Palmyra Atoll

Get your optimism from the past

When we think about a “pristine” untouched ecosystem we often have a single, preconceived image in mind. It could be a grassland with thousands of bison, a thick tropical forest, or a coral reef teeming with fish and sharks. These places certainly existed, and in many cases are now lost or replaced by alternatives, but there has always been variation and that variation must have contributed to the rich mosaic of life.

It is this variation that we propose can help conservation, but first we need to describe it. If we can describe it we can do a better job of placing modern ecosystems into context. In this paper, published in Conservation Biology, BaselineCaribbean members discuss our ideas of how the fossil record can be used to redefine what should be considered “pristine” and the positive benefits of doing so for conservation.

Open Access available

O’Dea, A., M. Dillon, E., H. Altieri, A. and L. Lepore, M. (2017), Look to the past for an optimistic future. Conservation Biology. doi:10.1111/cobi.12997

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A sediment core inspired road trip

US GEOLOGICAL SURVEY MENLO PARK CAMPUS
MENLO PARK, CA

As coral reefs accrete upward, their histories become buried beneath the surface. One way to unravel this history is to visit areas where the older reef has been exposed by excavations, road cuts, or storm channels. This is what we did in Bocas del Toro, Panamá and in the Dominican Republic’s Enriquillo Basin. In most places, however, living reef or mangroves grow on top of the Holocene reef. To access the underlying history, we can insert several-meter-long sediment cores into the substrate. While this technique samples a sliver of the surface area of a reef, it has the unique advantage of looking back in time. Depending on the rate of reef accretion and sedimentation, sediment cores can travel back several hundred to several thousand years with high temporal resolution. The remnants of the animals and plants captured in these cores help paint a picture of the reef in the past and how it has changed over time.

Today, I had the good fortune of sampling a gravity core extracted from Palmyra Atoll’s lagoon by a team of USGS scientists. In addition to being home to numerous sharks, Palmyra has an interesting human history despite never being settled. The atoll was originally discovered in 1802 when an American ship was blown off course in a storm. In 1862, Palmyra was claimed by the Kingdom of Hawaii, and it later became a U.S. territory following Hawaii’s annexation and subsequent statehood. At that time, it was privately owned by the Fullard-Leo family. During WWII, the U.S. Navy took over and drastically altered the atoll for use as a naval air facility. Afterwards, it was occasionally frequented by yachters despite its remote location – a nearly 1000-nautical-mile sail southwest of Hawaii. From 2000-2001 onwards, the atoll has been under the protection of the Nature Conservancy and U.S. Fish and Wildlife Service as a National Wildlife Refuge, and a handful of scientists and donors visit each year.

The 3.2m-long sediment core that I sampled covers nearly 650 years of history on the atoll, capturing its pristine state prior to discovery in addition to the last 200 years of sparse human occupation. We will use the core to begin investigating whether shark baselines on the atoll are naturally dynamic and whether the abundance and diversity of sharks changed after the arrival of humans. Palmyra has been the location of many shark tagging and survey studies over the last 12 years since the creation of the Palmyra Atoll Research Consortium (PARC), and it is considered to be a relatively untouched, healthy reef ecosystem. This new historical time series will help us understand whether its condition has fluctuated over time before these monitoring efforts began.

This opportunity was certainly worth the 10-hour round-trip road trip from Santa Barbara to Menlo Park, which is located about 40 minutes southeast of San Francisco. In addition to picking up the core from the sample storage refrigerator on the USGS campus, my secondary aim was to use their facilities to slice it into 64 5cm-long segments, each representing about 10 years of reef history. The core was composed of very fine, silty material, so cutting through it was not difficult with the help of some metal utensils and a meter stick. Furthermore, the challenging task of cutting the core in half through the PVC piping had already been accomplished. I carefully measured and cut each section and placed them into individual labeled plastic bags. After several hours of meticulous slicing and record keeping, I had amassed quite the pile of samples and was caked in a thin layer of dry mud.

My 250 pound delivery

Today was my lucky day! All of my precious samples are now here and ready to process. Hilariously, the mail distributors on campus lugged them up to the mail room on the 3rd floor, just so I could bring them all the way down again and into the building across the way where the lab is located. With the help of an old rickety cart (that fortunately did not collapse under the weight of the sediment), all of the boxes were transported in two exhausting trips. Another chapter of field work closed. May the sieving begin!

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Getting the samples packed up and shipped home

Now the time had come to get all of the sediment home, which proved to be a tad tricky. First, we had to get the samples to Honolulu. As plastic crates are bulky and expensive, I ended up packing the individual samples into ten sandbags. What better to use than a container designed for sand?

The charter flights off the atoll are both few and far between and weight restricted. Luggage is limited, and they sometimes swap people around in the plane for takeoff and landing. Therefore, fitting 250lbs of sediment onto one flight was not going to happen. The pilot was even grumbling about putting 1-2 bags on the plane. In fact, the sediment was shipped off the island on three separate flights over the course of about two weeks! I was still on the island (having transitioned by that point to bug counting and tree measuring), so I was able to help orchestrate this operation. Fortunately, one of the donor trips did not bring much luggage, so I was able to fit the majority of the bags on that flight. Later, I certainly breathed a sigh of relief when I had accounted for all ten sandbags at the airfield in Honolulu.

The next step, of course, was shipping the sediment samples back to the mainland. For anyone who’s shipped anything large or heavy recently, you know that it can add up fast. To partially circumvent this cost, we shoved the samples into 11 large flat rate boxes and sent them on their merry way only $200 later. This sounds simple enough, but it involved a lot of (somewhat unnecessary) running around the city. However, after this ordeal, we still had several hours to kill in Waikiki before our flight home. As a side note, the abrupt transition of living on a tiny remote island with 20 other people to arriving in the bustling tourist town of Honolulu was quite overwhelming! Particularly because it was Halloween.

The next few days were spent anxiously checking the package tracking information. Would the samples arrive in one piece?

Some pictures from today’s snorkel at North Barren Island

Today we went on the snorkel of a lifetime. Or perhaps it was just Palmyra’s way of saying goodbye, as this was also our last snorkel of the trip. I followed a couple of juvenile blacktip reef sharks around the reef, was circled by a curious turtle, and was blown away by the number and diversity of fish I observed. Despite being damaged by coral bleaching last year, this reef is incredibly resilient and is now on its way to recovery. Absolutely amazing!

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The final samples

Today was our last day of diving. It was bittersweet, for sure. We motored around the reef terrace in search of patches of sediment. While we were limited by the placement of moorings and inability to anchor (not allowed on the terrace for good reason), we still managed to collect sediment from one more section of the reef. I was quite pleased with our haul! Below is our final sample count:

14 collection sites, 7 on the reef terrace and 7 in the lagoon
10 replicate sediment samples taken at each site, except for one which had very little sediment available to sample
131 bulk bags total, weighing roughly around 250lbs

The next challenge: getting it all off the tiny atoll on the weight-restricted charter flights.

Sample bags drying in the sun to reduce their weight and save us money.

Exploring the hospital: a relic of a bygone age

Tromping through the jungle and forging our own path through the thick vegetation, we must have walked right past the old WWII-age military hospital a handful of times without even knowing it was there. This time, though, we were on a mission to find it.

We came across a machete-cut path through the Cocos seedlings and followed it until we practically ran into the structure itself. It was completely overgrown and barely discernible from the surrounding trees. We followed the concrete perimeter to the entrance and ducked inside. It was as if we had been swallowed by pitch-black darkness. We switched on our headlamps to illuminate our grim surroundings. Our voices echoed eerily in the domed entryway.

The structure was impressively still intact (the ceiling was only falling down in one spot), although some of the interior had been gutted. The building was massive, possessing at least two wings and three entry points. You could still walk down what would have been the hallway and glance into the various rooms, now lacking walls or doors. Rusted cabinets and beds lay strewn about, lost in time. It was haunting to imagine the men that used to inhabit this place: doctors strolling down the corridors and patients lying wounded in the beds. Now, all of this history had been swallowed up by the jungle, and the only remaining denizens are cane spiders and several-foot-long coconut crabs. Yet another example of nature taking back the atoll for its own.

A day in the life

6:30am – Alarm rings. Go for a run or do some work in the lab before breakfast.

7:00am – Load the boat and prep SCUBA and sampling gear.

7:30am – Breakfast in the galley. Pack lunches and fill water bottles. Sunscreen up!

8:30 or 9:00am – Depart the dock for our first site.

9:30am – Arrive at our first site. Check out the substrate suitability on snorkel. Dana and I don our SCUBA gear and jump in.

10:20am – Finish sampling our first site. Depart for our second site.

10:50am – Arrive at our second site. Snack time!

11:00am – Scope out site and start sampling.

11:40am – Finish sampling our second site.

12:00pm – Lunch on the boat. Enjoy the scenery.

12:30pm – Move to our third site (or back to the station if only sampling two sites).

1:00pm – Arrive at final site for the day. Scope out on snorkel.

1:15pm – Start collecting sediment on SCUBA.

1:50pm – Finish collections. Head back to the dock for the day.

2:30pm – Arrive at the station. Wash and store gear. Carry samples to the lab to dry.

3:00pm – Afternoon coffee break or snack time.

3:30pm – Record GPS points and sampling notes for the day. Select sites and make a plan for tomorrow’s sampling. Arrange boat usage with the station and other researchers.

4:00-6:30pm – The work doesn’t end here. Help the other UCSB team sort insects, write a grant proposal, read papers for the class I’m supposedly taking on campus, edit a manuscript, etc. Put on a sparkly gold flash tattoo with the rest of the team for field solidarity.

6:30pm – Dinner in the galley. Watch the sunset. Don’t forget your headlamp!

7:30pm – Stroll back to the lab. Or perhaps to the yacht club for some evening fun. Pet a manta ray.

9:00-10:30pm – Bedtime. Maybe see a fluorescent blue-purple coconut crab on the way back to my cabin. Be careful, as it could pinch your finger off.

[Repeat.]

Photo by Dana Morton.

A jaunt around camp

For a remote tropical island, Palmyra’s field camp is quite nice. First, we are fortunate enough to eat fantastic food… when the vegetables actually make it on the plane from Honolulu. For example, Alex, one of the chefs, made breadfruit pita and a heart of palm salad for dinner with sweet potato haupia pie for dessert one day. I wasn’t expecting to get to try new foods while in the field, so this was a welcomed surprise! Second, there are showers and washing machines, although water is limited as we in a drought and the field station is completely reliant on rainwater. Cleaning chores rotate between groups of researchers. Third, we stay in small but cozy cabins shared between two researchers. Some of them are even waterfront, although the donors were assigned to those when they flew down to visit.

With regard to the science, there is both a wet and dry lab to process samples on the island. One researcher even brought a tiny -80C freezer to keep samples cold before being transported back to Hawaii. We have access to four lagoon boats (shared between all researchers on the island), and there is also a larger boat for diving on the forereef. There were on average 23 people total during my stay, so resources weren’t spread too thinly.

When you’re not working – although it’s a pretty constant state of working – you can explore the main island Cooper and the adjacent island Strawn, stroll to North Beach, go swimming at the swimming hole, relax in the galley or yacht club, or run on the runway. We even have science presentations and movie nights in the yacht club and bonfires on North Beach occasionally.

The galley

The lab

Path from the lab to camp

Our cozy cabin

The swimming hole

Sunrises, sunsets, and avian friends

The sun rises a little before breakfast, so I occasionally head over to North Beach with my cup of coffee for a moment of tranquility before the hustle and bustle of the day begins. Later, the sun sets just as we’re having dinner. First, this means that you are in for a pitch-black stroll to the lab if you forget your flashlight or headlamp. However, it also means that we have a spectacular backdrop after a long day of field work. Rayn, the resident rescued red-footed booby, will occasionally sit outside and enjoy the sunset with you when she’s not begging for attention. Today, she’s the star of the blog post.

Sunrise at North Beach. Photo by Dana Morton.

View from the galley.

Gateway to the lagoon

On a good day, you can see the bottom of the channel from the boat. Today was not one of those days. What’s lurking out there beyond the edge of the murk?

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The channel has been identified as the main elasmobranch highway between the reef terrace and the lagoon. Acoustic receivers and cameras placed along the edges of the channel have pinged the positions of many a manta ray or shark cruising through, even documenting a “shark rush hour” in the evening. There’s also lore of a lone gray reef shark known as “The Gatekeeper” that supposedly patrols the entrance to the lagoon. Obviously it’s a very sharky place.

While sampling, we were easily circled by ten blacktip reef sharks, although not all at the same time. I would shovel a couple of scoops of sand into my bag, glance hurriedly over my shoulder into the heart of the channel, and catch the eye of several blacktips that were checking me out. We would politely exchange glances, and then they would meander off into the murk. Dana and I also spotted a gray reef shark from the boat immediately after getting all of our gear back aboard. While the paranoia of something really big coming up behind me may linger in the back of my mind, I look forward to these encounters. It was incredible to get to dive with these majestic creatures and be a part of their world, if only for an hour at a time.

Penguin Spit Round Two

In the afternoon, we returned to a more sheltered, inland portion of Penguin Spit. This section of the reef is located between the lagoon flat and Penguin Spit Middle, where we sampled last week, and is home to large patches of sand and corallimorph surrounded by corals. Needless to say, we had much better luck collecting sand here than at Crazy Corals. The patches of sediment were even large enough to actually kneel in without damaging the surrounding corals, which certainly made the task of digging into the sand easier. The alternative is either hovering over the corals or inverting yourself in a sort of awkward anti-gravity handstand to access the substrate without touching the corals (which harms them). However, in these sampling positions, it is difficult to exert enough leverage to insert your shovel into the sand without solely being pushed backwards or upwards.

While the sediments here were heavily bioturbated, meaning that we had to carefully search for good places to sample, the actual act of filling our sampling bags with sand went pretty quickly. We were able to collect all 10 replicate bulk bags in about 20 minutes. Another site down!

Photo by Dana Morton

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Crazy Corals!

We scoped out a reef called Crazy Corals this morning. It was low tide when we left the station, so we had to dodge corals as we traversed the reef terrace to access the site. One person stood at the bow and pointed out a safe path through the corals with their arm, while the driver cautiously followed with the engine one click up. As the tide dropped further, the gap between the top of the corals and the bottom of our boat narrowed. Then, we spotted the buoy on the horizon and quickly navigated to the site. We arrived safely and relayed our position back to the station through a radio call. “Palmyra Station, Palmyra Station. This is Lagoon Boat Two. Three POB [persons on board] have arrived at Crazy Corals and two divers and one snorkeler are getting in the water.”

I slid into the crystal clear water and was taken aback by the raw beauty of the reef. Indeed, it was an aptly named site. The corals were absolutely breathtaking! Massive, brightly colored coral bommies towered over our heads, nearly reaching the water’s surface. Massive schools of convict tang swirled around us while nibbling on bits of algae, and the occasional snapper lurked behind us with its sinister, toothy grin. Large blue-green steephead parrotfish noisily chomped down on the corals, ingesting mouthfuls of calcium carbonate and algae. In the distance, a large green turtle cruised by and fled the scene quickly upon acknowledging our presence. The reef was bustling with life!

Dana and I swam in a wide circle around the boat, searching for any available substrate to sample. The bottom was literally 100% coral. We kept our eyes peeled for sediment, but there was none to be found. Just corals growing atop other corals in a dance for space and survival. It was incredible. Large branching Acroporid corals, which are critically endangered in the Caribbean, abounded. No surface lay untouched.

After a 40 minute jaunt around the reef without seeing of a single open patch of sand, we returned to the boat with our empty sampling bags. This reef was so healthy and brimming with corals that it had thwarted us in our sampling efforts. While awe-inspiring to say the least (this reef in particular first sparked my interest in coral reef ecology five years ago), it was time to move on to another site to continuing the sampling.

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Coral Gardens

Today, we headed to the outskirts of one of the most protected areas on the atoll: South Coral Gardens. This little pocket of coral reef in the southeastern corner of the reef terrace is home to a great diversity of colorful corals and is incredibly shallow. Special permission is required to enter, since snorkelers can easily damage the corals with the mere kick of a fin. However, we were able to dive to collect samples a bit north of the area, which was slightly deeper (10ft max) yet still incredibly gorgeous. The water was crystal clear, almost giving off the ambiance of the aquarium in your dentist’s office or perhaps a swimming pool.

Protected behind the barrier created by the reef crest, the water here was very still and the corals could be picked out from the surface. This allowed us to navigate through the maze of coral heads to safely access the site. The sand was also very fine, and we were quickly immersed in swirling clouds of silt upon digging into it. It oozed between our fingers and clouded our vision. This was the type of sediment we were looking for!

Damselfish, hovering over their coral homes, watch us with interest, and a baby blacktip and several titan triggerfish cruised by toward the end of our dive. What a great day!

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The samples are piling up, but they’re much smaller than before

For all of the readers who followed our field work in the Dominican Republic, you may recall that we were collecting very large samples. In fact, each one of those bulk bags was on average 12x heavier than the samples we’re now collecting on Palmyra. Why is that? And no, it’s not because we wanted less work to do. Nice try.

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Last year, a collaborator of ours (who is now one of my co-advisors at UC Santa Barbara) collected some preliminary samples from Palmyra’s reefs. I brought some of them down to our lab at STRI and discovered that they contained almost an order of magnitude more denticles per amount of sediment than our bulk bags from Panama. Crazy, huh? Basically, this means that we can extract the same number of denticles from a much smaller pool of sediment, making this round of collections much more logistically manageable.