Continent-wide declines in shallow reef life over a decade of ocean warming

Human society is dependent on nature^1,2, but whether our ecological foundations are at risk remains unknown in the absence of systematic monitoring of species' populations³. Knowledge of species fluctuations is particularly inadequate in the marine realm⁴. Here we assess the population trends of 1,057 common shallow reef species from multiple phyla at 1,636 sites around Australia over the past decade. Most populations decreased over this period, including many tropical fishes, temperate invertebrates (particularly echinoderms) and southwestern Australian macroalgae, whereas coral populations remained relatively stable. Population declines typically followed heatwave years, when local water temperatures were more than 0.5 °C above temperatures in 2008. Following heatwaves^5,6, species abundances generally tended to decline near warm range edges, and increase near cool range edges. More than 30% of shallow invertebrate species in cool latitudes exhibited high extinction risk, with rapidly declining populations trapped by deep ocean barriers, preventing poleward retreat as temperatures rise. Greater conservation effort is needed to safeguard temperate marine ecosystems, which are disproportionately threatened and include species with deep evolutionary roots. Fundamental among such efforts, and broader societal needs to efficiently adapt to interacting anthropogenic and natural pressures, is greatly expanded monitoring of species' population trends^7,8.

Global COVID-19 lockdown highlights humans as both threats and custodians of the environment

The global lockdown to mitigate COVID-19 pandemic health risks has altered human interactions with nature. Here, we report immediate impacts of changes in human activities on wildlife and environmental threats during the early lockdown months of 2020, based on 877 qualitative reports and 332 quantitative assessments from 89 different studies. Hundreds of reports of unusual species observations from around the world suggest that animals quickly responded to the reductions in human presence. However, negative effects of lockdown on conservation also emerged, as confinement resulted in some park officials being unable to perform conservation, restoration and enforcement tasks, resulting in local increases in illegal activities such as hunting. Overall, there is a complex mixture of positive and negative effects of the pandemic lockdown on nature, all of which have the potential to lead to cascading responses which in turn impact wildlife and nature conservation. While the net effect of the lockdown will need to be assessed over years as data becomes available and persistent effects emerge, immediate responses were detected across the world. Thus, initial qualitative and quantitative data arising from this serendipitous global quasi-experimental perturbation highlights the dual role that humans play in threatening and protecting species and ecosystems. Pathways to favorably tilt this delicate balance include reducing impacts and increasing conservation effectiveness.

Assessing National Biodiversity Trends for Rocky and Coral Reefs through the Integration of Citizen Science and Scientific Monitoring Programs

Reporting progress against targets for international biodiversity agreements is hindered by a shortage of suitable biodiversity data. We describe a cost-effective system involving Reef Life Survey citizen scientists in the systematic collection of quantitative data covering multiple phyla that can underpin numerous marine biodiversity indicators at high spatial and temporal resolution. We then summarize the findings of a continental- and decadal-scale State of the Environment assessment for rocky and coral reefs based on indicators of ecosystem state relating to fishing, ocean warming, and invasive species and describing the distribution of threatened species. Fishing impacts are widespread, whereas substantial warming-related change affected some regions between 2005 and 2015. Invasive species are concentrated near harbors in southeastern Australia, and the threatened-species index is highest for the Great Australian Bight and Tasman Sea. Our approach can be applied globally to improve reporting against biodiversity targets and enhance public and policymakers' understanding of marine biodiversity trends.

Loss of native rocky reef biodiversity in Australian metropolitan embayments

Urbanisation of the coastal zone represents a key threat to marine biodiversity, including rocky reef communities which often possess disproportionate ecological, recreational and commercial importance. The nature and magnitude of local urban impacts on reef biodiversity near three Australian capital cities were quantified using visual census methods. The most impacted reefs in urbanised embayments were consistently characterised by smaller, faster growing species, reduced fish biomass and richness, and reduced mobile invertebrate abundance and richness. Reef faunal distribution varied significantly with heavy metals, local population density, and proximity to city ports, while native fish and invertebrate communities were most depauperate in locations where invasive species were abundant. Our study adds impetus for improved urban planning and pollution management practises, while also highlighting the potential for skilled volunteers to improve the tracking of changes in marine biodiversity values and the effectiveness of management intervention.

Past radioactive particle contamination in the Columbia river at the Hanford site, USA

One closed-loop and eight single-pass plutonium production reactors originally operated on the Columbia river. During the 26 years of single-pass reactor operations, small amounts of radioactive particles were released in liquid discharges to the Columbia river and were deposited in sediment and cobble along the shoreline and on islands in the river. Islands located adjacent to D island and immediately downstream of D island had the greatest density of particles. In 1979, the small particles contained between 63 and 890 kBq of cobalt-60 activity. Dose rates emanating from those particles ranged from 1 to 14 microGy h(-1). Because of the short half-life of cobalt-60 (5.3 y), the hot-particle problem at Hanford has taken care of itself through radiological decay. Some scientists have proposed that it is economically and environmentally advantageous to manage isolated low-level contaminated sites with institutional controls until the activity decays and the sites can be released rather than to pursue expensive clean-up options.

Lamotrigine protects hippocampal CA1 neurons from ischemic damage after cardiac arrest

BACKGROUND AND PURPOSE

Lamotrigine (LTG) is an anticonvulsant drug whose mechanism of action may involve the inhibition of glutamate release by blocking voltage-dependent sodium channels. Glutamate neurotoxicity may contribute to cerebral ischemic damage after recovery from cardiac arrest. Thus, LTG may prevent the brain damage associated with global cerebral ischemia by reducing the release of glutamate from presynaptic vesicles during the ischemic insult or the early recovery period.

METHODS

LTG was studied in cardiac arrest-induced global cerebral ischemia with reperfusion in rats. In the first set of experiments, LTG (100 mg/kg, p.o.) was administered before induction of ischemia; and in the second experiment, LTG (10 mg/kg, i.v.) was given 15 minutes after ischemia and a second dose (10 mg/kg,i.v.) was given 5 hours later.

RESULTS

In both experiments LTG reduced the damage to the hippocampal CA1 cell population by greater than 50%. Neuroprotection was not associated with changes in brain temperature or plasma glucose concentration. Plasma concentrations of LTG ranged between 8 and 13 micrograms/mL. Patients taking LTG as a monotherapy for epilepsy typically have plasma levels of LTG in the 10 to 15 micrograms/mL range.

CONCLUSIONS

These data suggest that LTG may be effective in preventing brain damage after recovery from cardiac arrest. Patients on LTG monotherapy for epilepsy have plasma concentrations very similar to those found to be neuroprotective in this study. Although difficult to extrapolate, our data suggest that LTG at neuroprotective doses may be well tolerated by humans.

Ambient air sampling for tritium--determination of breakthrough volumes and collection efficiencies for silica gel adsorbent

Ambient air samples for tritium (as HTO) can be collected using the solid adsorbent silica gel. The purpose of this study was to determine the maximum practical sampling volume and overall collection efficiency for water vapor collected on silica gel columns and to demonstrate the use of an impinger-based system to load water vapor onto silica gel columns. Breakthrough volumes (Vb) were measured and chromatographic efficiencies (expressed as the number of theoretical plates, N) were calculated for a 20 degrees C to 50 degrees C temperature range, with the relative humidity at approximately 30%. The tests yielded relative breakthrough volumes (air volume/adsorbent depth, m3 cm(-1)) of 0.36 for 20 degrees C, 0.20 for 30 degrees C, 0.15 for 40 degrees C, and 0.077 for 50 degrees C. For 18-cm columns, the average tritium tracer recoveries at 20 degrees C were 71% with no observed breakthrough for air volumes up to 5 m3, while at 40 degrees C mean tritium tracer recoveries dropped from 75% for volumes < or = 3.0 m3, to 0% for a volume of 5.0 m3. Frontal chromatographic profiles were measured for water vapor migrating through silica gel columns that were divided into 5 segments. The chromatographic efficiency of the silica gel columns was determined by graphical evaluation of the chromatography profiles. At a sampling rate of 0.25 L min(-1) and 30% relative humidity, the number of theoretical plates per adsorbent depth were 0.55 N cm(-1) at 20 degrees C, 0.68 N cm(-1) at 30 degrees C, 0.51 N cm(-1) at 40 degrees C, and 0.30 N cm(-1) at 50 degrees C. Chromatographic theory was used to estimate the overall collection efficiency of the silica gel columns as a function of the ratio of the sampling volume to breakthrough volume and the chromatographic efficiency. For a 9.5 m3 sample volume, 30% relative humidity, 0.25 L min(-1) sampling rate, and a 54-cm column, the overall collection efficiency was above 99.9% at 20 degrees C, above 95% at 30 degrees C, just below 80% at 40 degrees C, and <<80% at 50 degrees C.