Gulf of California

What are we studying? | Why are we studying? | What are we finding? | What does it mean? | Where can I read more?

What are we studying?

We are studying whales in the Sea of Cortez, which is also known as the Gulf of California. The Sea of Cortez is home more than a dozen whale species – including the humpback, fin, blue, sei, pilot, and sperm whales.  We are studying the impact of chemicals in the environment on the genetic health of whale populations.  To do this, we take a skin sample from the whales’ flanks using a crossbow and a specialized biopsy arrow that gives us a sample about the size of a ball point pen cap.  This biopsy, if successful, provides us with ~1 cm of skin and 2-3 cm of blubber.  The skin is then analyzed for metal pollutants, while the blubber will be analyzed for organic contaminants that accumulate in fatty tissue.  With these data, we can compare levels of chemicals in whale tissue to other regions of the world to evaluate relative threats to chemical exposure.  Furthermore, we can use established whale cell lines in our lab to determine how the levels of chemicals in the skin and blubber samples pose a threat to their genetic health – we evaluate this by determining what levels of a chemical kills cells, or breaks DNA, or disrupts DNA damage repair.

Why are we studying it?

We are now in an era where chemicals are everywhere in the environment, largely due to human activities.  Currently we have a poor understanding of the true extent of where chemicals go and what they do when they are released into the environment.  Part of our mission is to determine where these chemicals are going in the marine environment, and how they are affecting animals on an individual, population, and ecosystem-wide scale.  Some areas receive and retain more chemicals than others due to their proximity of point sources (e.g. factories, mines, oil rigs, harbor cities), while others are more remote and chemicals take longer to arrive there.  The Sea of Cortez is an area with minimal point sources due to the lack of industrialization and development of the desert coasts.  Point sources that do exist include mining efforts for silver, agricultural run-off from the Colorado River, and the slow growth of cities in the northern and southern parts of Baja California.  By comparing multiple regions, we can piece together a better picture of how chemicals in the environment are changing our ecosystems.

 

What are we finding?

Our work in the Sea of Cortez has only just begin. We have sampled a number of whales from 7 different species and the data are pending.  Work we did in the Sea of Cortez from 1999 in sperm whales has been published and gives us a baseline of exposure as metals were present in the whales. Those data show Sea of Cortez whales were one of the higher regions for cadmium, lead, mercury, titanium and strontium and one of the lower regions for arsenic, barium, chromium, gold and silver.

 

What does it mean?

Our data supports the suggestion that chromium(VI) poses a potential health risk to turtles who are exposed to it either through inhalation of chromium(VI) or other routes such as diet. Furthermore, because our data indicate that chromium(VI) damages chromosomes, chromium(VI) exposure may contribute to the development of cancer, developmental abnormalities and failure to reproduce.

 

Where can I read more?

• Wise, S.S., Xie, H., Fukuda, T., Thompson, W.D. and Wise, Sr., J.P. Hexavalent Chromium Is Cytotoxic and Genotoxic to Hawksbill Sea Turtle Cells. Toxicology and Applied Pharmacology, 279: 113–118, 2014. PMID: 24952338. PMCID: PMC4134996 Wise, Sr., J.P., Payne, R., Wise, S.S., LaCerte, C., Wise, J., Gianios, Jr., C., Thompson, W.D., Perkins, C., Zheng, T., Zhu, C., Benedict, L. and Kerr, I. A Global Assessment of Chromium Pollution using Sperm Whales (Physeter macrocephalus) as an Indicator Species. Chemosphere, 75: 1461–1467, 2009. PMID: 19324391.

• Wise, Sr., J.P., Wise, S.S., LaCerte, C., Wise, Jr., J.P., and Aboueissa, A. The Genotoxicity of Particulate and Soluble Chromate in Sperm Whale (Physeter macrocephalus) Skin Fibroblasts. Environmental and Molecular Mutagenesis, 52: 43-49, 2011. PMID: 20839228.

• Wise, Sr., J.P., Thompson, W.D., Wise, S.S., LaCerte, C., Wise, J., Gianios, Jr., C., Perkins, C., Zheng, T., Benedict, L., Mason, M., Payne, R. and Kerr, I. A Global Assessment of Gold, Titanium, Strontium and Barium Pollution using Sperm Whales (Physeter macrocephalus) as an Indicator Species. Journal of Ecosystem and Ecography, 1(1):1-9, 2011. doi:10.4172/2157-7625.1000101. PMID: Not applicable.

• Li Chen, T., LaCerte, C., Wise, S.S., Holmes, A., Martino, J., Wise, Jr., J.P., Thompson, W.D. and Wise, Sr., J.P. Comparative Cytotoxicity and Genotoxicity of Particulate and Soluble Hexavalent Chromium in Human and Sperm Whale (Physeter macrocephalus) Skin Cells. Comparative Biochemistry and Physiology – Part C: Toxicology & Pharmacology, 155: 143–150, 2012. PMID: 21466859. PMCID: PMC4084666.

• Savery, L.C., Evers, D., Wise, S.S., Falank, C., Wise, J., Gianios, Jr., C., Kerr, I., Payne, R. Thompson, W.D., Perkins, C., Zheng, T., Zhu, C., Benedict, L. and Wise, Sr., J.P. Global Mercury and Selenium Concentrations in Skin from Free-Ranging Sperm Whales (Physeter macrocephalus). Science of the Total Environment, 450–451: 59–71, 2013. PMID: 23467177.

• Savery, L.C., Wise, S.S., Falank, C., Wise, J., Gianios, Jr., C., Thompson, W.D., Perkins, C., Mason, M.D., Payne, R. Kerr, I. and Wise, Sr., J.P. A Global Assessment of Silver Pollution using Sperm Whales (Physeter macrocephalus) as an Indicator Species. Journal of Environmental and Analytical Toxicology, 3 (2):169-177, 2013. http://dx.doi.org/10.4172/2161-0525.1000169.

• Savery, L.C., Wise, S.S., Falank, C., Wise, J., Gianios, Jr., C., Thompson, W.D., Perkins, C., Zheng, T., Zhu, C., and Wise, Sr., J.P. Global Assessment of Oceanic Lead Pollution using Sperm Whales (Physeter macrocephalus) as an Indicator Species. Marine Pollution Bulletin, 79(1-2): 236–244, 2014. PMID: 24361115.

• Savery, L.C., Wise, J.T.F., Wise, S.S., Falank, C., Gianios, Jr., C., Thompson, W.D., Perkins, C., Zheng, T., Zhu, C., and Wise, Sr., J.P. Global Assessment of Arsenic Pollution Using Sperm Whales (Physeter macrocephalus) as an Emerging Aquatic Model Organism. Comparative Biochemistry and Physiology – Part C: Toxicology & Pharmacology, 163: 55–63, 2014. PMID: 24473067. PMCID: Not applicable.

• Savery, L.C., Li Chen, T., Wise, J.T.F., Wise, S.S., Gianios Jr., C., Buonagurio J., Perkins, C., Falank, C., Zheng, T., Zhu, C., and Wise, Sr., J.P. Global Assessment of Cadmium Concentrations in the Skin of Free-Ranging Sperm Whales (Physeter macrocephalus). Comparative Biochemistry and Physiology, Part C, 178: 136-144, 2015. PMID: 26456815. PMCID: Not applicable.