Guest Posts / How do we science? / Scientists in Action!

Mimicking Nature: Seagrass Restoration in the Chesapeake Bay

This guest post was written by Rachel Wimmer. Rachel is a senior at the College of William & Mary studying biology and marine science. She works in the Submerged Aquatic Vegetation (SAV) Lab at the Virginia Institute of Marine Science studying seagrass ecology under Jon Lefcheck. She also serves as an EcoAmbassador for W&M’s Committee on Sustainability, writing about sustainability research initiatives happening on the W&M and VIMS campuses. Aside from science communications, she is passionate about running, coffee, and making people laugh.

We, as marine scientists and lifelong students, are very dedicated to our work. We have consistently been taught to find the broader implications for our research to prove to the rest of the world that it matters. We are deeply connected to the ecosystems that we work in and can easily ramble off hundreds of reasons as to why our body of study is important and should be protected. But what is it that specifically draws our attention to a particular ecosystem in the first place? As an EcoAmbassador at The College of William & Mary, I work to uncover the oftentimes hidden importance of sustainability-based research.

Eelgrass (Zostera marina) in the Chesapeake Bay was historically taken for granted as an abundant, and even nuisance, seagrass and was therefore never studied particularly in depth. That is, however, until Tropical Storm Agnes swept through the bay in June 1972, carrying with it fresh water and sediment that decimated these eelgrass communities. This literal coup de grace changed the face of the bay overnight, wiping out 50% of the eelgrass that had been present in the previous decade. Only after it was gone did we start to realize just how critical eelgrass ecosystems are to the health of our oceans.

Seagrass. Photo by VIMS SAV Lab.

Seagrass. Photo by VIMS SAV Lab.

Seagrass beds are hugely important blue carbon sites, sequestering carbon from the atmosphere into long-term storage in the ocean. Despite only covering 0.2% of our world’s oceans, seagrass beds alone absorb about 17% of all carbon sequestered by the ocean – twice as much carbon as the world’s tropical and terrestrial forests combined. They are critical habitats for hundreds of species, including many that we are economically dependent upon. Seagrass also acts as the “canary for water quality” as they are responsible for improving water clarity by trapping particles suspended in the water column. However, eelgrass die-offs have been repeatedly observed when bay temperatures climb above 25° C. Decreased water quality and increasingly hotter summers are threatening the restoration of eelgrass back to its historical abundance in the bay.

At the time of Tropical Storm Agnes, Dr. Robert Orth was fortuitously an incoming graduate student at the Virginia Institute of Marine Science (VIMS). With funding from the newly founded Chesapeake Bay Foundation and an urgency to restore the lost eelgrass, Dr. Orth set out to research the unknowns of seagrass ecosystems. He had to start at the beginning, studying basic seed ecology and the role of eelgrass in marine environments. Orth eventually took particular interest in how seeds disperse and what triggers their germination.

Out of curiosity, he decided to see what would happen if he simply broadcasted seeds into the bay. He collected germinated seeds and tossed them from a boat as it zig-zagged through an empty transect. When he got up in the air the following spring, he saw near perfect lines of eelgrass growing along the exact transects that the boat had driven over months earlier. He took the photo that spoke a thousand words (below), giving us major insight into the ecology of eelgrass and how nature facilitates the recovery of eelgrass meadows using seed distribution. When seeds are released by eelgrass (or in this case, from a boat), they sink and are rapidly buried, not moving far from their landing spot in the sediment. When seagrass is abundant, this makes it easy for existing beds to slowly grow. However, with so few seagrass beds left in the bay today, it is difficult for there to be widespread delivery of seeds to areas deprived of grass, particularly secluded coastal bays. Therefore, our attempts to restore eelgrass beds in the Chesapeake Bay should mimic what nature would do naturally, given enough time.

Aerial photograph taken after Dr. Orth's initial seed broadcast. Photo by Robert Orth.

Aerial photograph taken after Dr. Orth’s initial seed broadcast. Photo by Robert Orth.

Now directing the Submerged Aquatic Vegetation (SAV) lab at VIMS, Dr. Orth runs the largest seagrass restoration effort in the world (in terms of area) and one of the few that has actually seen significant success. For the past 15 years, the SAV lab has broadcast 60 million seeds into 450 acres of seaside bays. This natural enhancement of these environments is simple, fast, and effective. Their 450 acres of seeded plots have naturally spread into 6,100 acres of eelgrass throughout the seaside bays. Though factors like rising temperatures and decreasing water quality threaten the permanence of efforts like this, restoration of seagrass beds is foundational to improving the overall health of ecosystems in the bay. All it takes to make these restoration efforts possible is curiosity and a bit of creativity to discover the secrets of ecosystems that still remain a mystery to us.

Volunteer dispersing seeds along a transect in one of the study plots. Photo by Rachel Wimmer.

Volunteer dispersing seeds along a transect in one of the study plots. Photo by Rachel Wimmer.

For more on seagrass, Dr. Orth, and sustainability research going on at William & Mary and VIMS, check out my EcoAmbassador blog!

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