Background
The exponential increase in anthropogenic emissions of carbon dioxide (C02) is warming the ocean, by greenhouse and heat transfer effects, and after dissolution of C02, alters the chemistry of seawater reducing the global ocean pH. Due to its unique physico-chemical characteristics, the Arctic Ocean is highly vulnerable to these changes, e.g. warming 4 times and acidifying 3-4 times faster than the global average. Ocean acidification and warming can impact the development, the behaviour, the metabolism, the physiology, the reproduction and ultimately the survival of marine organisms. Such rapid phenomena will pose a tremendous challenge to marine organisms in the Arctic, which will have to acclimate and/or adapt in a few decades to changes that normally occur over thousands to millions of years.
One of the first defense of organisms against such rapid environmental change is phenotypic plasticity that consist of adjusting metabolism, physiology and/or behavior to maintain physiological performances (e.g. survival, growth, reproduction). However, there are tipping point beyond which small environmental changes will cause abrupt physiological disruptions likely resulting in fitness loss and ultimately population decline. Beyond these tipping points, organisms will have to adapt over the long term or populations will decline and might disappear. It is therefore essential to identify these physiological thresholds to project the future of species in a changing world.
Copepods of the Calanus genus represent the largest zooplankton biomass in the Arctic and transfers high energy compound from the primary producers to high trophic levels (e.g. fish, whales). Therefore, they play a major role in Arctic ecosystem functioning. As a planktonic species, they do not have the ability to migrate towards more favorable environments in response to rapid environmental change. Thus, their only way of response to climate change over the short term is phenotypic plasticity. However, despite several articles studying the effects of ocean warming and acidification on the physiology of Arctic Calanus species, the tipping points have not yet been described. These tipping points should be particularly determined for the larval stages, the Nauplii, that are the most sensitive and represent a bottleneck in the survival of Calanus population.
Project description
In this project, the master student will carry out experiments to determine the tipping points of Nauplii Calanus glacialis exposed separately to ocean acidification (-15 pH conditions) and ocean warming (-7 temperature conditions). This project responds to the requirements highlighted in the latest IPCC report which recommends identifying tipping points in biological systems subjected to climate change. This master's project will be integrated into the research project "Vulnerability of overwintering Arctic zooplankton to multiple stressors".
Expected gains Owing to this project, the student will develop important skills in zoological techniques, animal handling, complex experimental design, polar biology and regression analysis. The project will include laboratory work at UiO and potential field trips in Svalbard. The student will be included in a stimulating research environment with other researchers and students in the Borg Ecotox Group. This is an opportunity to develop critical thinking and engage in research group activities. We also expect the student to attend seminars and/or international conference and to earn authorship and/or coautorship on scientific publication based on the outcomes of the experiments.
References
Dorey, NarimaneJ Pauline Lam;on, Mike Thorndyke, and Sam Dupont. "Assessing Physiological Tipping Point of Sea Urchin LaNae Exposed to a Broad Range of PH." Global Change Biology 19, no. 11 (2013): 3355-67. https:/ldoi.om!10.1111/gcb.12276.
Lutier, Mathieu, Carole Di PoiJ Frederic Gazeau, Alexis Appolis, Jeremy Le Luyer, and Fabrice Pernet. "Revisiting Tolerance to Ocean Acidification: Insights from a New Framework Combining Physiological and Molecular Tipping Points of Pacific Oyster." Global Change Biology 28, no. 10 (2022): 3333-48. https:/ldoi.om!10.1111/gcb.16101.
Sasaki, Matthew, and Hans G Dam. "Global Patterns in Copepod Thermal Tolerance." Journal of Plankton Research 43, no. 4 (July 1, 2021): 598-609. https://doi. om110.1093/planktlfbab044.
Thor, Peter, Fanny Vermandele, Allison Bailey, Ella Guscelli, Lea Loubet-Sartrou, Sam Dupont, and Piero Calosi. "Ocean Acidification Causes Fundamental Changes in the Cellular Metabolism of the Arctic Copepod Ca/anus G/acialis as Detected by Metabolomic Analysis... Scientific Reports 12, no. 1 (December 23, 2022): 22223. https://doi. om110.1038/s41598-022-26480-9.
Thor, Peter, Allison Bailey, Sam Dupont, Piero Calosi, Janne E. SreideJ Pierre De Wit, Ella Guscelli, et al. "Contrasting Physiological Responses to Future Ocean Acidification among Arctic Copepod Populations." Global Change Biology 24, no. 1 (2018): e36fr77. https:lldoi.org/10.11 11/gcb.13870