Shallow Seafloor Gas emissions Near Heard and McDonald Islands on the Kerguelen Plateau, Southern Indian Ocean

Bubble emission mechanisms from submerged large igneous provinces remains enigmatic. The Kerguelen Plateau, a large igneous province in the southern Indian Ocean, has a long sustained history of active volcanism and glacial/interglacial cycles of sedimentation, both of which may cause seafloor bubble production. We present the results of hydroacoustic flare observations around the underexplored volcanically active Heard Island and McDonald Islands on the Central Kerguelen Plateau. Flares were observed with a split‐beam echosounder and characterized using multifrequency decibel differencing. Deep‐tow camera footage, water properties, water column δ3He, subbottom profile, and sediment δ13C and δ34S data were analyzed to consider flare mechanisms. Excess δ3He near McDonald Islands seeps, indicating mantle‐derived input, suggests proximal hydrothermal activity; McDonald Islands flares may thus indicate CO2, methane, and other minor gas bubbles associated with shallow diffuse hydrothermal venting. The Heard Island seep environment, with subbottom acoustic blanking in thick sediment, muted 3He signal, and δ13C and δ34S fractionation factors, suggest that Heard Island seeps may either be methane gas (possibly both shallow biogenic methane and deeper‐sourced thermogenic methane related to geothermal heat from onshore volcanism) or a combination of methane and CO2, such as seen in sediment‐hosted geothermal systems. These data provide the first evidence of submarine gas escape on the Central Kerguelen Plateau and expand our understanding of seafloor processes and carbon cycling in the data‐poor southern Indian Ocean. Extensive sedimentation of the Kerguelen Plateau and additional zones of submarine volcanic activity mean additional seeps or vents may lie outside the small survey area proximal to the islandsThe overall science of the project is supported by Australian Antarctic Science Program (AASP) grant 4338. E.S.' PhD research is sup- ported by the Australian Research Council's Special Research Initiative Antarctic Gateway Partnership (Project ID SR140300001) and by an Australian Government Research Training Program Scholarship. S.C.J. is sup- ported by iCRAG under SFI, European Regional Development Fund, and industry partners, as well as ANZIC‐ IODP. J.M.W. is supported by ARC grant DE140100376 and DP18010228

Comparison of Walking Mechanics Between Those With FCAI and Those Without FCAI Using RunScribe™ Technology While Walking 800m on a Standard 400m Synthetic Track

Context: Ankle sprains are among the most commonly injured joints to the physically active and have become increasingly troublesome to the general population. Recurrent ankle sprains are categorized as chronic ankle instability (CAI), leading to walking gait pattern discrepancies that can affect a person\u27s lifestyle and well-being. Objective: To compare walking mechanics between those with functional chronic ankle instability (FCAI) and those without FCAI using RunScribe technology while walking 800m on a standard 400m synthetic track. Design: Case-control Setting: Artificial synthetic track Participants: 26 individuals (CAI: n = 11; Healthy: n = 15) participated in this study. Main Outcome Measures: FAAM, IdFAI, Pronation excursion, pronation velocity, impact g, contact time, and stride length of every step of two 400 m walks were collected using RunScribe™ sensors. Results: A total of 26 participants (FCAI: n=11, healthy: n=15) completed this study. The FCAI group had higher weight, more ankle sprains, and self-reported significantly greater ankle impairments and activity limitations compared to the healthy in the IdFAI than the Healthy group. ANOVA analysis showed a significant main effect of pronation velocity on walking mechanics (p = .016). Participants in the healthy group ranked lower on pronation velocity than those with unilateral FCAI but not with bilateral. Conclusions: Our study aimed to compare the walking mechanics of individuals with functional chronic ankle instability (FCAI) to those without FCAI using RunScribe technology while walking 800m on a standard 400m synthetic track. Our findings suggest that individuals with FCAI exhibit some significant differences in walking mechanics compared to those without FCAI