Observational data for the Kelp Ecosystem Ecology Network. These data come from transects of rocky reefs taken around the world using the KEEN observational data protocol (see http://kelpecosystems.org for full description of methods and handbook). See “How” for methods. Briefly, the observational data consists of the following components, all included here: site information, fish observations, quadrat sampling, band transect sampling, percent cover from uniform point counts, and kelp morphometrics. Data Files Data files included and what they contain are as follows: keen_sites.csv - Physical and locational data for all KEEN sites and transect. keen_cover.csv - Percent cover of sessile algae and invertebrates. keen_fish.csv - Counts of fish by size class along a transect. keen_quads.csv - Counts of common algae, sessile invertebrates, and demersal fish that can be individuated. keen_swath.csv - Counts of rarer algae, sessile invertebrates, and demersal fish that can be individuated. Data Use To use the observational data here for published work we ask that 1) You contact the network coordinator, jarrett.byrnes@umb.edu, and notify them of your intention so that we can coordinate among any ongoing projects using the same data, 2) if the data has not been used in a publication in the literature before, we request that you reach out to the PIs responsible for the data you will be using and engage in a conversation about co-authorship, 3) if it has been used previously, merely cite the datasets associated with each PI that you use. The references are listed below. For access to the entire data cleaning and processing pipeline, see https://github.com/kelpecosystems/observational_data. For access to scans of the original data sheets, contact jarrett.byrnes@umb.edu. ------------------------------------------------------ For general methods: Byrnes, Jarrett E.K., Haupt, Alison J., Reed, Daniel C., Wernberg, Thomas., Pérez-Matus, Alejandro., Shears, Nick T., Konar, Brenda, Gagnon, Pat, and Vergés, Adriana. 2014. Kelp Ecosystem Ecology Network Monitoring Handbook. Kelp Ecosystem Ecology Network. For specific data sets, use the following, but also include date the data is accessed from this record in order to track the data version used. Byrnes, Jarrett E.K., Haupt, Alison J., Lyman, Ted. 2014. Kelp forest communities at Appledore Island, the Boston Harbor Islands, and Salem Sound. Kelp Ecosystem Ecology Network. Dijkstra, Jennifer A., Mello, Kristen. 2015. Kelp forest communities at York, Maine. Kelp Ecosystem Ecology Network. Grabwoski, Jonathan and MacMahan, Marissa. 2015. Kelp forest communities in Nahant, Massachusetts, and Pemaquid, Maine. Kelp Ecosystem Ecology Network. Humphries Austin T., Paight C, Ben-Horin Tal, Green Lindsay, Thornber, Carol. 2016. Kelp forest communities in Narragansett Bay, Rhode Island. Kelp Ecosystem Ecology Network. Rasher, Douglass and Price, Nicole. 2017. Kelp forest communities of central and downeast Maine. Kelp Ecosystem Ecology Network. Peréz-Matus, Alejandro and Shaughnessy, Brianna. 2017. Kelp forest communities of central and northern Chile. Kelp Ecosystem Ecology Network.

Secchi disk data collected by students on the RV Investigator training voyage (Transit IN2018_T01).

Zooplankton was counted and identified from three sites over the 5-year period. The net used (200 m Bongo net) was designed to catch meso-zooplankton with an integrated vertical tow through the water column. One net from each of the paired Bongo samples was analysed and the data expressed as numbers per m3. Copepods dominated the zooplankton, with other groups such as salps, krill, appendicularians, cladocerans, chaetognaths and meroplanktonic larvae being seasonally dominant.

Phytoplankton was counted and identified from five sites over the 5-year period. Annual cycles in abundance are available (as cells mL-1), along with detailed species identification. Cell measurements and approximate geometric shape were also recorded for the calculation of biovolume (μL cell-1). Diatoms and dinoflagellates dominated the samples in terms of biomass, however, small cells were also very abundant throughout each year. The data are restricted to an integrated sample from the top 12 m of the water column. Fluorescence profiles elsewhere in this dataset can provide an indication of phytoplankton presence lower in the water column.

Understanding the patterns and characteristics of sedimentary deposits on the conjugate Australian-Antarctic margins is critical to reveal the Cretaceous-Cenozoic tectonic, oceanographic and climatic conditions in the basin. However, unravelling its evolution has remained difficult due to the different seismic stratigraphic interpretations on each margin and sparse drill sites. Here, for the first time, we collate all available seismic reflection profiles on both margins and use newly available offshore drilling data, to develop a consistent seismic stratigraphic framework across the Australian-Antarctic basins. We find sedimentation patterns similar in structure and thickness, prior to the onset of Antarctic glaciation, enabling the basin-wide correlation of four major sedimentary units and their depositional history. We interpret that during the warm and humid Late Cretaceous (~83-65 Ma), large onshore river systems on both Australia and Antarctica resulted in deltaic sediment deposition offshore. We interpret that the onset of clockwise bottom currents during the Early Paleogene (~58-48 Ma) formed prominent sediment drift deposits along both continental rises. We suggest that these currents strengthened and progressed farther east through the Eocene. Coevally, global cooling (<48 Ma) and progressive aridification led to a large-scale decrease in sediment input from both continents. Two major Eocene hiatuses recovered by the IODP site U1356A at the Antarctic continental slope likely formed during this pre-glacial phase of low sedimentation and strong bottom currents. Our results can be used to constrain future paleo-oceanographic modelling of this region and aid understanding of the oceanographic changes accompanying the transition from a greenhouse to icehouse world.