This data set describes the concentrations of copper, lead and iron in the calcareous tests of heart urchins that were exposed to spiked sediments for 60 days. Porewater is the water extracted from between sand grains. Filtered porewater has been filtered. DGT stands for Diffuse Gel Transfer. The HCl extraction listed in one of the excel spreadsheets is an extraction from the actual sediment. The fields in this dataset are: Isotope Concentration Porewater Filtered Porewater DGT Porewater

---- Public Summary from Project ---- Heard Island offers scientists a unique subantarctic laboratory for investigating climate change. We will establish a reference set of microalgal floras from lakes and lagoons and ultimately use the microalgal floras of today to investigate changes in fossil microalgal communities of Heard Island lake and lagoonal ecosystems to better understand regional subantarctic climate changes. Sediments were sampled with hand corers. Water samples were collected with a Niskin bottle. The dataset contains a summary of the locations data were sampled from, as well as average isotope concentrations from each sampling location. The fields in this dataset are: Date Location Salinity pH GPS Isotopes Concentration (ppb)

The sedimentological, chemical and isotopic characteristics of sediment cores from three slightly saline to hypersaline lakes (Highway, Ace and Organic Lakes) and two marine inlets (Ellis Fjord and Taynaya Bay) in the Vestfold Hills, Antarctica have been examined. Sections of the cores deposited in marine environments are characterised by uniform, regularly laminated, fine grained, organic-rich sediments, with uniform organic delta 13C values (-18.0 to 19.4 ppt vs. PDB) and sulfur contents. In contrast, sediments deposited in lacustrine environments are extremely heterogeneous, varying from finely laminated mat-like sequences to poorly sorted clastic-rich sediments. Authigenic monohydrocalcite and aragonite occur in some lake sediments. The delta 13C values of organic matter in the lacustrine sediments exhibit an extremely wide range (-10.5 to -25.3 ppt) that can be related to variations in physico-chemical conditions in the lake waters. Strongly negative organic-delta 13C values coupledwith high sulfur contents are indicative of an anoxic zone in the overlying lake waters, whereas less negative organic-delta 13C values coupled with low sulfur contents are indicative of well-mixed oxic conditions. Particularly high organic-delta 13C values result during high levels of microbial activity in the lakes, due to high rates of photosynthetic CO2 fixation. The large shifts in organic-delta 13C are not necessarily accompanied by any change in macroscopic sedimentological characteristics, illustrating the utility if isotopic investigations in these environments. The delta 13C composition of authigenic carbonate in hypersaline Organic Lake sediments provides a record of changes in palaeoproductivity, while the delta 18O of the carbonate provides information on rates of meltwater input and evaporation in the lake. 14C-dating suggests that Highway Lake was isolated from the sea by isostatic uplift at least 4600 years before present (BP) whereas Organic Lake was isolated at approximately 2700 years BP. Apparent emergence rates calculated from the 14C ages range from 1.0 to 2.1 mm per year. The 'reservoir effect' in the lacustrine and marine environments is variable, but probably does not exceed ~ 1000 years in any of the lakes examined.