Smiths, Bermuda
Smiths, Bermuda

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Fourqurean J.W.,Florida International University | Manuel S.,Applied Ecology Section | Coates K.A.,Applied Ecology Section | Kenworthy W.J.,National Oceanic and Atmospheric Administration | Smith S.R.,Bermuda Aquarium
Marine Ecology Progress Series | Year: 2010

Protecting a Thalassia testudinum-dominated seagrass meadow from grazing by sea turtles for 1 yr caused an increase in the biomass of seagrasses and an increase in the structural complexity of the seagrass canopy, as the length and width of the seagrass blades increased in comparison to grazed plots. Plots from which turtles were excluded had higher rates of primary production on a per-shoot or areal basis, but the relative growth rate was not affected. The leaves of seagrasses protected from grazing had lower concentrations of nitrogen and phosphorus than grazed blades, but the storage of soluble carbohydrates in the rhizomes increased markedly in the protected plots, suggesting that reduced carbon fixation caused by the removal of photosynthetic leaves is the mechanism for seagrass decline in heavily grazed meadows, not nutrient limitation as has been suggested in the literature. The continued grazing of sea turtles in our plots did not lead to significant changes in seagrass shoot density or nutrient content over the 1 yr duration of our experiments. The decreased canopy cover and the shorter, thinner seagrass leaves induced by sea turtle grazing in our experimental plots suggest that the progressive narrowing and thinning of seagrasses observed before the collapse of 2 offshore seagrass beds in Bermuda during the 1990s may have been in response to repeated and intense grazing of those seagrass beds. © Inter-Research 2010.


Dirks U.,University of Vienna | Gruber-Vodicka H.R.,University of Vienna | Leisch N.,University of Vienna | Sterrer W.,Bermuda Aquarium | Ott J.A.,University of Vienna
Marine Biology Research | Year: 2011

Paracatenula galateia sp. nov. is a mouthless marine catenulid platyhelminth with bacterial intracellular endosymbionts. The worms live in shallow back-reef sands in the Belize Barrier Reef system and are distinguished from the four previously described members of the genus by their large size combined with a ribbon-shaped body and characteristic bipartite inclusions in cells, which are interpreted as sperm. The bacteria are presumed to be sulphur-oxidizing chemoautotrophs. They are found in bacteriocytes which fill the body region ('trophosome region') posterior to the brain, whereas the anterior part of the worm (rostrum) is bacteria-free. Phalloidin staining reveals a delicate system of subepitheliar circular and longitudinal muscles and dorsoventral fibres. The serotonergic nervous system consists of a brain at the base of the rostrum and longitudinal fibres extending both anteriorly and posteriorly, the latter being concentrated in a structure called the 'dorsal cord'. © 2011 Taylor and Francis Group, LLC.


Meylan P.A.,Eckerd College | Meylan A.B.,Florida Fish And Wildlife Conservation Commission | Gray J.A.,Bermuda Aquarium
Bulletin of the American Museum of Natural History | Year: 2011

The existence of ontogenetic shifts in habitat by marine turtles, and of immature-dominated assemblages in "developmental habitat," were important concepts first proposed by Archie Carr in 1956. Results of long-term, in-water capture programs in Caribbean Panama (17 yr) and Bermuda (37 yr) allow the testing and refinement of these ideas, in particular the developmental habitat hypothesis for Chelonia mydas, Eretmochelys imbricata, and Caretta caretta. A literature survey reviews worldwide studies on these species, and also incorporates Lepidochelys kempii. The studies in Panama and Bermuda reported in this paper use netting, mark/recapture, laparoscopy, and satellite telemetry to investigate size distributions, maturity status, residency, site fidelity, and developmental migrations of three species of sea turtles at three study sites. Characteristics of benthic developmental habitat of C. mydas, E. imbricata, L. kempii, and, to a lesser extent, C. caretta in the Atlantic Ocean usually include benthic feeding; exclusive or nearly exclusive occupation by immature animals; seasonal or multiyear residency and site fidelity in specific areas; developmental migration from the habitat before maturation; and high genetic diversity. Variation of these traits worldwide, contradictory evidence regarding the concept of developmental habitat, and evolution of this life stage are presented. Laparoscopic data provide information concerning the process of sexual maturation; mean size and size range are presented for three maturity stages of C. mydas from Panama and Bermuda, and for size at onset of puberty and maturity for Eretmochelys and Caretta in the West Atlantic. Nicaragua is the primary site of recovery of immature green turtles tagged in Bermuda, representing a developmental migration of at least 2800 km. To the extent that tag returns and stranding data represent good proxies for mortality, transitions between life stages appear to be periods of decreased survivorship. © American Museum of Natural History 2011.


Leisch N.,University of Vienna | Dirks U.,University of Vienna | Gruber-Vodicka H.R.,University of Vienna | Schmid M.,University of Vienna | And 2 more authors.
Zoomorphology | Year: 2011

Marine catenulid platyhelminths of the genus Paracatenula lack mouth, pharynx and gut. They live in a symbiosis with intracellular bacteria which are restricted to the body region posterior to the brain. The symbiont-housing cells (bacteriocytes) collectively form the trophosome tissue, which functionally replaces the digestive tract. It constitutes the largest part of the body and is the most important synapomorphy of this group. While some other features of the Paracatenula anatomy have already been analyzed, an in-depth analysis of the trophosome region was missing. Here, we identify and characterize the composition of the trophosome and its surrounding tissue by analyzing series of ultra-thin cross-sections of the species Paracatenula cf. polyhymnia. For the first time, a protonephridium is detected in a Paracatenula species, but it is morphologically reduced and most likely not functional. Cells containing needle-like inclusions in the reference species Paracatenula polyhymnia Sterrer and Rieger, 1974 were thought to be sperm, and the inclusions interpreted as the sperm nucleus. Our analysis of similar cells and their inclusions by EDX and Raman microspectroscopy documents an inorganic spicule consisting of a unique magnesium-phosphate compound. Furthermore, we identify the neoblast stem cells located underneath the epidermis. Except for the modifications due to the symbiotic lifestyle and the enigmatic spicule cells, the organization of Paracatenula cf. polyhymnia conforms to that of the Catenulida in all studied aspects. Therefore, this species represents an excellent model system for further studies of host adaptation to an obligate symbiotic lifestyle. © 2011 The Author(s).


News Article | February 15, 2017
Site: www.eurekalert.org

A new study argues we should not count on deep coral reefs as a 'lifeline' for shallow reefs Dr Pim Bongaerts, a Research Fellow at The University of Queensland's Global Change Institute (GCI) and ARC Centre of Excellence for Coral Reef Studies, and lead author of the study, said deep reefs share coral species with the shallow reef, which has led to the idea that deep reefs could be an important source of larvae and help to 'reseed' shallow reefs. "We argue that this concept of deep coral populations 'reseeding' their shallow-water counterparts may be relevant to some species, but is ultimately unlikely to aid more broadly in the recovery of shallow reefs," he said. Given the impossibility of tracking the movements of individual coral larvae on the reef, understanding the 'connectivity' between shallow and deep coral populations relies on methods that assess the genetic similarity between coral populations. The team focused on the relatively isolated reef system of Bermuda in the Western Atlantic where they screened the genomes of more than 200 individual coral colonies from shallow and deep water, belonging to two coral species with similar depth distributions on the reef. The study demonstrates that the extent of 'connectivity' between shallow and deep populations can differ greatly between species on a reef, and can be strongly affected by natural selection processes that vary across shallow and deep reef environments. Director of GCI, and co-author, Professor Ove Hoegh-Guldberg said deep coral reefs had been highlighted as holding hope for shallow reefs that were badly damaged by bleaching events. "Our results, however, contribute to a growing body of evidence, that the role of deep reefs in shallow-reef recovery is likely to be very limited," he said. According to Dr Bongaerts, the study once again highlights that under the increasing disturbances that coral reefs continue to face, they are unlikely to just 'sort themselves out'. "Instead, the responsibility for their future lies with us. If we want to have any chance of preserving these unique and diverse ecosystems, it is crucial that we start curbing our emissions and divest from fossil fuels," he said. The research, published in Science Advances, was undertaken as part of the XL Catlin Seaview Survey, funded by XL Catlin in partnership with The Ocean Agency, GCI at The University of Queensland, and the ARC Centre for Excellence in Coral Reef Studies at the University of Queensland. The research was carried out with the support of the Bermuda Institute of Ocean Sciences and the Bermuda Aquarium, Museum and Zoo.

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