Toxicity of copper to two endemic Antarctic bdelloid rotifers Adineta sp. and Habrotrocha sp. (Bd14)

This dataset contains results of toxicity testing with two endemic species of bdelloid rotifer, Adineta sp. and Habrotrocha sp. (Bd14), isolated from samples originating from the Vestfold Hills. This study assessed the toxicity of copper to the two species in aqueous exposures performed at the Australian Antarctic Division.Toxicity testsGlassware and plasticware used for copper test solution preparation were soaked in nitric acid (10% [v/v] HNO3) for 24 h, then thoroughly rinsed with MilliQ. Exposures were performed in new polystyrene 12-well multi-well plates (well volume = 2 mL; Thermo Scientific Nunc Non-Treated Multidishes). Three replicate wells containing 1 mL of each exposure concentration were included in each test. Rotifers were fed once at the beginning of the test using 5 µL of a dilute algal mixture (1:50 RotiGrowPlus) made with MilliQ, added to each test well prior to the addition of rotifers. Plates were sealed with parafilm and kept in trays inside temperature-controlled cabinets at 15 °C, monitored with a Maxim iButton temperature sensor at 10-minute intervals. Temperatures fluctuated no more than ± 1.5 degrees throughout the duration of the tests. Test plates were kept under two layers of shade cloth (Coolaroo, green, 70% UV block) and light intensity was measured at 134 lux using a light meter (HopooColor, model OHSP-350P). Light conditions in the cabinets were 12hr light:12hr dark.Ten juvenile rotifers were transferred into each test well using a flame-sterilized Irwin loop. An initial range finding test for Habrotrocha sp. (Bd14) was completed with Cu concentrations from 0 to 500 µg L-1 Cu. Following this, exposure concentrations were amended (0, 10, 20, 40, 80, 120, 160, 320 µg L-1 Cu) and three replicate definitive tests for Adineta sp. and three replicate definitive tests for Habrotrocha sp. (Bd14) were performed. A stock solution of copper (100 mg/L) was made by dissolving 100 mg copper chloride in 1 L of MilliQ. This stock solution was diluted with MilliQ to make each of the treatment solutions to be used in tests. The stock and treatment solutions were stored in acid washed Nalgene bottles at 5 °C. Samples of treatment solutions (10 mL) were taken from Nalgene bottles at the beginning of each test for Cu analysis. Sacrificial wells (1 plate x 12 wells to make composite 12 mL) containing media and food were set up alongside exposure wells for each treatment to obtain samples of treatment solutions for Cu analysis at the end of each test. This was done to capture any changes in exposure concentrations after the addition of food, through evaporation during the test and through uptake by the organisms themselves. Samples for Cu analysis were acidified to 1% nitric acid after collection. Solutions were measured using an Agilent Inductively Coupled Plasma Mass Spectrometer (ICP-MS, 720ES) at the Australian Antarctic Division. Measured copper concentrations in exposure solutions used in tests were mathematically corrected for the 1% dilution by nitric acid. Visual observation were made using a stereomicroscope (Leica M165C on 160 to 200x magnification) to score of rotifers into one of three states: active, immobile, dead. Active rotifers displayed any movement such as swimming, wheeling, or crawling. Immobile rotifers were alive with their body contracted, not displaying any movement. Dead rotifers appear extended and relaxed or with their cuticle detached from body contents. Reproduction was also scored as the sum of eggs and hatched juveniles within wells. Observation counts were made on days 1, 2, 3, 4, 7, 10, 14, 18, 21, 24, and 28 for all tests. Dead rotifers were not removed from wells to minimize disturbance during the test. Newly emerged juvenile rotifers were scored and tracked in counts but not used in analysis except for their contribution to the reproductive endpoint. Statistical analysisCopper exposure concentrations used in dose-response modelling were the average of the measured concentrations at the start and end (sacrificial well) of tests for each treatment in each test. Measured concentrations of copper treatments and stock solutions used in each test are shown in the "measured" column of the data sheet. The results of this study are described in the manuscript 'Toxicity of copper to two endemic Antarctic bdelloid rotifers Adineta sp. and Habrotrocha sp. (Bd14)'.This work was completed as part of AAS projects 4100 and 4622.