In the life of a seagrass ecologist

Friends and family sometimes ask what I do at work so this is an attempt to at least partially answer that question. I am a marine ecologist at the Virginia Institute of Marine Science where I work in the Submerged Aquatic Vegetation (SAV) Restoration and Monitoring Laboratory. There we monitor and restore underwater seagrasses (SAV) and try to understand what factors are driving the trends that we observe during monitoring.

 

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Zostera marina (eelgrass) near Goodwin Island, in the York River, U.S.A.

Seagrass Background/Basics

Seagrasses are very important plants in aquatic ecosystems. They are not algae; they are true flowering plants, like the ones we see on land. They have all of the same structures such as seeds, flowers, and roots. They are also foundational species that, as the term implies, form the foundation of their ecosystem, like trees form forest ecosystems on land. They provide habitat for an abundance of marine life such as fishes, crabs, shrimps, other invertebrates, and even manatees. They remove carbon dioxide (CO2) and oxygenate the water via photosynthesis. They remove nutrients from the water column and sequester carbon in their surrounding sediments. The roots stabilize the sediment reducing shoreline erosion and their leaves clean the water by trapping suspended particles. The leaves also dampen the impact of wave energy on nearby shorelines. Basically, in a word, seagrasses are awesome.

You can learn more about SAV here.

My Job as a Seagrass Ecologist

As a marine ecologist, specializing in seagrasses, we spend much of our time from the spring to the fall seasons working in the field (underwater, in seagrass beds), which requires a boat and snorkel or SCUBA gear. One advantage is that seagrasses grow in shallow waters where they receive enough light for photosynthesis, so we never have to dive in deep dark waters. Therefore, we can almost always see underwater, even when it’s turbid. This also means that our air lasts for a long time allowing us to spend several hours at a time on the bottom. In the field, we do a lot of seed-based restoration, long-term monitoring projects and field experiments. The following sections go into more detail of this fieldwork but this section will continue to summarize our daily activities.

When not in the field we often spend time on land working in our restoration greenhouse where we process seagrass seeds and do controlled experiments. Every summer there are daily tasks to maintain our seed banks for the upcoming fall restoration efforts. For example, there is a daily regime of “paddling” our tanks where we use modified nets to scoop out the non-seed organic material. This work is dirty, hot and arduous. We also occasionally do controlled experiments in tanks to answer questions about seagrass ecology. These experiments often involve planting grass in tanks, and adding experimental treatments, which can be physical such as temperature or light manipulations or they can be biological such as animals to determine their effects on the seagrass.

When not working in the field or greenhouse, we can often be found either in the lab processing samples from the field or on a computer writing and performing data analyses. We analyze a lot of long term data from our surveys which we pair with physical data collected by remote sensors in the field. We employ the latest statistical techniques using the open source statistical computing software called R. Writing and analysis is challenging work and for this reason I find it to be one of the most rewarding aspects of my job. It is also the step in the scientific process where we take what we have learned and articulate it into a product (a peer reviewed scientific paper) that can be used to better understand seagrass ecology. This benefits the field of marine ecology and it provides information for our advisory services to decimate to policy makers so that they can make better decisions affecting our marine environment and by extension, our society. There are many benefits of healthy seagrass beds to fisheries, recreation and the community as a whole.

Overall, I am very fortunate to be in this dynamic high energy occupation, and I cannot overstate that our accomplishments are possible only due to the selfless dedication of our entire team including the many hard working and talented students, graduate students, technicians, and interns who work with us each year. I continuously find myself in the role of teacher or student – depending on the day. I learn things not only by occasionally taking a graduate course, but more often, by conducting basic research. Closely following what others in the field are doing is absolutely essential for our program to remain effective. Alternately, I teach by helping other researchers on the job or when engaged in outreach, either in public or in a classroom.

These are some of the basic duties that I engage in with our team. For the rest of this post I will highlight some of the main research projects happening in our lab.

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Just another day at the office, getting ready to survey some seagrass plots.

Seed Based Seagrass Restoration

Our seed-based restoration project is one of the cornerstones of our program. It involves the harvest of mature flowers from seagrass beds in the spring using an innovative underwater harvester designed by my predecessor, Scott Marion. Once harvested from a donor seagrass bed, we transport the flowers back to prepared tanks on land. With a continuous supply of estuarine water and bubbling air in these tanks, there the flowers mature, the seeds drop off, and as the summer wears on, we work daily to remove the organic material. We use dip-nets to scoop it out of the tanks during the hot and humid Virginia summer mornings. Then, in the late summer, we flume and further purify our seeds to be used for restoration in the fall months. As I mentioned previously, this is an arduous process akin to agricultural work or more aptly, aquacultural work!

Our efforts have resulted in one of the most successful SAV restoration projects in the world in the coastal bays on the Eastern Shore of Virginia. There we have planted over 500 acres of seagrass seeds that have spread into over 7000 acres. Historically, eelgrass was a dominant feature in those bays until the 1930s when a hurricane and disease wiped out the grass. Then in the 1990s, Dr. Orth and company began this seed based restoration in these bays. The rest is history and we continue to work in new areas in the coastal bays to expand on our success.

Seaside Scallop Restoration and Monitoring

In 2009 we began another restoration program, this time for the historical bay scallop (Argopecten irradians) fishery in the coastal bays of Virginia. The bay scallop was a robust fishery in the coastal bays until the 1930s when it was lost with the seagrass. Prior to its collapse, Virginia had the highest landings of all of the bay scallop fisheries on the east coast of the United States. Unfortunately though, bay scallops are dependent on the foundational seagrass for their existence. The baby scallops attach to the grass blades until they grow enough to drop off and live on the sediment surface as adults. The seagrass provides relative safety from predators by using the structure of the seagrass.

Because the bay scallop is broadly distributed along the east coast of the United States, we have successfully established broodstock, originating most from North Carolina that we use for our restoration program. Most of this work is done at our Eastern Shore Laboratory in Wachapreague, Virginia. Once the scallops reach a sufficient size, we deploy them into cages in the seagrass beds of South Bay. There we maintain them until they mature into adult scallops. Then, during the fall, when scallop predators are low in number we release adult scallops into the coastal bay seagrass beds. As with our seed maintenance, maintaining scallop cages in the field is also filthy and difficult work, although it is rewarding.

Each summer we survey the adult scallop populations in the coastal bays by hand. We have several teams of scientists and volunteers who go to thousands of random points, place a meter square quad in the seagrass bed and then “sample” all of the bottom area in each quad with their fingers and hands. Each year, collectively, our teams literally run their hands over 4 acres of seagrass bottom. From that we get an estimate of the scallop populations. We are seeing some promising data so far. As of 2017 we estimate that there are hundreds of thousands of scallops in each of the coastal bays surveyed. To sum it up, on average, if you searched 50m2 of bottom there, you would find one scallop. It’s not enough to open a fishery but it’s definitely a great start and who knows, maybe one day it will again be common to find bay scallops in the coastal bay seagrass beds.

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Me piloting some filthy bay scallop cages back to the VIMS Eastern Shore Laboratory.

You can also check out this short video that summarizes our restoration work in the coastal bays of the Eastern Shore of Virginia.

Seagrass Monitoring

On the monitoring front, we conduct quantitative aerial surveys of the entire extent of the seagrass beds in the Chesapeake Bay and the Eastern Shore seaside seagrass beds annually. Our monitoring group works tirelessly to compile these data and you can learn more about it from on our website where there are interactive maps of the aerial data. Our digital imagery monitoring team work long hours to classify the aerial coverage and digitize this data in their maps. To verify this process, we ground truth these areas to ensure that what we see from the air is not algae or something other than our target seagrass. It is a never-ending task to keep this dataset up to date for use by state and federal agencies, environmental organizations and citizens.

Seaside Seagrass Community Monitoring

In the seaside seagrass beds we also monitor the ecological communities there. Since their establishment in the early 2000s, we have been interested in the ecological structure and function provided by this restored habitat. We do this by sampling the grass and its inhabitants. Near the base of the food web are some very important invertebrates living in SAV. These include worms, slugs, and bugs such as amphipods and isopods. Many of these critters are absolutely essential to the grass because they eat the algae that grows on the grass blades. Also known as epiphytes, this algae by growing on seagrass leaves, can outcompete the grass for light and nutrients to its detriment. Thankfully the invertebrate grazer community usually keeps algae in check allowing the seagrass to thrive. Sometimes, however, a predator can decimate a grazer community which can release the epiphytic algae allowing it to outcompete and harm the underwater grasses. This is called a “trophic cascade” where one organism higher up in a food web can affect lower levels of the food web by rippling through it. There are many documented examples of this in nature. One very famous example involves killer whales, otters, sea urchins and kelp.

Since 2012, we have surveyed the fishes in our restoration seagrass beds in the coastal bays of Virginia using a trawl survey. We do this survey in concert with a grazer, grass and epiphyte survey, once a month from April to October. We are already seeing some interesting patterns in these data, especially when we couple them with local physical monitoring data. We are also seeing possible evidence of a trophic cascade where warmer waters, promote a tropical predator called pinfish that is a voracious predator of seagrass grazers and so we have some concerns its incursion could impact the foundational seagrass in these areas.

Lower Chesapeake Foundational Seagrass Survey

We also have some very specific long-term on-the-ground monitoring. There are two species of grasses; Ruppia maritima (widgeongrass) and Zostera marina (eelgrass) that grow in the salty (polyhaline) portions of the Chesapeake Bay. Once a year, at 19 – 26 sites in the polyhaline, we conduct a quantified survey of these two grasses. We have been doing this survey since 1978 off and on but have been very consistently sampling since 2006. We have a paper submitted to Marine Ecology Progress Series journal detailing the results of this study. After an extensive analyses, the short summary is that there appears to be a combination of physical forces, such as warming waters and nutrients, coupled with competition between the two seagrass species that are most responsible for their relative distributions. With the continued warming of waters in the Chesapeake Bay, the outlook for the historically dominant eelgrass does not appear to be very good. There is a possibility that widgeongrass could replace some of the functions provided by eelgrass, but it has less structure and therefore, probably less function. Hopefully, we will take actions to mitigate global change and enable the future restoration of eelgrass in the Chesapeake Bay. Our restoration efforts in the Chesapeake Bay have had some success but not like in the coastal bays. This may be due to the fact that the oceanic exchanged coastal bays tend to be consistently a few degrees cooler than the waters of the Chesapeake.

Other Projects

In addition to the core of projects above, we also conduct field experiments, and test plots each year to identify suitable restoration sites in the coastal bays of Virginia and in the Chesapeake Bay. We do on-the-ground quantitative surveys of our seed-based restoration plots. We also assist AJ Johnson with his PhD dissertation fieldwork. In the past we have assisted other graduate students by helping them conduct various field experiments such as when Erika Schmidt used tethering to test the predation pressure on baby scallops. There are other projects and our agenda is in constant flux. Staying nimble is essential to our program. The life of a seagrass ecologist is never dull!

You can learn even more at our website, or from some of our publications. We also have a facebook page SOS (Save our Seagrass/Save our Scallops) with other interesting information on seagrasses and seagrass related topics, including dispatches from our work in the field with photos.

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