On our way home

Here we are at the end of our expedition.  It's hard to believe - the time has flown by, but it also feels like ages since began this trip back in Guam a month ago.  We were 13 scientists from 5 different research institutions around the world.  We traveled more than 3,779 nautical miles (6,997 kilometers) and visited 7 small islands and atolls across the length and width of Micronesia.  The trip was a smash success in every sense.  Scientifically, we collected 694 whole coral samples, 551 coral tissue samples and 62 reef water samples.  We counted coral types and assessed their health along 1,350 meters of coral reef (nearly a mile!).  We'll combine the information on water quality with the amount of coral disease to get a good idea of how healthy the reefs are at each site.  We drilled 25.2 meters of coral skeleton cores (more than 82.5 feet).  The longest cores were up to.4.8 meters tall, nearly 16 feet, and will allow us to build maps of past climate change across Micronesia going back about 400 years. 

We also made a lot of friends along the way.  We met villagers and chiefs, fishermen and weavers, from 3 tiny atolls and 3 small islands (one atoll was uninhabited).  We met scuba divers and government officials working to help preserve and protect their fragile coral reefs.  We joined forces with the ship's crew (who helped us drive the boats, make our lunches and fix our equipment, and took care of us in every way), and became a single group dedicated to meeting the goals of our science mission.  We gave talks and explained what we were doing, and why, to non-scientists who asked us lots of good questions and helped it all become clearer.  Ultimately, we learned a lot about ourselves and the world around us, and learned that Micronesia is a beautiful special part of this planet we call home.  

Thank you so much for being a part of our trip.  We all enjoyed sharing it with you and we really hope you enjoyed it as well.  Remember to work hard, be nice, and have fun.  Hope to see you again soon!

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Fish Help Keep Coral Reefs Healthy

The sound of the engines on the ship drones on as we transit north to Pohnpei, our last destination on this expedition, and I am pondering all that we have seen on this trip thus far. In the past few days, we had the unique opportunity to survey reefs fringing islands inhabited by very few people. Not only are these reefs the healthiest the disease team has ever seen, they are teeming with fish, and apex predators patrol the deeper blue. Interestingly, the atolls with the healthiest reefs are those nearest the equator, where sea surface temperatures are higher than at Kosrae, for example, yet these corals exhibit very few signs of disease, if any.

On these reefs, every nook and cranny is occupied by a widely diverse group of corals of all sizes from the smallest nubbins to great big boulders. My job has been to count each coral colony, square meter-by-square meter, and classify them by genus and size. Others on the team are looking for signs of coral disease, counting fish and determining hard coral cover percentage along our two 25-meter transects per site. One observation suggests that human population size correlates with reef health in Micronesia. Although a number of factors could explain this including land-use and run-off, fishing effort may also be relevant. Herbivorous fish graze algae that colonize newly exposed coral skeleton when the coral experiences tissue loss (whether from disease or predation). This grazing is a fundamental service that benefits the corals as they are able to slowly grow over exposed skeleton but only if the fast-growing algae is not present. Both algae and coral live in a constant battle for reef real estate and fish act as agents for the slow-growing coral, effectively keeping the skeleton clean until coral tissue can grow back or other coral species colonize. Overfishing of these important reef grazers could have important impacts on the health of the coral reef.

It has been an amazing experience to be able to see coral reefs as they should be in the absence of the numerous pressures common to the reefs of more populated regions. All of the reefs we've surveyed in Micronesia look relatively healthy. One of the benefits of surveying reefs such as these is the ability to compare them to highly impacted reefs elsewhere in the Pacific. This research can help us understand the problems and therefore find solutions before it is too late. 

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Almost on the Equator

We've been here in Kapingamarangi for two days, and it's been so good we decided to spend one more day before we leave.  The atoll is nearly circular, with only one small channel entrance into the lagoon.  We went in yesterday morning to meet the acting chief and village elders, and learned that the area we were targeting for large corals, just inside the channel, was the right place to look.  One particularly huge colony was striking for its size and clean shape [Note Whitney swimming near the bottom for scale].  While I was underwater before starting to drill a core, I felt like I was touching the heartbeat of the ocean.  This is the site where the West Pacific climate pattern with a 100+ year beat is strongest, and this coral was the largest and oldest we saw.  It's been recording that beat for hundreds of years, and it kind of looks like a heart.  As I knelt on top, I was feeling a little overwhelmed and extremely grateful for the opportunity to be here.

Tomorrow we will finish coring, and the survey and tissue sampling teams will complete their work as well.  There has been almost no coral disease noted here, and we've seen lots of big fish, including many sharks and a few manta rays!  After we finish up, we'll go back to the village to say goodbye.  Everyone will get to come, and I hope it will turn into a big celebration.  We'll write about that in the next day or so, so stay tuned... 

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Do corals recycle?

You probably never look at pictures of colorful fish or dramatic coral reefs and wonder how they get their nitrogen.  But as a biogeochemist, I can't help but look at the abundance and diversity of life on a coral reef and wonder how all these organisms can exist in waters that are the ocean equivalent of a desert when it comes to nutrients like nitrogen.

All living things need the element nitrogen to build the proteins that make up their cells.  But too much nitrogen is a bad thing, and you and I have ways of getting rid of our extra nitrogen in our kidneys before it builds up to dangerous levels in our blood.  Corals, too, have nitrogen waste products. But what happens to this waste nitrogen is not well understood.  We think a lot of it may be recycled many many times by the organisms that make up the reef. 

One way we are investigating this is conducting incubation experiments that allow us to track the movement and transformation of nitrogen through the different parts of the coral, and between the coral and its microbial friends.  In this picture, I'm injecting a nitrogen-containing tracer called ammonium into a bottle containing a small piece of coral.  The ammonium tracer I use in my experiments is slightly different than the ammonium normally found on the reef and acts like an invisible dye to measure how much gets taken up by the coral, how much is transformed by bacteria living with the coral, and how much is transformed by bacteria living in the surrounding water.  Understanding how coral reefs are so efficient at recycling their nitrogen waste might help us understand how reefs can be productive ecosystems in such nutrient-poor waters.

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Coral Conservation in Kosrae

We spent two wonderful days in Kosrae, where the coral reefs were simply beautiful.  Before we arrived, we learned from local divers and government officials about efforts to conserve the reefs.  First, the local community has installed moorings to protect the corals all the way around the island, so no one has to put anchors directly on the reef.  In addition, each year people from all over the world come to Kosrae to conduct reef monitoring surveys and measure the abundance and diversity of corals and fish.  These efforts have clearly had an impact, as the reefs were full of vibrant corals of every description, and also had a large number of both reef fish and pelagic (open water) fish.  We also saw many sea turtles and one octopus (who was trying to hide in a big coral while we were sampling it).  Our coral disease experts gave a seminar to the local community, including dive operators, marine resource managers and village elders, to teach them how to recognize coral diseases, so they can add this information to their annual reef survey.  Kosrae is really a special place, where everyone works together to preserve and protect their beautiful environment, above and below the water.  As usual in Micronesia, it's all done with a smile! 

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Falalis Forever!

Of all the wonderful things we've seen and done so far on this trip, one of the most memorable was our visit to the island of Falalis in Woleai Atoll.  When we arrived at Woleai, we first went to meet the village elders to ask their permission to study the coral reefs. The information they shared helped ensure the success of the expedition, and when we left that morning, Fabian our translator asked us to return and tell the people what we had found.  We came back the following afternoon and sat down at what I call the council circle, where we were welcomed as friends and offered coconut shells filled with tuba, a ceremonial drink made of palm sap.  I described some of our findings - Fabian translated for the elders and other fishermen, and translated their questions back to us.  He said they were concerned that there weren't as many clams as there used to be.  Fabian then looked serious and said "We're going to be chased away".  I said "How?  By who?"  He winked and said "That rain storm right there."  Sure enough, it started raining within seconds and we all ran under the cover of the men's meeting lodge.  Normally, women aren't allowed in the men's meeting areas, but Fabian said the women in our group were scientists, and "that was different."  While we were in the lodge, many of the elders asked questions about climate change, and said they were concerned about what would happen to them if sea level started to rise.  They had nowhere they could go, and wanted our advice on what to do.  I told them because of the physics of greenhouse gases, global warming was likely to continue before we can start to make it better, and that they needed to prepare rather than hope it might not yet happen. They said they have noticed parts of the island eroding already, and that they needed supplies to help raise their homes off the ground.  They were sincerely thankful that we had come to study their reefs and gave me a beautiful cloth sarong as a gift, saying that they hoped we would come back again to continue our studies.  I hope we do!

We were invited to go for a tour of the village, and we all were eager to see their homes and how they lived.  [see the slide show on the left to follow along]  They can climb up 50 foot tall coconut trees in a flash, using the footholds carved in the trunks.  Their homes are covered with thatch from palm fronds, and some have plywood for the lower walls.  We met some of the women, who were weaving small baskets out of palm leaves to hold balls of breadfruit.  They bury the breadfruit balls in the ground for up to six months until they become ready to eat!  Their fishing boats are elegant outrigger canoes that they carve themselves, and the men meet at the council circle each night to hear the elders decide how they will all fish the next day.  Sometimes with hook and lines, sometimes with nets, and sometimes spearfishing.  All the men fish and all of the fish are divided communally among the entire village.  Nearly everyone we saw was smiling and happy, especially the kids who shrieked and laughed, pretending to be shy and then playing games with us as we walked on the beach.   Before we left, we returned to the council circle.  They offered us more tuba to drink and bananas and coconuts for the ship, and we told stories and laughed until it was time to go.  I felt like we had been welcomed into their society openly and sincerely, and as we left it was like saying goodbye to good friends.  Steven our guide said they love their island and enjoy living there.  They have a saying in the village - "Falalis Forever!" - and I couldn't possible agree more!

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Assessing the coral reefs of Micronesia

The atolls of Micronesia provide excellent reefs to study because many are so far from large human populations. Our work here is to perform a baseline study of the abundance, diversity and health of the corals that inhabit these reefs and gather information on any diseases present. During these dives, we count hard and soft corals and categorize them by genera and size class. We are also gathering information on the type of cover, i.e., macroalgae, coral, sand, crustose coralline algae, etc., that dominates along our transects, and the numbers and genera of fish that are present.

Many of the reefs we are accustomed to seeing in Hawaii and the Caribbean show obvious signs of disease and degradation. Happily, the corals at the Micronesian atolls we have thus far visited appear healthy and largely devoid of disease. We have sampled the few coral colonies found exhibiting signs of disease and those will be brought back to the lab for histological analysis. Histology is the study of cells and tissues and this is done by using light microscopy. Preserving the coral tissues in fixative at the time of collection allows us to better understand the disease processes that are taking place and how (if) the coral is responding to the stress.

Interestingly, we found that the abundance of reef fish at the inhabited atoll (approximately 1000 people) was very low and no top predators were spotted while at the uninhabited atoll fish abundance was quite high and sharks and large pelagic fish species were seen. Food for thought...

Check out the reef slideshow on the left!

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Drifter Deployment

On our second afternoon at Woleai, I had the opportunity to deploy my drifter.  I went out to the reef in one of the small boats that we use to move from the big ship, anchored in deep water, to the shallow reef area, near the shore.  

To begin, I looked around to observe the water movement, and I jumped in the water to feel which way the current was going.  Once I knew which end was upstream, I went to the upstream end of the reef and dropped the drifter in the water. At this point, I sampled the water and I left the drifter to float along with the water across the reef. The drifter tracked where the water was going.  After the water (and drifter) crossed the reef, I sampled it again. 

While the water was passing over the reef the water was interacting with the coral community.  As the coral were growing, they were extracting the chemical building blocks for their skeletons directly out of the water. When I measure the chemistry before and after the water interacts with the coral reef, I can determine how much they grew during that time. This means that I can calculate how fast the community is growing, collectively. The community is comprised of corals that generate carbonate (limestone) skeletons, coralline algae that also deposit carbonate mineral, sand which is dissolving carbonate back into the water, and a multitude of organisms with carbonate shells.  Measuring the net growth of this community is one way to evaluate the health of a community and to assess its sensitivity to changes in the environment.

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Studying the microbial associates of corals

As we explore the different reefs throughout Micronesia, my group is taking samples to learn more about the microbial associates of corals.  Corals, like all animals, associate with many different ‘types’ or ‘species’ of microorganisms.  Did you know that humans actually have 10 times more microbial than human cells in our body?!  We humans cannot live without our microbes, and we think that microbes are also very important for corals.   We hope that learning about the coral-associated microbes will help us understand more about the health of corals, and the conditions they need to stay healthy. 

In order to study coral-microbes, we utilize SCUBA to take small tissue samples from the corals.  We bring these samples back to the laboratory on the boat.  In the lab, we preserve the samples so that we can later examine the microbes using their DNA.  The DNA gives us information about the different species of microbes that reside with the coral.  The DNA can also provide clues about the roles or interactions that the microbes may be having with the coral. We are especially excited to learn about the microbes that reside on the Micronesian corals because these corals appear to be very healthy.  Studies of microbes on healthy corals will provide us with the background to better understand the role of microbes on sick, or unhealthy corals.

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Exceeding Expectations

We've been very busy the last few days!  Woleai Atoll was fantastically beautiful and over two days yielded some stunning scientific results.  On our first morning, we went to Falalis Island to meet with village elders to both ask for permission to conduct research within their reefs, and also to  seek their knowledge about the condition of corals and local fisheries within the atoll.  After introductions, I explained our science goals and the village chief, named Fabian, told us the elders agreed we were welcome to do our research.  I showed them pictures of the kind of large coral we were looking for, and Fabian showed me places on the map where we should go.  He asked in Woleaian who amongst his people would like to go out with us and show us the corals, and was met with silence.  He asked me if we would be OK alone and I said "Yes, of course".  He asked again who would like to guide us and again got silence.  He leaned over with a twinkle in his eye and said "It appears that no one wants to go with you - everyone is too shy".  We chatted some more, and I gave him some gifts to show our thanks - t shirts and hats, pens, pencils and notebooks for the kids, and food including canned meat.  Then we left the island to go study the reefs

A while later, as we were preparing to leave our ship in the small working tenders, Fabian pulled up in a small boat with several other fishermen.  They had decided to join us after all!  We all headed out together for the nearest spot indicated on the chart but only found small of broken-up coral colonies.  We kept looking and I found a larger one, but still too broken.  Fabian then said there was a bigger one near his island.  We went there and it was almost on their doorstep.  We had gone around it that morning on the way in to meet them.  It turned out to be truly huge and beautiful (to a coral scientist, anyway).  It was smooth with no deep cracks or crevices or worm burrows.  We drilled a core and it turned out to be 4.5 meters long - almost 15 feet!.  [Note in the photo you can see the pieces of core lying on the surface of the coral]  Looking at the annual growth bands, I guessed it might be close to 400 years old.  I was so happy I felt like I could fly.  We could never have done this without the help of our island friends.  We had a barbecue dinner on board the ship that night to celebrate and enjoyed another spectacular sunset, then dropped into bed exhausted.  There is much more to tell about the other science results and our return visit to the village.  Stay tuned...

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