The summer of 2023 will go down as the hottest in recorded history (thus far). Sadly, hot ocean water means coral bleaching, and Florida’s corals suffered tremendously this year. Fortunately the Coral City Camera was in position to create the world’s most comprehensive in-situ coral bleaching timelapses ever documented by human technology. Many attempts have been made to record a coral bleaching event, but to our knowledge, this is the most complete and longest running coral time lapse made underwater in a coral reef environment. The time lapse begins on May 1st, 2023 and you can see that the staghorn corals start growing and branching quickly. However, by mid-July water temperatures have reached the critical bleaching threshold of 87 degrees Fahrenheit (30.5C) and quickly turn white. The transplanted staghorns and elkhorn corals not only bleached, but they subsequently died. You can see how after turning white, they turn gray-brown as they are colonized by turf algae in August and September, and then they erode almost as quickly as they grew, expedited by the abundant parrotfish that graze this algae from the corals’ limestone skeletons.
Bleaching occurs when the metabolism of the golden-brown symbiotic algae that live in the coral tissue known as zooxanthellae goes into thermal overdrive. The algae’s production of photosynthetically-produced oxygen exceeds the limit the coral can safely handle inside its tissues, resulting in expulsion of the zooxanthellae (and its brown color) from its host. Because zooxanthellae normally provide a coral with photosynthetically-produced sugars, it begins to starve without these symbionts. Fast-growing corals like the endangered staghorn (Acropora cervicornis) and elkhorn (Acropora palmata) lack the energy stores that fleshier corals like brain corals have, and die from bleaching stress much more easily.
By the end of August 2023, all of the staghorn and elkhorn corals experimentally-transplanted by the University of Miami’s Rescue a Reef program succumbed to the excess heat and bleaching. These were corals that are native to cooler, cleaner waters offshore Miami, so it didn’t come as a complete surprise that they could not survive the urban reef environment around the CCC. However, a single strain of staghorn and elkhorn coral that are native to the Port did not bleach and continued growing happily despite water temps exceeding 90 degrees Fahrenheit (+32C). Not taking any chances, we brought fragments of these urban strains of stag and elkhorn coral into climate-controlled conditions at NOAA’s Atlantic Oceanographic Marine Lab in July. Once water temperatures cooled enough, these fragments were safely returned to the CURES (Coral Urban Research Experimental Site) nursery frame that sits about 20’ from the CCC.
Many corals like the mustard hill coral (Porites asteroides) did not fully recover from bleaching until December 2023. Most of the brain corals had recovered from bleaching by November 2023.
Amazingly, a significant number of corals native to PortMiami did not bleach, suggesting that they have a combination of genes and microbiomes that have enabled them to adapt to the Anthropogenic conditions along Miami’s urban coastline. The native urban corals that did bleach managed to survive for several months without any zooxanthellae to provide them with energy, before recovering new zooxanthellae in autumn when cooler water returned. It is possible that the higher levels of nutrients and plankton in the water helped provide these corals with additional energy captured as food.
These urban corals and the bleaching timelapses highlight the scientific value of the Coral City Camera and its ability to document what was previously undocumented. After 4 years of near-continuous recording, and more than 205 species of fish cataloged, there is no underwater coral reef site anywhere in the world that has been as thoroughly recorded and archived.
While corals throughout Florida and the Keys suffered tremendously in the summer of 2023, the stressful event also demonstrated that not all corals shared the same fates. Even within the same species, some corals did not bleach, bleached and recovered, or bleached and died. Studying the resilient strains of urban corals at PortMiami may illuminate how they’ve been able to adapt to marginal conditions and excessive heat. With global fossil fuel emissions continuing to rise unsustainably, we can expect even hotter summers in the years to come. Will corals be able to adapt naturally fast enough? Will scientists be able to accelerate the evolution of these corals to withstand hotter water temperatures? We are in an existential race against time, but we believe (now more than ever) that Miami’s urban corals will play an important role in finding out what makes a resilient coral ‘super’. The newly launched Coral City Foundation aims to build a land-based coral lab in 2024 to unlock these secrets and amplify their numbers.
We are over the moon to share we’ve contributed coral fluorescence cinematography to the Biscayne National Park episode in the second season of National Geographic’s series America’s National Parks, narrated by Garth Brooks. America’s National Parks premieres Monday, June 5 at 9/8c on the National Geographic channel, Hulu, and Disney+.
In a new paper published in the research journal Scientific Reports, ‘Coral persistence despite marginal conditions in the Port of Miami‘, the monitoring of sites throughout the Port since 2018 revealed periodic extremes in temperature, seawater pH, and salinity, far in excess of what have been measured in most coral reef environments. Despite conditions that would kill many reef species, we have documented diverse coral communities growing on artificial substrates at these sites—reflecting remarkable tolerance to environmental stressors. Furthermore, many of the more prevalent species within these communities are now conspicuously absent or in low abundance on nearby reefs, owing to their susceptibility and exposure to stony coral tissue loss disease.
As we hypothesized in 2014 and evidenced by our recent findings, Miami’s system of urban waterways provides an inadvertent anthropogenic laboratory whose corals hold keys to understanding how the world’s coral reefs might adapt to changing climate and water chemistry in the decades to come.
President of the UN Geneva General Assembly, Abdulla Shahid and Colin touring the Center for Marine Innovation upon its completion.
Coral Morphologic was recently commissioned by Fundación Grupo Puntacana (FGPC) at the Punta Cana Resort & Club to overhaul and upgrade their coral restoration lab infrastructure at their Center for Marine Innovation with funding support from the German GIZ. This project entailed re-plumbing an outdoor greenhouse that is capable of running either closed-loop, or pulling water directly from the ocean for easy flushing and water changes. Additionally, a climate-controlled indoor lab was also constructed utilizing the latest technology for coral aquaculture, including Ecotech G5 XR30 LED lights, Apex Neptune aquarium computers, Reef Octopus protein skimmers, and calcium reactors. This improved lab infrastructure is enabling marine scientists at FGPC to generate thousands of microfrags of massive reef-building species such as brain and star corals. These important corals will add needed biodiversity to their long-running reef restoration program that has successfully out-planted thousands of staghorn corals grown on their underwater nursery tables offshore.
The climate-controlled indoor coral microfragmentation systems and wet lab feature state-of-the-art LED and aquarium technology to keep freshly fragmented corals healthy.
Coral microfragmentation: growing corals smarter and faster.
Outdoor microfragmentation systems are utilized for long-term grow-out before the corals are transplanted back onto Puntacana’s reefs.
The indoor coral microfragmentation systems and wet lab were designed with a viewing window that enables tourists to observe marine scientists microfragging and growing corals, without interrupting their work.
We are excited to present Illuminating Coral, an eight-episode educational course created with our longtime collaborator John McSwain during the height of the COVID-19 pandemic. The course, made exclusively with Parley for the Oceans, dives into the lives’ of coral, sheds light on their vital role in our global ecosystem, and offers solutions on how humans and coral can live in symbiosis both now and in the future. Watch Illuminating Coral in full via the Parley Ocean School @ https://edu.parley.tv/course/illuminating-coral/
Undescribed fluorescent Palythoa species photographed along the shoreline of PortMiami.
We are happy to announce the publication of a scientific paper in Springer Nature analyzing the presence and potency of palytoxin (PLTX) in Palythoa spp. and Zoanthus spp. Zoantharians conducted by the Mediterranean Institute of Oceanography and Coral Biome in Marseilles, France. PLTX is one of the most potent toxins known on the planet. It is an extremely large and complex organic compound that has been described by biochemists as the ‘Mt. Everest of organic synthesis’. An organism that naturally produces large amounts of PLTX is of great importance for research scientists to better understand its pharmacology. PLTX has been found to have toxic effects on head and neck tumors, and therefore warrants further pharmaceutical investigation.
Initially, this compound was blue-prospected in Hawaii where native Hawaiian people used the the mucous of Palythoa found in a very specific (and taboo) tide pool (known as limu-make-o-Hana, the ‘seaweed of death of Hana’) to coat their spear points before battle. So taboo was this tide pool for outsiders, that when scientists sampled the Palythoa in 1961, they found their lab burned to the ground on the same day. A reminder to scientists to respect native wisdom, culture, and practices when performing science on other cultures’ land!
In this paper we found that an undescribed species (Palythoa aff. clavata) we sampled from PortMiami in 2012 was found to have five times the concentration of the notorious Hawaiian species Palythoa toxica. The experiment also tried to determine whether PLTX was produced by symbiotic microbial symbionts / zooxanthellae, or by the organism itself. Highest concentrations of PLTX were found within the tissue itself, and isolated cultures of zooxanthellae from these polyps failed to produce PLTX in the laboratory. This suggests, but does not confirm, that the Palythoa polyps themselves are producing this toxin. While the mechanism of its biosynthesis remains unknown, it highlights how Miami’s urban marine environs hold important scientific discoveries still waiting to be uncovered.
“A Green Jade Lake is envisioned as an experiential journey that invites the visitor to wander through its different rooms and landscapes and to reflect on the idea of nature in the contemporary moment. In a situation of ecological fragility, we need to rethink the relationships and flows that are established between humans, ecosystems and their environments, and to take into consideration the new complexities that exist between the natural and the artificial.
Taking the image of a forest as its starting point, as the threshold beyond which categories become entwined, the exhibition includes experience, fiction, artistic work and research to allow us to explore new ways in which we can interact with the planet. Addressing different subjects such as coexistence, botany, territorial policies or the aesthetics associated with the representation of nature, the exhibition is understood as a constellation that creates open and transformative universes.
This exhibition proposes a new contemporary approach to nature in which all audiences, all bodies and all voices can participate.”
Artists: Coral Morphologic, Daniel Steegmann Mangrané, Fabian Knecht, Geocinema, Gerard Ortín Castellví, Jana Winderer, Jessica Sarah Rinland, Jonathas de Andrade, Lola Zoido, Maria Nolla, Mauricio Freyre, Michael Wang, Mónica Mays, Tomás Díaz Cedeño, Ursula Biemann, +
Symmetrical Brain Coral (Pseuododiploria strigosa) emersed during low tide along the shoreline of PortMiami.
For more than a decade, Coral Morphologic has sought to shine a spotlight on Miami’s intertidal urban corals and their potential scientific value. These surprisingly resilient corals appear to avoid bleaching and stem disease better than their conspecifics offshore on the natural reefs. Over the past two years we have been working with scientists at NOAA’s Atlantic Oceanographic Meteorological Laboratory (AOML) to explain these differences using molecular lab analysis of tissue samples collected in the field. That work finally culminated in ‘Molecular Mechanisms of Coral Persistence Within Highly Urbanized Locations in the Port of Miami, Florida‘ published in the research journal Frontiers in Marine Science.
We found that the Symmetrical Brain Corals (Pseuododiploria strigosa) living in the urban environment (specifically alongside MacArthur Causeway and Star Island in Miami) were predominantly colonized by the Durusdinium sp. strain of symbiotic algae (zooxanthellae) that provides the coral with photosynthetic energy during daylight hours. Durusdinium is known to be a heat-tolerant genus of zooxanthellae, and has long been investigated by scientists seeking to create bleaching-resistant ‘super corals’. However, until this study, the Symmetrical Brain Coral had rarely been observed hosting this species of zooxanthellae elsewhere in the region, making these observations here in Miami quite remarkable.
Beyond the helpful symbionts, the Symmetrical Brain Corals living in the urban environment were also found to be producing proteins and enzymes known to identify and digest pathogenic invaders. These proteins could be a two-fold benefit to the coral since disease-causing microbes can be digested as food before they can infect the coral. The urban marine environments around Miami often have high concentrations of phytoplankton and turbidity in the water, along with high bacterial concentrations that frequently require ‘no swim’ public health advisories. The ability to capture and extract more energy from food could enhance its health and provide sustenance during times of bleaching.
These findings from a single species of urban coral in Miami’s coastal environment suggest further investigation is warranted in the variety of other reef-building species that have self-recruited to the City’s concrete and riprap shorelines. It also demonstrates how the human-made hydrogeologic conditions around PortMiami serve as an evolutionary gauntlet selecting for corals better adapted for life in the Anthropocene.
For Design Miami 2019/, we debuted a preview of the Coral City Camera, a 360° live stream underwater camera located at our collaborative research site with NOAA’s AOML Coral Program. The CCC aims to supplement our urban coral research with real-time scientific data and offer a source of natural wonderment to the public, with the live stream officially going live in February 2020.
Coral Morphologic was recently commissioned to build a high-tech indoor coral microfragmentation and wet lab by the Alligator Head Foundation in Portland, Jamaica. Additionally, a 300 gallon reef biotope was built to serve as an educational display. Over the course of three trips, the Coral Morphologic team coordinated purchasing, exporting, and constructing the AHF Marine Lab where it now serves both the local marine scientists working to protect the Alligator Head Marine Sanctuary, as well as international scientists that can visit and conduct their work with state-of-the-art equipment in a controlled laboratory setting.
2018 is the International Year of the Reef, a world-wide initiative enacted by the ICRI to strengthen awareness globally about the value of, and threats to, coral reefs. Learn more about #IYOR2018 with an immersive Google Earth Voyager Story.
We are psyched to make an appearance in a new episode of Hamilton Morris’ Viceland TV show, Hamilton’s Pharmacopeia. Colin & Hamilton dive on Miami’s Cosmic Reef in search of a marine sponge known to contain psychedelic compounds. Watch via Viceland.
Members of the Gables Earth Club with the 300 gallon Coral Morphologic reef aquarium post-installation in 2015.
In September 2015 the lease ended on our first lab warehouse and we had to downsize our systems. We decided to donate our 300 gallon glass reef aquarium system–complete with all the gear, rocks, and corals–to the students of Coral Gables Senior High School in order to plant the seeds of reefkeeping and coral aquaculture in the next generation. The lab is maintained by student members of the Gables Earth Club, and overseen by faculty science teacher Mr. Eric Molina. We believe that no other activity accomplishes the goals of STEAM (Science, Technology, Engineering, Art, Math) better than reef keeping, and includes an added R for Responsibility (STREAM). While math and science can be taught from textbooks, the holistic act of coral aquaculture requires hands-on attention and care. We’ve observed firsthand how these students understood the assignment and really have gone above and beyond to care for these delicate creatures.
These Palythoa sp. zoantharians contain a remarkably potent chemical, palytoxin, proven to selectively destroy cancerous cells.
Several years ago we were excited to report that our survey of Zoantharian soft corals from South Florida had resulted in the identification of several undescribed species. Today, we are even more excited to report that one of these Palythoa species zoantharians, collected off the PortMiami seawall, contains an extremely powerful compound with proven anti-cancer properties. Coral Biome, our partners in Europe, have officially received a patent for the chemical’s extraction and application in the treatment of cancer and other serious diseases. From Coral Biome’s inception in 2011 in Marseilles, France, we have been assisting them in the collection, identification, and aquaculture of soft corals that produce medically-valuable chemicals, a process known as ‘bioprospecting’.
We’re psyched to share a soundtrack of ours (‘Strand’) is part of Other Electricities‘ new “call and response” LP, where Emile Milgrim and T. Wheeler Castillo’s Floridian field recordings are included in original and remixed forms. Stream Archival Feedbackvia Spotify and pick up the album in digital and vinyl / deluxe editions @ https://other-electricities.bandcamp.com/album/archival-feedback
Coral Morphologic is proud to announce the digital release of the remixed and remastered Natural History Redux today, March 6, 2014. NHR compiles our original Natural History series of videos (that were previous only available online individually in 720p) into a digital 1080p collector’s edition. NHR sees these 23 films hypnotically datamoshed together into a half-hour odyssey of the sea. Watch the official film free above, @ https://vimeo.com/showcase/naturalhistoryredux, or purchase the film @ coralmorphologic.bigcartel.com/product/natural-history-redux-digital-hd-film
The release of Natural History Redux represents the closing of the early chapters of Coral Morphologic. The ‘Natural History’ series represents our early ‘demos’, as the acquisition of the landmark Canon 5D Mark II in 2009 had suddenly made high-definition macro videography an affordable prospect for us. At that time we were still based out of our original home-based lab, where we made do with miniaturized aquarium sets that we hand-crafted in DIY spirit, challenging ourselves to make living portraits of our local invertebrate marine life. Colin did the filming, and J.D. composed original soundtracks (except ‘Man O War’ which was scored by Animal Collective’s Geologist) to accompany each film. We charged ourselves to film and release a new portrait every week on this blog, which for the most part we delivered under self-imposed Monday morning deadlines. After filming ‘Man O War’ we found ourselves in a position where we felt constrained by our home-based lab, and took the gamble to move into a dedicated facility where we could expand our vision. It would be another two years before we had the time or resources to film anything new (the new Lab was considerably more expensive to set up and operate). 3 years later, we are pleased to offer a remixed and remastered compilation of these films as an audio-visual album. Enjoy!
Four Floridian zoanthids analyzed in our study. Clockwise from Top Left: 1) Undescribed Zoanthus aff. pulchellus 2) Undescribed Palythoa aff. variabilis 3) Zoanthus solanderi 4) Undescribed Terrazoanthus sp.
Recently, we spearheaded a study of the Zoanthids found in our local nearshore waters that has been published in the Journal of Marine Sciences titled ‘Species Diversity of Shallow Water Zoanthids (Cnidaria: Anthozoa: Hexacorallia) in Florida‘ with Dr. James Reimer and Yuka Irei of the University of the Ryukyus in Okinawa, Japan. This is the first comprehensive study of its kind, analyzing DNA to determine the taxonomic authenticity of our local zoanthid species. We discovered that there are as many as four species of zoanthids in South Florida that have been overlooked by scientists until now.
Despite their ubiquitousness in shallow tropical waters, zoanthids have been largely neglected by marine biologists who have otherwise been more focused on understanding reef-building stony corals, leaving the taxonomy of tropical zoanthids vague and out of date. This, combined with the natural morphologic variability of these animals, makes physical identification difficult for the casual observer. The advent of DNA analysis has allowed for an accurate picture to emerge, and it is clear that there is much more diversity than had previously been recorded.
‘Man O War’ Physalia physalis
Film and Aquarium: Coral Morphologic
Original Soundtrack: Geologist
In this special installment of our Natural History film series, Geologist soundtracks a macroscopic view of a Portuguese man-o-war’s beautiful, yet highly venomous tentacles.
The man-o-war is often mistaken as a jellyfish, but this is not the case. It does not swim, but is instead propelled by the winds, tides and currents across the ocean’s surface. In fact, a man-o-war is not even a single organism, but an entire colony of organisms called siphonophores, that live together as a singular unit. They are found floating across all of the world’s tropical and subtropical oceans. Even more impressive is that the man-o-war colony is comprised of four different types of polyps, called zooids, that each serve a different purpose to the overall functioning of the colony.
‘The Squat Urchin Shrimp’ Gnathophylloides mineri on Tripneustes ventricosus
Music, Video, and Aquarium
2010 Coral Morphologic
The Squat Urchin Shrimp (Gnathophylloides mineri) is an amazingly successful creature that can be found living amongst the spines of sea urchins throughout most of the world’s shallow tropical waters. In the Caribbean they hitchhike exclusively upon the black and white West Indian Sea Egg (Tripneustes ventricosus), traveling along where ever its host may go. The squat urchin shrimp is very small, reaching no more than 6mm in length, and orients itself parallel with the spines making it all but invisible and protected from a would-be-predator. Often colonies of up to half a dozen squat urchin shrimp of varying sizes will all share the same urchin. Beyond its circumtropical distribution and perfect camouflage, the squat urchin shrimp further demonstrates its successfulness by feeding upon the epidermal tissue of the very spines that grant it protection. This is a relatively benign form of parasitism that doesn’t seem to bother the urchin. These shrimp will also feed opportunistically upon detritus that the urchin picks up as it moves along the sea floor. The squat urchin shrimp is a creature that has found a near perfect niche in a truly self-sustaining, self-contained world of spines.
‘The Heart Urchin Pea Crab’ Dissodactylus primitivus on Meoma ventricosa
Music, Video, and Aquarium
2010 Coral Morphologic
Barely 7mm in size, the aptly named heart urchin pea crab (Dissodactylus primitivus) lives its entire life as a passenger upon the slow-moving red heart urchin (Meoma ventricosa). It is an example of the unusual life that can be found by looking in unexpected places on Floridian coral reefs. The red heart urchin is an unusual member of the echinoderm clan (e.g. urchins, sea stars, sand dollars, sea cucumbers) that spends most of its time burrowing in the sand. It sifts through the grains of sand searching for organic detritus that constitutes its diet. Likewise, the heart urchin pea crab lives a well-protected life (usually below the sand) amongst the spines of this fist-sized urchin. While most crabs move swiftly, this pea crab moves slowly in order to navigate through the corridors of spines, even spending time inside the urchin’s mouth. It is likely that the crab feeds upon some of the food that would otherwise be consumed by the urchin. This commensal relationship appears mildly parasitic, as the urchin doesn’t seem to gain any sort of direct benefit from the crab living amongst its spines. Frequently, several heart urchin pea crabs will live communally without any noticeable negative impact to their host urchin’s health.
If you look closely, you’ll notice the rhythmic working of its gills and circulatory system within the heart urchin pea crab’s translucent, eggshell exoskeleton.
‘Cleaner Pt. 3′ Periclimenes rathbunae on Stichodactyla helianthus
Music, Video, and Aquarium
2010 Coral Morphologic
The sun anemone shrimp (Periclimenes rathbunae) is the least common of the three species of Floridian anemone shrimp. While the other two anemone shrimp (P. pedersoni and P. yucatanicus) act as cleaners to passing fish, the sun anemone shrimp doesn’t seem to engage in this behavior. Instead, it spends its time living almost exclusively upon its namesake sun anemone (Stichodactyla helianthus). Aquarium observations suggest that this shrimp may supplement its diet by occasionally nipping off and eating the tentacles of the anemone. This parasitism suggests a more complicated symbiotic relationship than the sort of simple mutualism that these shrimp are often categorized by.
In Floridian waters, the scarcity of this shrimp is likely related to the infrequency of its host sun anemone. However, where they are found, the sun anemone often lives in dense clonal colonies that can literally carpet shallow reefs. The tentacles, while short and stubby, are packed with powerful stinging nematocysts that act like microscopic harpoons to deliver their venom. The end result of all these nematocysts and tentacles, is an anemone that is very ‘sticky’, and capable of producing painful welts to the careless diver.
‘The Porcelain Crab’ Petrolisthes galathinus feeding on passing plankton
Music, Video, and Aquarium
2010 Coral Morphologic
The porcelain crab’s common name is derived from its propensity to drop claws like a fragile tea cup breaking. When attacked, the would-be predator is usually left with nothing more than a few amputated (and still-twitching) limbs. In a few days the porcelain crab will undergo an ’emergency molt’ of its exoskeleton and begin regenerating its lost appendages.
The porcelain crab shown here, Petrolisthes galathinus, is a common resident of Floridian and Caribbean reefs, living under rubble and coral heads. Turning over loose rocks will often yield a fleeting glimpse of scurrying, purple legs. They can move incredibly fast and generally remain cryptic to the passing scuba diver. While many crab species are territorial and agressive towards members of their own species, these porcelain crabs can be colonial with several dozen porcelain crabs living together under the same rock.
Despite the similar appearances, porcelain crabs are not ‘true’ crabs; they are in fact more closely related to the squat lobster clan (Galatheidae) than the archetypal brachyuran crabs we are all familiar with. Porcelain crabs’ flattened bodies are adapted to their life under rocks and in crevices. One of the defining features of porcelain crabs are the comb-like appendages called ‘setae’ that sweep the water currents in order to collect edible particles that happen to float by. Another pair of specialized appendages scrape the the setae and bring the collected food to their mouthparts. This feeding strategy, with its alternating rhythm, appears robotic in its efficiency.
‘Transmission’ Pseudoceros crozieri or ‘Tiger Flatworm’
Music, Video, and Aquarium
2010 Coral Morphologic
The tiger flatworm (Pseudoceros crozieri) is a stunning species of flatworm that can be found living on rocks and mangrove roots along the shores of the Caribbean. Colonial orange tunicates (Ecteinascidia turbinata) constitute the tiger flatworm’s only food-source. At 35mm in length, it is considerably larger than the previously featured red flatworms. As simultaneous hermaphrodites, the tiger flatworm often travels as pairs and mate regularly. Their pseudotentacle antennae help aid them in finding mates by detecting chemical cues in the water.
Locomotion in this larger flatworm species is accomplished by rippling muscle contractions along the edges of the animal, and aided by a slippery mucous slime. The video is shown in real time.
‘The Lettuce Slug’ Elysia crispata on Halimeda opuntia
Music, Video, and Aquarium
2010 Coral Morphologic
Lettuce sea slugs (Elysia crispata) are a commonly found in protected nearshore Floridian waters where green macroalgae proliferates. They belong to a clan of sea slugs, the sarcoglossans, that are characterized by their ‘sap-sucking’ feeding habits of algae. These slugs slowly patrol mangrove roots and rocks searching for green algae upon which they feed. They store some of the chloroplasts from eaten algae in their tissue, giving it the green coloration. The chloroplasts continue to function, providing the slug with photosynthetic energy. The ruffles along the back of the lettuce sea slug are called parapodia, and help provide more surface area for the chloroplasts to inhabit. They also camouflage the slug amongst the leafy algae that they live amongst. It is very easy to swim past a lettuce nudibranch without ever noticing it.
The scrolled rhinophores (antennae) on the head of the lettuce sea slug help detect the chemical fingerprints of their preferred algal species. If you look carefully, just behind the rhinophores, you’ll notice the small black eye spots that act as rudimentary eyes to detect changes in light and dark.
The macroalgae featured in the film is Halimeda opuntia, (named after its resemblance to the prickly pear cactus Opuntia sp.). It is unique amongst green algae in that it produces a semi-rigid, calcareous skeleton. In fact, the dead ‘leaf’ fragments of Halimeda spp. algae are a more significant producer of coral reef sand than the corals themselves. It is not uncommon to find lettuce sea slugs on Halimeda opuntia algae, as it frequently lives amidst the softer green algae that the lettuce sea slugs prefer.
The flatworms (Convolutriloba retrogemma) featured in the video are shown at 3x normal speed. They each range from 2-4mm in total length.
These particular flatworms harbor symbiotic zooxanthellae in their thin tissue and utilize the excess sugars they create as their primary energy source. Packets of zooxanthellae can be seen as the tiny, red-brown dots along the back of flatworm. Their reliance upon this photosynthesis requires that these flatworms bask in sunlight like little photovoltaic cells, and enables them to live without a developed digestive system.
In the wild, this species can be found in the shallow water of protected lagoons and around mangroves. Reproduction is accomplished asexually via fission, in which the flatworms literally split into two. This strategy enables exponential population growth in optimum conditions. They are the preferred prey of several species of larger flatworms and sea slugs; animals that can tolerate their toxic bodily fluids.
While it appears that the flatworms just glide along like magic carpets, they are actually propelled by invisible cilia (flapping filaments) that slide them across a thin layer of mucous laid over whatever surface they happen to be upon.
Upon close inspection of flatworm-to-flatworm interaction, it is apparent that these flatworms do not like making direct contact with each other. If they do, they react as if stung. It seems that this reaction prevents the worms from piling on top of each other in an effort to gain the best solar power. Instead, they jockey for position until they each find a place in which to ‘park’ themselves, like sunbathers on a crowded beach.
The sally lightfoot crab (Percnon gibbsi) is an agile maneuverer on the rocky shores of the Caribbean. These crabs are particularly well-suited to life on craggy limestone rock in shallow water. The rockwork is the result of sea urchins eroding the limestone as they rasp off the algae growing on the surface. The cumulative erosion by sea urchins over many years creates a jagged network of fissures and channels through the solid rock. The sally lightfoot crab’s pancake-flat body allows it to scuttle beneath the protective spines of a nearby urchin at a moment’s notice. Anemonia bermudensis sea anemones like the ones seen in the film can also be common on the rocks in this surf-washed zone. The sally lightfoot’s nimble legs allow it zig-zag harmlessly between the tentacles of these stinging animals. Between the crab’s eyes you’ll notice a pair of fast-flitting antennae that detect the ‘smell’ of food in the water. The turbulence of the environment requires accurate detection and nimble response.
‘The Florist’ Leptopsia setirostris (Decorator Crab) scavenging amongst a Zoanthus polyp garden
Music, Video, and Aquarium
2010 Coral Morphologic
Once again we return to observe a cryptic red decorator crab (Leptopsia setirostris); this time living upon, and decorated with, zoanthid polyps (Zoanthus sociatus), close cousins to both sea anemones and corals. Zoanthus in Latin literally means ‘animal flower’. The species name sociatus refers to the fact they these flower animals live socially in dense groupings of identical polyps.
Decorator crabs demonstrate a remarkably prescient instinct to be able process the information required to successfully camouflage themselves to match their preferred habitat. Unlike the typically fast-scuttling crabs of the mainstream, decorator crabs move at a deliberately slow pace to reduce being noticed.
This particular decorator crab species boasts a brilliant red exoskeleton that it has disguised with the zoanthids. The crab has carefully nipped individual zoanthid polyps from a larger colony and placed them upon its carapace (back) where they attach down on their own and continue growing. My experience suggests that it takes at least two days for a polyp to begin attaching down to new substrate. I have yet to observe the crab going through the whole process of zoanthid ‘decoration’, but clearly it is a very patient animal.
The crab uses its small claws to pick at and remove pieces of detritus between the polyps. The animal nature of the zoanthids becomes especially apparent when the movements of the crab cause the polyps to close up in reaction. If you look carefully at the bottom right of the screen you’ll notice the periodic movements of a barnacle that these zoanthids are growing upon. Zoanthids are commonly called ‘sea mat’ due to their rubbery, encrusting morphology. They live together in interconnected colonies of cloned polyps, slowly expanding their colonies outward; growing over shells, in-between coral heads, and across shallow tide pools.
‘The Lynx Nudibranch’ Phidiana lynceus (Lynx Nudibranch) on Spondylus americanus oyster
Music, Video, and Aquarium
2010 Coral Morphologic
Last week we spent a moment making eyes with the oyster (Spondylus americanus). This week we’ll spend a moment with a diverse community of animals and plants that have colonized the upper shell of the very same oyster. Towards the left of the frame is a small colony of flower-like animals known as hydroids. Hydroids are most closely related to jellyfish, but instead remain attached to the reef their whole lives (unlike a jellyfish). But, like the jellyfish, hydroids can pack a powerful stinging punch. The brown, daisy-like creatures seen growing here on the oysters’s back are one such type of hydroid, Myrionema amboinense. This hydroid species derives its brown coloration from the symbiotic zooxanthellae (dinoflagellate ‘algae’) stored in its tissues. The ability to gain nutrition from both prey capture and photosynthesis, allows these hydroids to grow and colonize quickly. The sting from these hydroids is considerably more powerful than that of most corals. The gray, lumpy knobs on the back of the oyster shell are zoanthid polyps, close cousins of the sea anemones. However, these zoanthids are no match against the powerful sting of the hydroids. The zoanthids have all but acknowledged defeat by the encroaching stingers by simply closing up; effectively handing over control of the oyster shell to the hydroids.
‘Oyster Vision’ Spondylus americanus oyster
Music, Video, and Aquarium
2010 Coral Morphologic
Here we look into the face of the thorny oyster (Spondylus americanus). Unlike most shallow-water oyster species, the thorny oyster is a solitary creature that lives permanently cemented to the deeper coral reef. Its fleshy mantle is adorned with sepia-toned psychedelic camouflage that can vary widely from one individual to the next. The rim of the mantle is lined with dozens of eyes that stare out into the depths. These eyes are quite simple, only detecting changes in light that might suggest an incoming predator. If a threat is detected, the oyster will quickly snap its two shells together, sealing the animal inside with its two powerful adductor muscles. It is the adductor muscle that people eat when they eat ‘oysters on the half shell’. Oysters are filter feeders, spending their time siphoning water through gills that strain out particulate matter. As seen in the film, the oyster periodically expels waste and water with a quick contraction of its adductor muscles.
In the second installment (next week) we will explore the upper shell of the oyster and the community of organisms that has colonized it.
