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Diving Deeper: Episode 25 (July 15, 2010) —
Why do we map habitats on the sea floor?

HOST: Welcome to Diving Deeper where we interview National Ocean Service scientists on the ocean topics and information that are important to you! I’m your host Kate Nielsen.

Today’s question is….Why do we map habitats on the sea floor?
NOAA scientists use a variety of state-of-the-art tools and technologies to both visualize and map deep habitats on the sea floor.

To help us dive a little deeper into this question, we will talk with Tim Battista on habitat mapping. Tim is an oceanographer with NOAA’s National Centers for Coastal Ocean Science’s Biogeography Branch. Hi Tim, welcome to our show.

TIM BATTISTA: Hi Kate, thanks for having me here today.

HOST: Tim, so you’re part of the biogeography branch. What does biogeography mean?

TIM BATTISTA: Well, biogeography is the study of how animals and organisms, marine life, distribute themselves in the sea environment - how they associate with different habitats on the sea floor. And so we study how fish and whales and turtles and so forth how they explore and utilize the sea floor.

HOST: Tim, why is it important to do this kind of work?

TIM BATTISTA: We know so much about the world above the oceans – that is what’s going on on land, what types of environments are on land, just for example the state of our forests, the seagrasses, the wetlands, but we know so little about what goes on below the ocean surface. And that’s really where my role comes into play because there’s so much to understand and to just describe at a bare minimum. My role within NOAA is to help us better understand what is going on on our sea floor, what are the state of the habitats, the organisms, and the features on the sea bottom, and what are their distributions. For example, coral reef ecosystems, how much is there, what condition is it in, and where is it. So some very basic, fundamental questions that we really are just trying to address right now.

HOST: Who uses these maps and what do they use them for?

TIM BATTISTA: Right. So, a habitat map is basically a map – it could be a hard copy map or it could be a digital map – and there are a variety of different habitats on the sea floor, everything from something as simple as sand or mud to actually something that’s growing and living and breathing and providing a home for other organisms like fish or birds or so forth. And so we need to figure out what those are first and that’s very important information for a local community or a manager who is trying to conserve those resources. So providing the manager in a location that habitat map provides a critical piece of information for them to do their job. Once they have that roadmap of the bottom, then they can start determining what are the best rules or regulations or practices to preserve and conserve those features that all of us want to enjoy and make sure that those habitats continue into the future for everyone to enjoy.

HOST: Great, so helping to conserve the ocean resources for many generations down the road.

TIM BATTISTA: That’s correct, so we’re trying to come up with a map for the present state of things and from that we can evaluate how those habitats change over time and we know they change just in the normal course of action – things grow or expand or reduce – but there’s also impacts to those environments. Some of those are natural, we can think of hurricanes as being a natural event. Some of them are unnatural, that are human induced, it could be an oil spill, it could be a development of property on land which has an impact in the coastal environment, it could be fishing. So all those things are important to understand and make the connection with how they are impacting the habitats on the sea floor so that we can better understand how to protect them and maintain them.

HOST: So, it’s probably quite a challenge to collect data on the sea floor at all these different depths throughout the world as you’re saying you travel. How do you collect this data?

TIM BATTISTA: So, in making a sea floor map, we use a variety of technologies and those technologies have limitations. So I kind of envision it as a Swiss Army knife. A Swiss Army knife has a whole bunch of tools in it and we pick the right tool for the particular situation. So if you’re working in very shallow waters, say something like 0 to 30 feet (0 to 9.14 meters) which is pretty shallow, we can use one set of technologies, but as we work deeper, it gets much more challenging, and so we have to switch to other technologies that allow us to do that.

So again, in this Swiss Army knife approach, we end up using a variety of techniques to try and map the sea floor from generally we map from about water depths of 0 which is the shoreline out to 1,000 meters (3,281 feet) which is very deep, certainly well beyond scuba diving or humans typically visit. Again, the deeper you go, the greater stresses are, but the deeper you go, there are still important habitats out there that we need to know about and understand how they’re operating. And I can speak to some of the technologies that we use.

HOST: That would be great.

TIM BATTISTA: Some of them are actually fairly available to anyone. We’re all familiar with Google Earth and Google Maps, which allow us to see imagery, mostly of the land environment, we can bring up a satellite image of your house or something like that or street map. We use the same imagery to do habitat mapping and these are actually commercial satellites that fly in space, overhead, and we’re able to task those to take pictures of locations that we want to map. So those satellites are flying overhead, they revisit an area quite frequently and they can actually take pictures of the coastal/marine environment, and they’re quite effective to a depth of about 30 meters (9.14 meters).  

Beyond that we have to switch to other technologies and there’s a reason for that. Commercial satellites take pictures and light only penetrates so far to the sea floor and so we can only see things to the depth that the light penetrates. So once we get to that threshold where light doesn’t see the sea bottom any more we have to switch to something else. And typically what we use is what’s known as acoustic technologies. Acoustic being to use the sound to penetrate the water and get down to the bottom of the sea floor. And we’re also entering into using some of the latest technologies which are what they call autonomous vehicles, which are almost like a torpedo that operate on their own. So the acoustic and the commercial satellites are really pretty much what we’re using these days for mapping purposes.

HOST: Tim, can you talk to us a little bit more about these acoustic or the sound technologies that you’ve just mentioned?

TIM BATTISTA: We use acoustic technologies to help us map the features on the sea floor. And the acoustic technologies basically are equipment that broadcasts sound, it emits a sound pulse. And that pulse of sound, travels through the water to the bottom and is reflected back to the sensor, to the ship, and then we record that when it returns. And I like to think of it as, if you were standing say at the Grand Canyon, and you are a sound producing machine, you have a voice, so you say something really loud, and your voice goes out and then the echo returns back to you.

And that’s essentially what we’re doing with an acoustic system. It is broadcasting a voice and we’re measuring the amount of time for that echo to return. So as we’re sitting there at the Grand Canyon, if we hear a voice come back really quickly, then we know that property or the object that it’s bouncing off of is relatively close. If it takes a long time for your voice to return, then that feature that the sound is reflecting off of is pretty far away and that’s the same idea with an acoustic system. In this case, we’re just measuring how deep the sea floor is.

The other thing that we’re actually trying to record from the acoustic system is something about the feature that the sound is reflected off of because not only do we want to know how deep it is, we want to know what it is because we know the sea floor could be mud or sand or coral. I like to think of it as singing in the shower. We all like to sing in the shower because it makes our voice sound really great, right. We have very hard tile or something hard in the shower, your voice reflects off of it very strongly, it sounds great. But if you were to sing, let’s just say, in the closet where it’s full of clothes, the sound comes back sort of muffled, doesn’t it? And the reason is because a lot of that sound is being absorbed by the clothes.

So it’s the same idea when we use an acoustic system. The sound goes down to the sea floor. If there’s mud on the bottom, a lot of it’s going to be absorbed by the mud and not much of it’s going to return back up. But if it’s a hard bottom like a coral habitat, a lot of that sound is going to be reflected back to the sensor and we can detect those changes. So that’s what’s so great about these acoustic systems because not only can they tell us how deep it is, but they can also tell us something that’s on the sea floor.

HOST: Tim, can you tell us a little bit about what a day is like or what a mission is like when you go out to collect this data?

TIM BATTISTA: So typically my role is principal scientist, my job is to not only bring the scientists on board to do various tasks with their expertise, but also to come up with a design for the research mission, so all the bits and pieces that we want fulfilled during our research mission.

In any given day as a principal scientist, I have to articulate to my scientists what exactly we’re going to be doing within the course of a day, and that changes generally based on the time of day it is. So we know during daylight hours we can do scuba diving, we can work on small boats doing collection there, so that’s typically what we do during the day. I should also mention we also use a remotely operated vehicle, which is a robot, it has a tether that comes to the surface, to the boat, which allows us to control it and manipulate the robot and take pictures and samples. Those are all daytime activities.

And then at nighttime we switch over to what we call mapping I guess, taking our acoustics, the term is called ‘mowing the lawn.’ You literally draw, on the computer, lines that the ship is to follow, and those lines are parallel to each other and we mow the lawn at night collecting data and data. And we use that data the next day to figure out where we’re going to go with the ROV or the small boats or the diver. It kind of makes sense – you collect data at night to help you determine what you’re going to do the next day. So all this goes on 24 hours a day, every day for two and a half to three weeks. 

HOST: So Tim, when you’re out and you’re doing one of these missions, what might be some of the challenges that you run into to?

TIM BATTISTA: Right, we’re very fortunate that some of our work, we’re able to use NOAA ships – large oceanographic vessels. One of the ones in particular that we tend to use repeatedly is the NOAA ship Nancy Foster. That vessel’s about 180 feet long and 40 feet wide and that ship is able to go out for about two and a half weeks that we can go and conduct our research. So it’s great to be able to have that platform to use and have a station that we can conduct research.

We’re operating 24 hours a day in these locations, but being on a ship has its own challenges as well. We work a lot in the Caribbean, which as nice as it may sound also has its fair share of weather conditions. We have been in situations where there have been hurricanes that have come through. You just can’t operate in those kind of sea states. Even on a day-to-day basis, trying to get work done on a floating houseboat that’s moving up and down and sideways can be challenging for some people. And we’re down in these rooms down below, darkened rooms, looking at computer screens, trying to get the work done. So, working at sea conditions has been probably the most challenging thing.

HOST: Tim, what would you say is your most memorable mission?

TIM BATTISTA: A couple things come to mind. We’ve been working a lot in the Caribbean recently trying to better understand the coral habitats that are there. What we’ve been trying to study and learn more about are the habitats that are important for fish distribution. There’s an important fishing community down there catching fish that we all love to eat – grouper, snapper – and there’s not a lot known about where those fish are living at night or during the daytime, how many there are.

So last year, we were very fortunate, we were able to bring on board the NOAA Ship Nancy Foster a new technology and it is a scientific grade fish finder. And what it does is use again sound and it transmits sound into the water, but what’s different than a bottom mapping system where we’re trying to detect what’s on the sea floor. This particular system actually maps what’s in the water column – so what’s above the bottom to the surface. And it’s very useful for finding fish.

So we’ve been using this equipment to try to figure out where those spawning events are occurring, what types of fish are spawning, and how many there are. So we were fortunate that last year when we were working on the eastern side of Puerto Rico in an island known as Vieques, not a largely inhabited island, and we were actually able to detect a large spawning event of some grouper, a large school of them, it was just phenomenal to see this happening, and then once we detected it on the acoustic instrument, we put the ROV in the water, our robot, and we were able to take pictures of it simultaneously to see the behaviors of the fish, how they were interacting with each other. So we gathered a whole host of information just right in that one event that really nobody knew much about before. I think information like that will be really useful, both now and in the long term as we try to better protect fish populations.

HOST: Great. You have probably the dream job that so many people are interested in. Tim, can we talk a little bit about what is NOAA’s role? Why is NOAA doing these kinds of sea floor habitat maps?

TIM BATTISTA: So NOAA’s involvement, particularly in what I’m working with, and that is mapping coral environments, was started under President Bill Clinton. He signed an executive order and that was really the stimulus for NOAA to be engaged both in providing scientific expertise, platforms like the NOAA Ship Nancy Foster, but also funding dollars that went along with that. And that really has been the springboard for developing a huge program and it’s been critical. We know, or knew, so little about the state, the distribution, and the health of coral reef ecosystems. So we have been focusing on that since NOAA got engaged in 1999.

We’re studying not only Puerto Rico and the U.S. Virgin Islands, but anywhere within the U.S. that there are coral reef environments, so that includes states such as Florida, Georgia, any of the coastal states that have coral systems as well as Hawaii; territories like the Commonwealth of the Northern Mariana Islands, American Samoa, Guam; and also the Republic of Palau, the Marshall Islands. So NOAA’s involvement extends geographically to all those and we’re trying to support them in collecting at least in our case the mapping data, the fundamental information on the distribution of coral habitats in these locations. That provides a critical piece of information that ultimately will give the local managers, the people who are charged with protecting those resources in those locations, the information content that they can do their jobs better. So we, NOAA, are able to bring to bear expertise, we’re able to bring NOAA ships, platforms, and technologies. We work with them, very closely, to produce the products that they need to do their jobs better and that is an ongoing relationship and one that we hope to continue to serve.

HOST: Sounds like a very important relationship. I’m sure there’s a lot of other economic benefits as well for these local communities that you’re supporting. How do these maps tie to that?

TIM BATTISTA: Sure, I mean, when we think about the local economy of places where there are coral reef ecosystems, tourism is a huge part of their economy. People come to visit, to experience that, to enjoy it, and they want to go scuba diving on coral reefs and so it is in the best interest of these locations obviously to preserve and protect those to make sure that people keep coming back. Fishing of course is a big part of their economy as well. And maintaining a healthy balance of the fish that they take, but also maintaining those fish for the future as well. And then these locations also deal with the extreme events that we talked about, they deal with hurricanes, they deal with extreme events that change those environments, so we can provide information to help them better mitigate those risks.

HOST: Tim, when a habitat map is completed for an area, are you finished? Does it ever need to be remapped or other research that’s needed for that area?

TIM BATTISTA: What we are trying to do when we produce a habitat map, it’s a static snapshot of what’s on the sea floor at that given time when we collected the data. But those are living, breathing environments down there. So ultimately what we want to do is detect changes over time to assess the condition of those coral habitats and so that’s where we have to have repeat mapping. So if we are able to remap a location five to ten years after the initial mapping, then we can look for patterns of changes and then we can make those connections with how the humans are impacting, are utilizing those coastal environments. So mapping, yes, it’s not a static event, it’s something that we have to do repeatedly to monitor change and assess change and management practices over time.

HOST: Tim, do you have any final closing words for our listeners today?

TIM BATTISTA: My final closing words, I’d like to really encourage young folks that are out there that are considering oceanography, mapping, who are interested in state-of-the-art technologies – this is a really exciting profession and one that frankly needs a whole new generation of folks to take what we’re doing and push it even further. So I really encourage folks who are interested in this and hearing this to contact us or learn more about it. I think there’s tremendous opportunities and it is one of the most exciting professions that I know of.

HOST: Thanks Tim for joining us on Diving Deeper and talking more about sea floor mapping and coral habitats. To learn more, please visit   

That’s all for this month’s show. Please join us for our next episode in August.