Archaea are important contributors to marine biogeochemical cycling, yet their ecology remains poorly characterized in the Arctic Ocean. The three dominant marine archaeal lineages, Marine Groups I, II, and III (MG-I, MG-II, and MG-III), are generally reported to have distinct, clade-consistent vertical distributions that are attributed to light penetration and temperature. Here, we used shotgun metagenomic sequencing of seawater collected during the 2015 U.S. Arctic GEOTRACES expedition (GN01) to recover archaeal metagenome-assembled genomes (MAGs) from the Western Arctic Ocean and to relate their relative abundances to water mass structure. Temperature, salinity, silicate, and N* distinguished four water mass layers: the summer surface layer, the Polar Mixed Layer, Atlantic Water, and Arctic Ocean basin water. Of 155 MAGs recovered from a metagenomic co-assembly, 17 were archaeal and represented all three marine groups (four MG-I, eleven MG-II, and two MG-III). Abundance-based clustering of samples from two deep central Arctic stations separated microbial communities according to water mass. Mapping MAG relative abundance across several hundred samples revealed surface, mid-depth, and deep distribution ecotypes; members of every marine group displayed more than one ecotype, and ecotype was not consistent with MAG phylogeny. These results indicate that archaeal distributions in the Western Arctic Ocean are more closely tied to water mass stratification than to clade identity, and that previously reported clade-specific depth distributions of marine Archaea may partly reflect the limited resolution of amplicon-based surveys and shallow sampling. ### Competing Interest Statement The authors have declared no competing interest. Natural Sciences and Engineering Research Council, https://ror.org/01h531d29, RGPIN-2022-05280 Canada Research Chairs, https://ror.org/0517h6h17 Digital Research Alliance of Canada, https://ror.org/010r6td27

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Seeds from wild-type A. thaliana ecotypes (Col-0, Ws-2, Cvi-0, c24 and Ler) or the mutants aba2-3 (Col-0 background, ABRC stock number CS3834), pyl11458 (Col-0 background, ABRC stock number CS72390) and scr-3 (Col-0 background, NASC stock code N3997) were sterilized and densely sown in rows on 1× (or 0.5× when testing the effect of nutrient concentration) MS basal medium with vitamins (Austratec) on 0.9% agar plates supplemented with 1% sucrose (pH 5.7) and stratified in the dark at 4 °C for 2 days. Plates were subsequently grown in long day conditions (16 h of light, 8 h of dark) at 22 °C. At 6–7 days after germination (d.a.g.), root tips (up to around 3 mm) were collected for protoplast isolation using sharp tweezers. For all experiments, seedlings were grown under identical conditions and collected at the same time of day. For all comparative experiments (MS concentrations or water-deficit), seedlings from the different conditions were sterilized, plated, grown and harvested simultaneously. Hard-agar model of drought For the hard-agar water-deficit assay, seedlings were grown on 0.5× MS medium under control conditions (100% water content) or on 0.5× MS medium with the water content reduced to 50% or 20% of the control level (corresponding...

Recently compiled data from the Whale Museum in Friday Harbor shows a shift in the presence of two ecotypes of killer whales in the Puget Sound. Sitting on a bench at Marine Park along Bellingham Bay, local photographer Nate Bolton photographed one of his most memorable encounters with an orca. Jack, one of the most famous Bigg's killer whales in the Salish Sea, dove underneath a boat and emerged on the other side.

The upland and lowland rice ecotypes were adapted to agroecosystems with contrasting soil-nitrogen conditions. Upland and lowland ecotypes are independently differentiated within japonica and indica ...

'New Zealand stonefly' A Longtailed Stonefly (Gripopterygidae) genus endemic to NZ, with 5 accepted species, and two now considered ecotypes of  Z. fenestrata - one flightless, and the other very...