INTROPICA

23-32

Authors: Alix Barreto Hernández, Luz Adriana Velasco

In order to create a collection of marine benthic microalgae from the Colombian Caribbean, some strains were isolated and cultured under different temperature conditions. From periphyton samples of PVC plates placed in the rocky intertidal of Taganga, Santa Marta (Colombia), the type and number of isolated species, as well as the density and relative growth constant (K) of three of the isolated strains were assessed under three different temperatures (20, 25 and 28 °C). Constant conditions of culture medium Guillard F/2 (250 ml), artificial light (1500 lux) and initial values of salinity of 30‰ and pH of 7,0 were maintained. Five benthic microalgae strains were isolated at 20 °C (Cylindrotheca closterium, Komvophoron crissum, Tetraselmis sp. and 2 morphotypes de la familia Bacillariaceae); at 25 and 28 °C, none of the strains was obtained. In the diatom identified as Bacillariaceae diatom morphotype 1, the highest values of cell density (96,3 x 105 cells.ml -1) and K (1,03 div.day-1), were obtained at temperatures of 20 and 25 °C, while it was impossible to obtain their growth at 28 °C. Conversely, in the microalgae Cylindrotheca closterium and Tetraselmis sp. higher density values (2,6 and 7,7 x 105 cells ml-1, respectively ) were obtained in the 25 °C treatment, while the highest values of K occurred at 28 °C (0,64 and 0,60 div.d-1, respectively). This study allowed starting a collection of benthic marine microalgae, as well as to determine the most suitable temperatures for the microalgae isolation (20 °C) and cell production of Bacillariaceae morphotype 1, Cylindrotheca closterium and Tetraselmis sp. (25 °C).

43-59

Authors: Marcela de Avellar-Mascarello, Martin García Cartagena, Eddy Jara Torres

Ecuador (1989) and Sri Lanka (1990) began their Integrated Coastal Zone Management (ICZM) Processes through the same International Cooperation funds, counseling and evaluation. Taking these facts into account, we developed a comparative analysis of their Integrated Coastal Zone Management processes. Using the GESAMP ICZM cycle conceptual framework, and through an extensive literature and document review on the subject, both processes were analyzed in order to determine their strengths and weaknesses and evaluate the GESAMP cycle conceptual framework as an analysis tool. What appeared to be similar processes, turned out to be very different. Ecuador showed a more participatory approach towards ICZM plan design and implementation from the beginning, while Sri Lanka only implemented this approach in its third ICZM generation plan. On the other hand, Sri Lanka had a more institutional program, thus generating from the outset a better and more organized institutional framework for ICZM than Ecuador. Both countries have achieved first-order results (institutional changes), second-order ones (behavioral changes), and possibly third-order ones too (socio-ecological indicator improvements). We conclude through this paper that participatory approaches, political will, effective evaluation processes and international aid are fundamental elements for successful ICZM processes. We also conclude that the conceptual framework proposed by GESAMP is a very important theoretical analysis tool through which ICZM processes can be analyzed. But this theoretical tool should be revised and tested through empirically based analysis on other international ICZM application study cases.

75-83

Authors: Jorge Luna-Fontalvo, Adriana Rodríguez-Forero, Jonathan Sarmiento-Rodríguez

The bacterial and fungal communities associated to the skin and digestive tract of Isostichopus badionotus were identified in order to evaluate the antagonistic interactions among them. For this purpose, surface smears were made to the epidermis and digestive tract, and this smears were grown in bacteria – and fungi – specific culture media. The identification of microorganisms was performed considering colonial morphology on culture media and microscopic features. Also, biochemical tests through BBL Crystal® micromethods for Gram negative and Gram positive bacteria were applied to the purified bacterial colonies. The fungi were identified through microscopic observations and using taxonomic keys. The bacterial strains’ inhibitory activity was analyzed by the agar diffusion disk method. Results showed a total of 42 isolated bacterial strains from which ten species were selected for taxonomic identification: Bacillus cereus, B. subtilis, Bacillus megaterium, Corynebacterium aquaticum, Proteus vulgaris, P. mirabilis, Enterobacter agglomerans, Serratia marcescens, Pseudomonas maltophilia, and Acinetobacter anitratus. Confrontation among these bacterial species did not show growth inhibitory activity. A total of 27 fungal strains were isolated, from which eight species were identified: Penicillium sp., Paecilomyces sp., Aspergillus sp., Aspergillus niger, A. flavus, Gliocladium sp., Cladosporium fulvum and C. herbarum. Fungal species showed inhibitory effects in dual confrontation tests. The identified species could correspond to the normal microbiota of the cucumber or to the microbiota associated to the water and/or the sediment, thus further studies are needed to confirm the obtained results.

92-101

Authors: Martha Mogollón, María Paulina Aycardi, Jorge Galeano, Javier Villalobos, Carolina Arango

In seven sectors of the old delta Sinú River and at different hydrological times some limnological characteristics were evaluated and there were identified cyanoprokariotes that were present in the system, taking into account morphological characteristics and organizational levels. The results were analyzed taking into account their environmental differences. A total of 49 morphospecies were identified, distributed in 4 orders, 8 families and 14 genera such as: Microcystis, Merimopedia, Dolichospermum, Aphanocapsa, Anabaenopsis, Lyngbya, Oscillatoria, Pseudanabaena, Stigonema, Gomphosphaeri and Planktolyngbya and this representation varies according to the salinity gradient, nitrates concentration and ammonium in the system.

111-117

Authors: Alina Villa, Diana Herazo, Ana Carolina Torregroza

Growth of Chaetoceros calcitrans was evaluated in a static system at 35 ppt salinity and different photoperiods 0:24, 6:18, 10:14 y 24:0 hours light:dark. Bioassays were performed in bottles of 200 ml in quadruplicate under controlled laboratory conditions, using the medium F/2. Light, temperature, pH and direct cell counts, were monitored every 48 hours. The photoperiod directly affected cell concentration and growth rate of C. calcitrans, being higher with 24 h/light, with values of 2'713,333 cel.ml-1 and 0.17 div.day-1, while the low cell concentration and growth rate were 0 cel.ml-1 and -0.03 div.dia-1, respectively with 0 h/light. A positive linear relationship (r= 0.567; F(1,10)=4.754; P>0.05) was observed between photoperiod and algal growth rate. The pH ranged between 6.7 and 7.5 with values tended to decrease in all treatments with the time. A negative correlation between pH and cell density of C. calcitrans (r2= -0.369) was detected. The results indicate that the growth of C. calcitrans is determined by photoperiod with optimal growth at continuous light.

129-136

Authors: Rubén Darío Rivera-Fernández, Oswaldo Valarezo-Beltron, Leonardo Vera-Macías, Jesús Enrique Chavarría-Párraga, Ángel Monserrate Guzmán-Cedeño

The witches’ broom disease in the main phytosanitary problem of cocoa and its management is a function of pod removal, however, their efficiency is subject to application time. The aim was to establish the right time in summer season. Pruning the plant was studied in two months in the summer season. The first in August (1-15) and the second in December (1-15). Clones 575 and 576 of 15 years cocoa with a planting density of 1111 pl.ha-1 was used as experimental material. The life cycle of Moniliophthora perniciosa was identified: inoculation, incubation and infection, taken the time in days for each stage. Furthermore, after the pruning infections, bearings and ears were counted, and thus the average number of infections per tree was obtained. Between 10 and 15 January sporulation of the fungus starts. The presence of symptoms was observed 45,6 ± 0,9 days after sporulation. The parasitic phase was 39,4 ± 9,22 days and total necrosis was 10,11 ± 3,4 days. After the phytosanitary pruning in August, new formations of M. perniciosa were able to form basidiocarps in subsequent winter season. In December the fungus were not capable of forming basidiocarps. The evidence shows the influence of plant pruning in December on the biological cycle of M. perniciosa and infestation levels of cocoa.