Australia, which is mostly composed of evergreen forest. The released aerosols contained essential nutrients for the growth of marine phytoplankton and were transported by westerly winds over the Southern Ocean, with rainfall-induced deposition to the ocean beneath. Here, we show that a prominent oceanic bloom, indicated by the rapid growth of phytoplankton, took place in the Southern Ocean along the trajectory of fire-born aerosols in response to atmospheric deposition. Calculations of carbon released during the fire versus carbon absorbed by the oceanic phytoplankton bloom suggest that they were nearly equal. This finding illustrates the critical role of the oceans in mitigating natural and anthropogenic carbon dioxide releases to the atmosphere, which are a primary driver of climate change., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests that could have appeared to influence the work reported in this manuscript., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Stress-tolerant coral species, such as Platygyra spp., are considered to be well adapted to survive in marginal reefs, but their physiological response to short term exposure to abnormally high temperature and lowered salinity remains poorly understood. Using non-invasive techniques to quantitatively assess the health of Platygyra carnosa (e.g. respiration, photosynthesis, biocalcification and whiteness), we identified the plasticity of its energetics and physiological limits. Although these indicators suggest that it can survive to increasing temperature (25-32 °C), its overall energetics were seriously diminished at temperatures >30 °C. In contrast, it was well adapted to hyposaline waters (31-21 psu) but with reduced biocalcification, indicating short term adaptation for expected future changes in salinity driven by increased amounts and intensities of precipitation. Our findings provide useful insights to the effect of these climate drivers on P. carnosa metabolism and thus better forecast changes in their health status under future climate change scenarios., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

There is increasing concern that accelerating environmental change attributed to human-induced warming of the planet may substantially alter the patterns, distribution and intensity of Harmful Algal Blooms (HABs). Changes in temperature, ocean acidification, precipitation, nutrient stress or availability, and the physical structure of the water column all influence the productivity, composition, and global range of phytoplankton assemblages, but large uncertainty remains about how integration of these climate drivers might shape future HABs. Presented here are the collective deliberations from a symposium on HABs and climate change where the research challenges to understanding potential linkages between HABs and climate were considered, along with new research directions to better define these linkages. In addition to the likely effects of physical (temperature, salinity, stratification, light, changing storm intensity), chemical (nutrients, ocean acidification), and biological (grazer) drivers on microalgae (senso lato), symposium participants explored more broadly the subjects of cyanobacterial HABs, benthic HABs, HAB effects on fisheries, HAB modelling challenges, and the contributions that molecular approaches can bring to HAB studies. There was consensus that alongside traditional research, HAB scientists must set new courses of research and practices to deliver the conceptual and quantitative advances required to forecast future HAB trends. These different practices encompass laboratory and field studies, long-term observational programs, retrospectives, as well as the study of socioeconomic drivers and linkages with aquaculture and fisheries. In anticipation of growing HAB problems, research on potential mitigation strategies should be a priority. It is recommended that a substantial portion of HAB research among laboratories be directed collectively at a small sub-set of HAB species and questions in order to fast-track advances in our understanding. Climate-driven changes in coastal oceanographic and ecological systems are becoming substantial, in some cases exacerbated by localized human activities. That, combined with the slow pace of decreasing global carbon emissions, signals the urgency for HAB scientists to accelerate efforts across disciplines to provide society with the necessary insights regarding future HAB trends., (Copyright © 2019. Published by Elsevier B.V.)

Climate driven increases in ocean temperature and pCO 2 have the potential to alter the growth and prevalence of future Harmful Algal Blooms (HABs), but systematic studies on how climate drivers influence toxic algal species relative to non-toxic phytoplankton are lacking. In particular, little is known about how future climate scenarios will affect the growth of the toxic dinoflagellate Alexandrium catenella, which is responsible for the paralytic shellfish poisoning (PSP) events that threaten the health and economy of coastal communities in the Gulf of Maine and elsewhere. The growth responses of A. catenella and two other naturally co-occurring dinoflagellates in the Gulf of Maine-Scrippsiella sp., and Amphidinium carterae-were studied in mono and mixed species cultures. Experimental treatments tested the effects of elevated temperature (20 °C), lower pH (7.8), and the combination of elevated temperature and lower pH on growth rates relative to those in near-current conditions (15 °C; pH 8.1). Growth rates of A. catenella decreased under elevated temperature and lower pH conditions, a response that was largely attributable to the effect of temperature. In contrast, growth rates of Scrippsiella sp. and A. carterae increased under elevated temperature and lower pH conditions, with temperature also being the primary driver of the response. These trends did not change substantially when these species were grown in mixed cultures (A. catenella + Scrippsiella sp., and A. catenella + A. carterae), indicating that allelopathic or competitive interactions did not affect the experimental outcome under the conditions tested. These findings suggest that A. catenella blooms may become less prevalent in the southern regions of the Gulf of Maine, but potentially more prevalent in the northeastern regions of the Gulf of Maine with continued climate change., (Copyright © 2019. Published by Elsevier B.V.)

Ocean acidification (OA) has potential to affect marine phytoplankton in ways that are partly understood, but there is less knowledge about how it may alter the coupling to secondary producers. We investigated the effects of OA on phytoplankton primary production, and its trophic transfer to zooplankton in a subtropical eutrophic water (Wuyuan Bay, China) under present day (400 μatm) and projected end-of-century (1000 μatm) pCO 2 levels. Net primary production was unaffected, although OA did lead to small decreases in growth rates. OA had no measurable effect on micro-/mesozooplankton grazing rates. Elevated pCO 2 had no effect on phytoplankton fatty acid (FA) concentrations during exponential phase, but saturated FAs increased relative to the control during declining phase. FA profiles of mesozooplankton were unaffected. Our findings show that short-term exposure of plankton communities in eutrophic subtropical waters to projected end-of-century OA conditions has little effect on primary productivity and trophic linkage to mesozooplankton., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Blooms of Pseudo-nitzschia species are frequent, but presently unpredictable, in the Juan de Fuca Eddy region off the coasts of Washington (US) and British Columbia (Canada). This upwelling eddy region is proposed to be the bloom commencement site, before cells are entrained into the coastal surface currents. During a shipboard study, we characterized the different stages of the Pseudo-nitzschia bloom development from its initiation and intensification, to its eventual sinking and dissipation. Specifically, we followed a water mass using lagrangian ARGOS-tracked drifters released at the eddy water mass and quantified production of dissolved and particulate domoic acid, and the physiological status of the Pseudo-nitzschia cells with regards to photosynthesis, nutrient needs and sinking rates, along with its relationship with competing species - in this case, the marine euglenoid, Eutreptiella spp. The drifter study allows for an interpretation of the presence or absence of Pseudo-nitzschia and domoic acid against active environmental factors - particularly copper and iron., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Intense blooms of the heterotrophic dinoflagellate, green Noctiluca scintillans, have been reported annually in the Northern Arabian Sea since the early 2000s. Although not known to produce organic toxins, these blooms are still categorized as a harmful due to their association with massive fish mortalities. Recent work has attributed these blooms to the vertical expansion of the oxygen minimum zone, driven by cultural eutrophication from major coastal cities in western India. As diatoms are preferred prey of green Noctiluca scintillans, more frequent blooms of this mixotroph will likely impact the productivity of important fisheries in the region. The present study uses a satellite algorithm to determine the distribution of both diatom and green Noctiluca blooms in the Northeastern Arabian Sea from 2009 to 2016. The results from shipboard microscopy of phytoplankton community composition were used to validate the satellite estimates. The satellite algorithm showed 76% accuracy for detection of green Noctiluca and 92% for diatoms. Shipboard measurements and data from biogeochemical-Argo floats were used to assess the relationship between oxygen concentrations and green Noctiluca blooms in the Northeastern Arabian Sea. Regardless of the presence of a Noctiluca bloom, the dissolved oxygen in the photic zone was always >70% saturated, with an average oxygen saturation >90%. The variability in the relative abundance of diatoms and green Noctiluca is not correlated with changes in oxygen concentration. These findings provide no evidence that cultural eutrophication has contributed to the decadal scale shifts in plankton composition in the Northeastern Arabian Sea oceanic waters. Conversely, the climatic warming of surface waters would have intensified stratification, thereby reducing net nutrient flux to the photic zone and decreasing silicate to nitrate ratios (Si:N); both factors that could increase the competitive advantage of the mixotroph, green Noctiluca, over diatoms. If so, the decadal-scale trajectory of phytoplankton community composition in the Northeastern Arabian Sea may be a harbinger of future climate-driven change in other productive oceanic systems., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Ocean Acidification (OA) effects on marine plankton are most often considered in terms of inorganic carbon chemistry, but decreasing pH may influence other aspects of cellular metabolism. Here we present the effects of OA on the fatty acid (FA) content and composition of an artificial phytoplankton community (Phaeodactylum tricornutum, Thalassiosira weissflogii, and Emiliania huxleyi) in a fully replicated, ∼4 m 3 mesocosm study in subtropical coastal waters (Wuyuan Bay, China, 24.52°N, 117.18°E) at present day (400 μatm) and elevated (1000 μatm) pCO 2 concentrations. Phytoplankton growth occurred in three phases during the 33-day experiment: an initial exponential growth leading to senescence and a subsequent decline phase. Phytoplankton sampled from these mesocosms were fed to mesozooplankton collected by net haul from Wuyuan Bay. Concentrations of saturated fatty acids (SFA) in both phytoplankton and mesozooplankton remained high under acidified and non-acidified conditions. However, polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA) increased significantly more under elevated pCO 2 during the late exponential phase (Day 13), indicating increased nutritional value for zooplankton and higher trophic levels. Indeed, uptake rates of the essential FA docosahexaenoic acid (C20:5n3, DHA) increased in mesozooplankton under acidified conditions. However, mesozooplankton grazing rates decreased overall with elevated pCO 2 . Our findings show that these selected phytoplankton species have a relatively high tolerance to acidification in terms of FA production, and local mesozooplankton in these subtropical coastal waters can maintain their FA composition under end of century ocean acidification conditions., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

An intense bloom of red Noctiluca scintillans (NS) occurred off the Rushikulya estuarine region along the east coast of India, an important site for mass nesting events of the vulnerable Olive Ridley sea turtle. At its peak, densities of NS were 3.3×10(5) cells-l(-1), with low relative abundance of other phytoplankton. The peak bloom coincided with high abundance of gelatinous planktivores which may have facilitated bloom development by their grazing on other zooplankton, particularly copepods. Ammonium concentrations increased by approximately 4-fold in the later stages of bloom, coincident with stable NS abundance and chlorophyll concentrations in the nano- and microplankton. This increase likely was attributable to release of intracellular ammonium accumulated through NS grazing. Dissolved oxygen concentrations decreased in sub-surface waters to near hypoxia. Micro-phytoplankton increasingly dominated chlorophyll-a biomass as the bloom declined, with diminishing picoplankton abundance likely the result of high predation by the ciliate Mesodinium rubrum. Together, these data illustrate factors that can disrupt ecosystem balance in this critically important Indian coastal region., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Climate change pressures will influence marine planktonic systems globally, and it is conceivable that harmful algal blooms may increase in frequency and severity. These pressures will be manifest as alterations in temperature, stratification, light, ocean acidification, precipitation-induced nutrient inputs, and grazing, but absence of fundamental knowledge of the mechanisms driving harmful algal blooms frustrates most hope of forecasting their future prevalence. Summarized here is the consensus of a recent workshop held to address what currently is known and not known about the environmental conditions that favor initiation and maintenance of harmful algal blooms. There is expectation that harmful algal bloom (HAB) geographical domains should expand in some cases, as will seasonal windows of opportunity for harmful algal blooms at higher latitudes. Nonetheless there is only basic information to speculate upon which regions or habitats HAB species may be the most resilient or susceptible. Moreover, current research strategies are not well suited to inform these fundamental linkages. There is a critical absence of tenable hypotheses for how climate pressures mechanistically affect HAB species, and the lack of uniform experimental protocols limits the quantitative cross-investigation comparisons essential to advancement. A HAB "best practices" manual would help foster more uniform research strategies and protocols, and selection of a small target list of model HAB species or isolates for study would greatly promote the accumulation of knowledge. Despite the need to focus on keystone species, more studies need to address strain variability within species, their responses under multifactorial conditions, and the retrospective analyses of long-term plankton and cyst core data; research topics that are departures from the norm. Examples of some fundamental unknowns include how larger and more frequent extreme weather events may break down natural biogeographic barriers, how stratification may enhance or diminish HAB events, how trace nutrients (metals, vitamins) influence cell toxicity, and how grazing pressures may leverage, or mitigate HAB development. There is an absence of high quality time-series data in most regions currently experiencing HAB outbreaks, and little if any data from regions expected to develop HAB events in the future. A subset of observer sites is recommended to help develop stronger linkages among global, national, and regional climate change and HAB observation programs, providing fundamental datasets for investigating global changes in the prevalence of harmful algal blooms. Forecasting changes in HAB patterns over the next few decades will depend critically upon considering harmful algal blooms within the competitive context of plankton communities, and linking these insights to ecosystem, oceanographic and climate models. From a broader perspective, the nexus of HAB science and the social sciences of harmful algal blooms is inadequate and prevents quantitative assessment of impacts of future HAB changes on human well-being. These and other fundamental changes in HAB research will be necessary if HAB science is to obtain compelling evidence that climate change has caused alterations in HAB distributions, prevalence or character, and to develop the theoretical, experimental, and empirical evidence explaining the mechanisms underpinning these ecological shifts.

Objective: The study was undertaken to measure cerclage location within the cervix and to determine whether placement closer to the internal os is related to perinatal outcome., Study Design: We analyzed data collected during a randomized trial of cervical cerclage versus no cerclage that was conducted at Lehigh Valley Hospital between May 1998 and June 2001 in women with ultrasound findings of short cervix less than 25 mm or funneling between 16 and 24 weeks' gestation. Women who were randomly assigned to the cerclage arm had cervical measurements performed before cerclage, including dilation of the internal os, depth of membrane prolapse into the endocervical canal, cervical length below any funnel (distal length), and total cervical length (including any funnel). Measurements obtained after cerclage placement included the distance from external os to cerclage (A), and a repeat of the same four measurements. The distance from the external os to the cerclage (A) was divided by the total cervical length (B) and a cerclage to cervical length ratio (A/B) was calculated. The relationship between these measurements and gestational age at birth was assessed by linear regression analysis., Results: Of 150 patients enrolled, 74 received a McDonald cerclage suture. Mean distal cervical length was 1.9+/-0.9 cm before and 2.9+/-1.0 cm after cerclage (P=.001). The mean distance between the cerclage and external os (A) was 1.8+/-0.6 cm; the total cervical length after cerclage (B) was 3.6+/-0.9 cm. The mean cerclage to cervical length ratio (A/B) was 0.5+/-0.1. Linear regression analysis did not demonstrate a correlation between either the cerclage to external os measurement (A) or the cervical length ratio (A/B) and gestational age at birth (R(2)=0.0006 and 0.008, P=.8 and.6, respectively)., Conclusion: The length of the cervix below the level of cerclage is not related to duration of pregnancy in women treated with cerclage because of ultrasound evidence of cervical effacement.

Adult human bone marrow (ABM) is an important source of hematopoietic stem cells for transplantation in the treatment of malignant and nonmalignant diseases. However, in contrast to the recent progress that has been achieved with umbilical cord blood, methods to expand ABM stem cells for therapeutic applications have been disappointing. In this study, we describe a novel culture method that uses human brain endothelial cells (HUBECs) and that supports the quantitative expansion of the most primitive measurable cell within the adult bone marrow compartment, the nonobese diabetic/severe combined immunodeficient (NOD/SCID) repopulating cell (SRC). Coculture of human ABM CD34(+) cells with brain endothelial cells for 7 days supported a 5.4-fold increase in CD34(+) cells, induced more than 95% of the CD34(+)CD38(-) subset to enter cell division, and produced progeny that engrafted NOD/SCID mice at significantly higher rates than fresh ABM CD34(+) cells. Using a limiting dilution analysis, we found the frequency of SRCs within fresh ABM CD34(+) cells to be 1 in 9.9 x 10(5) cells. Following HUBEC culture, the estimated frequency of SRCs increased to 1 in 2.4 x 10(5) cells. All mice that received transplants of HUBEC-cultured cells showed B-lymphoid and myeloid differentiation, indicating that a primitive hematopoietic cell was preserved during culture. Noncontact HUBEC cultures also maintained SRCs at a level comparable to contact HUBEC cultures, suggesting that cell-to-cell contact was not required. These data demonstrate that human brain endothelial cells possess a unique hematopoietic activity that increases the repopulating capacity of adult human bone marrow.