A new marine prasinophyte genus alternates between a flagellate and a dominant benthic stage with microrhizoids for adhesion.

Prasinophytes (Chlorophyta) are a diverse, paraphyletic group of planktonic microalgae for which benthic species are largely unknown. Here, we report a sand-dwelling, marine prasinophyte with several novel features observed in clonal cultures established from numerous locations around Australia. The new genus and species, which we name Microrhizoidea pickettheapsiorum (Mamiellophyceae), alternates between a benthic palmelloid colony, where cell division occurs, and a planktonic flagellate. Flagellates are short lived, settle and quickly resorb their flagella, the basal bodies then nucleate novel tubular appendages, termed "microrhizoids", that lack an axoneme and function to anchor benthic cells to the substratum. To our knowledge, microrhizoids have not been observed in any other green alga or protist, are slightly smaller in diameter than flagella, generally contain nine microtubules, are long (3-5 times the length of flagella) and are not encased in scales. Following settlement, cell divisions result in a loose, palmelloid colony, each cell connected to the substratum by two microrhizoids. Flagellates are round to bean-shaped with two long, slightly uneven flagella. Both benthic cells and flagellates, along with their flagella, are encased in thin scales. Phylogenies based on the complete chloroplast genome of Microrhizoidea show that it is clearly a member of the Mamiellophyceae, most closely related to Dolichomastix tenuilepsis. More taxon-rich phylogenetic analyses of the 18S rRNA gene, including metabarcodes from the Tara Oceans and Ocean Sampling Day projects, confidently show the distinctive nature of Microrhizoidea, and that the described biodiversity of the Mamiellophyceae is a fraction of its real biodiversity. The discovery of a largely benthic prasinophyte changes our perspective on this group of algae and, along with the observation of other potential benthic lineages in environmental sequences, illustrates that benthic habitats can be a rich ground for algal biodiscovery.

Adoption of technology and management practices by Canadian cow-calf producers.

Statistics Canada's 2016 census data were analyzed to determine the proportion of Canadian cow-calf producers who had adopted the use of 7 different technologies and 2 different grazing/feeding management practices, collectively referred to as "management tools." The 4 most commonly used management tools were rotational grazing, in-field winter grazing/feeding, smartphones/tablets, and computers/laptops. Differences in the adoption of these technologies by geographical region, number of producers/operations, herd size, operator gender, and operator age were examined using logistic regression. Estimates of the mean proportion of producers in eastern (65%) and western (60%) Canada using rotational grazing were similar (P = 0.24). However, a greater proportion of producers in western Canada versus eastern Canada were using in-field winter grazing/feeding (P < 0.001), smartphones/tablets (P < 0.001), and computers/laptops (P = 0.002). Adoption of all 4 tools was higher on farm operations with ≥ 2 operators versus those with 1 operator (P < 0.001). Larger herd size was associated with higher adoption rates across all 4 management tools. The effect of gender on adoption rates was equivocal.

Adoption de la technologie et des pratiques de gestion par les éleveurs-naisseurs canadiens. Les données du recensement 2016 de Statistique Canada ont été analysées afin de déterminer la proportion d'éleveursnaisseurs bovins canadiens qui avait adopté l'usage de 7 différentes technologies et de 2 différentes pratiques de gestion pour le pâturage et l'alimentation, collectivement appelées «outils de gestion¼. Les quatre outils de gestion les plus communément utilisés étaient la rotation du pâturage, le pâturage et l'alimentation dans les champs en hiver, les téléphones intelligents et les tablettes et les ordinateurs/ordinateurs portables. Les différences au niveau de l'adoption de ces technologies selon la région géographique, le nombre de producteurs/exploitations, la taille du troupeau, le sexe de l'exploitant et l'âge de l'exploitant ont été examinées à l'aide d'une régression logistique. Les estimations de la proportion médiane de producteurs dans l'Est (65 %) et dans l'Ouest (60 %) du Canada qui avaient recours à la rotation de pâturage étaient semblables (P = 0,24). Cependant, une proportion supérieure de producteurs dans l'Ouest canadien avait recours au pâturage et à l'alimentation dans les champs en hiver (P < 0,001), aux téléphones intelligents/tablettes (P < 0,001) et aux ordinateurs/ordinateurs portables (P = 0,002). L'adoption des quatre outils était supérieure dans les exploitations agricoles de ≥ 2 exploitants par rapport à celles ayant 1 exploitant (P < 0,001). Un troupeau de taille supérieure était associé à des taux d'adoption supérieurs pour les quatre outils de gestion. L'effet du sexe sur les taux d'adoption était équivoque.(Traduit par Isabelle Vallières).