David L. Ballantine

Population dynamics and toxicity of natural populations of benthic dinoflagellates in southwestern Puerto Rico

Abstract Population dynamics of two benthic dinoflagellates, which have been implicated in ciguatera fish poisoning, were studied over a 3-yr period in southwestern Puerto Rico. Ostreopsis lenticularis Fukuyo and Gambierdiscus toxicus Adachi et Fukuyo populations were not strongly correlated with temperature or rainfall, however, both dinoflagellates did display seasonal fluctuations. Crude methanolic extracts of wild cell O. lenticularis varied in toxicity from nontoxic to 182 MU · cell −1 (× 10 6 ). Toxic materials found in the aqueous methanolic extracts were not soluble in ethyl acetate, a more nonpolar solvent. Peak toxicities in wild O. lenticularis cells recurred in October 1985 and October 1986. While additional data are needed, present results suggest a seasonality in Ostreopsis toxicity as well.

Effects of the Caribbean threespot damselfish, Stegastes Planifrons (Cuvier), on algal lawn composition

Abstract Algal lawn communities within territories of herbivorous threespot damselfish, Stegastes planifrons (Cuvier) were studied in a shallow back-reef environment at La Parguera, Puerto Rico. Caging exclusion experiments, monitoring of non-manipulated lawns and gut content analyses were used to determine the effect of S. planifrons on algal species composition of the lawn. An average of 40 algal species per sampling period were found in naturally occuring lawns, with a total of 53 species being recorded throughout the course of study. Examination of algal species found in damselfish guts and comparison with natural lawns indicate that damselfish feed primarily on their algal lawns and graze the algae present in proportion to abundance. Caged algal lawns showed significant decline in algal species number and abundance over time. Non-selective feeding by Stegastes planifrons within their territorial lawns appears to result in an “intermediate disturbance” which maintains a greater algal species richness than is found in their absence.

Biogenesis and Biological Function of Marine Algal Oxylipins

The biogenetic source of most marine algal oxylipins, which are many and of diverse structure, can logically be unified through a common lipoxygenase-derived hydroperoxide to epoxy allylic carbocation transformation. The biological role of oxylipins in algae remains an enigma, although numerous ideas have been put forth. Herein, we hypothesize and provide some evidence for an osmoregulatory role for these metabolites.

Effects of culture conditions on production of antibiotically active metabolites by the marine alga Spyridia filamentosa (Ceramiaceae, Rhodophyta). I. Light

The effect of irradiance over the range 5 to 70 μmol photon m−2 s−1 on production of antibiotically active metabolites was assessed for male and female gametophytes and tetrasporophytes of the red alga Sphyridia filamentosa (Wulfen) Harvey in Hooker in culture. Whole-algal extracts and ten recognizable TLC-separable zones were assayed against five human microorganisms pathogenic to humans. For all experimental irradiance conditions, the ten TLC zones displayed activity against four of the microorganisms. The maximum number of TLC zones with activity under any of the culture conditions was six each for male and female Spyridia at 70 μmol photon m−2 s−1. Small changes in irradiance resulted both in different activities against specific microorganisms and degree of activity. The fact that every TLC zone showed differing activities at different light conditions or when extracted from different life history stages strongly suggests the presence of multiple antibiotic principals in individual TLC zones.

The genus Hypoglossum Kützing (Delesseriaceae, Rhodophyta) in the tropical western Atlantic, including H. anomalum sp. nov.

Observations are made on the occurrence and distribution of the red algal genus Hypoglossum Kützing (Delesseriaceae, Ceramiales) in the tropical western Atlantic. In addition to the type of the genus, H. hypoglossoides (Stackh.) Coll. & Herv., three other species are reported: H. anomalum sp. nov., H. involvens (Harv.) J. Ag., and H. tenuifolium (Harv.) J. Ag. A key is presented to distinguish these four species. The newly described species, H. anomalum, is like other species in the genus in that its branches arise endogenously from the primary axial row but it is unique in that the branches emerge from the parent blade at some point between the midline and the margin of the blade. The new species is reported from Puerto Rico and Florida.

Discovery of 12-(S)-hydroxy-5,8,10,14-icosatetraenoic acid [12-(S)-HETE] in the tropical red alga platysiphonia miniata

The potent mammalian immunohormone, 12-(S)-hydroxy-5,8,10,14-icosatetraenoic acid (12-(S)-HETE), is a 12-lipoxygenase metabolite of arachidonic acid that is widely distributed in animal tissues. In humans, it is produced and secreted by platelet cells and elicits both chemotactic and degranulatory responses in target neutrophils. As widely as 12-lipoxygenase activity and one of its major products, 12-(S)-HETE, have been found in animal tissues, it has never been found in plants. Herein, we report the first isolation of the 12-lipoxygenase product, 12-(S)-HETE, from a plant, the tropical marine alga Platysiphonia miniata (C. Agardh) Børgesen.

Notes on the Marine Algae of Puerto Rico. I. Additions to the Flora

Although the marine algal flora of Puerto Rico is the best known of all Caribbean islands, offshore and inshore collections continue to yield new species and new records. Recent collecting along the south and west coasts has led to the recognition of seven additional species for the flora. Collections were made with the use of SCUBA or by snorkeling. Specimens of all species have been deposited in the Herbarium of the Department of Marine Sciences, University of Puerto Rico (MSM), and duplicates are deposited in the Algal Collection of the U.S. National Herbarium, Smithsonian Institution (US). Herbarium abbreviations follow Holmgren et al. (1990) and authority abbreviations follow Brummitt and Powell (1992).

Dasya magnei sp. nov. (Dasyaceae, Rhodophyta) from the Caribbean Sea

Abstract Dasya magnei is newly described from Puerto Rico in the Caribbean Sea. The newspecies is principally characterized by its rhizoidal cortication and possession of verticillately arranged ultimate branchlets. Tetrasporangial stichidia are borne on proximal dichotomies of the ultimate branchlets and possess four sporangia per segment.

Opercular algal growth on the cichlid fish Tilapia aurea, cultured in sea water

Abstract Enteromorpha lingulata J. Agardh (Chlorophyta) and Giffordia mitchellae (Harvey) Hamel (Phaeophyta) were found growing on opercula of Tilapia aurea (Steindachner) cultured in sea water. Fish observed had mild Vibrio and Aeromonas bacterial infections, manifested by abscesses on their opercula and other areas of the body. Algal growth was observed only on the operculum, which appears to be a more suitable attachment site due to its bony nature. Abscessed areas on opercula were devoid of scales. Mechanical abrasion resulting in scale loss appears to provide a suitable attachment site for algae. Plants examined were small, up to 6 mm in length. Tufts of algae covered opercular abscesses. Fish did not appear to be attracted to tufts of algae growing on other fish; all fish appeared normal in behavior, exhibiting a positive response to feeding and satisfactory growth.

Revisiting the systematics of Ganonema (Liagoraceae, Rhodophyta) with emphasis on species from the northwest Pacific Ocean

Abstract: The genus Ganonema was distinguished from the other genera in the Liagoraceae morphologically by several reproductive and vegetative features, including spermatangia formed in dense, dendroidal clusters; carpogonial branches remaining unfused after fertilisation, having compact gonimoblasts; and medullary filaments being relatively broad. In addition, the generitype G. farinosum was uniquely characterised by its carpogonial branches being borne on small, specialised branches arising from the basal part of assimilatory filaments, a feature not seen in other species of Ganonema. Our molecular analyses, incorporating several species currently attributed to Ganonema, showed that the genus was polyphyletic and represented in three independent lineages, one including the generitype G. farinosum, a second including ‘G’ dendroideum, and a third containing three ‘Ganonema’ (‘G.’ clavatum, ‘G.’ borowitzkae and ‘G.’ samaense) from the northwest Pacific Ocean. We have therefore proposed two segregate genera, Gloiocallis gen. nov. for ‘G.’ dendroideum and Hommersandiophycus gen. nov. for ‘G.’ clavatum, ‘G.’ borowitzkae and ‘G.’ samaense. Morphologically, Gloiocallis differed from Ganonema and Hommersandiophycus in having only a few involucral filaments produced from the cortical cells above the supporting cell and most cells of the gonimoblasts differentiating into carposporangia. Hommersandiophycus can be separated from related genera by a combination of unfused carpogonial branches, involucral filaments produced from the cortical cells above and below the supporting cell and its neighbouring cells, carposporangia differentiating sequentially in chains of two to three and gonimoblasts being hemispherical to spherical. The taxonomy of other species currently placed in Ganonema but not analysed in this study requires further work.