Research in the Tift Lab is interdisciplinary. The major focus of the lab is the field of comparative physiology. One of the primary areas of research right now focuses on physiological mechanisms that allow certain animals to tolerate extreme hypoxia and ischemia-reperfusion events. Another area of research we are currently working on is the brain lymphatic system in marine mammals. We are also working on projects related to the ecophysiology and conservation of marine mammals from North Carolina to Antarctica.
Current Research Projects
Endogenous Carbon Monoxide
This project is funded by the National Science Foundation. One specific area of interest has been investigating the beneficial aspects of endogenous carbon monoxide (CO) in wild animals. The gas has a reputation for being strictly toxic (a.k.a. 'The Silent Killer') and a byproduct of carbon-based fuel combustion (e.g., car exhaust or cigarette smoke). However, CO is also naturally produced in virtually all bacteria, plants, and animals from the natural breakdown of heme, found in many proteins in nature. Recently, it has been found that low concentrations of CO exposure can actually protect tissues from certain injuries associated with conditions such as chronic hypoxia and ischemia-reperfusion injuries.
Our work has shown that some deep-diving mammals with elevated hemoglobin and myoglobin stores produce and maintain CO at levels which resemble those seen in chronic cigarette smokers (Tift et al., 2014). Although these levels are high, it appears that they also potentially help the animals avoid injuries associated with diving and could even increase oxygen transport in hypoxic tissues (Tift and Ponganis, 2019). Work with colleagues has also revealed that certain high-altitude human populations that experience chronic hypoxia, also exhibit increased endogenous CO (Tift et al., 2020). It is likely that these levels of CO in certain species are linked to the rate of heme production and removal from the body, and may be closely tied to the turnover of red blood cells (Pearson et al., 2024).
Our lab is interested in investigating the role of endogenous CO in the performance of both animals and humans. We are excited to talk about collaborations studying this unique physiological system, so please feel free to reach out!
Brain Lymphatic System
We have also begun work on the recently discovered brain lymphatic system. This project is funded by the Office of Naval Research and the purpose of this project is to investigate the presence of, and variability in, the brain lymphatic system of several marine mammal species with varying diving abilities (shallow vs. deep divers). To confirm the presence of a brain lymphatic system and identify its localization relative to the intracranial venous system (e.g., dural sinuses, cavernous sinus, etc.) our approach will merge gross and microscopic techniques that are already well-established and routinely practiced in our laboratories. It is not uncommon for animals to strand with identifiable disease states that could impact brain lymphatic function (e.g., Domoic acid and Cetacean Morbillivirus), and it is now becoming more common to identify gas emboli in tissues and vessels of stranded cetaceans, which would allow us to compare results between healthy and diseased/injured animals. Collection and examination of tissues from these animals is essential to establish normal species-related anatomic baselines of the brain lymphatic system. Expanding our knowledge of the brain lymphatic system morphology of several species of mammalian divers is critical to the evaluation of pathobiology, including the assessment of potential disease, injury, and anthropogenic impacts on the organisms.
Crabeater Seal Ecology and Physiology
This is a highly collaborative project funded by NSF to investigate the physiology and ecology of crabeater seals in Antarctica. The lead PI on the project is Dr. Luis Huckstadt, with Drs. Tift and Costa as Co-PIs on the project. We are also collaborating with Dr. Peter Fretwell and Dr. Jaume Forcada from the British Antarctic Survey for this work. The crabeater seal is the most important predator of Antarctic krill and is considered an excellent sentinel species through which to examine the effects of a changing climate on the extended krill-dependent predator community and structure of the entire ecosystem. We are combining animal movement, stable isotope analyses, whole-animal physiology, and novel survey technologies (UAS, satellite imagery) to investigate the differences in the trophic ecology, foraging success, diving physiology, and distribution of crabeater seals across a latitudinal gradient along the western Antarctica Peninsula and to build models to project future changes as the environment of the Peninsula continues to change.