Wade Elmer
	Plant Pathologist

What is sudden wetlands dieback?

The shot right here is on Hammonasset State Park, actually just a little bit west of there. This area here was all covered in Spartina grass, but now it's dying back. It might be that the water is going there. But if that's the case, that's okay, because Spartina should be able to grow right back into it. This should not be a problem, but spartina is not growing back into it. And that's why we're looking for pathogens.

How can we stop the problem of sudden wetlands dieback?

I think by understanding first of all what's causing it. This is the third year in New England that we've been studying this problem. This is the year we're going to test a lot of hypothesis; these are ideas of what we think might be happening and we set up experiments and see if what happens supports the hypothesis or doesn't support it. So right now we're thinking that global warming and rising sea levels along Cape Cod and Long Island Sound are causing this problem. What we want to know is why doesn't the spartina plant grow into the new areas rapidly. And that's where we think there might be a stress factor that we need to identify this year, and fusarium might be one of the stress factors. Another stress factor, I told you about nemotodes? Microscopic worms. Well, when I was on Cape Cod last summer, we found there were plant roots here. In this photograph there are tiny little balls, we call them gulls on the roots here. You look up here you can see them a little bigger, and then here's a blown up picture. That should be the tip of the root right there. And if you look in there you see that little dark spot that's a male nemotode. There's a female. This big old fat thing is a female, she is full of eggs, and this is the male. We think this nemotode might also be a factor in causing salt marshes to decline. You see here for some reason the plants just can't grow into these new areas. Here's a picture of a auger plate where i took pieces of the tissue and i put them on the auger plate and you see here fuzz growing of there? That's the fusarium. If you took that and looked at it under the microscope, you would see these type of spores, and over here are some innoculation i have to take the fungus. Then i take the healthy spartina plant and i inject a little bit of fungus into the tissue, into the stem, and sure enough i was able to get the browning, the same effect there. We call that proof of pathogenicity. In other words, we have proven that the fusarium can cause disease. That was a important point in the story.

What does the fungus look like?  Can we see it without a microscope?

Now the fungus and the spores you have to see under a microscope. This about four hundred times less than it is. Now that would be the actual size of it. So it's very, very small. But I can grow the fungus on an auger plate and you'll see this mold sort of growing out. You've seen mold before on bread, oranges, strawberries? That's kind of what it looks like when it grows on an auger plate. You can see that with your eye.

Can you tell us more about the fungus that is growing in the salt marshes?

The fungus that I'm studying is called fusarium. Fusarium is the name of the fungus. There's lots of different types of fusarium. This fungus exists on the salt marshes happily, not causing any problems. But when the plants become stressed, the fungus is abe to cause diseases. I have poster here, these are the spores of fusarium. They look like little canoes or little cigars. That's how they spread in the salt marshes.

What kind of plants grow on the salt marsh?

The "a" stands for the a in alternaflora, spartina alternaflora, which is the main one that grows in the lower marsh lands. It is a very unique plant. It is the only plant that can survive and take flooding for long periods of time. That's because inside the roots there are great big air pockets and they actually keep air down there. they actually pull air down by the roots so they are able to breath in these wet conditions. They can also take salt out of the water and they'll actually excrete the salt through the leaves. Now if you try to grow a tomato in a salt marsh it will die right away. The tomato cannot take that salt. You try to grow strawberries in there, they'll die. Spartina can survive wet conditions and it can survive salt conditions. So that's spartina alternaflora. As you go into the higher marsh, there is another type of spartina grass, it is really soft and very green. Have you seen that? You just want to lie down in it if it is not too wet. They mow that grass and use it for hay, it is called salt hay. That is spartina patiens. It can't live down here in the wet conditions, but it likes the lower conditions. In facts many times you can go through there and you can tell where the low marsh ends and the high marsh begins by when these two species start and stop.

Why is spartina important to the salt marsh?

The plants themselves are always transporting oxygen down to their roots. The are also, more importantly, taking up the nitrogen. They utilize the nitrogen and store it in the plant. So if spartina uses the nitrogen than algae won't use it. If algae uses it, you would get those big algal blooms, and they just use up all the oxygen and die. So it is much better to have the spartina use it.

Why are salt marshes important?

In the tide, are all the dead spartina plants that died last spring. The roots stay alive, but the top part dies back. That all breaks up and the tide collects it all in great big huge masses of just dead tissue. And so it comes, in piles of it and just dumps it. Then the next tide comes, lifts it up and takes it back. It’s called rack, it comes in there, and there’s tons of nurtrients in there. So as that rack breaks down, crabs eat it, crustaceans eat it, and the phytoplankton can use it. There’s lots of nutrients. So this is probably the most important.

In what ways is the fungus affecting Sudan?

If this is the same fungus in Sudan, it probably is living happily as just a normal little organism on the leaf, not causing any problems. Many times when you take a fungus and it's happy in it's own little forest or it's own little swamp or it's own little area, and you take it and move to a new area where there's all of the sudden lots of plants that don't have any resistance, then it becomes a problem. So it's probably not causing any problem in Sudan.

Do any creatures need the salt marsh to survive?

Well initially the fiddler crabs, they love this area here because as this starts to die away, the roots start to wash away and all these little tunnels start to form. The fiddler crabs love that because they can go down and nest in there.  But then eventually, if this doesn’t grow again, the spartina, and this will just all become a mud flat and it will just start to slide back into the water and erode away.  You know, that's what we’re concerned about.

How does the fungus attack the plants?

Well the fungus is probably on the leaf, living there happily. As long as the leaf is healthy, it doesn’t cause any problems. If you're healthy there are a bunch of viruses in the air, but you're not getting sick because you’re healthy. But if you're sick and somebody comes by with a virus, then you catch it. But when the fungus causes these brown little spots on leaves, that's what I believe fusarium is causing to the plants. They may also be affecting the roots, working with the nematode. Because the nematode breaks in there and causes wounds and then the fungus might be able to get in there. So these fungi can work in many different ways. On the leaves, possibly on the roots.

Where is the sudden dieback happening?

These are the different places that we have found the Salt Marshes are dieing. If you look at the green dots here, this is the coast of Connecticut, you have all seen that. Here we are right there New Haven, there's a dot. I haven’t been to this site yet, but it's over there on the Quinnipiac River estuary. These are the very sites that I am going to be sampling this year to find out whether I can find the fungus and nemotodes and so forth. Now this is the coast line of the United States. The Atlantic coast line, this green dot here, shows you where Louisiana is this is where the Katrina Hurricane hit really hard. These are different spots Florida, Georgia, South Carolina, Delaware, and actually Maryland, Long Island, Connecticut, Cape Cod, and Maine. These are the places that we have been seeing dieback occur and I have actually got samples of spartina grass. They mail it to me in the mail. Let me tell you it smells terrible when it comes out of there because, you know, it's a salt marsh and its been in the bag for all those days. So I have to take it and clean it up and then I isolate it. I put it onto the auger and the fungus grows out, then I identify the species. I am in the process right now of innoculating plants to see if the species I am finding from all these different places are pathogenic. That’s why, when I go back to my greenhouse, I am going it get out of this tie and get into dirty old clothes and I am going to sit down and start innoculating spartina plants. These will be all different sorts of fungi from different places. Is there anything else here I can show to you? This shot right here is on the Hammonassett State Park, actually just a little bit west of there, and this area here was all covered with spartina grass. But now it's dieing back. It might be that the water is getting in there, but if that’s the case, there shouldn't be a problem because spartina should be able to grow right back into it. But spartina is not growing back, and that’s why we are looking for pathogens.

How does the fungus spread? 

The fungus itself probably survives on the seeds. So whenever you take seeds from one area to a new area, you're probably taking the fungus with you.  This particular plant hasn't formed a seed head yet, that will probably take about a month.  One of these stalks will all of a sudden get really big and a big fluffy thing of seeds will form up there.  That's a good source of nutrients for birds and a lot of things that eat those.  So when they eat these things they can then take the seeds elsewhere.

What is the history of this fungus?

That was all based upon some studies we did on the fungus. And actually this is the fungus that is causing the problem down in Louisiana. It is not so much causing a problem here in Connecticut. But done there they found a different type of fusarium species that they found. When we took the DNA, which is the genes inside the fungus, and we actually looked at teh DNA itself. We put it on the computer and we said search all the DNA in the world, does this DNA match up with anything? It matched up with a fungus from the Sudan. We don't know if the fungus was originally here and we gave it to Sudan, or if it was originally in the Sudan and they gave it to us. Maybe it was originally in the Sudan hundreds and hundreds of years ago and it was brought here by settlers and such, but we don't know. That's all we nearly know about that fungus.

Is there anything else we should know about fungus?

Just that most of the species of this fugi are good. In fact in Europe they're actually making a food from fusarium. And its like its kind of like a mushroom tofu type like that. It hasn't been marketed in the United States much yet, but it is available. Some of these fungi are actually good. I use them to protect plants from the bad fusarium. I take a good fusarium and I put it on the roots of the plant and it protects it from the bad fusarium. So most of the fusarium probably don't cause any problems for anything. Some of them are good and some of them are bad.

How fast does the fusarium grow compared to the growth of the salt marsh?

Salt marsh plants can grow quite fast. This is a plant right here called spartina. There are like four or five species in Connecticut. But most are this species. As you look at into the salt marshes, this is the one you see mostly in the really wet areas. This plant actually grows quite fast. The fungus itself probably grows very slowly and just lands on the leaf, and just sits there living off the normal salts and nutrients that come out of the leaf. It is not causing any problems for the plant. But if the plant is stressed, let's say, too much water, or not enough rain and we have drought, then the fungus will start to infect. So that plant probably grows much faster than the fungus.

Are there other kinds of fungi that can cause problems?

There are lots of different fungi that cause problems on plants. Who here is of Irish descent? You know about a hundred and fifty years ago all the irish had to leave Ireland and they went all over? They went to Australia, they went to Canada, America, and a lot came in to Boston. They all left because of a fungus attached to all the potatoes and all the potatoes died, and that was the main source of food. in fact, my ancestors came from Switzerland and had to leave around the same time. Even though they weren't starving to death, there was such poverty that one fungus went through and caused all these problems. If you go out in the forest, you'll see old chesnuts stands and old chestnut logs, in the nineteen thirties and forties, chestnut was the number one tree in the forest. They all died within twenty-five years because of a fungus that came from Japan and our chestnuts had no resistance. New Haven is called the Elm City. I don't know if you know this, but there have been three epidemics of a disease of elm that have gone through. It's called Dutch Elm Disease that came frome Holland, as you might expect, and this killed all the trees. Now the ones we have now on the green are probably the only ones left because they had some resistance. Even to this day when you drive up Route 10 our up Route 69 or any where you can see young elms dieing every spring and these are the young ones that are still susceptible. So yes, there are still many, many problems on plant pathogens around the world and they still cause problems for everybody.

What is your prdiction of what will happen if nothing is done?

That's a good question. We don't know right now. The fungus itself will probably not cause any problems on the salt marsh if the salt marsh stays healthy. Because if you are healthy, you don't catch a cold. It is only when you've been outside, you let yourself get run down, that's when you catch a cold. So if we can find out what is making the salt marshes unhealthy, or stressing them, then we'll probably be OK. This year, we tend to think that maybe global warming which is actually causing the sea levels to rise. As the sea levels rise, the tide goes in further and comes out further. If it is going in further, it is probably keeping some areas of the marsh land wetter for longer periods of time. This is stressing them. So if that is the case, those salt marshes might actually disappear. But that's OK because if the salt marshes goes in further, the marsh will just move further upstream. As long as we have land for the marshes to grow into, we will still have plenty of healthy salt marshes.

What can we do to help the salt marshes?

Right now we're building our houses so close to the ocean. If a marsh dies and a marsh wants to move into your backyard, people say, well... I can't have a marsh in my backyard, this is my house.  So I think being able to protect certain areas in the Sound and not developing them for houses, so that the marshes can move into those is the most important thing we can be doing here.  Also, when it rains out here, all the water along the street goes into sewers, and that all get put right into the Sound and that fresh water sometimes take salt water marshes and turns them into fresh water marshes. And as soon as they become fresh water, phragmites, that big tall grass, starts to take over, and if it’s all fresh water phragmites, it can push out this plant.  This is a tough plant, but it's tough because it can survive in the salt marsh. But if it's fresh water, then there's a lot of other plants that can push it right out.  So trying to direct our storm water into certain areas so that it seeps into the ocean slowly is better.  And we're learning these things, you know.