Moorean Creatures of the Deep, Large and Small (Part 2)
Posted on August 17, 2012
Below I’ve included my favorite macro shots that I’ve taken so far of sea life in Moorea this summer. This particular group of shots was collected while on a night snorkel on Gump Reef, which is adjacent the the research station where I reside and literally 3 meters from my front doorstep. In just an hour of snorkeling around in 1-2 m depths, we encountered some very interesting, although tiny, creatures (Please note that the following photos were all taken with a macro lens, thus, to do them justice, please click each to enlarge):
I hope you enjoyed the photos. My experiments are wrapping up nicely, and I plan to post some more updates on my progress as the field season comes to a close. Stay tuned!
Moorean Creatures of the Deep, Large and Small (Part 1)
Posted on August 7, 2012
Out here on Moorea, we spend our days diving and snorkeling to study the reef, and, as such, we get some pretty incredible photo opportunities. The trouble is, our boat is usually so packed with gear that bringing a clunky dive camera is often not an option (this thing is a bit of a monster).
However, I also use photos to monitor my experiments; for example, I am currently running a long-term study looking at the effects of nutrient pollution on reef communities. The idea is that nutrients enhance the growth of fast-growing algae that can then out compete corals for reef space (to read more: https://michaelgil.wordpress.com/research/). Thus, photos of my study plots to monitor the relative abundance of corals and algae are invaluable to evaluate changes over time.
In addition to being used as an invaluable data-collection tool, sometimes I get to use my camera for entertainment. For the next two posts, I will share some of my favorite underwater shots from this summer, capturing creatures large (see below) and small (see next post).
On just my second dive with my camera, I had some great luck, running into both a hungry hawksbill sea turtle, who couldn’t stop eating in front of us…
…and a beautiful ~3.5 m (10.5 feet) lemon shark, who was fortunately less hungry than the turtle:
We were thoroughly ogled by a triggerfish (reminiscent of our GoPro encounters earlier in the season):
And at the end of the dive, we posed for a group photo:
Later, while scoping out potential study sites, we had a pitstop at a popular stingray feeding site off the northwest corner of the island. Here, tourists can hand-feed stingrays, who are more than happy to aggregate in large numbers for the event. Though I don’t condone feeding wild animals, especially predators (what happens when you show up empty handed??), the spectacle makes for some unforgettable photo opportunities.
And one more (my favorite) stingray shot, for the road:
I’m happy to report that these first few plunges with my new camera were incident free (i.e., no flooding!). Please check out my next post, in which I will share some images of the tinier life forms we find out here.
Magical Moorea: The Stars, the Moon, and, of course, the Fish.
Posted on July 17, 2012
The past few weeks have been intense here in Moorea–tons of snorkeling, diving and science, mixed with rough seas, wet weather and sustained gale-force winds. But I’m happy to report that all of my experiments remain under control (for the time being anyway 🙂 ). And at the end of every storm in paradise, there is a rainbow:
I’ve even been fortunate enough to find a bit of time to play with my new DSLR camera (quarter-life crisis gift to myself). This thing is the real deal, and its capacity for quality photos vastly exceeds my own abilities. BUT, you have to start somewhere, right? Please check out the breathtaking beauty that is Moorea, as only timelapse photography and a fish-eye lens can capture it:
First is a night scene of the mountainous backdrop surrounding Cook’s Bay, where I currently reside at UC Berkeley’s Gump Research Station-
Second is a similar shot with a better emphasis on the Milky Way, which is often breathtakingly clear here-
I also captured Venus’ Transit across the sun last month with the help of a lot of light filters, but the end result was too underwhelming to post here (white circle with a dark dot on it…certainly nothing like this: http://venturebeat.com/2012/06/06/venus-crossing-sun-hd-video-nasa/). Nonetheless, I plan to have other photography to share before the summer ends, including some underwater shots.
In closing, I wanted to provide a quick update to my last post, by sharing that we’ve had a few more run-ins with the now-infamous GoPro-loving triggerfish of Moorea. Since the initial attack was unexpectedly caught on film at one of my experiment sites, our GoPros have captured three other similar encounters. Perhaps more humorous, these encounters occurred in our vermetid X sedimentation experiment (read a description in this post), so they were captured with photos, shot every 10 seconds for 6 hours at a time. We use these photos to create time-lapsed videos that allow us to look at how our different experimental corals are dealing with the presence/absence of vermetid mucus and/or sedimentation (which we deposit daily—read more about vermetids here). So, as you may have guessed, we captured another curious (and likely hungry) triggerfish:
S/he is clearly not camera shy! Fortunately, our 5 GoPro video cameras (upon which much of our work this summer is based) remain intact, functional, and, most importantly, in our possession (as opposed to, say, that of an octopus).
Thanks for reading/watching! More soon…
Science Vs Nature!: The Wildlife of Moorea React to GoPros
Posted on June 26, 2012
To pick up where I left off, after the Great Vermetid Surveys of 2012 (see previous posts), for the past few weeks I have been focusing my efforts on deploying several field experiments out here on the island of Moorea in French Polynesia. These experiments are part of my dissertation research, and this summer in particular, I am looking at the effects of coral reef habitat loss and isolation as well as nutrient pollution on herbivory. Herbivory is essential on coral reefs, because it helps to control the abundance algae, which can outcompete coral and take over reefs, with drastic ecological consequences (simply put, from teeming coral reefs to slime).
One of our first focuses is to look at the relationship between distance from the reef and herbivory. The assumption is that herbivorous fish are scared to travel across open sand flat to find food, because they don’t want to get gobbled up by a predator or speared by a fisherman. This ‘fear effect’ could have very important implications for reef habitat loss and fragmentation that result from natural and human-driven processes. So, for one of our experiments, we have created an “algae hors d’oeuvre platter” (i.e., a cinder block with a variety of algae tied to it), which we place at 5 different distances from the reef and video tape what happens. This approach allows us not only to get a sense of how herbivory may change with distance but also tells us who is doing the eating—what species, what size, how much eating etc. After a few weeks of running these trials, we are starting to get some interesting results and also some surprises. The best so far happened two days ago, when we returned to our cameras after leaving them for 4 hours. This time, we noticed that one of the far cameras (30 meters from the reef) was now facing the sky instead of the algae hors d’oeuvre platter. This was upsetting, because it meant that we did not get the full 4 hour observation period for that unit, but we were happy that the camera was still there. We assumed that the current, which had picked up that afternoon, could have been the culprit, but fortunately the camera was still recording when we arrived, so we knew that whatever caused the camera to move was caught on video. So, we took the camera back to the lab to analyze the video. This is what we saw (turn up your volume if you can when you watch this for the full effect):
SPOILER ALERT BELOW.
The hungry animal featured in the video is called a triggerfish, a Yellowmargin triggerfish to be exact, and it primarily eats sea urchins and shellfish (hence the impressive/grotesque teeth). As evidenced by the video, these guys can be quite aggressive and bitey—lucky for me, the GoPro camera housing stood up to the challenge, except for a bit of chipped plastic. On a side note, a close but much, much larger relative of the Yellowmargin triggerfish, the aptly named Titan triggerfish (measuring nearly 3 ft long), attacked me during a dive in January.
Fortunately, the biting was restricted to my fins, but the encounter was a stressful one to say the least.
The next day (yesterday), we deployed the video cameras again, only this time to capture a different experiment. In this experiment, we are looking at the effects of sedimentation and vermetid snails on coral growth. Sedimentation is a big problem for coral reefs around the world, because sediment can smother corals, and increased coastal development tends to lead to increased runoff and sedimentation of nearshore marine ecosystems (like coral reefs, seagrass meadows, and kelp forests). We also know that vermetid snails that use mucus nets to feed can also be quite detrimental to corals (see previous posts for more info). So, we wanted to see how these two stressors together may affect corals—for example, maybe sediment is actually pulled off of the coral by the vermetid mucus net, or, alternatively, maybe the mucus net, being sticky as it is, allows sediment to better adhere to the coral surface, causing more damage. These are the hypotheses we are testing, and to help us understand what exactly is going on, we have been shooting photos of each coral at 10-second intervals throughout the day. Yesterday was one of these days, so we again left our GoPro cameras out in the field for several hours. Upon our return to retrieve the cameras just before dusk, my assistant Julie noticed that one of the cameras was missing from the 5 lb dive weight to which we’d had it cable tied. The cable tie was mangled. She also noticed a very large octopus atop the reef next to where the camera was. When she called me over, I approached the octopus. Yes…he stole our GoPro:
Fortunately, we got the camera back in one piece, and even more fortunately, the camera was snapping photos throughout the ordeal! So we got some pretty interesting shots:
The first is the standard, (now considered boring) shot of our experiment coral:
But then, our Hero is kidnapped!
And plunged into darkness…
And finally rescued. Woohoo!
What a wild couple of days it has been. I can’t wait to see what else these cameras capture over the next two months…
Thanks for reading/watching! More soon.
Diving ’round the Island of Moorea
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!
Island Hopping Adventure!: Volume 2
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…
Island Hopping Adventure!: Volume 1 of ?
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…
Back in French Polynesia for the summer!
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!
Quick expedition to the South Pacific
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!
Little Cayman Underwater: A Snapshot
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 😦