Objectives The occurrence of metallo-beta-lactamase-producing Pseudomonas aeruginosa (MBL-PA) isolates is increasing globally, including in Switzerland. The aim of this study was to characterise, phenotypically and genotypically, the MBL-PA isolates submitted to the Swiss National Reference Center for Emerging Antibiotic Resistance (NARA) reference laboratory over a 12-month period from July 2022 to July 2023. Methods Thirty-n...

It is widely projected that under future climate scenarios the economic importance of Arctic Ocean fish stocks will increase. The Arctic Ocean is especially vulnerable to ocean acidification and already experiences low pH levels not projected to occur on a global scale until 2100. This paper outlines how ocean acidification must be considered with other potential stressors to accurately predict movement of fish stocks toward,...

We measured denitrification rates using a field 15 NO 3 − tracer‐addition approach in a large, cross‐site study of nitrate uptake in reference, agricultural, and suburban‐urban streams. We measured denitrification rates in 49 of 72 streams studied. Uptake length due to denitrification ( S Wden n) ranged from 89 m to 184 km (median of 9050 m) and there were no significant differences among regions or land‐use categories, likely...

The number of combinations of anthropogenic stressors affecting global change is increasing; however, few studies have empirically tested for their interactive effects on ecosystems. Most importantly, interactions among ecological stressors generate nonadditive effects that cannot be easily predicted based on single‐stressor studies. Here, we corroborate findings from an in situ mesocosm experiment with evidence from a whole‐e...

Amoebic gill disease (AGD) of maricultured salmonids, turbot, Scophthalmus maximus (L.), European seabass, Dicentrarchus labrax (L.), and sharpsnout seabream, Diplodus puntazzo (Cetti), caused by Neoparamoeba pemaquidensis has been reported from Australia (Tasmania), Ireland, France, Chile, North America (Washington State and California) and Spain. Of the salmonids, Atlantic salmon, Salmo salar L., appears to be the most susce...

We examined long‐term phytoplankton data records for four oligotrophic boreal lakes situated in the Experimental Lakes Area (ELA), western Ontario, for responses to climatic change. ELA experienced a cyclical wet‐dry‐wet pattern from 1968 to 1998, with the early 1970s and 1990s having above‐average precipitation and the 1980s being a period of drought with a 2°C increase in air temperature. During this drought, the length of i...

Levamisole, a known T‐cell stimulator and immunomodulator in mammals, has been demonstrated to enhance resistance to amoebic gill disease in Atlantic salmon, Salmo salar L. When used in fresh water baths, dose rates of 1.25, 2.5 and 5 ppm levamisole stimulated resistance to reinfection with Paramoeba sp. that was evident from 2–3 weeks post‐treatment. It is proposed that this response is related to enhancement of the non‐speci...

Fossil pigment analyses and 19 year‐long historical records were used to quantify whole‐lake algal response to changes in optical and chemical properties following experimental acidification of Lake 302 with H 2 SO 4 (south basin, 302S; 1981—1989) or HNO 3 (north basin, 302N; 1982–1986) and HCl (1987–1989). Undisturbed sediments were collected by freeze‐coring, sectioned in approximately annual intervals, and analyzed for foss...