Welcome to our blog for the 2011 Field Course in Tropical Marine Biology!
With support from the Henry L. and Grace Doherty Professor of Oceanography Fund, we brought six MIT-WHOI Joint Program students to the Liquid Jungle Lab, located on a small remote island off the Pacific coast of Panama. In Fall 2010, the students prepared for the field course, by enrolling in “The Biology and Ecology of Coastal Ecosystems in Tropical Oceans,” a topics course within WHOI’s Biology Department. The fall course focused on ecology of coral reefs, mangroves and intertidal environments.
We are now exploring these environments with an emphasis on interactions between the biological and physical components and on unique aspects of the Eastern Pacific coastal ecosystems. During this two-week course, the students will also develop and complete independent projects.
Our journey started in Boston. After a brief delay (snowstorm!!), we embarked on a two day journey, along with seven extra suitcases of equipment and eventually arrived ready to take the field by storm. This year, the participating students come from three WHOI departments: Whitney Bernstein (Marine Chemistry and Geochemistry), Liz Drenkhard (Geology and Geophysics), Amalia Aruda, Li Ling Hamady, Meredith White, and Maya Yamato (Biology). We are fortunate to receive assistance from Vicke Starczak, a former resident of Panama and seasoned expert in the local mangrove environments. We hope you enjoy reading the blog postings from the students!
Jesús Pineda and Ann Tarrant (instructors)
Photo caption: All smiling during the 3-hour boat ride to the island (Photo by J. Pineda).
Sub Heading:17 January 2011Maya YamatoMIT-WHOI Joint Program
Today was our first full day at the Liquid Jungle Lab. We were supposed to arrive a few days ago, but our original flight got canceled due to the snowstorm in Boston. Thankfully, we were able to reschedule and landed in 30-degree weather… Celsius. After breakfast, we took the exciting roller coaster “mule” ride to the Service Marina with our snorkeling gear – the island terrain provided a thrilling start to the day. The water was a pleasant temperature even without a wetsuit and despite the occasional stings from siphonophores, we had a great time out there. Today’s goal was to get an overall sense of what’s out in the bay and to see if we can see consistent patterns in how different types of substrates, corals, fish, etc. are distributed. Some people in the group were interviewed for a Turkish TV show while we were snorkeling, but I was too caught up in looking at:
Massive corals (Pavona and Porites) Branching corals (Pocillopora) Fan corals (Gorgonians) Guineafowl puffers (Arothron meleagris) – both color phases: gold and black/white spots Threebanded butterflyfish (Chaetodon humeralis) Giant damselfish (Microspathodon dorsalis) Scissortail damselfish (Chromis atrilobata) Cortez rainbow wrasse (Thalassoma lucasanum) Panamic Sergeant Major (Abudefduf troschelii) Sunstar (Heliaster kubiniji) Clams (Pinctada mazatlanica) Sea urchin (Arbacia incisa) Slate pencil urchin (Eucidaris thouarsii) Spotted eagle ray (Aetobatus narinari)After lunch, we took a boat ride to two mangrove sites at Bahía Honda (“Deep Bay”, not “Bay of Japanese Cars”): La Isleta and Managua. We wanted to see how a freshwater river input at Managua affects water stratification compared to La Isleta, which doesn’t have a river. We measured temperature and salinity both at the surface and at depth using a digital YSI probe at various locations, moving from the open ocean towards the land. In La Isleta the water was warm and salty with little differences in temperature or salinity between the surface and bottom water. In Managua the bottom water was consistently warm and salty, indicating that it came from the ocean. However, the surface water changed dramatically towards the river mouth, becoming much colder and fresher, indicating that it came from the river.
We’ll further develop these two projects tomorrow, when we do a line transect survey of the Service Marina bay and plot the temperature and salinity data from Bahia Honda. You can find out about our progress from Li Ling, who will be our blogger tomorrow.
Photo Caption 1: Maya Yamato (carefully) holding a Pencil Urchin
Sub heading:18 January 2011 Li LingMIT/WHOI Joint Program
The sun’s rays peek through the curtains, and a chatter of Spanish and the clatter of plates and utensils waft into our dorm room on the breeze, signaling to my bunkmates and me that desayuno is about to begin. My second day on Isla Canales began with a hardboiled egg, queso fresco, thick cornmeal flat cakes, and water, with a side of yawns. After a brief meeting to firm up the plan for the day, we headed down the mountain to the dive locker, to suit up for our second coral reef foray.
The categories we decided to use to standardize the line transect benthic reef survey data formed a convenient mnemonic, MBLSCROD. Scrod, according to the always reliable Wikipedia, is a small cod, split and de-boned, perhaps a dish served in the Marine Biological Lab’s Swope cafeteria. Some corny Woods Hole humor, but useful for remembering the codes when you’re spitting water from your snorkel, peering through a semi-fogged mask and flailing around for the pencil to write on your dive slate after a 4m free-dive down to the bottom. M for mound: Pavona sp. and Porites sp. corals, known for their lump-like morphology. B for branching: Pocillopora sp. corals, the only abundant branching genus present. L for loose: rubble that is, coral rubble, or smaller rocks; hard things of a small-ish size that wouldn’t be ideal habitat for settling coral larvae because of their tendency to roll. S for sand. C for coralline algae: a rough, flat, hard algae that coral larvae cue into for settling. R for rock, bare. O for other: a whale shark? a puffer fish? Anything our transect tape sits on that isn’t covered by the other categories. And finally, D for detritus: of the terrestrial sort. Isla Canales has lush forests and a lot of terrestrial input, both in the form of runoff and physical debris like leaves that wash into the water.
Several members of our group went on the boat to SCUBA dive in the deeper region just outside of Service Marina, though I was part of the snorkel team that tackled transects inside the calm, shallow mini bay. Previously, Maya casually referenced the stinging siphonophores. Fair warning: mild, they are not. My snorkeling was rudely cut short yesterday when I was attacked from all sides, and I still bear welts. Determined to avoid the “mal agua” today, I borrowed a thin wetsuit and hood (thanks Whitney!), which saved my skin. Snorkel team conducted two 100m transects through the right side of the bay, though closer to the middle than the shore, with the second transect starting where the other ended, heading towards the rock at the mouth of the bay dubbed One Tree Island. At every meter mark, we recorded the substrate immediately underneath the tick on the meter tape. A somewhat unfortunate side effect of snorkel transects is the narrow observation field; work needs to get done in a timely manner (read: before you run out of breath), so you don’t get to leisurely peruse your surroundings. I enjoy free diving, and was glad of the opportunity to redeem myself from the early cop-out the day before by surveying the deeper parts. Though there were coral colonies and fish along the tape at other points and to either side of us, and occasionally at the meter marks, we came away with an overall impression of rubble, rubble, sand, rubble. We didn’t see a clear pattern in the overall substrate distribution, and our transects lacked bare rock and coralline algae, though I did find one stick (detritus!) at a rather deep spot in the second survey. Yesterday’s casual survey around the marina contrasted with today’s methodical one. Lesson learned: when forced to examine substrate at set intervals, you really focus on what’s actually there, rather than the things you want to see.
Tomorrow, Meredith will describe our planned second mangrove escapade, where we’ll be sampling plankton in a mangrove estuary over an incoming tide.
Photo caption: Though I was chasing after the Three-banded Butterflyfish (Chaetodon humeralis), the background dominated by coral rubble is highly representative of the substrate in Service Marina. Pocillopora sp. coral is in the foreground, while the mound coral to the right of the freaked out fish is likely Pavona varians.
Photo caption: Most people would expect a scene like this with dive and snorkel reef transects, with Whitney Bernstein diligently recording benthic information and abundant Pocillopora sp. in the foreground. Picture courtesy of Whitney, taken by Ann Tarrant.
Sub heading:19 January 2011Meredith WhiteMIT/WHOI Joint Program
Tidal Flooding in an Estuarine Mangrove: Coastal Larval Supply
Today we went back to the estuarine mangrove forest (near isla Managua in Bahia Honda) in order to understand how tidal flooding supplies coastal barnacle larvae. Barnacles, like many marine benthic invertebrates have separate larval and adult stages. When a larva is released from the adult before it metamorphoses to the juvenile stage, it is called a planktonic larva. These larvae are very small and cannot swim against horizontal currents. Therefore, they are swept around by coastal and tidal currents. When a barnacle larva is developed enough to settle out of the water column and metamorphose to the juvenile stage, it tries to settle in a place where there are other barnacles to ensure future reproductive success. That means that as the barnacle is being carried by currents, when it detects cues in the water that indicate a population of adult barnacles, it settles to try to live with those adults.
Photo Caption: Red mangroves near the Isla Managua (Bahia Honda) estuarine mangrove forest. (Photo by A. Tarrant)
Managua (Bahia Honda) is an estuarine system, with an input of freshwater upstream. When the tide comes in, the estuary floods with salt water from the ocean, which means that any organisms living in the estuary must be able to cope with a broad range of salinities. Barnacles can cope with unfavorable salinities by tightly closing their opercular plates. However, they need to open the opercular plates to feed, so if unfavorable conditions are too frequent, they won’t be able to feed enough and will not survive. We wanted to observe and quantify barnacle larvae coming into the estuary by way of incoming tides.
We took a boat into the estuary, aiming to get there before the tide flooded the channel, when the water would be fresh. Unfortunately, we were a little bit late, arriving when the water already had a salinity of about 2.5. (Quick note on salinity: salinity is measured on the practical salinity scale (PSS), which is the conductivity ratio of a sea water sample to a standard KCl solution and therefore, as a ratio, has no units. The salinity of freshwater is 0 and the average salinity of the ocean is about 35, with coastal waters being lower due to terrestrial input of freshwater.) We anchored the boat and we monitored the salinity and temperature of the water every 0.2 m from the surface to the bottom. Because salt water is heavier than freshwater, the tidal influx of seawater should be on the bottom. By watching the salinity of the bottom water increase, we essentially watched the tide come in!
Photo Caption: Liz (in the blue shirt) is monitoring the temperature/salinity levels. The probe is close to the bottom of the estuary and the display in Liz’s lap shows the temperature and salinity. The plankton pump is about 10 cm from the bottom (so we don’t suck up sediment) and the clear tube next to Liz leads over to Amalia (in the teal shirt) so she can let the water go through the sieves. (Photo by A. Tarrant)
We wanted to see how the abundance of barnacle larvae in the bottom water changed as the tide came in, so we used a plankton pump (sump pump) to pump water from the bottom through a fine mesh net (100 μm), catching the larvae on the net. Instead of pumping for set time intervals, we decided to use salinity as our intervals. This would allow us to see the abundance of larvae in a certain range of salinities. We collected samples at the salinity intervals 2.5-5, 5-9, 9-13, 13-17, 17-21, 21-25, and 25-29. Back in the lab, we looked at each sample under a microscope to count the barnacle larvae.
We’re still working on counting the samples, so no data yet. All in all, it was a great day! We saw some beautiful birds, and got some beautiful samples!
Photo Caption: Amalia is letting the water from the plankton pump go into a series of mesh sieves. The first sieve is 500 μm to catch debris and the second sieve is 100 μm to catch the larvae! (Photo by A. Tarrant)
Movies (our internet connection is a little slow…we might not be able to post the movie until we return from the field, but check back. It will be worth it!):
Here, we were in the process of switching between salinity intervals. This means we needed to switch from one set of sieves to the other for the next salinity interval. Vicke then rinsed the sieves into a sample bottle to save the sample until we could look at it under the microscope in the lab to find the larvae. (Video by A. Tarrant)This video shows barnacles feeding. Please note that these are not the same species of barnacles that we were looking for at Managua. However, it’s pretty cool to see how these barnacles open their opercular plates and use their appendage as a net to catch tiny plankton in the water as food! (Video by M. White)This is Hester the Hermit Crab. We found her on Monday, January 17 while snorkeling in the Service Marine Bay. She is so beautiful, I really wanted to show her to the world! Disclaimer: I don’t actually know that this hermit crab is a girl, but I decided to refer to her as such due to her beautiful pink legs. (Video by M. White)
Sub heading:20 January 2011Liz DrenkardMIT/WHOI Joint Program
One of the interesting quirks of Canales is the electricity. During the day, LJL is powered primarily by solar cells. In the evening when the sun sets, we’re switched to generators resulting in a slightly confounding 5-minute power outage during the change over. Then, around 5:30am, the generator is turned off leaving the station without power for about an hour. All of the students in our field course are conducting mini individual projects while here in Panama and mine focuses on coral heterotrophy. So this electricity situation was particularly noteworthy for me today because it necessitated getting up early to swap my brine shrimp culture (a.k.a. coral food) from an electric aeration pump to one that’s battery operated before morning yoga with Vicke. The eastward facing porch at LJL affords a great view of the sunrise and for the past several days, Vicke has generously led sun salutations to the unique backdrop of chattering toucans and the distant and slightly eerie calls of howler monkeys.
At breakfast our instructors debriefed us on our mission of the day: Hi ho, hi ho it’s off to the intertidals we go! Unfortunately, several among our cohort were feeling under the weather so they held down the fort while the rest of us hopped into our trusty boat, LOBO, and puttered to Puerto Escondido (“hidden port”) on the mainland for an excursion through the rocky intertidal zone. Following Jesús’s warnings of maliciously unstable trees, we clambered over the exposed rocks and explored the pools abandoned by the receding tide. We found all sorts of critters from crabs, to fish and various mollusks. Along the beach was a small cave in which we could hear the distinct chirruping of bats. On shore, Meredith pointed out a large piece of driftwood that was full of wood-boring clams. We even encountered a large iguana, which, after some deliberation we decided was indeed alive!
Photo Caption: Meredith at Puerto Escondido. She uncovered a trove of intriguing shells including several, luckily unoccupied cone snail shells! (Photo courtesy of Li Ling)
Photo Caption: IGUANA (Photo courtesy of Li Ling)
Finally it was time to get down and serious with science. We broke out our transect lines and set to work analyzing several of the invertebrates we found cemented to the rocks. We first worked on determining the coverage of the “carremojos” (barnacles: Chthalmalus sp.). To do this we put down 50 mm by 50 mm quadrats and recorded whether there was barnacle or bare rock at 100 randomly chosen points under the quadrate grid. Just to emphasize – these quadrats are TINY! Like going blind before we’re thirty, tiny. Fortunately we prevented this by using a loupe: a sort of single ocular, hand-held magnifying glass. From our observations, we calculated that the carremojos covered approximately 71.2% of the rock surface in that part of the intertidal zone. Next we looked at the vertical gradient in the size of “lapas” (limpets: Siphonaria gigas). We set up two transect lines, about 1 meter apart down the side of a large rock. Then, starting at the highest point and working our way down, we used calipers to measure the largest diameter of all the lapas that we found between our two transect lines. It was a little difficult to draw any definitive conclusions about lapas size vs. vertical position from our measurements especially since some of the larger lapas had smaller ones growing on top of them (lapas fractal!), which may have skewed our results. They are also mobile so who knows where they will end up. However, it would appear that, generally speaking, smaller lapas occur at higher elevation on the rocks while larger ones tended to be lower. This would be consistent with the idea that lapas at lower rock positions are able to grow larger because they are exposed to more food (algae) and other resources since these areas are submerged in seawater for longer periods of time than higher rock positions.
Photo Caption: Close up of the carremojos (Chthalmalus sp.) and lapas (Siphonaria gigas) – (Photo courtesy of Ann)
Photo Caption: Li Ling, Liz and Whitney measuring and discussing the lapas (Photo courtesy of Ann)
On our return to LJL, we were running late for lunch (no bueno!) so we disembarked at Cocos Beach, which is closer to our accommodations and, most importantly, the noontime grub. Another fortunate aspect of leaving from Service Marina in the morning and returning via Cocos Beach was we were able to see a considerable portion of Isla Canales de Tierra’s beautiful northeastern coastline. After lunch we worked up the data from the past two days, compiling our information from the mangrove larvae as well as what we’d learned about intertidal limpets and barnacles. After a short presentation of our results, we discussed the projects we would be working on individually tomorrow and for the remainder of our trip.
Sub heading:21 January 2011Amalia ArudaMIT/WHOI Joint Program
With four days in the field remaining, today all of us eagerly began work on our independent research projects. Whitney and Liz were busy collecting coral samples from the Service Marina; Whitney is interested in measuring the densities of zooxanthellae (i.e. the symbiotic photosynthetic organisms that live inside coral tissues) between different coral taxa while Liz is studying the feeding behavior of a range of hard and soft tissue corals in the area. In shallower areas of the Service Marina, Meredith and Maya began working on their joint project to survey the benthic organisms (i.e. associated with the ocean floor) and plankton present both during the day and at night. A boat ride away, Li Ling started her project in the intertidal of Puerto Escondido to measure how physical parameters including salinity, dissolved oxygen, and temperature change in the isolated tidal pools. Meanwhile, Vicke, our trusty guide Bernabé, and I headed off for an adventure of our own as we returned to the estuarine mangrove near the Isla Managua (Bahia Honda) at low tide to begin my barnacle settlement project. As Meredith mentioned in her previous blog entry, when barnacle larvae are exploring locations to permanently settle, they preferentially select areas where other barnacles are present to ensure future reproductive success. I am interested in investigating how the presence or absence of barnacles affects the numbers and/or types of barnacles that settle and how these patterns may differ between two locations within the mangrove (i.e. at the mouth and deep in the mangrove).
To reach the mangrove forest we trudged through the slurping mud towards a landscape transformed by the low tide. The falling sea level revealed the river flowing into the estuary and the mud flats subtly teeming with life, including the beautifully colored snapping shrimp pictured below. After a 20 minute walk from where Edwin, the boat driver, dropped us off, we reached the mouth of the mangrove where the tree roots were crowded with barnacles. We collected a few of these barnacle-filled roots, chopped them up into even pieces, and attached settlement plates (specially designed PVC pieces that barnacle larvae can settle on). These barnacle branch and settlement plate pairs were in turn attached to stable aerial roots (see picture below) at the mouth of the mangrove and deep in the mangrove, representing our ‘barnacle present’ treatment. To recover roots clear of barnacles for our ‘barnacle absent’ treatment, we headed deep in the mangrove where barnacles are much sparser. Wading thigh deep in murky water through the mangrove, we collected some pieces of roots bare of barnacles and attached them with settlement plates to stable roots nearby our barnacle root-settlement plate treatments. I felt like Indiana Jones as I clambered through the mud to reach the mangrove trees lining the banks and snaked my way over and under the thick, tangled mangrove roots to attach my settlement plates. Over the course of three hours we had set up 19 settlement plates with 10 at the mouth of the mangrove (5 with barnacle roots alternating with 5 roots bare of barnacles) and 9 deep in the mangrove (5 with barnacle roots alternating with 4 roots bare of barnacles). We will return to the mangrove at low tide on Sunday afternoon to recover the settlement plates and hopefully find newly settled barnacles.
Overall, our class enjoyed a day of explorative and adventuresome science across three major marine habitats of Panama!
[Picture: quadrat benthic survey]
Figure 1: Maya, Meredith and their assistant Li Ling (sheltered from the sun) pump plankton from their quadrat in Service Marina.
[Picture: mangrove shrimp]
Figure 2: A stomatopod (snapping shrimp) from the estuarine mangrove near the Isla Managua (Bahia Honda)
[Picture: mangrove root barnacle]
Figure 3: An example of a barnacle settlement plate attached to a root with barnacles.
[Picture: sampling mangrove roots]
Figure 4: Collecting mangrove roots for the experiment with Bernabé
Sub heading:23 January 2011
Today was our last day to wrap up our independent projects. The morning was devoted to lab work and data processing. Maya and Meredith counted and classified plankton, occasionally exclaiming at their fun finds, such as this crab in its megalopa stage (Fig 1).
I was stationed at my lab bench, preparing coral samples for determination of the density of zooxanthellae (algal endosymbionts) in the coral tissue. I collected these samples in the Service Marina from a single Porites lobata colony that had varied coloring (Fig 2). Because the coral get most of their color from zooxanthellae, I hypothesized that the samples of lighter shades would have a lower zooxanthellate density than the darker samples. I blasted the coral bits with a dental waterpik to push the coral tissue off the skeletal surface. I crushed an aliquot of the frothy mixture in order to homogenize the tissue and mucus matrix, and I used a hemocytometer and a dissecting microscope to find and count the tiny red dots that were zooxanthellae. My initial results are showing little difference between the various samples. Perhaps a different result would be found if I had a larger number of samples, or if I had more practice with the method. Alternatively, the variety of shades in the colony may be due to variability in pigment, rather than differences in zooxanthellate density. I would suggest that future interested students bring a fluorometer to measure chlorophyll levels in order to test the alternative hypothesis.
The afternoon rolled in with the low tide and occasioned another excursion to the mangroves for retrieval of the settlement plates that Amalia placed two days ago. This time, most of the class joined Amalia in order to explore the mangrove environment in its alternate state. We walked across the wide expansive of mud flat (Fig 3) and then waded through the river (Fig 4) amongst the fully exposed roots of the trees from which Amalia collected her plates.
Amalia examined the plates that evening in the lab and was very excited to see that some settlement had occurred after only a couple of tidal cycles! Meanwhile, Liz was stationed at her microscope, urging her corals to gobble up the scrumptious sea monkeys that she had hatched from the package (“fast food” for corals). It is really exciting to peer through Liz’s microscope and see the polyps in action. Some stony corals appear so rigid at times that their vitality remains an abstraction until you see them under the microscope, literally making a living by their various feeding strategies. Liz is documenting these different feeding strategies with photos. I look forward to seeing her results, as well as everyone else’s results in the presentations tomorrow.
[Picture: fig 1 – megalopa]
Figure 1: A crab in its megalopa, or post-larval, stage prior to metamorphosis into the immature form. The clear legs are indicative of the megalopa stage.
[Picture: fig 2-multi-colored porites]
Figure 2: This Porites lobata coral had tissue of several different shades of brown. I took three samples from this colony: pale, intermediate and dark. Future students may wish to sample multiple colonies in this way in order to have more confidence in their results.
[Picture: fig 3 – mudflat]
Figure 3: The mud flat was a beautiful transient landscape between the bay and the mangrove that was soon flooded by the rising tide.
[Picture: fig 4- wade in river]
Figure 4: Victoria Starczak and Amalia Aruda wade through the river in search of the settlement plates.
Sub heading:25 January 2011Li Ling HamadyMIT/WHOI Joint Program
A typical Monday morning question from officemates in grad school: “What’d you do on Saturday night?”
Had a couple beers at a bar with friends. Went to a raging house party. Had a deadline to meet and stayed up late doing problem sets/lab work/writing. Spent a quiet evening at home, cooked, and watched a movie from Netflix. Plankton pumping.Yes, I said plankton pumping. It isn’t the name of the newest fitness craze, though regular excursions would probably improve arm strength, balance, and breath holding ability. And the Saturday before last, some of us partook in a little of choice “E.” Actually, twice. For their personal project, Meredith and Maya decided to compare the day and night plankton, pelagic, and benthic communities in a meter square plot in the marina, and I tagged along as their trusty recorder.
Juggling the logistics of sampling proved a bit difficult. First, the large, heavy battery necessary to operate the pump required a steady platform, and the flow meter, for measuring the volume of water filtered, needed to be kept dry, so the site had to be close to the pier. When we went down in the morning, the site, typically watery regardless of tide, was practically high and dry. A negative tide! Maya and Meredith scrambled to set up the pump apparatus, while I stationed myself on a convenient rock near the water. To get the 75 liter filtered plankton sample, Maya operated the vacuum end of the pump in the quadrat, Meredith manned the filters, and I monitored the flow meter. In the end, the nearly intertidal nature of the site was a boon for the benthic sampling. They split the meter square plot into four quadrants, and Meredith and Maya examined the creatures on and under the rocks for 5 minutes per section. Due to the tide, Maya decided to use “general impressions” taken while snorkeling around the marina during the day and night as a substitute for pelagic sampling over the plot.
Perched on my rock, Rite in the Rain notebook in hand, I was able to leisurely observe our surroundings. During the day, the hot tropical sun beat down on us, necessitating abundant slathering of sunscreen, and a towel shade cape in my case. At night, while wading in knee-deep water, with masks pressed close to the rocks and dive lights waving wildly about, my partners looked a bit like stranded mermaid adventurers, attempting to infiltrate the terrestrial environment. There were sparks of bioluminescence in the water, and on the rocks all around us, I saw little glowing dots that I first thought were either crab or spider eye shine. Upon (tentative, as I’m afraid of spiders) closer inspection, I discovered tiny inchworms with glowing butts! Maya intercepted a fishing bat in her flashlight beam that dove and wove through the air, and in the water, observed hundreds of tiny silver fish, amassed at the surface.
The project wrapped up after a late, late night and full morning of post-field sampling microscopy to identify and enumerate the plankton samples.
Briefly, some findings:
Copepods (See PHOTO) constituted ~50% of the plankton during both the day and night and the night sample was almost 2x larger than the day sample.
Besides the copepods, amphipods and shrimp dominated the night plankton, while branchiopods dominated during the day.
It’s much easier to make benthic and pelagic observations during the day than at night, due to human vision limitations.
Now that we’ve returned to the Great White North, it seems ludicrous that a little over a week ago we were in bikinis, battling the tropical tides. Two days ago, most of us in Woods Hole chose “B”. But the previous Saturday, we were plankton pumping. A study in contrasts.