Posted on June 13, 2012
Our third and final island to survey for vermetids (snails that are linked to coral die off in French Polynesia—read more in my previous post) was our home island: Moorea (pictured above). We surveyed each shoreline—north, east and west, over three days. To give you a better idea of what our surveys are like, I’ve uploaded a video clip of one of our dives off the west coast (This time we were diving in Haapiti, another famous surf spot, as evidenced by the surge in the video. BUT, It did not compare to the big wave in my previous post…) :
As seen in the video, we place quadrats (square metal frames) on top of the reef at different locations and count up the number and species of vermetids as well as branching corals that fall within the square. By doing this many, many times in many locations (and across islands), we are able to get a better sense of vermetid distribution patterns and how these patterns may be linked to potential drivers, such as human development.
Fortunately, the weather cooperated nicely throughout all our inter-island surveys, aside from a little rain. But who cares about rain when you’re submerged all day anyway?
In the end, we completed all of the work we set out to accomplish and got to experience some epic scenery while island hopping. The video below features our triumphant boat ride home along the north shore of Moorea after completing our final site survey–kite surfing, trans-Pacific yachts and a lush-green mountainous backdrop are all regular sights on the way to/from work out here:
The inter-island vermetid survey is now complete for this summer. We had a great time and a great team, and I look forward to what these data can tell us about vermetids and how we might better understand their role on the reef. Now, and for the rest of the summer, I will be conducting experiments for my dissertation (read more about the topic here). Stay tuned for more South Pacific island adventures for science!
Posted on May 30, 2012
Last Wednesday, we left at dawn to survey all along the south shore of Tahiti, in our ongoing effort to understand the causes and consequences of population booms of vermetids (reef snails that have been implicated in coral die off)—See previous post for more details. We lucked out and had great weather, allowing us a striking view between our home island of Moorea…
We decided to conquer the most challenging sampling site first: underneath the famous wave Teahupo’o (see it in all its glory here: http://www.youtube.com/watch?v=9RXGY9KDifU). As you might guess, surveying the reef for tiny snails within small study quadrats (PVC squares) underneath a high-speed mountain of water is pretty challenging. Here’s a video of me trying to work under these conditions:
And if you’re signed into Facebook, check out my Kiwi co-worker, Snout, as he tries to work at the same site, without clutching the reef (funny stuff):
But despite being tossed around like rag dolls a bit, we got all the data we needed and moved on. The rest of the day was pretty stress free compared to Maiao two days earlier, aside from when I spotted an oceanic white tip shark when we were passing between Tahiti Iti and Tahiti–beautiful animal, but very intimidating to swim with… Luckily, we never saw him/her underwater, and the workday went on as planned, allowing us to tackle 10 sites along the south shore of the island. Also, on the way home at the end of the day, we trolled for just a few minutes and caught a benito (small tuna)– Dinner doesn’t get any fresher!
Tahiti: Check! Last but not least is our home island of Moorea…
Posted on May 24, 2012
At 5 am Monday morning, we set off under cover of darkness to travel across 60 miles of open ocean on a 26 ft boat to reach the remote Polynesian island of Maiao.
To give you the inside scoop on this expedition, Maiao is the second of three islands that we are surveying for vermetids—small snails that live on top of corals and are linked to coral die off (see previous post). In this study, we aim to see whether the densities of vermetids differ among reefs that surround three different islands, with hopes to better understand what is causing vermetid populations to flourish and, in turn, kill off corals. Some data suggest that vermetids may thrive under high nutrient conditions, due to higher food availability. Because human development leads to nutrient pollution, it is possible that human population density is the key to vermetid outbreaks that have recently plagued areas of French Polynesia. As such, the three islands we will survey are subjected to a range of human development, from high: Tahiti, medium: Moorea, and finally low (Maiao). Maiao is inhabited by less than 300 people.
Shortly before arriving at Maiao, we realized that we didn’t have enough fuel to complete the trip back home to Moorea, which was planned for the end of the afternoon. Our captain, Jacques, came up with the McGyver-like contingency plan to have another station boat (this one even smaller) meet us halfway on the return to bring us more fuel–that is, wherever our boat ran out of fuel somewhere between the two islands. This was unsettling for the group, but we saw no alternatives aside from sleeping on Maiao, which would make us lose a day of field work. So, we went along with it, hoping for the best…
When we arrived at Maiao, we were greeted by an unexpected procession. The Mayor of the island, along with some of his family, met us at the one dock (and the one sign of human settlement) on the island’s perimeter. They seemed very excited to see us–men, women, children—a little over a dozen in all. Some of them were especially interested in checking out our scuba gear on our boat. They also brought an impressive brunch, which they setup with some patio furniture. Tuna steaks, fa fa snails (snail salad), fresh coconut milk, tea and firi firi (donut-like pastries) were served in Tahitian portions (large piles). We were happy to oblige and put an impressive dent in the food pile before thanking our generous hosts profusely, grabbing a quick photo with the mayor to commemorate the unique encounter (below), and heading off into the rising sun to collect some data!
Our work went pretty smoothely, aside from a challenging tidal surge and a kamikaze-like swim into the reef lagoon over the reef crest, which almost claimed our lives (the reef crest is the part of the reef where the waves break–BIG waves in some cases–an important protective service that reefs provide to coastlines around the world). Interestingly, the reef, as well as the vermetid population, seemed to exhibit some clear differences to Moorea, which could yield some interesting results at the conclusion of our study. We sampled from the perimeter of the entire island, which made for some cool sights—the island appeared completely untouched from the reef’s edge and from the shore.
Just before calling an end to our work day and making the arduous, journey back to Moorea, which included the super-risky fuel exchange, we received a call from the Mayor offering us fuel to complete our return. Thank goodness! We obviously took him up on the thoughtful offer, and once fueled, headed off into the sunset with some nice data and an unforgettable memory.
Next on the island-hopping list: Tahiti. Stay tuned…
Posted on May 20, 2012
The post below marks the first in a series that I plan to produce while I am conducting research in French Polynesia throughout this summer. So, if you find what I am doing interesting, please stay tuned for more posts 🙂 As usual, all comments are welcome!
Two days ago, I arrived on the island of Moorea in French Polynesia to begin my third summer of data collection for my dissertation. Though this is my 6th visit to this place, it never ceases to captivate (pictured below is Moorea with Tahiti in the background):
For the start of this trip, however, I will be working with an international group of researchers in an ongoing effort to understand the ecological consequences of vermetid gastropods on coral reefs. As I mentioned in my last post, these little critters seem to have devastating effects on reef corals, as they feed using projected mucus nets that cover the surface of corals and are linked to extensive coral mortality.
Back in January, we started a long-term experiment that will examine vermetid effects on coral communities over the next several years. We did this by removed vermetids from some reefs and allowing them to flourish naturally on others. This time (and for the next week), we will be looking at patterns of vermetid abundances across islands, by conducting extensive surveys on the islands of Moorea (where we currently reside), Maiao (an uncultivated island with a population of <500), and Tahiti. We are leaving to sample Moorea in an hour and, weather permitting, we will leave for the 60-mile open ocean journey to Maiao at 5 am tomorrow. Keep your fingers crossed for good weather and calm seas!
Thanks for reading, and much more is soon to come throughout the summer!
Posted on January 23, 2012
Two days ago, after 24 hours of travel from Gainesville, Florida, I arrived on the island of Tahiti in French Polynesia to be a part of a research group conducting an intense week of field work. Just before reaching our final island destination of Moorea, I spotted the SSV Robert C. Seamans at anchor next to our ferry–the same ship that I sailed from Mexico to Tahiti in winter 2007:
The ship was a sight for sore eyes and a reminder of many great people and adventures–certainly an inspiration to shake off the jet lag and get to work! And then these vistas further inspired:
The purpose of this trip is to spend the week setting up a long-term experiment looking at the effects of a marine snail on coral communities. These uncoiled snails, called vermetids, are interesting little creatures that are highly abundant in Moorea and project wide mucus nets to capture food from the water column. These mucus nets cover the substrate surrounding the snail and may have a variety of effects on the organisms below (namely corals). Thus, our work will measure the longer-term effect of vermetids on the composition of reef corals to better understand how these snails may affect the composition of the reef.
Despite being in the middle of the Austral summer (stifling heat, lots of mosquitoes!), it should be an action-packed week. Plus, by pure coincidence, we happen to be overlapping with many friends on this trip, so we will certainly balance work with play. Here is a deck view at our hilltop bungalow, where many a gin and tonic will be consumed 🙂
Thanks for reading– More soon!
Posted on November 2, 2011
Unfortunately, poor weather plagued my last days on Little Cayman before I made an abrupt exit, just missing the hurricane. Despite the weather, I did make a couple of dives and a handful of snorkels, which gave me a better feel for the quality of this reef ecosystem. In a nutshell, the reef seems to be in great shape, with large, abundant carnivores (grouper, snapper, jacks, barracuda, sharks), abundant herbivores (parrotfish and surgeonfish), abundant coral (>20% cover in some areas), and low benthic algae cover (remember, algae are the enemy–see Research for more information). This pattern in the food web is an interesting one, because it seemingly contrasts classic ecology theory, which suggests that the base of the food web (in this case, benthic algae) should be much more abundant than the consumers (in this case, herbivores; conceptual diagram below).
But in the healthy reef system of Little Cayman, if you took out and weighed all of the herbivores and all of the algae, the herbivores would weigh more.
How is this possible?
Well, a similar pattern was recently observed in the Northwest Hawaiian Islands, home to what are considered by some to be the most pristine coral reefs in the world (click here for more information on this study). These pattern can exist, with consumers outweighing their food source and not starving to death, due to differences in turnover. In the reefs around Little Cayman and the Northwest Hawaiian Islands, the standing stock of algae is suppressed by the abundant herbivores that are protected from fishing, but the growth rate of algae is astronomically higher than that of herbivorous fish. This means that production over time (instead of standing stock), remains much higher for algae than fish in healthy reef systems. As a result, when disturbances are diligently limited in a reef, you can get a lot of fish of all types and still have a lot of coral cover to regenerate and maintain the reef structure. In short, if we scale back our impacts, the ecosystem can take care of itself! Go Mother Nature!
Here are some of my favorite pics from the trip from below the surface:
This trip was successful in that I was introduced to a lush, healthy reef system, teeming with life. As I mentioned in my last post, this has changed my perspective (or shifted the baseline in my mind) for reefs in the Caribbean. However, while working in Little Cayman would be a pleasure, obtaining permits to conduct nutrient pollution research may be difficult or impossible, given the amount of protection allotted to this ecosystem. Either way, it’s nice to know this reef exists and it was great to meet and interact with the staff at CCMI. If I go back, I will certainly explore the famous reef wall at Bloody Bay. Weather prevented this trip this round 😦
Posted on October 19, 2011
We dodged a storm in South Florida and made it to Little Cayman Monday night, as planned. Upon viewing it from the island-hopper prop plane, Little Cayman was smaller than I’d expected. It is just 10 x 2 miles, but the limited land cultivation on the island contributes to its ‘small feel’. This was my first impression anyway.
The station where we are staying at is the Central Caribbean Marine Institute (CCMI), a modern research station with very friendly staff, an incredible location next to the reef (will revisit this) and, much to my surprise, air conditioned dorm rooms! Rare in my experiences at remote, tropical field stations…
We spent the day yesterday getting a tour of the perimeter of the island from Professor Tom Frazer, who traveled with us from the University of Florida, followed by an afternoon-long snorkel in the station’s backyard.
The reef closest to shore (fringing reef) was a lively place, full of small schools of herbivorous fish, feeding voraciously on turf algae–a similar site to the reefs in and around Akumal, Mexico. The snorkel took a turn for the unexpected when I ventured further off, ~ 3oo m past the reef crest. After swimming over 150 m of barren sand flats, we arrived at a lush barrier reef, teeming with life. This area was covered in hard and soft corals and overrun with reef fish, from large predatory barracuda, snapper and jacks to an array of small, algal-eating surgeonfish. We also encountered a hawksbill seaturtle and several rays and nurse sharks, but the most striking encounter for me was with a Nassau grouper over a meter long. When I ducked down to get a closer look at this massive fish at about 8 meters depth, it did not seem even slightly disturbed by my presence. If anything, it seemed curious. I’ve spent the last two summers in the reefs of Moorea, French Polynesia where fishing of groupers and other sizable reef fish is widespread. As a result, these fish are not commonly seen there, as they associate humans with spears being shot at their faces. I can tell that this Caymanian reef has been protected from fishing for a while (over 25 years, actually).
The reef may have been a little too nice actually, as I flooded my 10 ft waterproof-rated camera when I took video at 25 feet depth. You tend to forget these details when a lush reef takes you by surprise. Nonetheless, I got a few shots: