School of Science

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https://hdl.handle.net/10292/1333
Research at AUT's School of Science is focused on key scientific issues with regional and global significance. The common theme connecting all research areas is sustainability – in the broadest sense as it relates to environmental and human health. Our research is closely allied to teaching and learning opportunities at undergraduate and postgraduate level within the school. Research is organised in three thematic areas:

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Browsing School of Science by Subject "04 Earth Sciences"

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    Microplastic Pollution Distribution: Differences Between Marine Reserves and Urbanised Areas
    (Elsevier BV, 2023-09-09) Ribó, Marta; Watson, Sally J; Novikova, Nina I; Deppeler, Stacy; Seabrook, Sarah; Hale, Rachel; Strachan, Lorna J
    Microplastic particles (<5 mm) have been observed to be widely distributed in the oceans, from estuaries the deep ocean trenches. While plastic pollution in the marine environment is a growing concern worldwide, relatively little is known about microplastic distribution and accumulation on the seafloor, particularly in marine protected area (MPAs). The delimitation of MPAs frequently follow jurisdictional or political boundaries, however the distribution of species, habitats and ecosystems does not always follow these same confines. Likewise, pollution in the marine environment do not have boundaries. This study compares microplastic content in sediment cores from two sites: an urbanised area, near the coastal township of Picton; and a site distal from the township (∼30 km) but proximal to open ocean, adjacent to the Kokomohua Marine Reserve, in the region of Queen Charlotte Sound/Tōtaranui (QCS), Aotearoa/New Zealand. Microplastic particles were identified throughout the sediment cores from both locations, reaching depths of ∼45 cm below the seabed. Our findings revealed that marine sediments adjacent to the marine reserve had four times the microplastic accumulation of marine sediments from near the coastal township. The abundance of microplastics across the sediment depth profiles also varied between the two sites, suggesting different accumulation of microplastics on the seafloor due to differences in the frequency and extent of seabed disturbance experienced by the two locations. Our study demonstrates the extent to which human stressors such as microplastic pollution proliferate and concentrate in the environment, particularly in areas considered to be near-pristine with strict environmental protections.
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    Robbins Island: The Index Site for Regional Last Interglacial Sea Level, Wave Climate and the Subtropical Ridge Around Bass Strait, Australia
    (Elsevier BV, ) Goodwin, Ian D; Mortlock, Thomas R; Ribo, Marta; Mitrovica, Jerry X; O’ Leary, Mick; Williams, Rory
    A unique index-record of Last Interglacial (Marine Isotope Stage 5e MIS5e) relative sea level (RSL) and wave climate history in South-east Australia is presented from Robbins Island, in western Bass Strait. This is applied to interpret the wider MIS5e coastal evidence around Bass Strait. At Robbins Island, the combination of low wave and wind energy, a tide-modified regime and a sand supply resulted in the shoreline progradation throughout MIS5e. This preserved a time-series of paleo-sea level across a 7 km wide strandplain (Remarkable Banks). After a highstand, MIS5e RSL attained a stillstand of +5.75 ± 0.5 m above modern mean sea level during 126 to ∼119 ka BP. The MIS5e RSL interpretation is underpinned by modern analogues and hydrodynamic modelling of waves, tides and currents. A high resolution LiDAR Digital Elevation Model (DEM) supported by morpho-sedimentary studies, ground-penetration radar (GPR) surveys and a geochronology based upon Optically Stimulated Luminescence (OSL) methods were used to define the proxy RSL record. The observed RSL history was compared to modelled RSL history that accounted for the theoretical fall in RSL (regression) throughout MIS5e, due to the Glacio-Isostatic Adjustment (GIA) forcing. Three stages of RSL change occurred during MIS 5e: (i) RSL fall during phase 1 from ∼129 to 126 ka BP, and during phase 3 between ∼118 and 114 ka BP.; and, (ii) a multi-millennial stillstand during the intervening phase 2 from 126 to ∼119 ka BP. The stillstand departure from GIA theory, points unambiguously to persistent polar meltwater contributions to sea level of ∼2 m from 126 to 119 ka BP, where the component of RSL fall due to GIA was balanced by the RSL rise from meltwater. The potential contributions of paleo wave climate (direction) and boundary current histories were reconstructed from across all Bass Strait sites to determine an RSL budget. In addition, the paleo wave climate history allowed the triangulation of directional ocean wave synoptic sources and identified a 5° poleward shift in the Subtropical Ridge during MIS5e.
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