Award: OCE-1924011

Oxygen in the world's oceans is essential for organisms to breathe and function. However, declining oxygen can lead to stressful 'hypoxia' events when there is not enough oxygen for organisms to thrive or survive. The impacts of hypoxia can include physiological stress, changes to consumed prey, and even death. However, the impact of these hypoxia events may change depending on the species that are affected. This project used a unique combination of methods to determine what kind of impacts hypoxia has on three ecologically and economically important fish species in the northwestern Gulf of Mexico. We used the chemical signatures in parts of these fishes that naturally record environmental stress histories, such as the chemistry of their otoliths ('ear stones'), eye lenses, and other tissues. These chemical signatures provided individual records of hypoxia exposure and changes in their diets and physiological function. We found that the impacts of hypoxia were complex, and difference between individuals and between species. While some species showed impacts of hypoxia on their physiology, others appeared more resilient to stress. We also examined relationships between hypoxia exposure and the accumulation of pollutants such as mercury in fish tissues. The results show that hypoxia is one of many environmental factors that can influence how pollutants travel through marine food webs, and our results illustrate how different species can accumulate pollutants in unique ways. This project supported a variety of outreach activities to educate stakeholders and the public about hypoxia and environmental stressors in coastal ecosystems. Results from this project were communicated through public lecture series at regional libraries as well as online platforms available to interested members of the public. Fish ear stone data were converted into 'songs' that demonstrate the unique life histories and stress patterns that individual fish can experience. This project supported the training of numerous graduate and undergraduate students who each increased their skills in cutting-edge methods, data analyses, and communication to audiences ranging from scientific specialists to interested members of the public. Last Modified: 01/28/2025 Submitted by: BenjaminDWalther