Rothera Runway Extension Biodiversity Survey Report 2023-2024

The data presented here was captured around Rothera Point, Adelaide Island on the West Antarctic Peninsula between November 2023, and February 2024. The data was captured as part of a biodiversity survey to investigate the current status of benthic biodiversity in an area that would be affected through land reclamation for a potential proposed extension of the runway located at BAS’s Rothera Research Station, Antarctica. Operations were conducted off small boats and allowed data to be collected in shallow waters between 10 m and 60 m water depth. Seabed imagery was captured using a down facing drop camera and video was acquired using a Boxfish Luna ROV. Sediment samples were collected using SCUBA techniques for particle size analyses, inorganic and organic carbon content, species identification and eDNA analyses. Furthermore, water samples were obtained for eDNA analyses and comparison to the sediment samples. 107 morphospecies were identified on the image capture techniques and 61 morphospecies were identified in the sediment samples across the survey area. No rare species or assemblages were detected in the survey area which would be lost or heavily impacted by a potential runway extension. The total loss of some habitat, and the species living there, are unlikely to have long-term ecological consequences to local and regional populations/assemblages. However, there could be some potential adverse effects from any realized runway extension, which may need to be explored further. The direction and extent of any sediment plume generated by the proposed works remains unclear, although this will likely be a temporary disturbance event during construction, which might happen over several seasons. Another consideration would be an effect on the natural disturbance regimes in this area. Firstly, a runway extension may change the local water currents, which could divert icebergs away from frequent areas of impact, or concentrate them into a smaller area. Both mechanisms have the potential to alter local disturbance regimes, and hence biological assemblages. Although out of scope of this survey, the two adverse impacts presented here have the potential to change the seabed sediment properties, benthic biotic assemblages, and marine mammal and seabird behaviour.

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