Imagine Magazine - Johns Hopkins - January/February 2015 - (Page 38)

exploring career options Marine Scientist Interview by Amy Entwisle Mak Saito, Ph.D. Associate Scientist Department of Marine Chemistry and Geochemistry Woods Hole Oceanographic Institution In 2007, while on an expedition to map chemical composition and microbial life in the South Atlantic Ocean, Dr. Mak Saito made a discovery with the potential to change our understanding of how the chemistry and biology of the oceans interact. In his work, Dr. Saito studies the trace element requirements of marine life and the co-evolution of biogeochemical cycles and life throughout Earth's history-with the broader goal of sustaining them for the future. How did you become interested in marine science? I wasn't one of those kids who wanted to grow up to be a marine scientist. I was majoring in environmental studies at Oberlin College, and I realized that so many of the environmental problems humans face are related to chemical imbalances on the planet. I was drawn to the young field of biogeochemistry, which focuses on the interactions between biology, chemistry, physics, and geology, and to ocean science in particular. The scale of the questions people were asking was global, because the oceans are global. I went on to earn my doctorate in chemical oceanography at the MIT/Woods Hole Oceanographic Institute Joint Program in Oceanography. Can you describe the work you do? I study metals as they relate to the nutrition of marine life. Just as we need iron and other nutrients to live, all life needs a variety of elements to produce their own biomass tissues and cells. Trace elements such as iron, cobalt, zinc, cadmium, nickel, and also vitamins are extremely scarce in the oceans, partly because there's no soil in the ocean and partly because metals don't dissolve very well in water. Seawater has much lower levels of those metals than your tap water does. 38 imagine Ocean life has to figure out how to get all its nutritional needs out of seawater when it contains very little of these metals. There are a lot of evolutionary stories, chemical strategies, and geochemical cycling related to how these metals and vitamins are acquired and utilized. The availability of these nutrients is known to impact the global carbon cycle, the global nitrogen cycle, and the controls on the rate of climate change. Our larger goal is to understand how the planet works so we can find the path to creating a sustainable human society. You discovered a large amount of iron in the South Atlantic. Why is that important? Iron is necessary for photosynthesis in all plants, but we've only recently understood how to accurately measure iron in the oceans. For decades, people thought they were measuring iron and other metals in seawater when they were really measuring metal dust contamination from the big metal ships they were on. When scientists obtained the first correct measurements of iron in seawater in the 1980's, the levels were far lower than we had thought. We're trying to understand how much iron is in the oceans so we can determine how that's changing. We know that dust from the Sahara will bring in many tons of iron, and that there's iron coming from run-off and sediments. Simultaneously, that iron is forming into small iron oxides-basically rust-and then sinking to the bottom of the ocean. It's also being taken up by marine life. Once scientists understand these inputs and outputs of iron, they can create 3D circulation and ecosystem models that are the basis for ocean climate models. '' Once you enter the research domain, it's no longer about getting the right answer. Jan/Feb 2015

Table of Contents for the Digital Edition of Imagine Magazine - Johns Hopkins - January/February 2015

Big Picture
In My Own Words
Land & Sea
Going Full Circle with Ocean Conservation
At Home in the Water
Diving into Marine Science
Ocean Views
Becoming a Steward of the Seas
Engineering for Ocean Health
Selected Opportunities and Resources
The Wonderful World of MOOCs
Super
Off the Shelf
Word Wise
Exploring Career Options
One Step Ahead
Planning Ahead for College
Students Review: UC San Diego
Creative Minds Imagine
Mark Your Calendar
Knossos Games

Imagine Magazine - Johns Hopkins - January/February 2015