Submarine sedimentary bedforms and benthos surrounding the Heard and McDonald Islands World Heritage Site

• Main Authors: Watson, SJ, Lucieer, V, Whittaker, J, Fox, JM, Hill, N, Coffin, MF
• Format: Book Part
• Language: English
• Published: Elsevier Science 2020
• Subjects: Earth Sciences; Geology; Stratigraphy (incl. biostratigraphy; sequence stratigraphy and basin analysis); Heard Island; Heard; McDonald Islands; Antarc*
• Online Access: https://www.elsevier.com/books/seafloor-geomorphology-as-benthic-habitat/harris/978-0-12-814960-7; http://ecite.utas.edu.au/133932

We present highlights of the first multibeam and bottom sampling survey surrounding the UNESCO WorldHeritage listed Heard and McDonald Islands (HIMI), conducted in the HIMI Marine Reserve InnerMarineZone. These insular shelf data reveal that persistent eastward flowing currents and retreating glaciers drivepatterns of sediment distribution. Sedimentary bedform directionality, corroborated by drifter data, suggestthat the prevailing energy in this region dominates from west to east, and is deflected in an anticlockwisedirection around Heard Island, causing sediment deposition to be concentrated on the eastern (downcurrent)side of the islands. Sediment bedform morphology likely mirrors the eastward flowing AntarcticCircumpolar Current and oscillating east!west tidal currents. Thick sediment accumulations north ofHeard Island may be related to deglaciation since the Last Glacial Maximum. Sample sites on the northern down-current side of Heard Islands and on the western up-currentside of the McDonald Islands contain a diverse range of taxonomic groups compared to all othersample sites. Benthic specimens obtained in rock dredges and sediment grabs show a range ofinvertebrate species that are likely endemic to the HIMI region.