Teacher practices during high school PE lessons are significantly related to students' participation in MVPA. SOFIT+ is a valid and reliable tool to examine relationships between PE teacher practices and student MVPA during PE.

Abstract. As part of the 2019 Southern oCean seAsonal Experiment (SCALE) Winter Cruise of the South African icebreaker SA Agulhas II, first-year ice was sampled at the advancing outer edge of the Antarctic marginal ice zone along a 150 km Good Hope Line transect. Ice cores were extracted from four solitary pancake ice floes of 1.83–2.95 m diameter and 0.37–0.45 m thickness as well as a 12×4 m pancake ice floe of 0.31–0.76 m thickness that was part of a larger consolidated pack ice domain. The ice cores were subsequently analysed for temperature, salinity, texture, anisotropic elastic properties and compressive strength. All ice cores from both solitary pancake ice floes and consolidated pack ice exhibited predominantly granular textures. The vertical distributions of salinity, brine volume and mechanical properties were significantly different for the two ice types. High salinity values of 12.6±4.9 PSU were found at the topmost layer of the solitary pancake ice floes but not for the consolidated pack ice. The uniaxial compressive strengths for pancake ice and consolidated pack ice were determined as 2.3±0.5 and 4.1±0.9 MPa, respectively. Young's and shear moduli in the longitudinal core direction of solitary pancake ice were obtained as 3.7±2.0 and 1.3±0.7 GPa, respectively, and of consolidated pack ice as 6.4±1.6 and 2.3±0.6 GPa, respectively. Comparing Young's and shear moduli measured in longitudinal and transverse core directions, a clear directional dependency was found, in particular for the consolidated pack ice.

This study presents the first dataset of physical and textural properties of sea ice collected in the South Atlantic and Indian Ocean sector of the Antarctic marginal ice zone (MIZ). Observations of sea ice from this region in the austral spring 2019, including sea-ice core temperature, salinity, crystal size, texture, oxygen isotopes and stratigraphy, were used in conjunction with a Lagrangian back-tracking algorithm and atmospheric reanalyses. This method relates the reconstructed synoptic conditions to sea-ice growth along the transect. A significant difference was found between the stratigraphy of consolidated pack ice samples collected at the same latitude and spanning over 550 km eastwards. The eastward group was found to have more disturbances in their stratigraphy which is attributed to the highly variable atmospheric and sea-ice conditions together with varying wave penetration through the sea-ice pack, notably during the passage of an intense polar cyclone, while the westward group showed no signs of disturbance or deformation. These results indicate that consolidated Antarctic sea-ice floes of similar thickness and from the same latitude in the MIZ have distinct stratigraphic properties, which will influence their physical and biogeochemical features.

Sample collection and field studies of sea ice take place under harsh conditions which, combined with the logistical difficulties and high cost of voyages to the polar regions, limits the abilities of researchers to determine its properties. Observations of laboratory-grown sea ice can help quantify important sea-ice properties and incorporate them into numerical models. The growth of laboratory sea ice requires experimental set-ups that consider the complexity of sea-ice growth. Regulation and monitoring of environmental variables allow for growth and melt conditions to be controlled, manipulated and reproduced. Facilities thus vary widely because of differing research objectives. This paper presents a summary of some of the published sea-ice laboratories that study the physical properties of sea ice and an overview of their major design considerations, such as tank size, freezing method and instrumentation. It also discusses how these design considerations were implemented in the set-up of the new sea-ice growth laboratory at the Marine and Antarctic Research for Innovation and Sustainability. This paper should guide others in designing their facilities as well as in their understanding of other facilities for results comparison.

<p><span>The study of Antarctic first-year ice as a biogeochemical habitat has been limited by samples mostly collected in pack ice during summer. Fewer winter data are available, and due to the harsh conditions, data from the marginal ice zone (MIZ) are even more difficult to obtain. The MIZ is broad and circumpolar in the Southern Ocean; it is found at different latitudes during the year with sufficient light and nutrients to sustain primary production and affect ecosystem functioning. We present the first dataset of biogeochemical properties of first-year ice collected in the Atlantic sector of the Southern Ocean during winter 2019, obtained from young pancake ice and consolidated first-year ice. Temperature, salinity, crystal structure, δ18O, chl-a and bulk macronutrient data were used to investigate the winter habitat and explain the transition from young ice to first year ice through exchanges with the ocean biogeochemistry. Data suggests that the sea ice sampled at the consolidated station was a result of thermodynamic processes combined with possibly multiple cycles of breaking and rafting induced by waves and dynamics, which ultimately enhanced the biogeochemical activity beyond what expected for first-year ice. A numerical model was used to support the hypothesis that winter first-year ice buffers biogeochemical components differently from the upper ocean winter concentrations, and this may determine the conditions for the biogeochemical development later in spring.</span></p>