Process Study 2 was undertaken between 20-22 September 2005 in the Huon Estuary offshore from Hideaway Bay. During this Process Study, two sediment traps were deployed at each of two sites (near sites P3 and P4 from the spatial survey) on the bottom for 24 hours.Prior to the deployment of the traps surface sediment samples were collected with a benthic grab from each site. Each sediment trap consisted of three collection tubes, material from each tube was filtered on 47 mm GFF filters, with several filters required to filter all of the particualte matter from each tube. Combined filters from each of two tubes labeled A and B (typically 3 filters for each tube) were extracted for lipid analysis. Tube C was used either for isotopes or Fauna indent.

Process Study 3 was undertaken between 03-05 October 2006 in North West Bay. Sediment traps were deployed and sediment samples taken at five sites in NWB. The primary aim was to investigate the composition of material being deposited to the sediments from the water column at these times and to compare this organic matter with that found in the sediments at the same sites. Additionally, we wished to see whether any organic matter of obvious fish farm origin could be detected. One sediment trap was deployed at each North West Bay (NWB) site in water varying in depth from 10 m (site 9) to 20 m (site 2). The trap sites were numbered 2, 4, 5, 7, and 9. Traps were deployed at their respective sites and left for at least one hour before the caps were removed in order to eliminate sediment re-suspended during deployment from entering the traps. The traps were left in place for 48 hours and then retrieved, capped and returned to Hobart for recovery of the samples. Each trap had 3 tubes, each of these tubes was split into three. One litre was taken and filtered for lipids using pre-weighed 47 mm GFF filters, one litre for pigments and the rest was split in two and stored in 500ml bottles, one for zooplankton analysis and the other for microalgal samples. Several filters were required to filter the lipid sample depending on the amount of particles in the tube. Selected filters were then analysed for lipid biomarkers. Organic matter from selected filters was also analysed for stable isotope 13C and 15 N values and carbon content. The contents of one tube from each trap was inspected for identification of zooplankton remains and faecal pellets using light microscopy. Sediments were collected at each of the above trap sites using a Wilco box corer.

Process Study 1 was undertaken between 12-14 April 2005 in the Huon Estuary offshore from Hideaway Bay. During this Process Study, two sediment traps were deployed at each of two sites (near sites P3 and P4 from the spatial survey) on the bottom for 24 hours.Prior to the deployment of the traps surface sediment samples were collected with a benthic grab from each site. Each sediment trap consisted of three collection tubes, material from each tube was filtered on 47 mm GFF filters, with several filters required to filter all of the particualte matter from each tube. Combined filters from each of two tubes labeled A and B (typically 3 filters for each tube) were extracted for lipid analysis. Tube C was used either for isotopes or Fauna indent.

Ecosystem process measurements were made on sediment sampled with a box core and water sampled from CTD profiles. For sediments, measurements were of wet/dry weight ratio, total organic carbon, chlorophyll and stable isotopes, nitrogen cycling (nitrogen fixation and denitirification) and oxygen demand. For water samples, measurements were of total suspended solids, chlorophyll and stable isotopes. The survey design was a natural experiment (i.e. control-impact, but not before-after) to test the long-term, broadscale effects of prawn fishing on non-target species and habitats. Deployments were stratified by fishing intensity (three strata) and day/night. The survey was repeated in three regions: (a) north of Groote Eylandt, (b) north-east of the Vanderlins, and (c) north of Mornington Island.