Atoll ambi, Wind, Terns
Atoll ambi, Wind, Terns
Coral Reef Biology
NPR/NGS Radio Expeditions
United States Minor Outlying Islands
- Cooper Island
- 5.88333 -162.08333
- Sennheiser MKH 40
- Sennheiser MKH 30
Stereo=1; Omnis; DPA 4060 Omnidirectional Microphones
NPR/NGS RADIO EXPEDITIONS
Log of DAT #: 3
Engineer: Chuck Thompson
Date: May 2000
ng = not good
g = good
vg = very good
AC: ALEX CHADWICK
CT: CHUCK THOMPSON
0:40 CT: 11 :20 AM, overcast, Palmyra, pair of DP A 40160 omnis, rycote housing
1:44-3:55 AMB-walking, birds in bkgnd, sometimes no walking (birds only)
4:33-6:56 AMB-wind or rain, birds in bkgnd
CT: terns, and palm leaves blowing after rain shower
7:17-9:55 AMB: palm trees, wind, birds, another location G
CT: another palm grove, high wind
10:22-11:30 AMB: same deal
11 :44 CT: these are MS mics, MKH 40/30¬AC: on previous recording, those were white terns flying at about 20 ft above us, the sound they make is quite distinctive ... Jim could you imitate that sound? JIM: (IMITATES SOUND) and there were four of them in their courtship behavior. AC: the terns are perfectly white and they have a black beak like a pair of needlenose pliers. Very sharp, like a supersonic jet nose.
CT: a walk on the trail, following AC and Jim
12:56-14:51 AMB walking on the trail, some bird noise
14:52 AC: hello, camp visitors ...
14:53-15:36 AMB: walking, a little squishy sounding
15:46 JIM MARAGOS (JM): I'm JM, coral reef biologist for the F & W service. AC: would you describe this place? JM: we're standing on the north side of cooper island and we're looking out to sea. In front of us is a reef flat about 'l4 mile wide, it's v glassy. Off to our right we've got some palm trees hanging in the water, straight ahead of us we've got some low surf, 2-3 ft high, breaking on the outer edge of the reef maybe 113 mile in front of us. Off to the left we have the curvature of the beach, few palm trees in the water, some terns flying in the sky and making some noise.
AC: in terms of the structure of Palmyra, what's going on here? What is all this, the physiology of the island.
JM: the main situation going on here right now is that this shoreline is eroding and has been eroding for probably the last half century. The main reason is the navy put in causeways to the east and west of us, and those ca8useways block the flow of water across the reefs and into the lagoon. And so the water has had to pile up and move along the coast at a greater rate, and as it does it's more erosive and its taking sand with it and causing the beach to erode and the reefs to be covered with sediment.
17:21 AC: but in terms of the reef flat and the reef crest out there, when you look at this what do you see about how atolls work.
JM: the reef flat represents an equilibrium depth in which corals and coral (?) and other reef building ) organisms, they grow up, they're marine in nature so they cant grow up any higher than mean low water. So once they reach mean low water they can only grown out, away from the atoll. So what we have here is a reef flat that has grown probably over the last 10tousand years, and it keeps extending seaward if it s growing. And in all cases in the pacific and the central pacific, all the coral reefs are growing fairly vigorously. and so what's happening then is its growing outward inch by inch over millennia, and on the outer edge of the reef is where the battle is being fought, between wave action crashing on the reef and the reef trying to grow in the face of this wave action.
What basically, how the reef is successful in growing in this kind of environment is two reasons. One is the formations themselves, they form these fingerlike spurs and grooves that project at maybe a 30degree angle towards the ocean, and when a the waves break on them, the spurs, the raised parts of the reef, cause the wave to collapse in the grooves. And so it causes the wave to basically fall on itself and wash back out. Some of that wave energy however is washed over the top of the reef and this is what goes in the lagoon or goes along the coast.
The other major factor that allows reefs to be building in the tropics is that nutrients are not a major requirement external source of nutrients-are not a major requirement of coral reef growth. Coral reef systems can recycle nutrients, so even in these waters which are clear and transparent and nutrient poor, they're able to grow in the face of heavy wave action in and low nutrient waters. The only ecosystem on earth that can do this.
19:35 AC: something's biting my foot. ETC
19:45 AC: when I come out here and I see this, it doesn't look like what I imagined .. .I mean my experience is east coast, Caribbean, it doesn't look like what I imagine a reef to
be. I mean these big reef flats are a very interesting phenomenon for me. I see it and I say boy this is different, this is not. ..
JM: and the reason is, again, there's active growth. Even if there's wave action that comes in and erodes it once in a while in a big storm, if it becomes sub tidal again the reef flat will grow back up again because there's living creatures out there, coral and algae and corals, that'll fill those voids and grow back up. We noticed that on those reef pools on the east side. There's tremendous variety and diversity of corals growing in a sub tidal pool, and eventually it'll just keep growing and growing until it basically just eliminates all the sub tidal space and it gets reincorporated back as a reef flat.
So that s the key process going on out here....you find the living coral s sub tidally because the res space, there's water there, that once they reach mean low water they have no place to grow and they can only grow out, they cant grow upward anymore. And so the whole ecosystem, the growing edge then moves out into the space of wave action.
21 :08 AC: you mean the coral gardens that we saw in the pool are just eventually going to turn into this, which is a flat kind of concrete uninteresting mass of. ..
JM: that's correct. So im gonna try to set up a transect out there to see if maybe we can see what happens over a short period of time, how fast the corals are growing, what kinds of factors are affecting their growth, whether there's a storm that comes in and changes the dynamics of the system there. And it's a very interesting spot, and its probably the most beautiful reef pool ive ever seen in the pacific. There's are so many species of fish and corals and its really kind of a microcosm of what happens on a growing reef.
21 :54 AC: I swim thru there and look down and here's this purple coral that looks like lichen or moss that's covering all this stuff and it's a very distinctive purple. Then there are patches of green and pink and red that's just beautiful. then there are these structures that are growing out of this patchy mossy kind of stuff. Amazing structures. One coral I saw looked like trunks flowering in baby corn, and each little kernel is a mouth. Its just amazing.
22:37 JM: it is amazing. There's maybe 130 species of corals here and they fall into very, 10 different growth forms and many varieties. The color is caused by single celled plants called zoezanthili, that live in the tissues of the coral. And they give the pigment to the coral, primarily chlorophyll so they can take sunlight and turn it into food, and the coral takes some of that food for its own. So that gives you all the different colors. Now the coral animal itself also has pigments and that contributes to the overall color of the reef coral. They're called reef building corals, the corals that have both the plants inside and the animal tissues.
23 :21 The growth forms are adaptations of corals to take over space as quickly as possible and try to monopolize the bottom and exclude other corals from taking their space. Some of them like those encrusting purple one that you mentioned just runs along the contours of the bottom and then at the edge it'll meet up with other corals and they have a sort of warfare going on there between the two. So those corals are very adaptable for living where there's heavy wave action because they cant break as easily,
they're there almost part of the bottom, and so they are the most adaptive in terms of
rigorous wave conditions. But they don't grow as fast nor obviously do they grow as high as the other corals. So the branching corals that you mentioned, the one with the little com cobs on it, that one can grow up, and then as it grow s up it forms small table, it grows out horizontally. And then that casts shade on the surrounding corals, which causes them to slow down their growth or die. So these table corals, and com cob table corals, that's their strategy.
24:33 On the other hand, if they had a wave event or a strong surge comes in there and maybe a rock or something hits that coral and breaks it off then it has to start all over again and reestablish its prominence on the reef. Whereas a crusting coral may be able to survive that kind of event. So it's a constant battle between some kinds of corals that are kind of there for the long haul ... brain corals are another one, they form massive hemispheres, they grown very slowly, but they can also withstand wave action and storms and also competition from other corals. A lot of times-like the acropera, that's a type of coral that grows up and forms these branches and tables-you'll see them coming close to a brain coral. Well the brain coral will have these-something called mesoterrial filaments that comes out of the polyps. And they'll attack the coral if it comes too close and kill it. So that if you look on the reef, you'll see that these other corals that are prevented from growing over the top of the brain coral. And you'll see that in many places. So there's a lot of competition on reefs between corals, especially if they can grow and it's a favorable place for them, then really the competitions between each other rather than against each other.
25:52 AC: when we look out here at this coral flat a quarter of a mile away, out there
there's the living edge of the coral ..
JM: that's right, that's where its growing, its more alive than back here.
AC: as a biologist, is this all one organism here?
JM: no its one ecosystem, or one part of the reef ecosystem, so the back part
of the reef flat where we're standing now on the edge, is usually a sediment dominated environment. Wave action comes over the top of the reef, it hits corals pieces of rock will hit the coral O~ hit the coral on algae, and they'll break into smaller pieces. And those get washed to the back part of the reef. So a different kind of coral community and reef community forms back here, often dominated by seaweed, sea cucumbers, mantis, snapping shrimp and other types of organisms. And the front edge of the reef where you have the what's growing, you're gonna have a lot of pink crusted coral and algae and corals themselves, robust corals that are able to live in that environment where you have a lot of wave action and withstand that wave action. So they're constantly growing, and as the reef extends out, then more sediment accumulates behind and so really each flat has two zones to it, a sediment dominated zone near the shoreline which then contributes sand to the beaches that we're standing on right here, and the generative part of the reef, which is growing, and produces all the material for the reef ecosystem.
27:33 AC: I hear people say that coral is one living organism, that the great barrier reef is the largest living organism on earth, and the oldest. In that sense, is this coral 10
thousand years old and that's the front edge of it which is 10 years old or one year old or
something and its somehow related. Could you go back and do DNA analysis or
something and say that this coral is related to that coral?
JM: well, this is not an organism, we're talking about an ecosystem, so there's many individuals. So getting at the ecosystem level, we're not really standing on the whole reef flat here, we're only standing on the front part. Remember, we have an island behind us and on the other side of the island there's more reef flat. So what's happened here, this reef flat actually extends all the way from the ocean side, out here facing north, all the way into the lagoon. the island is an after thought. The island comes in when there's storms that face, that come in from this direction, and during really heavy, say a typhoon or a hurricane, rocks and rubble get tossed up on the reef flat and then eventually get washed on shore to form the island. Also there's been sea level rise and fall of maybe a meter or 2 over the last 10 thousand years so these islands are basically an afterthought. They have to form after there's a large enough reef flat and enough rock and rubble and sand debris to accumulate, get cemented together naturally, and form an island. So in terms of this whole system, I don't know the distance, its probably up to a mile across, from the lagoon edge to here-this has all grown up in the last 10 to 15 thousand years. During the last ice age, which I think ended 17 thou years ago, sea level began to rise from about 330 ft lower than it is today, and during that time period, the reefs have had to maintain upward growth in the face of sea level rise, keep up with that sea level rise, and eventually, when sea level stop rising, the reef caught up, and then started to grow out. So this is a very rapid process when you consider that a hundred meters or 330 feet, what a distance that is, esp when you have wave action and a very rigorous environment.
30:06 So that's the way all atolls have grown up over the last 10-15 thousand years.
31 :31 AC: I'd asked you earlier what it is that's special about Palmyra. Tell me again.
JM: first of all, it's a wet atoll, and it's the only one left in the pacific if not the world, that is not inhabited by people. So its relatively undisturbed, and its an opportunity for us now to conserve this beautiful place. The wetness is a result of being over the intertropical convergence zone that's about 5degrees north of the equator, there's abundant rainfall. When you have water on atolls, people are allowed to live on them more easily than on dry atolls. So throughout the pacific there's a whole number of dry islands and atolls that never became inhabited. All of the wet ones did, except for Palmyra and a few others in the Hawaiian islands. The rest are now heavily populated, Palmyra's the last one, and we have a great opportunity to protect it for posterity.
32:37 The other aspect of Palmyra being unique is that the a current systems running by it vary depending upon where the intertropical convergence lies with respect to the atoll. We have the counter current that runs past P from the west during situation where the intertropical convergence is right over the atoll, or we have the pacific equatorial currents either from the north pacific or the south pacific running from the east. During times when the convergence is not over the atoll. The significance of that is that reef larvae from a variety of organisms can approach P from either direction, colonize it, as well as P serving as a stepping stone for the dispersal of species and larvae to other nearby islands and atolls.
33:28 Aside from those two major things, the wet ecosystem also helps to promote a more productive ecology on the reef. We have a number of seabird species that nest here, their guano deposits because of the marine fauna can wash down into the rock and contribute to the natural productivity, the nutrients in the guano contribute to the natural productivity of the atoll. And so more fish larvae, a variety of other organisms might be able to benefit from this.
Aside from those things at the ecosystem level, P has some of the largest red footed booby and other seabird nesting colonies in the world, it has a very important sea turtle nesting and feeding area, there's giant clams that are abundant here that are found in only a few other US areas in the Pacific, and it has a very diverse coral and fish fauna that is present here, much higher than the comparable levels of diversity in nearby atolls.
Fish stocks here. Up until a few years ago, P was fairly pristine and unfished. Now we have fishermen coming down here, one came down here recently and fished out the sharks, but within a few years that can come back to pristine unfished level, provided that P continues to be protected. So there's just magnificent schools of sharks, a Maui wrasse, a napoleon wrasse here, pumphead parrots, groupers .... fish that are basically being wiped out elsewhere in the world, esp in the pacific, and w2ill probably be listed as endangered. In addition, the giant clam, the black lipped pearl shell, a couple of other species that are probably gonna be listed as endangered. the coconut crab is now here in abundance on several of the islands. The coconut crab is the largest land invertebrate in the world. It's a marine species, at some point in its life cycle, the adults go into the water and spawn and then the young of that species comes back later on. So its another marine species that lives on land.
35:53 So there's a lot of variety and diversity here. The plant life here, pisonia trees, I'm sure Beth has talked about this. They have these rows of these (?)-community forest groves here. And there's another species as well, nyzosperma, another climax tree species that's found especially in the eastern part of the atoll. And those then support other bird species, seabird species, and add to the variety and diversity.
Another unique attribute of the atoll is it has 3 sub lagoons and it has the reef pools on the east end which are growing, sort of smaller lagoon areas where corals are v diverse and abundant, and then beyond the atoll proper, where we have the reef flat and the islands, we have huge submerged reef terraces, one extending 3 1/2 miles to the west from a depth from a depth of about 10 feet to about 60 feet shallow, maybe 3 miles long and up to 2 miles wide. And then off the east end of the atoll there's another terrace of similar proportions except that its only a mile and a half, extending a mile and a half to the east. So if you take a look at the whole ecosystem, it has such a variety of habitats:
lagoons, terraces, reef pools, sand flats, wet environment in the atoll also contributing to the productivity and the great variety of plants and seabirds here.
37:26 AC: you've been diving all over the pacific, how does P compare? When you're snorkeling around and looking at things, how do you know you're here?
JM: First it has a unique vegetation and ecosystem both on land and in the ocean. The reef life is different here, the variety and the abundance of fish are spectacular. The climate here is also very mild. If! compare this to other atolls that I've been to, they're usually drier, much more humid, hotter, and much more uncomfortable. Whereas here we're standing out here, it's overcast, it's very pleasant right now. This is a very common environmental condition here, slightly overcast, there's a lot of rain here but its very pleasant and makes for a very interesting and unique atoll.
38:32 AC: I mean when you're snorkeling underwater, when you're underwater on the reef, you told me before that you've been diving on thousands of reefs over 30 years and this one is ...
JM: special. Yes. I guess the most spectacular thing that I've seen at P are the 2 terraces off the west end, where the ... it's so hard to dive on them cuz the currents run 2 or 3 knots or more, so you have to pick and choose where its safe to dive. There's tremendous coral growth out there and fish populations, its magnificent. Yesterday we were diving and we saw these beautiful schools of parrot fish, they came and circled us and two different species of green parrot fish.
The other things are these reef pools. I've never seen any reef pool habitat so diverse and aesthetically spectacular. Thirty species of corals that I found out of the 70 that I found in those holes that I haven't' found elsewhere on the atoll yet. Although I'm sure that they're here. Its just the fact that there's so much variety in these pools is just astounding and makes for a very interesting place for visitors to experience as well as for scientists to do surveys. And to understand why these special microcosms are flourishing.
40:00 AC: We hear a lot about coral bleaching. How's the overall health of the corals here?
JM: it looks like P was experiencing a coral bleaching event probably in late 97 early 98, which is part of a global coral bleaching event. And its of great concern to many reef scientists because in most cases the corals will expel their zozanthelli. We talked earlier about how these single celled plants impart their color to the coral. So they first expel those, leaving the coral transparent and bleached white cuz all that's left is the coral which is transparent, and beneath it is the white skeleton that characterizes all reef corals except a few. The corals are then in a more vulnerable state. They cant get as much food as they could get if the plants were present, and as a result most often the corals will die. And then so the bleaching event usually leads to massive coral death as occurred on the south side of P atoll about 2 to 3 years ago. But there's now showing signs of rapid recovery. Many of the coral and algae species are coming back and the corals themselves are
coming back to recolonize the reef slopes and reestablish the communities that existed there..
41 :34 JM: In contrast the north side of the atoll didn't seem to get affected by the coral bleaching event, nor the tops of the reef terraces. And Kingman reef, which is to the north also was not affected. So it seems like this latest bleaching event which came
up from the equator probably just grazed P, maybe hit the south side of it, but didn't get
42:02 AC: that's amazing. That's not much ... how far are you talking about? You're talking about the whole pacific ocean and drawing a line that's a couple of miles?
JM: there's a boundary out there. So they can now, with sea surface temps satellites, they can now monitor where these warm water plumes come in. well it might have been a shear from the currents too. There might have been a counter current going past it or the shear between two currents which prevented that warm water mass from moving across the boundary. But its clear that there was a coral bleaching event. It wasn't merely caused by wave action cuz a lot of the coral were dead standing, which would have been knocked down in a wave. A wave storm.
42:51 AC: one last question. Are you going to be able to protect this? If the nature conservancy is able to acquire the island, are you going to be able to prevent people fishing out the sharks, fishing out the ... you told me these wrasse are very valuable fish ...what happens if someone comes down here and says hey I want to get em?
JM: that depends on the ultimate details of the protected area that's established. I think it's a goal of both the nature conservancy and the F & W service to protect all oft the coral reef ecosystem here. Down to the depth where it functions. And far enough offshore to prevent this kind of activity. My philosophical belief is that if they cant sustainably harvest maori wrasse and sharks elsewhere in the world, they're not gonna come here to help feed a dying industry and a dying way of life. I think we need to save places like P, particularly P, which has these magnificent fish, so that they can replenish some of these areas once the fisheries management authorities can get their act together and better manage fisheries throughout the pacific. And that includes monitoring the fisheries, and monitoring the population size class so that if they're overfishing they're gonna have the fortitude to cut back on quotas. Right now there doesn't seem to be much fortitude, there doesn't seem to be much management , it seems to be a mining industry, nut a fishing industry. So I think our goal is to establish a protected area that will protect all of the coral reef ecosystem at P as well as the species that live in it.
45:12 CT: I'd like t do something if! could. Both of you walk up, you say can I
ask you a question. You say great and walk on and carryon a conversation.
45:33--45:41 AC: Jim, can we stop here to talk for a minute?
JM: sure. What do you want to talk about.
AC: coral. Coral and Palmyra.
46:16 AC: ok thanks.
JM: its been fun.
AMB: WALKING AWAY, BIRDS SQUAWKING, THE SEA
47:00 AC: this is a battle. We're watching there's a frigate bird, its swooping in ...
AMB: VERY FAINT BIRD SOUNDS
AC: the frigate bird is much bigger, its about a 4 foot wingspan. The sooty tern is half that size. The tern has got some fish and the frigate is diving at the tern, trying to make it give up the fish so the frigate can get its lunch. Now the tern is down, right out in the middle of this great reef flat, and the frigate is just circling overhead, waiting and waiting and waiting. When that tern takes off, trying to get away again, the frigate's gonna dive it.
AMB: WE DON'T HEAR ANY OF THIS
AC: ok they're up and they're moving, they're out about reef line, and the frigate is just hanging over the tern, flapping its wings, flapping its wings .. .it wont let the tern, the tern tries to fly off the surface of the water, the frigate dives and dives, and hovers over the tern and wont let it escape.
Now the terns moving away down the
49: 17 FX: SQUAWKING
AC: the terns moving away down the reef. The frigates following it at about a hundred feet or so and then swooping low.
50:02-51:09 AMB: OCCASIONAL SQUAWKING
AC: they moved off far away, and the frigate now is up and circling high. I think he's given up on that tern, he's gonna go look someplace else. Find some other bird to harass.
51:24 FX: water splashing
51:48 END OF DAT