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Interview 4:33 - 25:52 Play 4:33 - More
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Mark Fonseca  







Benthic microalgae and coral reefs  

Interview 4:33 - 25:52 Play 4:33 - More
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John Burke  







Benthic microalgae and coral reefs  

NPR/NGS Radio Expeditions
30 Jun 2001

  • United States
    Monroe County
  • Dry Tortugas National Park
  • 24.71501   -82.78051
  • Stereo
    Sampling Rate
  • 48kHz
    Bit Depth
  • 16-bit
    Equipment Note
  • Stereo=1; Decoded MS stereo; Neumann RSM 190 through Sonosax preamp into Sony TCDD8

Show: Dry Tortugas
Log of DAT #: 2
Engineer: Leo del Aguila
Date: June 30, 2001

John Burke (John)
Mark Fonseca (Mark)
Craig Quirolo ?? (Craig)
Alex Chadwick (Alex)
Leo del Aguila (Leo)

ng = not good
g = good
vg = very good

[Note: This is a good short scene: Use all three of the following clips with Craig]

00:06 -00:11 -FX Good banging about on the launch

00:12 Craig is getting back in boat from dive + intercom chatter.

*00:41 -Craig: "Ok Good dive. Lots of fish ....going out to an algae covered sand plain where the species composition changes -less numbers and less diversity, and that's what we expect to find."0l:08 [VG]

JB: "Yes, it was a beautiful spot" + chatter about the dive/tanks etc. 02:00 *02:24 -Craig: "It was a pretty good transect It was definitely into two different habitat zones, and that's what we're looking for, that interface, so we can come back and look at the two different habitats and see what happens after this place falls under protection -which it should, it's a beautiful place 02:41 [VGl
John: went over a great big anchor, now covered with corals and sponges, fishing gear down there.

*03: 11 -Craig: "Successful dive, one more to go. 3:14 [VGl

FX: 03:22 -3:25 Whistle and boat start Craig: "Ok let's go pick up the buoy ...."

Back on the Ferrel: -in the van looking over data from the previous dive:

04:51 Mark: So now that we've done the dive, we've got the position fixed, we're criss-crossing the area with the towed sonar system. And what we're seeing scrolling by on the monitor is the sand flat area, but in reality it's revealing itself to be quite a combination of small sand patches about a meter wide, a lot of corral rubble, farther out from the reef. We're about 300-400 meters out from the reef. The ship is going to turn around. We're going to make a run across the reef face. We've dropped down to about 19 -20 meters of water, and we'll come up to about 14 meters to get to reef top. Very gentle slope. A lot of rubble, heavily colonized with gorgonian sponges and live coral. It's opening up a lot more sand here, and when you were in the boat, you could look down and see the dark areas, and the sand break, you get pretty good visibility, it's 61 feet at the bottom .... so this is what you're picking up..... colonized by more than sand. See isolated sponges .... John over here is extracting that micro algae off of the sediment particles.

06:45 One thing we've found that really surprised us was some studies we've done near this area that the productivity just in this top centimeter of the sediment is as much production as we're finding in the entire water column in 90 feet of water that has phyto plankton in it is not producing as much carbons from photosynthesis. It's just that top skim of the seafloor where light is reaching the seafloor. This is why we're exploring this area. It's clearly the breadbasket for the reef systems around here, and separating out how much is coming off the non-reef environments, how much is recycled within the reef is the whole mystery we're after here.

[move to a more sound friendly place]

AC: explain again about this top centimeter

08:40 MF "The shallow ocean floor where we can look over the side of the ship right here and see the dark and light patches. We're in an area where there's a tremendous amount of sunlight reaching the seafloor, maybe as much as 30% of the light that's getting past the water surface is reaching the seafloor, so there's a tremendous amount of plant growth. A lot of the large plants require something hard to attach to. So once we move off the reef we don't have that. We have nothing but this unconsolidated soft bottom sand. So we cross the reef interface, we're out there in the sand, and what you have there is micro algae, small single celled organisms that are photosynthetic just like any other plants, but they are growing at a tremendous rate, and they colonize about the top centimeter. Essentially what is going on is that top unremarkable sand layer of the seafloor where the sun reaches it is just a huge engine of primary production. It fuels the rest of the food chain, and through the studies we're doing down below, others are doing ...stable isotope samples, where they look at the signature of the primary producers, at the tissue of the animals, such as they fish, we can tell where those fish are getting their original source of food. The signature we're getting back is benthic microalgae, algal communities out here on the sand flats and what's bringing a lot of food to the coral reef ecosystem. [10:36]

AC: This is a new discovery ? MF: I think it's been well known that when you have sunlight reaching the seafloor that it was that production that contributes to near shore and estuarine production. What we haven't had a lot of is separating that in the coral reef system. Coral reef is so important just in and of itself. But in a context like the Tortugas Ecological Reserve, where we really need to understand what's driving this whole system and not just documenting what exists, we have to go the next step and differentiate the contribution of the corals and the coral reef system aside from all the other parts of the reserve, which is the sand, soft bottom area is about 70% of the protected area.

*AC: When I've spoken to you about this earlier there is a sense of excitement and discovery and delight ....

*11:55 MF: It is exciting, it's the kind of thing you always hope your data will show you so clearly, and when Carolyn got those data back and the signature was just separating so cleanly for all the different kinds of fish we were getting from the sand and hard bottom environments, it was very unusual. A lot of it is because NOAA has been able to put a lot of resources into this and we've been able to do something different, and spend a lot of money on isotope samples. They're expensive samples to process. Historically the data sets tend to be small. This is a very large data set. There are several hundred samples comprising it, and it makes for some pretty clear statistical discrimination, so we can turn around to the public and say, yes, this actually is what's happening out here, this sand ecosystem is driving a lot of this spectacular reef ecosystem that we care about. [12:53]

AC: is something you may have suspected. This is a new and significant between one part of the ocean -and another.

MF: We're putting it in the context of managing a whole resource. And I think that's where the real excitement comes in, where we can tie all this together.

13:46 John: "I think intuitively as biologists, we've known that these systems are linked, but the stable isotope analysis has allowed us to quantify that linkage. There are lots of other intermediary pieces..... more..... [ng]

AC: Having had a chance to look at this environment in February, now ... what's your general impression of the health of the area?

MF. Looks to be a healthy system .... more ..... *[15:05] but it is the kind of thing by taking experience from lots of other systems and having a diverse team of people, like fish biologists, ecologists, geochemists, landscape ecologists, geologists, geographers, we start to do a more integrated picture of what's going on. It's a beautiful system, it's so deserving of protection. I deal with a lot of places, but that dive yesterday at Station 8924, landed on the bottom, and I had to stop work for a minute and just look. I said this is incredibly beautiful. There is just this coral wall with 100% coral cover, teaming with fish, and next to it is this sand flat running out .... with sea grass and algae, it was just like a little Eden {16:01]

AC: And when you're down there, do you ever think you're first explorer ....

MF: People have looked at the reef. We're looking at the interface between two fundamentally different portions of the ecosystem, and that's clearly a new exploration and that's why we're all so excited to put this altogether. [16:32]

AC: Marine reserves I'm thinking of the teams that were sent out to explore the national parks....and I'm thinking of you all in that kind of way....exploring the marine world ....this is as remote as Yosemite

MF: The information level may start to approach that sort of thing, but in terms of what people had to deal with .....

John: I think what's very exciting about this ....very diverse team [better to use Mark's comments about this]

MF: Other people will have to judge ...the raw discovery of finding it isn't there...

John: I think we're looking at the system in a more holistic way ....and hopefully the avenue we've chosen to look at the system will be productive in terms of how we can manage it in terms of its future health.

MF: We have lots of different systems ....NOAA, state of Florida etc .....

AC: What are you going to do with the data.....

MF: The most difficult processing will be what John's doing ..... We can use the data as we go ....

AC: How is it possible you could get more energy level at that one centimeter than you can get in 50 feet of phytoplankton .....

? MF: As you get into these tropical waters offshore, less nutrients here ......more

AC: reef fishes come out at night .....

John: fish come out at night under protection of darkness.... Ferocious predators, and if you get into the open you're history.... So they wait until it's dark....

AC: And that's when this transfer takes place. They eat the little things that are eating the plant growth that's going on the bottom, and that's how this is the base of the food chain.

John: Right. The animals that are in the soft bottom that are eating the microalgae maintain the carbon signature of that micro algae and that gets passed up the food chain to the fishes. That's how we can trace the source of the carbon, the source of the energy [25:50] [plus ambi to 26:16]

26:52 -29:22 More ambi from interview


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