Caribbean Coral Reef Ecosystems Program
Smithsonian Environmental Research Center
Smithsonian Marine Station
Smithsonian Tropical Research Institute
R/V URRACA

As we consider that the Smithsonian Marine Science Network is much greater than the sum of its parts - in both existing and potential research productivity, outreach and education - an increased coordination of activities and resource allocation will further this notion. Some SI scholars feel that research is best advanced by curiosity and individually prioritized objectives. At the same time, large-scale environmental research often requires team approaches to gather big data sets over enormous regions to address pressing problems in the coastal zone.

The Marine Science Network is well suited to support both approaches, and simultaneous individual and collaborative inter-unit approaches will work synergistically to advance marine research objectives. These research elements form the foundation of expanded comparative work in the future.

The Caribbean Coral Reef Ecosystems Program (CCRE) – Belize

The Carrie Bow Cay Laboratory primarily serves to support SI marine scientists' research projects on a year-round basis. Hurricanes Fifi (1974), Greta (1978), and Hurricane Mitch (1998) could not damage Carrie Bow Cay facilities the way a devastating fire did in December 1997. Improved facilities now include dry and wet labs, housing, generator, compressor, small boats and scuba cylinders, and essential facilities such as solar power, running-seawater system, and a weather station.

Biodiversity, Morphology and Developmental Biology. Studies cover the evolutionary range from microbes to manatees. Several new toxic species of dinoflagellates that occur in blooms (red tides) were identified based on cytological characteristics. A study of benthic macroalgae was completed and will serve to prepare an illustrated field guide. Earlier work on sponges led to a multimedia computer key on mangrove sponges with digitized underwater color photographs. The balance of nutrient release and uptake by abundant sponges and bivalves was found to be a decisive factor in the coupling of seagrass and mangrove prop-root. Also in the mangrove, a sessile ciliate (Zoothamnium) symbiotic with chemoautotrophic bacteria was discovered and cultivated on sulfide-producing substrates to measure reproduction and growth rates. 

Species Interactions and Behavior. Study of a sponge-inhabiting shrimp (Synalpheus spp.) confirmed its advanced social structure for the first time in a marine animal. Morphological, life-history, and phylogenetic analyses were also conducted on fishes (labrids) and a new blenny (Acanthemblemaria) was discovered. 

Ecophysiology and Responses to Environmental Change. Another experimental study shows how water flow affects coral shape and growth rates, either by force and direction or by nutrient distribution. Solar radiation, including UV radiation, was measured on the Carrie Bow reef down to 39m and in experiments has been found to affect rates of photosynthesis and bleaching in symbiotic coral (Agaricia) and a sponge (Calyx). A monitoring program has been established to quantify the long-term temperature change effects on the distribution and progress of black-band disease in reef corals.

Processes Linking Species and Environment. Mangroves are a dominant coastal ecosystem throughout the tropics and a major research focus at Carrie Bow Cay. A large multidisciplinary team of researchers from SERC, NMMH, and several collaborating institutions are studying the control of biocomplexity of mangroves on small islands and along the mainland. The program conducts manipulative experiments on nitrogen, phosphorus and herbivores above the water, and also uses scuba to study fouling communities of the subtidal mangrove prop-roots. Several recent projects (Macintyre and Ruetzler, 2000) investigated the Pelican Cays, an undisturbed and highly diverse group of reef-mangrove islands 15km SSW of Carrie Bow Cay. The atoll-like reef structure on which the cays are located is obvious only from the air. Core drilling (to 15m) of the characteristic reef-ridge system at Manatee Cay showed an open framework construction made up of the branching coral Acropora cervicornis and confirmed the original hypothesis that reef ridges are all established on points of high karst relief on the underlying pleistocene limestone. A. cervicornis has disappeared from many Caribbean sites due to white band disease but here it has been replaced by other coral (Agaricia spp.) rather than by algae. High levels of herbivory by an echinoid may be responsible for this difference.

Smithsonian Environmental Research Center (SERC)- Chesapeake Bay  

Global Change.  A major component of SERC’s research investigates the environmental consequences of human-induced global change. In addition to the “greenhouse effect” of global warming and rising sea level, increased atmospheric carbon dioxide concentrations (due to burning of fossil fuels) markedly affect the rates of photosynthesis and carbon storage in plant communities. SERC has the world’s longest running field experiments using chambers to test the effects of CO₂ increase on marsh plants at the Rhode River site and on scrub oak communities at Kennedy Space Center in Florida. Studies of harmful ultraviolet solar radiation examine its effects on phytoplankton and macroalgae in the Chesapeake Bay and in polar seas, where UV radiation is intensified due to the formation of “ozone holes”. Damage has been documented in the light-capturing ability of plants and marine algae that support Earth’s food web. SERC research on biogeochemical cycles show how carbon, nitrogen, phosphorus, and silicate cycles are being altered by human activities related to agriculture, forests and wetlands in the coastal zone.

Ecological Indicators at the Land-Sea Interface. Productivity in coastal waters and estuaries is enriched by nutrient runoff from the land. More than 70 percent of the world’s people live in coastal zones. This concentrates development and water pollution around bays and estuaries where the sea’s richest fisheries are declining at alarming rates. By relating nutrient discharge from the watershed to phytoplankton growth in the estuary, SERC has gained new insights into the coupling of land and sea. SERC’s watershed research in Chesapeake Bay shows that excessive nutrient runoff from agricultural crops and livestock stimulates overproduction of dinoflagellates and other planktonic algae, which block light from reaching aquatic plants and deplete oxygen. Excess nutrients can cause algal blooms that are sometimes poisonous to fish and humans. Other plankton studies alter the traditional portrayal of bottom-up control of marine food chain production. Studies of planktonic protistans show that single-celled parasites may infect larger single-celled hosts. Epidemic outbreaks of these parasites can cause plankton blooms to collapse, effectively short-circuiting the food chain.

SERC has developed new instruments to measure the quantity and spectral quality of light penetration into coastal waters. These radiometers monitor changes in underwater light in response to plankton, particles and chemicals in the water column, and SERC research shows how these measurements serve as good indicators of water quality. Low light penetration limits the presence of submerged aquatic vegetation in shallow water, and loss of sea grasses has been a major loss of habitat for small fish and crustaceans that support commercial fisheries.  

SERC has explored connections in Chesapeake Bay’s food web leading from plankton production up to commercially important species of fish and crustaceans, like the blue crab.  One study examines the value of the shoreline habitat as a refuge from predation by large fish and blue crabs on small fish, grass shrimp and juvenile crabs. SERC experiments show how this refuge is being eliminated by shoreline development.  Fisheries in Chesapeake Bay have collapsed under over-fishing and environmental degradation, leaving the blue crab as the only species with a sustained commercial catch. Fundamental aspects of blue crab behavior remain shrouded by the turbid waters in which they live. To record movement and behavior of blue crabs in their natural environment, ongoing SERC research uses diving and innovative biotelemetry devices (Hines et al., 1995; Wolcott and Hines, 1996) that transmit information abut crab movement, feeding, fighting, and mating.

Marine Biological Invasions. Invading non-native species introduced by human activities have disrupted ecosystems around the world, causing major ecological changes and enormous economic impacts. SERC is the national center for the study of alien invasive species in coastal ecosystems. Presently, ballast water in commercial ships is the major vector for marine species introductions. Each day ocean-going vessels transport millions of gallons of ballast water containing live plankton. When ballast water is discharged, organisms are released into new environments where, lacking natural predators or other controls, they may become established and wreak ecological havoc.  SERC’s Invasions Biology Program uses plankton nets to search for creatures stowing away in ballast tanks of ships arriving in Prince William Sound Alaska and the Chesapeake Bay, among other sites. The SERC Invasions Biology Program uses scuba and other sampling methods to analyze broad patterns of marine invasions and their ecological interactions.  

Smithsonian Marine Station at Fort Pierce (SMSFP)

Marine Biodiversity. Many components of the SMSFP program study marine biodiversity. SMSFP has developed the Indian River Lagoon Species Inventory, which is accessible electronically on the Internet. The Inventory is a relational database that documents the 2,500 species of plants and animals found in the Indian River Lagoon, making it the estuary with the highest biodiversity in the Nation. The on-line database includes summary information for a growing number of these species, including images and data on their taxonomy, distribution, life history, ecology, and special status.

Many other SMSFP projects analyze the systematics, biogeography, natural history and ecology of species in the coastal zone of Florida and adjacent areas. “Caribbean Reef Plants” (Littler and Littler, 2000) is a comprehensive field guide that contains approximately 550 color plates and 2,750 black and white illustrations. It features species descriptions, photographs, and morphological, anatomical, and habitat/distributional data for nearly all algal species found in the Caribbean. A study of the diversity and phylogenetics of nemerteans is also in progress. These are unsegmented, shallow-water worms ranging in size from a few millimeters for interstitial forms to several meters long for subtidal forms. Of the twenty species collected from Florida, half are undescribed. Flatworm collections from southeastern Florida and the Keys sampled 17 different species, most of which are undescribed. Studies on the biology and diversity of isopod crustaceans of the Indian River Lagoon add to material that will be used for an illustrated electronic field key to the isopods. Isopod sampling stations included intertidal and subtidal mud, rubble, sand, oyster beds, mangroves, algal turfs, live sponges, rotten wood, macro-algal clumps and seagrass beds. Other crustacean studies include classifications of xanthid (mud) crabs and callianassid (ghost) shrimps. Resin casts of the burrows of ghost shrimp were found to be highly complex, with numerous perfectly coiled passages descending to the lowest points of the casts. Speculation is that these coils stop predatory eels from swimming into these passages, as such features in prairie dog burrows have been proven to stop snakes from descending into their burrows. Studies of genetic diversity in marine populations are also underway. Distinct populations of the crowned conch, a highly variable species, exist in Florida, Alabama and the Yucatan Peninsula. DNA data is being analyzed to clarify ambiguities in these populations. Deep-sea snails called “slit shells” (Pleurotomariidae) are one of the most ancient gastropod families being studied using Harbor Branch Oceanographic Institution’s Johnson Sea-Link submersible to depths of 3000 ft.

Life Histories of Marine Species. Life history studies are another major research theme at SMSFP. With particular emphasis on reproduction, embryonic development and larval biology, these studies focus on many groups, including: sponges, copepods, molluscs, bryozoans, crabs, sipunculans (peanut worms) and echinoderms. The SMSFP research vessel Sunburst is used to sample larval stages in the Gulf Stream offshore, while diving and other studies sample larval stages passing through inlets to the Indian River Lagoon. Recent studies of crab larvae coming through the inlets recorded numbers of two dozen species’ megalopae settling each day for 15 months continuously, including during a direct hit by a hurricane. Other larval studies provide information about control and cues to metamorphosis. Still others measured depth distribution and diversity of cephalopods (squids and octopuses) in the blue waters of the Gulf Stream. Recent experimental studies determine interactions in complex life cycles of trematode parasites that infect birds, snails, and fish.

Ecosystems.  Ecosystem studies at SMSFP have focused on various reefs (including corals, oysters and cochina shell), sea grasses, and soft benthos. Presently, ecosystem studies are focused on the role of nutrients and herbivores in regulating the biocomplexity of mangroves along the Indian River Lagoon. Experiments use fertilizer treatments and cages to determine interactive effects of nutrients, crabs’ burrowing, and insect herbivores. Long-term studies involve multi-year data sets to document fluctuations in ecosystem processes and population dynamics. For example, decadal studies of foraminiferan populations in soft sediments of the Indian River Lagoon measure marked changes in species composition, abundance and stability of these important benthic protists. At the same time, population and species diversity of planktonic ciliates, dinoflagellates, and other protists are being tracked in the water column of the Lagoon.

Smithsonian Tropical Research Institute (STRI) – Republic of Panama  

Inter-Ocean Comparisons. STRI’s Marine Environmental Sciences Program (MESP) collects and analyzes fundamental oceanographic information that provides critical information for studies such as El Niño and coral bleaching. The Panama Paleontology Project in Bocas del Toro seeks to record the history of the divergence between the two oceans over the last 10 million years, and the evolutionary response of marine organisms to these changes. Results from this project are the geological reconstruction of the closure of the Isthmus of Panama 3 million years ago, and the discovery of a major extinction event in the Caribbean about 2 million years ago. Through a combination of molecular and paleontological information, STRI’s molecular evolution program has developed a model system for determining the rate at which organisms diverge genetically through time (Panama molecular clock). This allows for the phylogenetic reconstruction of marine life elsewhere in the world.

Tropical Instability.  STRI’s marine research has clearly shown that tropical marine environments are highly dynamic on many temporal scales. Perhaps the most dramatic revelation of long-term major changes was the demise of the long-spined sea urchin (Diadema) throughout the western Atlantic (Lessios et al, 1984;  Lessios, 1995). Apparently due to a disease originating near the mouth of the Panama Canal in 1983, 95% of these once abundant organisms disappeared over the course of two years.  Notwithstanding the high reproductive output of this urchin, recovery has largely failed to occur and many overfished reefs throughout the Caribbean have been smothered under algae freed from the urchin’s grazing. This diving research showed how over-fished reefs persisted for years with high coral cover prior to the urchin die-off, but then rapidly succumbed to the decimation of this single keystone species, showing that synergy between multiple stresses on marine environments can have unpredictably severe consequences. The sea urchin saga also demonstrates how even extraordinarily abundant organisms are potentially vulnerable to rapid elimination by diseases that combine the lethality of Ebola with the contagion of the common cold.

Marine environments are also subject to man-made disasters in contrast to the urchin epidemic, which was a natural event. The escape of 60,000-100,000 barrels of oil into the mangroves and reefs of Bahia Las Minas (Caribbean) has had unexpectedly prolonged effects (Jackson et al 1989). Oil seeps into the sediments around mangroves and returns to coat the coral reefs year after year as heavy rainfalls (exacerbated by the effects of deforestation) slowly wash it out. The skeletons of corals record the history of acute disasters, as well as chronic stresses, and x-ray analyses inspired by the oil spill document a worrying decline in coral growth over the past century.  

Marine Biodiversity. Corals are the building blocks of coral reefs and are renowned for the diversity of organisms that they shelter. STRI’s studies have revealed that marine tropical environments contain 4-5 times more species on average than has been generally realized. The most abundant and best-studied coral “species” (Montastrea spp.) of the Caribbean is in fact a complex of at least three species (Knowlton et al, 1992). Even more surprisingly, these species each host a diverse array of symbiotic algal partners, so that the combinatorial diversity of Caribbean reefs is an order of magnitude greater than previously assumed. The ecological importance of this diversity was sharply highlighted during an episode of coral bleaching caused by a Caribbean-wide temperature increase in the summer of 1995. Only certain corals and certain parts of corals bleached and the pattern could be predicted by knowing which algae occurred where (Rowan et al, 1997). Thus basic research on patterns of biodiversity have led to important insights into the likely consequences of global warming.

Biotic diversity is expressed at many levels, and one of the most fascinating is animal behavior. Patient observation using scuba has revealed many surprising details of how marine organisms function. Transmitters attached to the backs of sea snakes show that these creatures can spend up to 200 minutes at depths down to 50m. Identification of fishes throughout the eastern tropical Pacific has contributed significant biogeographical and distributional data (Allen and Robertson, 1994). Decoding the meaning of color change in squids has led to new appreciation for the communicatory complexity of these organisms.

STRI pioneered studies of the bizarre sex life of reef fishes, where sex change and sex role reversal appear to be the norm rather than the exception, because they maximize the reproductive success of individual fish. Parrot fishes spawn regularly, every day at sunset. But what happens to their larvae, which can spend a month floating in the ocean before settling onto a reef, is less well understood. Giant underwater light boxes are being used to trap larvae and measure the rate at which different species recruit onto reefs. Fish collected from around the Caribbean show, through molecular data, that larvae often travel long distances before settling down to a more sedentary adult life.  

Research Vessel URRACA

Built in 1987 by Lifeline Ship Construction in England, the R/V URRACA is based in the Republic of Panama and has been operated by the Smithsonian Tropical Research Institute since 1994.  The overall length of the vessel is 96.0 ft with a 22 ft beam.  The navigational draft is 8.5 ft and full load displacement is 124 tons.  The vessel's molded fiberglass hull and aluminum superstructure has a waterline length of 81.3 ft.  The stern A-frame has a lifting capacity of 5,000 lbs.  4 meter and 5 meter rigid hull inflatables are available to support scientific diving operations.  The URRACA, with a crew of 5, can accommodate scientific parties of up to 9 in comfort.  She has a range of of 4000 miles and 30 days endurance.  For more information contact Pierre Fuentes: fuentesp@naos.si.edu

Allen, G.R. and D.R. Robertson. 1994.  The Complete Divers’ and Fishermen’s Guide to   Fishes of the Tropical Eastern Pacific.  University of Hawaii Press.  332 pp.

Clifton, K.E.  1997. Mass spawning by green algae on coral reefs.  Science 275:  1116-1118.

Hines, A.H., T.G. Wolcott, E. Gonzalez-Gurriaran, J.L. Gonzalez Gurriaran and J. Freire. 1995.  Movement patterns and migrations in crabs:  Telemetry studies of juvenile and adult behavior in Callinectes sapidus and Maja squinado.  J. Mar. Biol. Assoc. U.K. 75:  27-42.

Knowlton, N., E. Weil, L.A. Weigt, and H.M. Guzman.  1992.  Sibling species in Montastrea annularis, coral bleaching and the coral climate record.  Science 255: 330-333.

Lessios, H.A. and I.G. Macintyre (eds.) 1997.  Proceedings of the 8th International Coral Reef Symposium (Vols. 1 and 2). Smithsonian Tropical Research Institute, Republic of Panama.  2119 pp.

Lessios, H.A. D.R. Robertson and J.D. Cubit.  1984.  Spread of Diadema mass mortality throughout the Caribbean.  Science 226:  335-337.

Lessios, H.A. 1995.  Diadema antillarum 10 years after mass mortality: still rare despite help from a competitor.  Proc. R. Soc. Lond. B 259:  331-337.

Littler, D.S. and M.M. Littler.  2000.  Caribbean Reef Plants:  An Identification Guide to the Reef Plants of the Caribbean, Bahamas, Florida and Gulf of Mexico.  Offshore Graphics, Inc., Washington, D.C. 542 pp.

Macintyre, I.G. and K. Ruetzler (eds.) 2000.  Natural History of the Pelican Cays.  Atoll Res. Bull. Nos. 466-480.  National Museum of Natural History, Smithsonian Institution, Washington, D.C.  333 pp.

Rowan, R., N. Knowlton, A. Baker, and J. Jara 1997.  Landscape ecology of algal symbionts creates variation in episodes of coral bleaching.  Nature 388: 265-269.

Ruetzler, K and I.G. Macintyre (eds.) 1982.  The Atlantic Barrier Reef Ecosystem at Carrie Bow Cay, Belize. 1:  Structure and Communities.  Smiths. Contrib. Mar. Sci. 12:  539 pp.

Wolcott, T.G. and A.H. Hines. 1996.  Advances in ultrasonic biotelemetry for animal movement and behavior: the blue crab case study. In: Lang, M.A. and C.C. Baldwin (eds.).  Methods and Techniques of Underwater Research. Proceedings of the American Academy of Underwater Sciences, Smithsonian Institution, Washington, D.C. Pp. 229-236.  

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