Five Franklin & Marshall College students and Assistant Professor of Geosciences Paul Harnik boarded boats along the Louisiana and Alabama coasts and sailed hours into the Gulf of Mexico to collect live clams and the empty shells left by past clam populations.
“When we get to our sites, we lower a large, open-ended metal box off the back of the boat,” Harnik said. “When it hits the seafloor, it sinks into the sediment. Then, as it is pulled up, a trap door is tripped, capturing the top 10 to 20 centimeters of sand and mud.”
Junior biology majors Stephanie Liu and Jared Benjamin, senior Andy Marquez, an environmental science major, and sophomores Jamila Gowdy and Michellee Garcia, worked alongside Harnik to sieve the sediments deposited on the rocking boat’s deck.
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The marine bivalve, Nuculana acuta, lives in organic-rich sands across the northern Gulf of Mexico. Students study this species in Earth & Environment Professor Paul Harnik’s lab.
Image Credit: Paul Harnik
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An Atlantic Ghost Crab (Ocypode quadrata) scuttles along the shores of Dauphin Island, Alabama. It is not a species the researchers study; but the students came across them occasionally in their swims at the beach.
Image Credit: Paul Harnik
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Research staff Tom Guoba and Grant Lockridge from the Dauphin Island Sea Lab use a box corer, an ocean instrument designed to collect sediment samples, off the coast of Alabama. They will repeat this task 40 to 50 times a day.
Image Credit: Paul Harnik
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A Royal Sea Star, Astropecten articulates, recovered in a box corer off the coast of Alabama and returned to the sea because it is not a species the researchers study.
Image Credit: Paul Harnik
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A mole crab, another species recovered in a box corer, also returned to the sea.
Image Credit: Paul Harnik
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Empty shells of clams and snails that lived on the Alabama continental shelf in the past are among a variety of clam species studied in Harnik’s lab. The shell materials establish baselines for what the marine environments were like before industrial agriculture, commercial fishing, and other human activities.
Image Credit: Paul Harnik
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F&M senior Andy Marquez and Harnik sieve seafloor sediments off the coast of Louisiana.
Image Credit: Paul Harnik
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The researchers travel and work near major shipping routes along the coast of Alabama.
Image Credit: Paul Harnik
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F&M junior Jared Benjamin and Marquez sieve seafloor sediments off the coast of Alabama.
Image Credit: Paul Harnik
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Sorting through shell debris off the coast of Alabama: F&M junior Stephanie Liu, Marquez, Benjamin, and sophomore Michellee Garcia.
Image Credit: Paul Harnik
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Off the coast of Louisiana, Liu and Garcia continue the work of sieving seafloor sediments.
Image Credit: Paul Harnik
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On windswept, sunny Alabama waters, F&M sophomore Jamila Gowdy and Garcia sieve yet another collection of seafloor sediments.
Image Credit: Paul Harnik
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Back on campus, students sort through dead shells in Harnik’s lab. To determine the age of the shells they collect, labs at Northern Arizona University and University of California – Irvine conduct radiocarbon dating. A University of Alabama lab analyzes oxygen, carbon and nitrogen stable isotopes in the shells to determine changes in water temperature and food supply over the last thousand years.
Image Credit: Paul Harnik
The team then sorted through the material remaining on their sieves. “Species that we don’t study we return to the sea,” Harnik said. “We keep the live clams and old empty shells to study here on campus.”
A rising sophomore who intends to major in environmental science, Jamila Gowdy said the field experience was transformative.
“I loved how we all started off as timid and unsure of what we were getting ourselves into, but by the third day offshore, we were shouting out the names of different species of clams and were excited to see who would find the most alive,” she said. “I learned that even though the work is difficult, fieldwork allows scientists to figure out what the environment used to look like, and compared with today, what changes have occurred.”
This summer’s research project is part of a five-year, $634,000 National Science Foundation CAREER award that Harnik, a paleontologist who studies biodiversity in the world’s oceans, received this spring. The grant provides for three years of fieldwork on the Gulf Coast with more than a dozen F&M students participating.
“The primary purpose of the research is to understand what is natural in the ocean and answer the question, ‘How are humans affecting ocean ecosystems?’” the professor said.
The research vessels, operated by collaborating local marine labs, pass oil and gas platforms on the way to the team’s sampling sites on the continental shelf. Shrimp boats, part of the region’s commercial fishing industry, dot the horizon. The Mississippi River, carrying agricultural and urban runoff, empties into the Gulf of Mexico.
“There are all these different ways that we interact with coastal environments, and some of those you might expect to affect the organisms that live in those environments,” Harnik said. “In order for us to understand the ways in which species are responding to human activities, and what our impacts are, we need to know what things were like before those activities started.”
For the students, a central research goal is to use the empty shells in the sediment to determine what conditions were like in those environments before industrial agriculture and commercial fishing began, and then compare that baseline with clam species alive today to see how they changed over the last 100 years.
“The students sort through our samples, searching for particular species, and prepare these shells for the scanning electron microscope on campus,” Harnik said. “Then they measure features on the shells that are roughly the width of two human hairs – 150 microns – to learn how species have adapted over time.”
The field experience has given Andy Marquez, a rising senior considering graduate school, confidence in his abilities as a researcher.
“When I’m in a classroom, I get to learn about the work others have done to understand the environment, but in the field I get to do the work myself,” Marquez said. “I’m learning proper research techniques, which are important for generating reliable results that can make a real contribution to the field of environmental science.”