The full
moon of midsummer brings with it the annual spawning of the corals. This
year we will be collecting gametes from Acropora palmata (elkhorn coral)
in the waters off of Key Largo. A. palmata is a federally listed threatened
species which, though once common throughout the Caribbean, has declined
by up to 90% through much of its range. Our goal is to enhance efforts
to protect and expand populations of this species by promoting a better
understanding of their reproduction and helping to establish new colonies
for reseeding reefs.
The
forecasted night for this year's spawn is the Wednesday the 1st of August.
That night we will go diving to collect gamete bundles as they are released
from the coral polyps. The bundles, which are composed of both sperm
and eggs, are designed to float to the surface where they would naturally
be carried by the current. Shortly thereafter they break up releasing
the sperm to fertilize other eggs. Once the gametes are collected, we
will need to work quickly to separate and prepare the sperm and eggs
for further research and get them back to the lab where they can be
cared for. With the samples we collect we will perform experiments related
to coral larval survival and settlement, and with luck, we will end
up with a number of young coral colonies for aquaculture and future
study!
Tuesday,
31 July 2007:
After arriving in
Key Largo on Friday we have been steadily building up for this year's
coral spawn. The various downstairs parts of the rental house we are
staying in have been converted to a temporary laboratory, an aquarium
facility, and a workshop, and the collection gear has all been prepared
and packed.
Today
we went diving to scope out the reefs we will be collecting from tomorrow
night and designate which colonies we will target. Conditions on the
water have not been ideal, with a brisk wind kicking up choppy waves,
and a stiff current to fight below the surface. Visibility underwater
is good, but the intense sun and heathave raised the water temperature
to above 86F, and there already appears to be scattered patches of corals
showing the initial signs of bleaching.
Tomorrow's
forecast is for more of the same, scorching hot and a chance of thunderstorms
withwinds up to 10 knots. Our plan is to spend the day finalizing the
collection gear, and preparing the lab for the expected influx of samples.
Then we will set out in the evening for a dusk dive to orient the collection
teams. If all goes as planned we will be bringing back an abundance
of gametes and then things will get really busy!
Wednesday,
1 August 2007:
We
set out on the NOAA boat R/V Oddesey just before six for our first collection
dive. Thankfully the wind had died down and the water was relatively
calm. By about six thirty we were in the water preparing the plots for
the night's dive. After marking the target colonies with glowing bouys,
we returned to the boat to wait for sunset.
There
was a sense of anticipation as darkness fell and we were surrounded
by glowworms spawning in the water all around us. We waited until after
nine then got back in the water to see if any of the colonies had begun
producing bundles.No
bundles were observed tonight, but there was plenty else to see.
It
was an amazing night dive (especially for one used to Pennsylvania's
murky quarries) with many cool critters that come out at night. We headed
back after about an hour and returned to the field house where we met
up with the other crew who had similar luck. Maybe tomorrow will be
the big night!
Thursday,
2 August 2007:
The
water was calm as we submerged for our dusk dive this evening. The boat
was thrumming directly overhead while we set up the bouys, the reef
seemed more active than the night before. Large schools of seargent
majors were up feeding by the surface and barracuda and nurse sharks
were both nearby.
After setting up
and checking on all our colonies we returned to the boat to wait for
night to fall. As the stars came out, the glowworms again became active
causing the darkness to glitter from above and below!
We
returned to our colonies at about nine thirty to check for any signs
of gamete formation. The coral polyps were extended, but no gamete bundles
were seen on our initial survey, so we practiced setting up the collectionnet
and swam around taking pictures of the various fish and spiny lobsters
hiding among the branching arms and many crevices of the reef.
By
ten thirty and several more scans of the colonies we decided to pack
it up for the night. It was just a short swim to the boat from our plot,
but as we approached it a huge adult male loggerheadsea turtle emerged
from the darkness to pass just below us. It turned and looped around
us for a second
look before heading off in the opposite direction.
Word from the other
team was much the same. Highlights from their evening included a visit
from a curious squid (video below), and fun with cylums! Hopefully tommorow
night spawning will begin, as it seems the long evenings on the boat
are starting to have an effect on people.
Friday,
3 August 2007:
This
morning there were reports from other sites that a dribble of spawning
had begun last night. Research teams in Mexico, Puerto Rico and further
south in the Keys observed the release of small numbers of gamete bundles
yesterday, and expect more tonight.
The
imposing thunderclouds in the distance however, were a bad omen for
our expediton, as night four brought dissapointment.
No spawn was collected at either site. It is now far enough away from
the full moon that some think the corals on our study plots are not
going to spawn this month. Our last hope now seems to be tomorrow night,
but the weather forcast calls for thunderstorms with winds of 15 - 20
knots and waves 4 - 6 feet high. If this is correct we will not be able
to go diving and may be forced to try again next month.
The
reef did seem especially alive this evening though. We were greeted
by a large school of barracuda when we entered the water, and after
dark, the water was swarming with tiny creatures attracted to our lights.
There were numerous crabs and anemones observed as well as reef squid
and trunkfish.
Saturday,
4 August 2007:
This morning we
all sat down to discuss our options. The forcast is still shaky, and
it seems we will be limited to a single boat. There is a great deal
of uncertainty about whether the coral will spawn at all this month.
It is now the fith day after the August full moon. Looking over past
records it is unusual (but not unheard of) for spawning to occur this
late. In 2001 spawn occured on day five, and in 2003 it was seen as
late as night nine, but that was a month earlier in July. Unfortunately
there is still quite a bit of uncertainty about what triggers coral
to spawn. It is known to occur following the full moon, but that is
clearly not the only factor. Additional influences may come from the
timing of the full moon in the summer months, variation in water temperatures,
and of course the health and condition of the corals. This all leads
to a rather complicated situation for us and the corals themselves.
In order to be able to outcross they must coordinate their spawning
somehow, but it seems that different reefs actually spawn at different
times. This of course reduces the probabalility that gametes from various
reefs will encounter each other at all, a heavy price to pay for a species
that puts all its reproductive effort into a single annual event!
Weather permiting,
we will try again with at least one crew tonight. Currently it is clear
but kind of breezy. So, we will have to see what this evening has in
store.
After
enjoying some birthday cake in honor of Harold and his nameless friend,
a pair of corals that were the products of the coral team's efforts
three year's ago, we set out aboard the R/V Palmata for sand island
reef at around seven pm . Once there, Abel snorkeled down to mark the
target colonies. The wind was not as strong as we thought it was going
to be, but the waves were substantial, so we moored near the three sisters
area to wait for a couple hours until dark.
When
it was finally dark we went down to check for gamete bundles. I thought
I saw bundles on a few colonies, but it must have just been wishful
thinking since no spawning was observed once again. We will continue
to go out the next couple nights to collect Montastrea spawn, but it
appears that the palmata will not spawn until next month.
The evening's dive was highlighted by visits from a pair of friendly
reef squid, and a well camouflaged reef octopus.
Sunday,
5 August 2007:
Tonight
the collection team focused their efforts on Montastrea faveolata and
returned with several vials of eggs and sperm. Break-up of the bundles
was rapid and fertilization
occured on the boat before they returned. Back at the house we put the
developing embryos into plastic containers with filtered sea water.
Samples of the sperm and eggs were separated and preserved for future
genetic analyses.
An initial inspection
of the eggs under the microscope showed that fertilization had indeed
taken place, by the presence of numerous dividing cells. We will assess
the fertilization rate when we check on them tomorrow morning.
The
collection tubes that were brought back also contained a host of interesting
planktonic creatures from down on the reef. These are the same things
that have been swarming our lights on all of our dives. They are actually
quite beautiful once you slow them down and have a look at them, and
they aren't trying to swim in your ear.
Monday,
6 August 2007:
The
Montastrea larvae collected yesterday are continuing to develop, and
tonight we went out to try to get some more. We dove at a site known
as Grecian Rocks where there are many large colonies of Montastrea,
and a number of Diplora (brain coral) colonies. We set up collection
nets over several of them, then waited til about 10:30 to check on them.
The
site was physically more complex than where we had been diving previously,
and extremely shallow in parts. The reef was surrounded with soft sandy
substrate, so a number of different fish species including some interesting
gobies were present. The corals themselves were home to quite a few
large beautiful anemones, and scallops. And the rocks were inhabited
by many worms, shrimp, and a moray eel.
Unfortunately
the spawning was less than we had hoped for. Rather than a coordinated
mass spawn there was just a trickle of polyps releasing bundles here
and there throughout the reef. We did succeed in collecting a small
amount of gametes from a few different colonies between 11 and 12 pm
however, enough to make some crosses to bring back with us.
The
eggs were mostly fertilized on the boat before we returned. Once back
on land we washed the them several times to remove the unused sperm
and left the young larvae in a container to develop overnight.
Tuesday,
7 August 2007:
Well,
today is our last day here in the Keys. Because the corals do not seem
to want to spawn we will cut our expedition short and work with the
Montastrea larvae that we have. So, for now we are packing up a container
of larvae and hitting the road
for Pennsylvania. It is certainly a dissapointment that we were not
able to rear more larvae, but hopefully we will be able to return next
month to try again the first week of September.
If I do return I
will resume updates, but it seems that is all for now....Thanks for
reading along!
Final
Update, September 2007:
This month Iliana
returned to the keys to have another attempt at collecting Acropora
spawn. I was unable to join her since classes had resumed at Penn State.
Fortunately, she was able to collect a good number of gametes and successfully
carry out some crossing experiments. At this point we can say that we
have some very exciting results regarding larval survival rates and
how they relate to parental genotypes!
During her visit
Iliana gained some valuable experience rearing larvae with the help
of our friends from SECORE, which puts us in a good position to do some
very cool work next summer!
The full
moon of midsummer brings with it the annual spawning of the corals. This
year we will be collecting gametes from Acropora palmata (elkhorn coral)
in the waters off of Key Largo. A. palmata is a federally listed threatened
species which, though once common throughout the Caribbean, has declined
by up to 90% through much of its range. Our goal is to enhance efforts
to protect and expand populations of this species by promoting a better
understanding of their reproduction and helping to establish new colonies
for reseeding reefs.
The
forecasted night for this year's spawn is the Wednesday the 1st of August.
That night we will go diving to collect gamete bundles as they are released
from the coral polyps. The bundles, which are composed of both sperm
and eggs, are designed to float to the surface where they would naturally
be carried by the current. Shortly thereafter they break up releasing
the sperm to fertilize other eggs. Once the gametes are collected, we
will need to work quickly to separate and prepare the sperm and eggs
for further research and get them back to the lab where they can be
cared for. With the samples we collect we will perform experiments related
to coral larval survival and settlement, and with luck, we will end
up with a number of young coral colonies for aquaculture and future
study! 
Today
we went diving to scope out the reefs we will be collecting from tomorrow
night and designate which colonies we will target. Conditions on the
water have not been ideal, with a brisk wind kicking up choppy waves,
and a stiff current to fight below the surface. Visibility underwater
is good, but the intense sun and heathave raised the water temperature
to above 86F, and there already appears to be scattered patches of corals
showing the initial signs of bleaching. 
Tomorrow's
forecast is for more of the same, scorching hot and a chance of thunderstorms
withwinds up to 10 knots. Our plan is to spend the day finalizing the
collection gear, and preparing the lab for the expected influx of samples.
Then we will set out in the evening for a dusk dive to orient the collection
teams. If all goes as planned we will be bringing back an abundance
of gametes and then things will get really busy!
We
set out on the NOAA boat R/V Oddesey just before six for our first collection
dive. Thankfully the wind had died down and the water was relatively
calm. By about six thirty we were in the water preparing the plots for
the night's dive. After marking the target colonies with glowing bouys,
we returned to the boat to wait for sunset. 
There
was a sense of anticipation as darkness fell and we were surrounded
by glowworms spawning in the water all around us. We waited until after
nine then got back in the water to see if any of the colonies had begun
producing bundles.No
bundles were observed tonight, but there was plenty else to see. 
It
was an amazing night dive (especially for one used to Pennsylvania's
murky quarries) with many cool critters that come out at night. We headed
back after about an hour and returned to the field house where we met
up with the other crew who had similar luck. Maybe tomorrow will be
the big night!
The
water was calm as we submerged for our dusk dive this evening. The boat
was thrumming directly overhead while we set up the bouys, the reef
seemed more active than the night before. Large schools of seargent
majors were up feeding by the surface and barracuda and nurse sharks
were both nearby. 
We
returned to our colonies at about nine thirty to check for any signs
of gamete formation. The coral polyps were extended, but no gamete bundles
were seen on our initial survey, so we practiced setting up the collectionnet
and swam around taking pictures of the various fish and spiny lobsters
hiding among the branching arms and many crevices of the reef. 
By
ten thirty and several more scans of the colonies we decided to pack
it up for the night. It was just a short swim to the boat from our plot,
but as we approached it a huge adult male loggerheadsea turtle emerged
from the darkness to pass just below us. It turned and looped around
us for a 
second
look before heading off in the opposite direction. 
This
morning there were reports from other sites that a dribble of spawning
had begun last night. Research teams in Mexico, Puerto Rico and further
south in the Keys observed the release of small numbers of gamete bundles
yesterday, and expect more tonight.
The
imposing thunderclouds in the distance however, were a bad omen for
our expediton, as night four brought 
dissapointment.
No spawn was collected at either site. It is now far enough away from
the full moon that some think the corals on our study plots are not
going to spawn this month. Our last hope now seems to be tomorrow night,
but the weather forcast calls for thunderstorms with winds of 15 - 20
knots and waves 4 - 6 feet high. If this is correct we will not be able
to go diving and may be forced to try again next month.
The
reef did seem especially alive this evening though. We were greeted
by a large school of barracuda when we entered the water, and after
dark, the water was swarming with tiny creatures attracted to our lights.
There were numerous crabs and anemones observed as well as reef squid
and trunkfish. 
After
enjoying some birthday cake in honor of Harold and his nameless friend,
a pair of corals that were the products of the coral team's efforts
three year's ago, we set out aboard the R/V Palmata for sand 
island
reef at around seven pm . Once there, Abel snorkeled down to mark the
target colonies. The wind was not as strong as we thought it was going
to be, but the waves were substantial, so we moored near the three sisters
area to wait for a couple hours until dark. 
When
it was finally dark we went down to check for gamete bundles. I thought
I saw bundles on a few colonies, but it must have just been wishful
thinking since no spawning was observed once again. We will continue
to go out the next couple nights to collect Montastrea spawn, but it
appears that the palmata will not spawn until next month. 
Tonight
the collection team focused their efforts on Montastrea faveolata and
returned with several vials of eggs and sperm. Break-up of the bundles
was rapid and 
fertilization
occured on the boat before they returned. Back at the house we put the
developing embryos into plastic containers with filtered sea water.
Samples of the sperm and eggs were separated and preserved for future
genetic analyses. 
The
collection tubes that were brought back also contained a host of interesting
planktonic creatures from down on the reef. These are the same things
that have been swarming our lights on all of our dives. They are actually
quite beautiful once you slow them down and have a look at them, and
they aren't trying to swim in your ear.
The
Montastrea larvae collected yesterday are continuing to develop, and
tonight we went out to try to get some more. We dove at a site known
as Grecian Rocks where there are many large colonies of Montastrea,
and a number of Diplora (brain coral) colonies. We set up collection
nets over several of them, then waited til about 10:30 to check on them.
The
site was physically more complex than where we had been diving previously,
and extremely shallow in parts. The reef was surrounded with soft sandy
substrate, so a number of different fish species including some interesting
gobies were present. The corals themselves were home to quite a few
large beautiful anemones, and scallops. And the rocks were inhabited
by many worms, shrimp, and a moray eel.
Unfortunately
the spawning was less than we had hoped for. Rather than a coordinated
mass spawn there was just a trickle of polyps releasing bundles here
and there throughout the reef. We did succeed in collecting a small
amount of gametes from a few different colonies between 11 and 12 pm
however, enough to make some crosses to bring back with us. 
The
eggs were mostly fertilized on the boat before we returned. Once back
on land we washed the them several times to remove the unused sperm
and left the young larvae in a container to develop overnight. 
Well,
today is our last day here in the Keys. Because the corals do not seem
to want to spawn we will cut our expedition short and work with the
Montastrea larvae that we have. So, for now we are packing up a container
of larvae and hitting the 
road
for Pennsylvania. It is certainly a dissapointment that we were not
able to rear more larvae, but hopefully we will be able to return next
month to try again the first week of September.