Understanding the current and future stability of Antarctica’s ice shelves is critical for assessing the potential for rapid sea level rise emanating from Antarctica’s marine ice sheets.The acceleration in ocean-dri...Understanding the current and future stability of Antarctica’s ice shelves is critical for assessing the potential for rapid sea level rise emanating from Antarctica’s marine ice sheets.The acceleration in ocean-driven mass loss from the West Antarctic Ice Sheet(Shepherd et al.,2018)is one such focus for intense research interest.The scale and urgency in understanding ocean-driven Antarctic mass loss motivates better integration and cooperation between modelers and observational展开更多
Despite the many submarine telecommunications and power cables laid world-wide there are fewer than ten published studies of their environmental effects in the refereed literature.This paper describes an investigation...Despite the many submarine telecommunications and power cables laid world-wide there are fewer than ten published studies of their environmental effects in the refereed literature.This paper describes an investigation into the effects of laying and operating the Basslink High Voltage Direct Current(HVDC)cable and its associated metallic return cable across Bass Strait in South East Australia.Over more than 95%of its length the cable was directly laid into a wet jetted trench given the predominantly soft sediments encountered.Underwater remote video investigations found that within two years all visible evidence of the cable and trench was gone at over a third of the transects at six deep water sites(32-72 m deep).At other deep water transects the residual trench trapped drift material providing habitat for the generally sparsely distributed benthic community.Diver surveys at both of the near shore sites(<15 m deep)on the northern side of the Strait also found the cable route was undetectable after a year.On the southern side,where the cable traversed hard basalt rock near shore,it was encased in a protective cast iron half shell.Ecological studies by divers over 3.5 years demonstrated the colonization of the hard shell by similar species occupying hard substrates elsewhere on the basalt reef.Magnetic field strengths associated with the operating cable were found to be within 0.8%of those predicted from theory with strength dropping rapidly with distance from the cable.Beyond 20 m the field was indistinguishable from background.展开更多
文摘Understanding the current and future stability of Antarctica’s ice shelves is critical for assessing the potential for rapid sea level rise emanating from Antarctica’s marine ice sheets.The acceleration in ocean-driven mass loss from the West Antarctic Ice Sheet(Shepherd et al.,2018)is one such focus for intense research interest.The scale and urgency in understanding ocean-driven Antarctic mass loss motivates better integration and cooperation between modelers and observational
文摘Despite the many submarine telecommunications and power cables laid world-wide there are fewer than ten published studies of their environmental effects in the refereed literature.This paper describes an investigation into the effects of laying and operating the Basslink High Voltage Direct Current(HVDC)cable and its associated metallic return cable across Bass Strait in South East Australia.Over more than 95%of its length the cable was directly laid into a wet jetted trench given the predominantly soft sediments encountered.Underwater remote video investigations found that within two years all visible evidence of the cable and trench was gone at over a third of the transects at six deep water sites(32-72 m deep).At other deep water transects the residual trench trapped drift material providing habitat for the generally sparsely distributed benthic community.Diver surveys at both of the near shore sites(<15 m deep)on the northern side of the Strait also found the cable route was undetectable after a year.On the southern side,where the cable traversed hard basalt rock near shore,it was encased in a protective cast iron half shell.Ecological studies by divers over 3.5 years demonstrated the colonization of the hard shell by similar species occupying hard substrates elsewhere on the basalt reef.Magnetic field strengths associated with the operating cable were found to be within 0.8%of those predicted from theory with strength dropping rapidly with distance from the cable.Beyond 20 m the field was indistinguishable from background.
