Earth & Sky

Useful links:

Bay Grasses (SAV) in Chesapeake Bay and Delmarva Peninsula Coastal Bays (Virginia Institute of Marine Science, includes tracking data for grasses)

Life Stages of Crabs (Virginia Institute of Marine Science)

Chesapeake Bay Waterfowl (ChesapeakeBay.net)

Striped Bass (ChesapeakeBay.net)

Yellow Perch (Maryland Department of Natural Resources)

Estuaries (Estuaries.gov)

Harmful Algae Blooms (Maryland Department of Natural Resources)

Chesapeake Wastewater Treatment Plants (Chesapeake Bay Foundation)

Riparian Forest Buffers (ChesapeakeBay.net)

Chesapeake Bay Pollutants (ChesapeakeBay.net)

Maryland Chesapeake Bay Watershed Restoration Fund (Maryland Department of Natural Resources)

Crabs and Shellfish (ChesapeakeBay.net)

Bay Grasses (Maryland Department of Natural Resources)

Chesapeake Bay Fish (Maryland Department of Natural Resources)

Maryland Bay Grasses Coverage 1984-2003 (Maryland Department of Natural Resources)

Chesapeake Bay Watershed (ChesapeakeBay.net)

Chesapeake Bay Foundation (CFA)

Chesapeake Bay Foundation Report Card

John Smith, 17th century Chesapeake Bay explorer (ChesapeakeBay.net)

Map of Chesapeake Bay Tributary Regions (Maryland Department of Natural Resources)

Atmospheric Deposition in Maryland (Maryland Department of Natural Resources)

Bay Grasses Planting Programs found here and here (Maryland Department of Natural Resources)

Wild Celery (Maryland Department of Natural Resources)

Eel Grass (Maryland Department of Natural Resources)

Widgeon Grass (Maryland Department of Natural Resources)

Tangier Sound Map (Maryland Department of Natural Resources)

Smith Island Map (Maryland Department of Natural Resources)

Long Island Sound Study

Transcript of Today’s Interview with Thomas Parham:

SG: Could you give us an idea of what the bay looked like before the arrival of European settlers, that is, if we were to take a canoe trip out there and look around, how would it look? What would you see when you look in the water that you don’t see now?

TP: One of the major differences would be the increased water clarity. Water clarity’s important because the plants need sunlight. If you have very turbid water, very cloudy water, the light can’t penetrate the water column for growth of that plant. The clearer the water is, the deeper these plants can survive with the available light that is reaching them.

Back before there were large populations on the bay, the water clarity was over 2 meters deep. Some of our earliest historical photos, taken from the 1920s and 1930s, show that was pretty common in several areas of the bay. So you had large grass beds growing in 2 meter [depths] which is about 6 to 7 feet.

In addition, with all the clear water, the population of fish and shellfish that rely on the bay grasses would have been increased. The bay grasses are important, for instance, to the blue crabs. They use the grasses when they molt. The younger blue crabs go through [a series of growth stages] from egg to zoea, then to something called a megalops, before they become adult crabs. The juvenile crabs, you find very high concentrations of them in areas where you have underwater grasses as opposed to areas with none. They’re real important as a nursery for crabs. For juvenile fish, bay grasses are very important to them too.

In addition, waterfowl rely on bay grasses. There are several species with the same genus that eat underwater plants. Several hundreds years ago, you would have higher populations of these [waterfowl] species because you would have higher amounts of those bay grasses. Obviously there would be some effects – from some local fishing and shellfish harvesting but generally, compared to today, you would have high amounts of those species.

SG: Quick question about fish – are you just talking about fish that are local [to the bay] or do you also have ocean fish in these nurseries?

TP: Well, there are bunches of different fish, and some types use the plants for nurseries. For instance, the rockfish or striped bass spawn early in the spring, and as the juvenile fish grow, they do at some point use the underwater grasses as habitat. But there are other species, such as yellow perch, where if you actually look at the coloration on the side, they’re yellow and have green bars [for camouflage], so they really rely on the underwater grasses for feeding. It’s basically where they live and find their food. There are other species that use it at different times. [The grasses] are generally important because the plants themselves have organisms that grow on them which are in turn used as food for larger and larger species in the bay … and finally you end up with the crabs and fish that feed off the organisms that live on the plants.

SG: What were the critical periods of human activity that have caused the major declines that we see in the bay’s health?

TP: The primary time was in the late 1960s. What happened during that time period is that you had increased populations along the coast of the Chesapeake Bay. With the large population starting to move towards the coast, you have increased agriculture so the nutrients – from the fertilizers would run off into the bay. You’d have increased populations, so the nutrients coming out of the wastewater treatment plants from all the people living there would run out into the bay. And those would provide, basically, food for the algae to grow.

Algae can grow and die very quickly. So what happens is if there’s excess food in the water, the algae will grow – it’s called algae blooms – and cloud the water, preventing light – from reaching the bottom where the plants are growing. So with excess nutrients in the water, you tend to have more algae blooms, or higher concentrations of algae in the water, and this would block light or reduce light for the underwater grass areas.

SG: And it would also suck out the oxygen in the water?

TP: Certainly. Like all plants [algae] produces oxygen but at night, like all plants, they also produce carbon dioxide. What happens is that the algae dies – their life cycles are relatively short – they settle to the bottom and decompose. When things decompose they use oxygen. So you have these big algae blooms that settle to the bottom and when it decomposes they take up a lot of oxygen. So you end up with higher number of fish kills, which is caused by the low [dissolved] oxygen. Once [the algae] dies, the nutrients get back into the system again and you have these continuing algae bloom problems until the nutrients are flushed down to the lower area of the bay, eventually out of the bay.

Because the bay is an estuary, there tends to be a fair amount of nutrients resulting in high productivity, which is typical in estuaries. But in the late 1960s, you had this larger than normal influx of folks moving towards the shoreline, and you ended up with a lot more problems. It wasn’t a single day event but generally that was the period when we had the biggest decline in grasses. We know this by looking at old historical photos of the area taken for other reasons, where you can actually see these grasses in the water at the edges of the pictures, or when the photographers were photographing something else near the shoreline.

We have a relatively good idea of the population of grasses in the 30s and 40s and 50s. Starting about 1984 onwards we have been doing annual surveys, aerial surveys, of the bay that’s done by the Virginia Institute of Marine Sciences or VIMS. What they do is they contract a plane to fly along all the shorelines of the bay and they photograph all the shorelines. That information is taken back and [scientists] identify where the grass beds are [located]. All that grass bed [data] are converted to electronic files and [by using it] they can track how those grass beds expand and shrink from year to year.

From 1984 on, we have a pretty good idea throughout the bay where the grass beds are. In general, since 1984, they have been increasing. But looking at some of those historical photos it looks like the 1960s was a low period. There were also times, like in coastal bays, in the 30s and 40s, diseases caused decline in plants there, but they’ve all rebounded. So the primary thing is, when you have more populations living near shore, [you have] increased nutrients getting into the water through fertilizers, through wastewater treatment plants, and also increased shoreline development which increases the amount of sediment reaching the water that clouds the water too. So all these things make it hard for the plants to receive light.

SG: In terms of percentage of coverage, how has that fluctuated since the 30s? What percentage of grasses were left after the 60s, and how much has it increased since?

TP: In the bay region, there are several states that deal with the bay. Obviously there’s Maryland and Virginia, but for the Chesapeake Bay program, we deal with all the states in the Chesapeake Bay watershed. Using these historical photos we’ve come up with a bay-wide goal based on these old photos. The current bay grass goals for the Chesapeake Bay is right around at 185,000 acres for the whole Chesapeake Bay. That’s the intermediate goal for how much they’d like to have vegetated. And currently, just to kind of give you an idea of where we are … in 2002, there was approximately 90,000 acres of plants. In 2003, we had a wet year, when you have a lot of rain it washes more nutrients and sediment in the water, and that clouds the water. So last year, 2003, we had about 65,000 acres or so. It dropped off [for 2003], but if you’ve seen some of the bar charts on the web site, there has been a general increase since 1984.

SG: Historically, how widespread do you think the grasses were?

TP: By using information from the 1930s, 1940s, and 1950s, looking at historical photos, that goal value was kind of based on those historical averages. But as you can imagine, the photographs weren’t taken at the optimum times for when the plants were there. There are chunks of areas where we don’t have any photographic record. So the numbers most likely would have been higher [than 185,000 acres].

SG: But it’s hard to pin it down?

TP: It’s hard. There’s been a lot of numbers bounced around.

SG: What is it going to take to achieve the target of 185,000 acres of grasses? I was looking at some of the material from the Chesapeake Bay Foundation as well, and they have a list of goals of what they want to achieve by certain times.

TP: Their report card?

SG: Yes. Are those goals realistic?

TP: Well I believe their goals for …

SG: For 2010, their goal is an index of 40, where 100 represents pristine conditions. And (an index of) 70 by 2050. What is it going to take to achieve these levels?

TP: Well, actually that’s a very good question. First of all, let me address the goals of these different organizations. The Chesapeake Bay Foundation will have goals that vary from the 185,000 acres that we have, and I think they’re basing their information on anecdotal information from John Smith’s time. Obviously there was no survey back then. They’re trying to estimate what was available back then. It’s anyone’s guess. The 185,000 acres, our goal, is kind of based on what we have in photography, using what plants were available, what areas were shallow enough for the plants to grow, what areas they could actually grow in, so different organizations have different ways of doing that. Their [goal] is based on John Smith’s time. I forgot … what’s the other part of your question?

SG: Well, I was wondering how realistic it is, and what it will take to achieve the goals. Oh, another quick one, the 185,00 acres, is the goal of all …

TP: Maryland and Virginia.

SG: So it does involve the other watershed states like Pennsylvania and Delaware?

TP: Well, the reason they’re involved is because the runoff from their land, large portions of the runoff, will actually make it into the Chesapeake Bay. The watershed for the Chesapeake Bay is 164,000 sq. miles, and it goes all the way up to parts of New York.

SG: So we’re looking at Pennsylvania, Delaware, New York … what about West Virginia, is that a part of it?

TP: Portions of it drain into the Potomac River, which makes it way to [the bay]. Actually, we’ve got a diagram with all the [watershed] states [on the website].

Obviously, Maryland has a lot of the shoreline, as well as Virginia. So far as how you’d reach [the goal of 185,000 acres of grass beds] … the number one way to bring the plants back is to reduce the amount of nutrients going into the water, basically reducing the amount of food for the algae. For the state of Maryland, the governor has an initiative for improving wastewater treatment plants. Basically they improve wastewater treatment plants throughout the watershed to make sure they’re all operating as efficiently as they can. So that’s going to reduce a big chunk of the nutrients coming into the bay. The other part of that is, not everybody is hooked up to wastewater treatment plants, and some people are on septic tanks. So there’s also a surcharge for folks that are on septic systems, and that money is used for helping to reduce nutrients, and working on bay restoration. The big thing is to reduce the nutrients going into the bay. There have been several estimates on how much it’s going to cost to reduce [nutrients] and obviously those are quite large numbers.

Maryland and Virginia, to some extent, have divided the Chesapeake Bay into some of the watersheds in their states, into tributary regions. They know [what’s needed] to reduce the nutrients in those areas, they know how much [land] area is in each one of these tributary watersheds. For instance, what is the Patuxent River watershed? It’s whatever runs off into the Patuxent, and they know what that area is. They know it for all the different tributaries.

For the time being, it’s all voluntary for reducing nutrients for the different needs of each watershed. They have teams called ‘tributary strategy teams’ and what they do is look at all the different options. They work with the state agencies. For instance, our group has a large monitoring network of water sampling throughout the Maryland portion of the bay. As we collect information, we can track the trends over

TP: Well it’s actually the one in the beginning … with the gentleman down in Virginia, where he had good success on a large scale.

Once you get below, pretty much … little bit north of the [Maryland] state line, kind of like in the Smith Island and Tangier area, there’s primarily, in these higher salinity areas, primarily only two species of plants there, eelgrass and one called widgeon grass. So by default, we pretty much work with eelgrass because eelgrass is pretty important for habitat, and plants stay around all year round. As opposed to widgeon grass, which is an April to October or summer species.

SG: Just to make sure I understand… Eelgrass is year-round?

TP: Correct. But they grow the fastest during the spring and the fall. During the summertime when it’s warm, they’re really not growing at all.

SG: With the seeds, you’re adding, not replacing, plants that have died in the previous year?

TP: The plants can reproduce a couple of different ways. Eelgrass produces seed but they also put out rhizomes or runners kind of like strawberries, so one plant can produce many plants. So when they do go to seed, in heavy dense beds of eelgrass, they put out seed and the ones that settle on the grass bed, some of them can help replenish the bed but a lot of them are consumed by crabs and other organisms, because in these beds, lots of times, what’s happening is that the plants are producing these rhizomes, producing adult plants that way. But when the plants are flowering, the seeds are getting ready to let off. What happens is that the upper part of the plants will break off and float so that the currents and tides can take it away. It will drift around, and when the seeds mature, they will drop out of the reproductive part of the plant. So that way, it’s kind of nature’s way of spreading the population around over a bigger area.

SG: OK that explains those bags you were talking about!

The idea with the bags is … these bags are like mesh bags that have floats in them, and one ends is tied down to a block. So it swings around in the tide, but stays in one general area. The material that we have in there is the reproductive parts of the plant, and that includes the seeds. So as the seeds mature, they’ll drop out on their own through the mesh and they drop down to the sediment around where we have these things tethered. So that’s the idea right there, as opposed to the way it naturally works, where the plant breaks off and just drifts off, and they go all over the place. So we’re trying to keep them in certain areas to see how it works.

SG: Another quick follow-up to planting in general – do you have limits of depth that you can work in right now? You said 2 meters when conditions were pristine in the old days.

TP: It’s probably more than 2 meters. In reality … some may have even been 3 meters or deeper. As far as limits, in an estuary typically, the freshwater and saltwater are mixing, there are areas where the water’s not as clear. So pretty much where the plants can grow is where there’s available light. So you don’t want to plant plants in 50 feet of water since there’s no light down there. So it’s more… you choose your sites according to how much light is available, so typically, right now, that’s around 1 meter, so that’s relatively shallow. But in some tropical areas, there are plants that live certainly 20 feet deep. But it’s all keyed on how much light is getting down to where these plants are.

Let me just back up one second … when we’re collecting these seeds off these plants, obviously we don’t want to impact the population that we’re removing the seeds from. So all these sites we monitor very carefully. We have people who do aerial photography before and after in these areas. We also do it on the ground, in the water for these different sites. It makes no sense to damage one site, to hopefully restore another one.

The following person was interviewed for today’s program. Our thanks to:

Thomas Parham
Chief of Living Resources Assessment
Tidewater Ecosystem Assessment Program
Maryland Department of Natural Resources