This archive includes post-processed model out and code for visualisation pertaining the to the evolution of phytoplankton loss rates in CMIP6 model. The core data set is recomputed diagnostic loss terms for grazing and non grazing losses across 11 CMIP6 models as well as a diagnostic deconstruction of the drivers of evolving loss rates.

Zooplankton samples were collected at inshore coastal waters of south eastern Tasmania, between the years 1971 and 1972. Three stations were selected to cover the D'Entrecasteaux Channel, mouth of the Derwent River and the Storm Bay areas. Surface, midwater and bottom zooplankton samples were collected monthly for a period of twelve months during the day as well as night time, using horizontal tows. Data for temperature and salinity were also obtained from the stations.

Zooplankton samples were collected at two sites in south eastern Tasmania, between the years 2000 and 2001 using two types of plankton net. Samples were collected using horizontal hauls during the daytime only. All copepods, salps and chaetognaths were identified and enumerated.

Zooplankton samples were collected at ten stations within the Derwent River estuary, in south eastern Tasmania, between the years 1973 and 1974. Temperature and salinity data was collected at the same time.

This dataset consists of hyperspectral particulate absorption, particulate attenuation, and the first order (calculated) scatter coefficient from a Wetlabs Absorption and Attenuation Sensor (ACS). Data was collected from October 8th to November 1st 2023 aboard the RV Investigator (IN2023_V06). This voyage focused on sampling mesoscale eddies and across frontal features in a strong ecologically significant west boundary current, the East Australian Current (EAC). Throughout the cruise, the sensors continuously measured surface waters through the ships underway system, measuring 87 wavelengths (from 400-735 nm, with ~3 nm spacing) at a rate of 25 times per second. The data was later binned to 30 second intervals and aligned with the ships underway system (data for this can be found here: https://www.marine.csiro.au/data/trawler/survey_details.cfm?survey=IN2023_V06). Further information on the methodology for data acquisition and cleaning of the ACS data can be found in Mears et al., 2026.

The Southern Ocean spring phytoplankton bloom impacts regional food webs and the marine carbon cycle, but we do not fully understand which drivers – environmental, ecological, or biological – control the timing or productivity of the spring bloom. Nutrients, and particularly iron, are likely replete in the austral winter, but the importance of underwater light availability and grazing pressure are topics of ongoing discussion. Furthermore, in the extreme polar winter, phytoplankton physiology may impart additional constraints on phytoplankton variability when ocean mixing decreases. Of particular interest is the impact of highly variable sea ice on the Southern Ocean environment, where over the last decade the Antarctic sea ice extent (SIE) has recorded record highs and lows. The anomalous low in 2023 suggested a new reduced sea-ice state, with unknown impacts on phytoplankton bloom dynamics, including bloom phenology and magnitude. Such changes in SIE will alter the physical environment, and in turn will have profound implications for the Southern Ocean ecosystem. Phytoplankton are especially sensitive to such changes in the physical environment, but understanding and predicting future changes resulting from a reduced sea-ice state remains challenging.

We dissect the spokes of the ferrous wheel associated with Fe demand by quantifying the uptake rates of heterotrophic bacteria and phytoplankton in the subantarctic Southern Ocean during summer and situate these findings within a seasonal context. To do so, we conducted bioassays in which the effects of light on Fe photochemistry and uptake physiology were studied by comparing light and dark incubations, and the effects of DOC supply and competition between phytoplankton and heterotrophic bacteria were examined by isolating bacteria from the larger members of the ferrous wheel by pre-incubation size fractionation.