Ocean acidification represents one of many severe global consequences of climate change. Increased atmospheric CO2 has already lowered the pH of oceans from 8.2 to 8.07 since the beginning of the industrial revolution and a pH of 7.7 is predicted by year 2100 with an increase in daily pH fluctuations. Past research focused mainly on the impact of lower pH on calcifying species and the process of biomineralization. Another potential and poorly understood impact of ocean acidification is the disruption of chemical communication within and between species. Chemical communication is important for finding mating partners or for the detection of preys and predators and its alteration in lower pH could have dramatic consequences on marine communities. AcidICC proposes a systematic study of the effect of ocean acidification on chemical communication in an experimentally tractable laboratory model species, the globally distributed marine annelid Platynereis dumerilii. The project will combine chemical analyses, behavioral assays, electrophysiology, transcriptomics, and CRISPR-Cas9 genome editing to study the production and detection of the sperm release pheromone (uric acid) in P. dumerilii and how these change in low pH. To study under controlled conditions a characterized receptor-ligand pair involved in chemical communication, this project aims to identify the P. dumerilii receptor for uric acid. This study will help to better predict how ocean acidification impacts marine communities by modifying their chemical communication. With AcidICC, VM will learn to design, manage and carry out a complex interdisciplinary project and broaden her knowledge on chemical ecology in marine species, being supervised by Prof. Hardege (UHull) and during secondments by Prof. Jekely (Exeter). The fellowship would pave the way for her to become a leading researcher in ocean acidification and climate change to obtain an independent position at a leading academic institution in the future.