#992 Coral
Bleaching transcript
00:12-00:37 [boat
on sea, near island]
VO- In the beginning of 1998, some British researchers from Cambridge set
out for the coral islands of the Seychelles. On St Pierre, an
uninhabited island, no scientific studies have been made recently and the
island has not even been mentioned in scientific contexts since 1985.
00:43-01:04 [underwater, divers, view of dying
coral]
VO- Corals are the seas’ equivalents to the rainforests of the mainland and
researchers now wanted to study untouched or virginal corals in the sea
situated outside the islands. They found, however, that an ecological disaster
had taken place and that the corals were dead. What they saw was
the skeletons’ gleaming white colour over large areas.
01:06-01:36 [underwater
diver surveying reefs]
Woman- Yes, I had no idea before I came that this area was affected. I know
that a lot of areas in the world have been affected recently by coral bleaching
but there hadn’t been any reports that I’d heard of before I came. I think it
was a fairly recent event, maybe only a month or so
before we arrived that the coral started to die. So, it was quite an opportune
moment to come on the scene and survey these reefs just after they had died.
01:40-02:02 [boat on sea]
VO- Alve Henriksson is master on board the Searcher. He and some
volunteers have built this special boat that could take them to remote islands
at reasonable prices and on which the crew could stay for a longer period of time.
02:04-02:33 [boat
on sea, interior of boat]
Woman- It’s quite small for twelve people but it’s possible! I think the boat
has been superb, it’s run really well and had no
problems at all with the running of the boat. It’s small enough that it can get
into areas that maybe larger research vessels couldn’t get into, and with an
inflatable boat we can get anywhere really, with Searcher. It’s been fantastic.
02:34-03:01 [boat
on sea, dolphins]
VO- The crew besides Alve consists of three men,
all of whom are volunteers and have felt the attraction of adventure of diving
and sailing. The geologist Tom Spencer has spent much time on
surveying.
03:03-03:30 Spencer- What we’re trying to do here,
is to reconstruct the paleo environment of this island. What was it like when
it was an atoll? What was the reef like and what was the lagoon like? Was it
deep, was it shallow? Were there lots of passes through the reef or were there
very few? That kind of thing.
VO- Both the grounds around the islands and here within the lagoon around Alphons have been surveyed.
03:32-04:09 [on
boat collecting samples]
Man- This is coral sand all of
it?
Spencer- Yeah yeah.
Well, if not from the corals, from the animals that live on the coral reefs as
well. But this is very different from some of the sand elsewhere which is much
courser than this. What we need to do with this now is dry it, we dry this out,
and then we’ll take it back to the laboratory. And then the laboratory will
look at the different sizes of sediment here, will put it through a nest of
sieves of different sizes, and then weigh the amount of sediment that’s caught
on each sieve. And we’ll be able then to put together what’s known as a particle
size distribution
04:22-05:01 [small
boat on water, research divers underwater, marine life, fish]
VO- The most time-consuming work has been on marine surveys.
Woman- We’ve done…well there’s been a
team of roughly eight divers...but we’ve done around 275 dives I think, in six
weeks between us all. That’s quite an achievement!
VO- All the islands visited are remote and isolated and the seas around
are not subject to any human impact but the virginal reefs that the researchers
were looking for were gone. An ecological disaster has occurred and all has
taken place very rapidly.
05:06-05:27 [fish
on coral reefs]
Man- Vitality of corals really
is a link to the rest of the marine environment. It provides…if you will it’s
the base structure for the rest of the health of the coral reef community. Without
the health of the corals you often, in most cases, see a breakdown of the
ecology that we’re finding here.
05:31-05:59 [research
divers underwater, marine life, fish, coral]
VO-The temperature of the sea was 30 degrees celsius,
which is 5 – 6 degrees above the normal level of temperature. Corals that are
exposed to this kind of stress can lose their symbiotic algae that live inside
the coral tissue. The coral is coloured by the algae and is also totally
dependent on it for its survival. When the algae disappears,
the coral will die within a few weeks and only the white skeletons will remain.
06:02-07:26 [divers
underwater, marine life, coral, fish]
Man- We’ve seen some pretty
horrific bleaching. Everywhere we’ve gone, it seems large amounts of corals
have died already. And of the remainder, many are bleached white, and they die.
It’s very hard at this stage to pre-guess what’s going to happen in the next five years or so. I think we’ve
already seen and quantified large amounts of coral death. A lot of this has
happened very recently in the last few months. Probably too recently to have
had a major effect yet on the fish populations. Most of the fish, you see, on
coral reefs don’t feed directly on coral, so they’re going to survive even if
the coral dies, at least in the short term. But the longer-term effect is very
hard to predict. You’ve certainly got a major change in the substrate, from the
benthos. Algae is moving in where the corals have died and grown over the
algae. A lot of fish feed directly on that algae. Those fish might do quite
well, at least in the short term. Slightly longer term of course you’ve got a
weakening of the entire substrate; the corals are dead. A big storm may come in
and flatten areas of reef; knock the corals down. Then you’ve lost the complexity
of the surface of the reef, which many fish rely on for protection, for cover
when they sleep at night. With that loss of complexity, you may lose large
numbers of fish.