Ms. Patricia Cockett, an Undergraduate Research and Mentoring (URM) Program intern in the Hadfield Lab, has been exploring the rocky intertidal zones of her home island of Kaua'i for as long as she can remember.
"Growing up I collected opihi (Cellana sp.), kupe'e (Nerita polita), and limu (marine algae) for food at family gatherings," recounts Ms. Cockett. "My childhood explorations have led me to ask questions of why intertidal animals occupy the areas they do and how they're able to survive in such environments."
Ms. Cockett's first experience in independent research was as a participant in the Science Technology Engineering and Mathematics (STEM) program at Kapiolani Community College in 2009. As a STEM participant, she worked as a peer mentor helping other students in addition to conducting her own undergraduate research project under Dr. Wendy Kuntz.
"My first project was funded by the Center for Microbial Oceanography: Research and Education (CMORE) scholars program," explains Ms. Cockett. "I tested the cues for movement of the littoral gastropod Nerita picea. I compared my results to 'Olelo No'eau (ancient Hawaiian proverbs) and it was through my research that I recognized the similarities between the observations of my ancestors and those of western science."
Ms. Cockett joined the Hadfield lab here at Kewalo Marine Lab in the summer of 2010 as a URM intern, where she has continued her research interests in intertidal ecology and has begun to explore the susceptibility of this ecosystem to increased thermal stresses caused by global climate change. As a Hawaiian, Ms. Cockett feels strong cultural ties to the islands, and believes that she shares a responsibility to malama ka 'aina (care for the land) and malama ke kai (care for the ocean).
"I am deeply concerned about the current state of the marine organisms inhabiting the intertidal zone with regards to climate change and anthropogenic impacts," shares Ms. Cockett. "This is one of the main reasons that I am studying intertidal ecology at UH and getting my degree in Biology."
Organisms that live within the littoral zone of Hawaii's shores tolerate extreme environmental stressors, including daily temperature fluctuations ranging from 25° to 45°C within a single tidal cycle. Exposure to such extreme temperatures suggests that these intertidal organisms may be living at the edge of their thermal limits for large parts of the day, making them extremely vulnerable to the increases in average surface temperatures that have been predicted by the Intergovernmental Panel on Climate Change (IPCC).
As part of her initial studies, Ms. Cockett examined the population structure of one of the abundant intertidal snail species, Nerita picea, using mitochondrial DNA sequencing and correlated their distribution with different bacterial populations on the intertidal rocks using molecular techniques.
Currently, Ms. Cockett is examining the vertical distributions and thermal limitations of four Hawaiian gastropod species thought to occupy different niches that extend from the uppermost portions of the littoral zone to mean low tide.
"The four Hawaiian gastropod species that I have chosen to study include: Littoraria pintado, Nerita picea, Siphonaria normalis, and Morula granulata. During low tide, these animals experience abiotic stress such as, increased temperatures and dessication," she explains.
At her field site at Leahi Beach at the base of Diamond Head, Ms. Cockett conducted transect surveys to determine the vertical distributions of the different snail species.
"I found that there are significant differences in intertidal level among the four species," said Ms. Cockett. "Additionally, I measured temperatures at the levels occupied by the gastropods using iButton® temperature loggers and found a positive correlation between intertidal height and temperature."
Ms. Cockett also determined the lethal temperatures for the four gastropods using thermal stress experiments in the laboratory and compared these data to the temperatures she measured in the field. She found that each of the snail species she studies lives close to its uppermost thermal limits, making them vulnerable to any additional thermal stress.
In order to better understand how well these gastropods are able to respond to environmental stressors, Ms. Cockett, in collaboration with Dr. Lars Tomanek's proteomics lab at California Polytechnic State University in San Luis Obispo, has been studying changes in the levels of protein expression in the snails in response to thermal elevation. Specifically, they have been studying changes in expression of the heat-shock proteins (HSP), which are involved in the heat shock response. HSP's help to protect cells by stabilizing proteins that have been damaged by thermal stress. Using 2-D gel analysis, they have been able to visualize changes in the proteome of the animals as they experience environmental stress, which may provide insight into how vulnerable, or resistant, the gastropods may be to climate change.
Ms. Cockett will graduate with her Bachelor's in Biology this Spring, and will pursue her graduate studies at Texas A&M University in Corpus Christ with Dr. Chris Bird, continuing her research on the Hawaiian intertidal zone and helping to monitor Hawaii's shorelines.