In 2021 our lab began a collaborative project to investigate the cumulative effects of multiple stressors in northern elephant seals funding my the Strategic Environmental Research and Development Program (SERDP). How an animal survives, grows, and reproduces within its environment is influenced by its response to intrinsic and extrinsic stressors. Intrinsic stressors can arise from life history stages and result in significant changes to homeostasis. Extrinsic stressors, environmental factors that alter physiology and behavior of an individual, have been the focus of studies aiming to understand the effects of the stress response. Responsiveness of the neuroendocrine stress axis, hypothalamic-pituitary adrenal or HPA , has been studied extensively in elephant seals, making them an excellent system for investigating links between stressors, at-sea behavior, and health. Together, we developed a multi-investigator interdisciplinary study using the northern elephant seal as a model system to significantly improve our understanding of the response of marine mammals to exposure from multiple stressors. Our team is integrating physiological and ecological approaches including immunology, stress physiology, toxicology, animal behavior, population biology, and life history theory and will examine cumulative effects of exposure to multiple stressors in elephant seals. This research focuses on specific responses of individual animals, but by incorporating information from our long-term database on elephant seal population demographics we will extend this understanding to population-level impacts. Our effort will be integrated into the proposed Interdisciplinary Working Group that is led by The Sea Mammal Research Unit at St Andrews University entitled “Towards an Understanding of the Cumulative Effects of Multiple Stressors on Marine Mammals”. We finished the field effort portion of this project in the spring of 2024 and are now in the analysis phase.
Principle Investigator: Daniel P. Costa
Co-Principle Investigators:
Daniel E. Crocker – Sonoma State University
Birgitte I. McDonald – Moss Landing Marine Laboratory
Sarah H. Peterson – US Geological Survey
Joshua T. Ackerman – US Geological Survey
Additional Personal:
Rachel R. Holser, Assistant Researcher – Institute of Marine Sciences
Arina B. Favilla, Post-Doc – NIPR and UCSC
Garrett T. Shipway, Graduate Student – UCSC, Costa Lab
Daphne M. Shen, Field Technician – UCSC, Costa Lab (Former McDonald Lab Graduate Student)
Amber R. Diluzio, Graduate Student – Moss Landing Marine Lab, McDonald Lab
List of Project Publications (so far)
- AD Northey, RR Holser, GT Shipway, DP Costa, and DE Crocker. (2023). “Adrenal response to ACTH challenge alters thyroid and immune function and varies with body reserves in molting adult female northern elephant seals.” Am J Physiol Regul Integr Comp Physiol 325(1): R1-R12.
- SH Peterson, JT Ackerman, RR Holser, BI McDonald, DP Costa, and DE Crocker. (2023). “Mercury Bioaccumulation and Cortisol Interact to Influence Endocrine and Immune Biomarkers in a Free-Ranging Marine Mammal.” Environmental Science & Technology.
- SH Peterson, MG Peterson, JT Ackerman, C Debier, C Goetsch, RR Holser, LA Huckstadt, JC Johnson, TR Keates, BI McDonald, EA McHuron, and DP Costa. (2024). “Foraging behavior and age affect maternal transfer of mercury to northern elephant seal pups.” Sci Rep 14(1): 4693.
List of Graduate Student Theses
-
AD Northey (2021). “Adrenal response to ACTH challenge alters thyroid and immune function and varies with body reserves in molting adult female northern elephant seals.” Master’s Thesis, Sonoma State University.
-
TR Brown (2023). “Maternal Stress Affects Offspring Development and Oxidative Stress in Northern Elephant Seal Pups (Mirounga angustirostris).” Master’s Thesis, Sonoma State University.
-
OM Daniels (2023). “Transgenerational Effects of Stress, Immune Function and Response in Northern Elephant Seal (Mirounga angustirostris) Offspring.” Master’s Thesis, Sonoma State University.
-
JN Carvalho (2024). “Elevated maternal adrenocorticosteroids alter adrenal responsiveness in weaned northern elephant seals (Mirounga angustirostris).” Master’s Thesis, Sonoma State University.
-
AR Diluzio (in progress). Master’s Thesis, Moss Landing Marine Lab.
-
GT Shipway (in progress). PhD Dissertation, University of California Santa Cruz.