a b s t r a c t a r t i c l e i n f oThe West Antarctic Peninsula (WAP) has experienced marked recent climate change. Air temperature increased by ≤ 3°C since the 1950s, glaciers are in retreat, and adjacent ocean sea ice cover has decreased. WAP also exhibits considerable inter-annual ocean-atmosphere variability, governed by the Southern Hemisphere Annular Mode (SAM) and by the Antarctic Dipole (ADI), which is itself modulated by ENSO. Both climate trends and oscillations affect WAP ecosystems, but sound evidence for mechanistic coupling of distinct processes to climate change is scarce. We analyzed decadal variability in shell growth over the past 49 years for the bivalve Laternula elliptica at Maxwell Bay, King George Island. Distinct changes in shell growth pattern include a near doubling of specific growth rate, a 25% decrease in maximum size, and a shift in individual energy expenditure from production to respiration. ENSO forces shell growth through local air temperature that constitutes the major link between regional climate forcing and the direct marine drivers of L. elliptica growth. The close coupling of shell growth to local and regional climate variability renders L. elliptica a promising tool for tracking climate forcing of Antarctic coastal systems in general, as well as for the reconstruction of coastal ecosystem variability from fossil shells.
A bench‐scale treatability study was performed to evaluate the effectiveness of alkaline ozonation on removing per‐ and polyfluoroalkyl substances (PFAS) present in groundwater at a former industrial site in Michigan. The study involved testing the PFAS‐impacted groundwater under alkaline ozonating conditions under a range of experimental conditions, including modifying pH, hydrogen peroxide‐to‐ozone molar ratio doses, length of ozonation pretreatment times, and sampling techniques. PFAS‐spiked samples were used to determine if inorganic ions such as fluoride (F−), sulfate (SO42−), formate (HCOO−), acetate (CH3COO−), and trifluoroacetate (CF3COO−) were generated or if there were decreases in total organic fluorine resulting from PFAS treatment. The results from all tests indicate that decreases in PFAS concentrations were due to a combination of removal and destructive mechanisms with enhanced removal under acidic pH ozonation pretreatment conditions. Short‐chain PFAS concentrations increased during the experiments followed by an overall decrease in concentration under continuous alkaline ozonation conditions. Reductions in concentrations in perfluorooctane sulfonic acid of 75–97% were observed. Reductions in concentrations were also observed in other PFAS such as 6:2 FTS, PFHxS, PFOA, and PFNA. To our best knowledge, this is the first time that alkaline ozonation has been performed on PFAS‐impacted water while monitoring a larger suite of PFAS analytes in addition to destruction byproducts. Treatment of PFAS under the conditions discussed in this paper suggests that alkaline ozonation may be a viable remediation option for PFAS‐impacted waters.
Regulatory agencies are increasingly lowering metals limitations to part-per-billion and part-pertrillion levels driven by water-quality based standards as well as technology-based standards. Depending on the wastewater characteristics, achieving low levels through treatment can be a challenge. This paper presents several challenges and successes in achieving low levels with a specific focus on coal-fired power plant Flue Gas Desulfurization (FGD) scrubber blowdown treatment and municipal wastewater. Mercury can be limited to part-per-trillion levels, making it especially difficult to treat. The effects of particle size, wastewater residence time in scrubber, and type of coal burned are evaluated for FGD blowdown. In addition, a full-scale evaluation of copper removal through organosulfide addition in a municipal wastewater treatment plant is presented.
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