Factors Influencing the Morphology of Sea Ice

Due to the continuous melting of sea ice and rising sea levels, more studies are conducted on sea ice morphology and factors influencing the growth of ice. Sea ice is an integral part of the global climate system. It plays a vital role in the polar ecosystem, providing a habitat for organisms. Sea ice growth and behaviour has been observed to be largely affected by climate change and global warming. However, the consequences thereof, on sea ice extent and seasonal changes are still being studied. Artificial sea ice experiments have been used as they offer an advantage of control and help isolate variables during sea ice growth. Additionally, in-situ experiments are expensive, and can present logistical difficulty for measuring these variables long term. Factors such as growth dynamics, crystal texture and brine inclusions were investigated by variation of ambient temperature, starting artificial ocean salinity, reactor volume and the presence of microorganism' secretions: extracellular polymeric substances (EPS). Salinities of 10 psu, 20 psu, and 30 psu, were used at the following temperatures: -20°C, -10°C and -5°C. The temperature and salinity data showed that the growth rate of ice, increases with the decreasing ambient temperature, decreasing starting artificial sea ice salinity, decreasing reactor volume, as well as in the presence of microorganisms' secretions. The cross-polarisation results revealed a decreasing percentage of granular texture with increasing starting artificial ocean salinity and increasing ambient temperature. Similarly, the same trend was observed for increasing reactor volume. In the presence of microorganisms, however, a blotchy granular and a disordered columnar texture were observed. An increase in artificial sea ice porosity due to brine inclusions was revealed by the micro-ct scanning data for an increasing starting artificial ocean salinity. Furthermore, overall porosity increased with decreasing ambient temperature and in the presence of microorganism secretion

Physical and morphological properties of first-year Antarctic sea ice in the spring marginal ice zone of the Atlantic-Indian sector

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