Refer to antFOCE report section 4.4.1 for deployment, sampling and analysis details. https://data.aad.gov.au/metadata/records/AAS_4127_antFOCE_Project4127 The download file contains an Excel workbook with 2 data spreadsheets - one for the greater than 1mm fraction and one for the 0.5mm to 1mm fraction of the macrofauna - and a third of notes relevant to the data. The data are the total number of each organism collected from sediment cores taken in and adjacent to chambers or open plots during the antFOCE experiment. Analysis methods are detailed in the Notes spreadsheet. Background The antFOCE experimental system was deployed in O’Brien Bay, approximately 5 kilometres south of Casey station, East Antarctica, in the austral summer of 2014/15. Surface and sub-surface (in water below the sea ice) infrastructure allowed controlled manipulation of seawater pH levels (reduced by 0.4 pH units below ambient) in 2 chambers placed on the sea floor over natural benthic communities. Two control chambers (no pH manipulation) and two open plots (no chambers, no pH manipulation) were also sampled to compare to the pH manipulated (acidified) treatment chambers. Details of the antFOCE experiment can be found in the report – “antFOCE 2014/15 – Experimental System, Deployment, Sampling and Analysis”. This report and a diagram indicating how the various antFOCE data sets relate to each other are available at: https://data.aad.gov.au/metadata/records/AAS_4127_antFOCE_Project4127

Ten sediment cores were collected from 3 marine bays in the Windmill Islands. Two cores were collected in Sparkes Bay, one in Shannon Bay, and seven in Brown Bay. Only diatom data are presented here, however Pb210 and metal analyses have also been undertaken - contact Ian Snape (ian.snape@aad.gov.au) for more information regarding this. The diatom spreadsheet (diatom_data) lists the relative abundance of benthic species. The abbreviation used to identify species are explained in the separate file called sp_list. Each core has been saved as a separate file. The STE cores were collected from within a couple of meters of each other. These cores were collected in close proximity to a tip site at one end of Brown Bay. BBMid was collected from the middle of the bay, while BB Outer 1 and 2 were collected from the outer regions of this bay, and thus represent the greatest distance from the tip site. Unless otherwise stated, the lowest number within each core represents the youngest sample. This work was completed as part of ASAC project 1130 (ASAC_1130) and project 2201 (ASAC_2201). Public summary from project 1130: Algal mats grow on sea floor in most shallow marine environments. They are thought to contribute more than half of the total primary production in many of these areas, making them a critical food source for invertebrates and some fish. We will establish how important they are in Antarctic marine environments and determine the effects of local sewerage and tip site pollution. We will also investigate the impact on the algal mats of the additional UV radiation which results from the ozone hole. Public summary from project 2201: As a signatory to the Protocol on Environmental Protection to the Antarctic Treaty Australia is committed to comprehensive protection of the Antarctic environment. This protocol requires that activities in the Antarctic shall be planned and conducted on the basis of information sufficient to make prior assessments of, and informed judgements about, their possible impacts on the Antarctic environment. Most of our activities in the Antarctic occur along the narrow fringe of ice-free rock adjacent to the sea and many of our activities have the potential to cause environmental harm to marine life. The Antarctic seas support the most complex and biologically diverse plant and animal communities of the region. However, very little is known about them and there is certainly not sufficient known to make informed judgements about possible environmental impacts. The animals and plants of the sea-bed are widely accepted as being the most appropriate part of the marine ecosystem for indicating disturbance caused by local sources. Attached sea-bed organisms have a fixed spatial relationship with a given place so they must either endure conditions or die. Once lost from a site recolonisation takes some time, as a consequence the structure of sea-bed communities reflect not only present conditions but they can also integrate conditions in the past. In contrast, fish and planktonic organisms can move freely so their site of capture does not indicate a long residence time at that location. Because sea-bed communities are particularly diverse they contain species with widely differing life strategies, as a result different species can have very different levels of tolerance to stress; this leads to a range of subtle changes in community structure as a response to gradually increasing disturbance, rather than an all or nothing response. This project will examine sea-bed communities near our stations to determine how seriously they are affected by human activities. This information will be used to set priorities for improving operational procedures to reduce the risk of further environmental damage. The fields in this dataset are: Species Site Abundance Benthic