To continue to improve our understanding of Ross Sea marine benthic ecosystem structure and function, investigations were conducted to determine how key benthic organisms (i) respond to ocean acidification, (ii) utilise pulsed addition of primary food sources, and (iii) how the diversity and abundance of benthic communities varies over time. (i) Specimens of the Antarctic gooeyduc Laternula ... elliptica were collected and used for laboratory experiments to investigate the impacts of ocean acidification on key Antarctic benthic species. (ii) The uptake and incorporation of a pulsed input of an important primary food source (ice algae) by benthic invertebrates was investigated via a field experiment in Granite Harbour. Concentrated ice algae was added to seafloor chambers containing known densities of ophiuroids and molluscs. The uptake and incorporation of this food by was measured by sampling these key species and associated sediments, including fluxes of oxygen and nutrients. (iii) Sampling was conducted to determine benthic invertebrate community composition, sediment characteristics, and seafloor habitat structure. Sampling involved SCUBA diving. Physical habitat characteristics and biodiversity of the seafloor were characterised using video. The resulting footage will be analysed for the abundance of specific epifauna and flora, and species composition. Nested within this video footage, we also sampled epi- and macro-fauna and flora, and sediments. Samples of epi- and macro-fauna and flora, and sediments were collected for determination of isotopic C and N composition and sediment characteristics.