Chemical, biological, and statistical considerations for ocean acidification experiments

This workshop is designed for early career researchers and those new to the field of ocean acidification. Over three days, the hands-on modules will introduce and explore the range of opportunities and challenges facing OA researchers. By the end of the workshop, participants should have the confidence to design and carry out scientifically meaningful OA experiments.

Biology (Sam Dupont, University of Gothenburg, Sweden):

Every biological experiment is an abstraction of reality and designing any experiment always lead to trade-off and compromises. In the context of OA, emerging challenges such as evolution, ecology or multi-stressors requires creative and often complex experimental design and strategies.

This module will cover the key biological aspects of OA experimental design. Biological concerns will be introduced, including understanding organism sensitivities, controlling for multiple stressors, acclimation and lengths of experiments, and variable responses within a single species. We will also discuss common methods for measuring biological responses (e.g. calcification and respiration) and how to design experiments to avoid common pitfalls in OA studies.

To illustrate these concepts, participants will work in groups to design and carry out their own experiments using Virtual Marine Scientist. A review of each group’s results will highlight the range of challenges associated with OA research and approaches to solve them.

Chemistry (Christina McGraw, University of New England and IMAS):

Making high-quality carbonate chemistry measurements (i.e. DIC, AT, pH, or pCO2) is challenge for many researchers. Since seawater pH is viewed as the simplest of the carbonate parameters to monitor, it is the most common of these measurements. However, the measurement of pH with the degree of accuracy and precision needed for meaningful interpretation of the data requires more care and planning than is usually applied.

This hands-on module will serve as a practical guide to making high-quality spectrophotometric pH measurements. In addition to making measurements using a standard bench-top spectrometer, participants are will have the opportunity to test the automated spectrophotometric pH systems that are integrated into IMAS’s coastal ecosystem culture system and trace-metal clean culture systems.  Finally, complementary approaches (beyond pH) to understanding seawater chemistry will be introduced, including laboratory sensors, deployable devices, and profiling bio-floats.

Statistics (Peter Dillingham, University of New England):

Experimental design is fundamentally linked to analysis, motivated by scientific questions, and constrained by available resources. For example, multi‐stressor OA studies in culture tanks are constrained by the number of available tanks, making it difficult or impossible to perform traditional full factorial experiments for more than a few stressors.

In this workshop, several approaches to experimental design relevant to OA studies will be discussed. Using multi‐stressor culture tank OA experiments as motivation, a number of design and analysis choices will be presented. We will explore the trade‐off between the number of replicates and the number of stressors for settings where the number of experimental units is constrained (e.g. culture tank experiments).

  • Dates: 28 and 29 April (Thursday and Friday) and 2 May (Monday)
  • Venue: IMAS, Hobart
  • Contact: Christina McGraw,
  • Cost: No cost
  • Expected Number of Participants: around 30 people