Hector M . Guzman
Smithsonian Tropical Research Institute, Naos Marine Lab, Department Member
Warming events in the Pacific Ocean are becoming more frequent, intense, and on a larger temporal and spatial scale. This has caused critical habitats of marine species to lose their quality and marine organisms respond by modifying their... more
Warming events in the Pacific Ocean are becoming more frequent, intense, and on a larger temporal and spatial scale. This has caused critical habitats of marine species to lose their quality and marine organisms respond by modifying their critical feeding and reproduction behaviors, as well as their distribution. The Northeast Pacific humpback whale of the Central America distinct population segment (DPS) remains Endangered due to its small population size and because its response to climate change and human interventions is unknown. In this work, we showed the encounter rates of humpback whales in their breeding grounds in Costa Rica for breeding seasons comprised in the period 2000-2020. We analyze the influence of climatic indices that influence the Pacific and environmental variables related to temperature and productivity in the feeding grounds of this population (United States). We hypothesize that the more intense the warming events, the fewer humpback whales complete their m...
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Chemical examination of the octocoral-associated Bacillus species (sp.) DT001 led to the isolation of pumilacidins A (1) and C (2). We investigated the effect of these compounds on the viability of Plasmodium falciparum and the mechanism... more
Chemical examination of the octocoral-associated Bacillus species (sp.) DT001 led to the isolation of pumilacidins A (1) and C (2). We investigated the effect of these compounds on the viability of Plasmodium falciparum and the mechanism of pumilacidin-induced death. The use of inhibitors of protein kinase C (PKC) and phosphoinositide 3-kinase (PI3K) was able to prevent the effects of pumilacidins A and C. The results indicated also that pumilacidins inhibit parasite growth via mitochondrial dysfunction and decreased cytosolic Ca2+.
Research Interests: Chemistry, Organic Chemistry, Biology, Calcium, Mitochondria, and 14 moreApoptosis, Medicine, Anthozoa, Animals, Bacillus, Peptides, Molecules, Plasmodium falciparum, Antimalarials, THEORETICAL AND COMPUTATIONAL CHEMISTRY, Coral Associated Bacteria, Protein Kinase Inhibitors, Molecular Structure, and Protein Kinase C
This work presents a methodology to automatically detect and identify manatee vocalizations in continuous passive acoustic underwater recordings. Given that vocalizations of each manatee present a slightly different frequency content, it... more
This work presents a methodology to automatically detect and identify manatee vocalizations in continuous passive acoustic underwater recordings. Given that vocalizations of each manatee present a slightly different frequency content, it is possible to identify individuals using a non-invasive acoustic approach. The recordings are processed in four stages, including detection, denoising, classification, and manatee counting and identification by vocalization clustering. The main contribution of this work is considering the vocalization spectrogram as an image (i.e., two-dimensional pattern) and representing it in terms of principal component analysis coefficients that feed a clustering approach. A performance study is carried out for each stage of the scheme. The methodology is tested to analyze three years of recordings from two wetlands in Panama to support ongoing efforts to estimate the manatee population.
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Research Interests: Biomass, Biodiversity and Ecosystem Function, Biology, Coral Reefs, Ecology, and 15 moreBiodiversity, Ecosystem health, Fish and Marine Ecology, Biological Sciences, Humans, Animals, Fishes, Coral Reef, Human impact, Ecosystem, BIODIVERSITY LOSS, Ecosystem Function, Conservation of Natural Resources, Environment, and Medical and Health Sciences
Abstract One new prenylated xanthone, 1, 5-dihydroxy-3-methoxy-4-isoprenylxanthone (1), along with four previously known prenylated xanthones, ananixanthone (2), 1, 3, 7-trihydroxy-2, 4-diisoprenylaxnthone (3), 8-desoxygartanin (4), and... more
Abstract One new prenylated xanthone, 1, 5-dihydroxy-3-methoxy-4-isoprenylxanthone (1), along with four previously known prenylated xanthones, ananixanthone (2), 1, 3, 7-trihydroxy-2, 4-diisoprenylaxnthone (3), 8-desoxygartanin (4), and toxyloxanthone A (5), ...
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Research Interests: Chemistry, Mass Spectrometry, Macrophages, Magnetic Resonance Spectroscopy, Medicine, and 14 morePanama, Anthozoa, Mice, Nitric oxide, Animals, Stereochemistry, Anti-inflammatory agents, Lipopolysaccharides, Diterpenes, Ketone, Marine Drugs, Minimum inhibitory concentration, Pharmacology and pharmaceutical sciences, and Minimum Inhibitory Concentration
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The shallow waters of the Tropical Eastern Pacific (TEP) harbor a species-rich octocoral fauna, with seven genera and 124 octocoral species described to date for the region. Of these lineages, Pacifigorgia, with 35 species, is by far the... more
The shallow waters of the Tropical Eastern Pacific (TEP) harbor a species-rich octocoral fauna, with seven genera and 124 octocoral species described to date for the region. Of these lineages, Pacifigorgia, with 35 species, is by far the most speciose and abundant shallow-water octocoral occurring in the region. The speciation mechanisms resulting in this remarkable diversity remain speculative, despite the extensive taxonomic and molecular systematic research conducted so far in the TEP. Using genome-wide SNP markers, we provide evidence for hybridization and extensive cryptic speciation in Pacifigorgia, suggesting that the genus’ diversity has been underestimated by traditional and molecular systematic research. Our study highlights the difficulties faced by both traditional taxonomy and single-marker based molecular approaches to characterize octocoral diversity and evolution, and the role genome-wide molecular studies coupled to morphological research play to advance our underst...
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Se estimo la tasa de bioerosion interna y externa sobre colonias muertas de Orbicella annularis en el arrecife de Playa Mero del Parque Nacional Morrocoy (estado Falcon, Venezuela), como parte de una evaluacion preliminar de los... more
Se estimo la tasa de bioerosion interna y externa sobre colonias muertas de Orbicella annularis en el arrecife de Playa Mero del Parque Nacional Morrocoy (estado Falcon, Venezuela), como parte de una evaluacion preliminar de los potenciales efectos de la perdida de esqueleto coralino en la estructura del arrecife y el reclutamiento de especies tras la mortandad masiva de corales ocurrida en el Parque Nacional durante el ano 1996. Se realizaron colectas aleatorias de 12 pilares de colonias de O. annularis a profundidades de tres, seis y nueve metros, respectivamente. Posteriormente, siguiendo el eje principal de crecimiento, cada colonia fue cortada a un espesor de 10 mm y fotografiadas mediante rayos X para la deteccion de huellas correspondientes a grupos bioerosionadores. Para cada corte y huella se determino el area de superficie erosionada (𝑘𝑔.𝑚−2.𝑎n𝑜−1), las tasas de bioerosion externa a partir del ancho de las bandas de crecimiento coralino anual (#𝑏𝑎𝑛𝑑𝑎𝑠.𝑎n𝑜−1) y el Indice de...
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Gorgonian octocorals are considered a prolific source of secondary metabolites with a wide range of biological activities, including anti-inflammatory activity. In particular, the genus Briareum is known for producing a wealth of... more
Gorgonian octocorals are considered a prolific source of secondary metabolites with a wide range of biological activities, including anti-inflammatory activity. In particular, the genus Briareum is known for producing a wealth of diterpenes with complex chemical structures. The chemical study of the methanolic extract of Briareum asbestinum collected in Bocas del Toro, on the Caribbean side of Panama, led to the isolation of three new eunicellin-type diterpenes: briarellin T (1), asbestinin 27 (2), asbestinin 28 (3) and the previously described asbestinin 17 (4). The structures of the new compounds were determined by extensive NMR analyses and HRMS. Anti-inflammatory activity assays showed a significant reduction of the pro-inflammatory cytokines TNF-α, IL-6, IL-1β and IL-8 as well as a downregulation of COX-2 expression in LPS-stimulated THP-1 macrophages. These findings support the potential use of these marine compounds as therapeutic agents in the treatment of inflammatory disea...
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Pseudoalteromonas is a genus of marine bacteria often found in association with other organisms. Although several studies have examined Pseudoalteromonas diversity and their antimicrobial activity, its diversity in tropical environments... more
Pseudoalteromonas is a genus of marine bacteria often found in association with other organisms. Although several studies have examined Pseudoalteromonas diversity and their antimicrobial activity, its diversity in tropical environments is largely unexplored. We investigated the diversity of Pseudoalteromonas in marine environments of Panama using a multilocus phylogenetic approach. Furthermore we tested their antimicrobial capacity and evaluated the effect of recombination and mutation in shaping their phylogenetic relationships. The reconstruction of clonal relationships among 78 strains including 15 reference Pseudoalteromonas species revealed 43 clonal lineages, divided in pigmented and non-pigmented strains. In total, 39 strains displayed moderate to high activity against Gram-positive and Gram-negative bacteria and fungi. Linkage disequilibrium analyses showed that the Pseudoalteromonas strains of Panama have a highly clonal structure and that, although present, recombination ...
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Coastal ecosystems and the livelihoods they support are threatened by stressors acting at global and local scales. Here we used the data produced by the Caribbean Coastal Marine Productivity program (CARICOMP), the longest, largest... more
Coastal ecosystems and the livelihoods they support are threatened by stressors acting at global and local scales. Here we used the data produced by the Caribbean Coastal Marine Productivity program (CARICOMP), the longest, largest monitoring program in the wider Caribbean, to evidence local-scale (decreases in water quality) and global-scale (increases in temperature) stressors across the basin. Trend analyses showed that visibility decreased at 42% of the stations, indicating that local-scale chronic stressors are widespread. On the other hand, only 18% of the stations showed increases in water temperature that would be expected from global warming, partially reflecting the limits in detecting trends due to inherent natural variability of temperature data. Decreases in visibility were associated with increased human density. However, this link can be decoupled by environmental factors, with conditions that increase the flush of water, dampening the effects of human influence. Besi...
Research Interests: Environmental Science, Climate Change, Environmental Monitoring, Medicine, Environmental Change, and 14 moreMultidisciplinary, Humans, Salinity, Habitat, Temperature, Seawater, Caribbean region, PLoS one, Ecosystem, Threatened Species, Agricultural and Biological Sciences, Conservation of Natural Resources, Stress Physiological, and stressor
Latitudinal preferences within the breeding range have been suggested for Breeding Stock G humpback whales that summer in different feeding areas of the eastern South Pacific. To address this hypothesis, humpback whales photo‐identified... more
Latitudinal preferences within the breeding range have been suggested for Breeding Stock G humpback whales that summer in different feeding areas of the eastern South Pacific. To address this hypothesis, humpback whales photo‐identified from the Antarctic Peninsula and the Fueguian Archipelago (southern Chile) were compared with whales photo‐identified from lower latitudes extending from northern Peru to Costa Rica. This comparison was performed over a time span that includes 18 austral seasons. A total of 238 whales identified from the Antarctic Peninsula and 25 whales from the Fueguian Archipelago were among those photo‐identified at the breeding grounds. Our findings showed that humpback whales from each feeding area were resighted unevenly across the breeding grounds, which suggests a degree of spatial structuring in the migratory pathway. Humpback whales that feed at the Antarctic Peninsula were more likely to migrate to the southern breeding range between northern Peru and Col...
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Research Interests: Evolutionary Biology, Geology, Biology, Ecology, Panama, and 3 moreArctic, Archipelago, and Growth rate
A new pedunculate aplysinid sponge, Aplysina chiriquiensis, is described from shallow waters (1.5–35 m) in the Gulf of Chiriquí, western Panamá, Eastern Pacific. The species chiriquiensis is a common component of coral reefs and soft... more
A new pedunculate aplysinid sponge, Aplysina chiriquiensis, is described from shallow waters (1.5–35 m) in the Gulf of Chiriquí, western Panamá, Eastern Pacific. The species chiriquiensis is a common component of coral reefs and soft coral reefs in that region. After examining the systematic status of related taxa we conclude that there are only two valid taxa of stalked Aplysina, A. bathyphila Maldonado and Young from the Caribbean, and our new species from the eastern Pacific. A. chiriquiens is a yellow to purplish, stalked and branching sponge with oscules arranged in one or more rows along the branches. The branches can be cylindrical with smooth tapering ends, or stubby and laterally compressed. A. chiriquiensis is the first Aplysina species described from Panamá, and its distribution elsewhere in tropical and subtropical Eastern Pacific has yet to be evaluated.
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Species of the genus Pacifigorgia are surveyed for the first time in the shallow Pacific seas off Costa Rica. They are identified and described with detailed illustrations. The main collection belongs to the Zoology Museum, University of... more
Species of the genus Pacifigorgia are surveyed for the first time in the shallow Pacific seas off Costa Rica. They are identified and described with detailed illustrations. The main collection belongs to the Zoology Museum, University of Costa Rica. Most of this material has been collected by means of SCUBA. This regional account of Pacifigorgia includes four species that were previously described: P. adamsii, P. eximia, P. irene and P. stenobrochis, and another nine that are new species.
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Leptogorgia ignitais a new gorgonian species characterized by its conspicuous bright orange colour, irregular branching pattern and combination of sclerite types in the coenenchyme, all of the same orange colour, with abundance of... more
Leptogorgia ignitais a new gorgonian species characterized by its conspicuous bright orange colour, irregular branching pattern and combination of sclerite types in the coenenchyme, all of the same orange colour, with abundance of capstans and blunt spindles, and less abundant acute spindles. The species was found in a shallow water coral community, 4–12 m deep in Samara Bay, Pacific Costa Rica. Morphologically,L. ignitabelongs to theL. rigida-group comprising eight species for the group; 13Leptogorgiaspecies are known for Costa Rica, and 23 for the entire eastern Pacific. The new species is described, illustrated and compared to the other valid taxa of the group.
Research Interests: Zoology, Plant Biology, Biology, Ecology, Anthozoa, and 5 moreTropical Eastern Pacific, Coral, Gorgonian, Bay, and Octocorallia
The genus Heterogorgia is reported for the first time from the shallow waters of the Galápagos Archipelago, and a new species found in the southern islands is described. The new species is distinguished from the other species of the genus... more
The genus Heterogorgia is reported for the first time from the shallow waters of the Galápagos Archipelago, and a new species found in the southern islands is described. The new species is distinguished from the other species of the genus described thus far by having thick branches with large, densely packed calyces, being mostly unbranched, and having larger sclerites. The occurrence of Heterogorgia verrucosa is also reported.
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Resumen: The coral reefs at Isla del Caño, Costa Rica, were apparently affected by the 1982/83 El Niño Southern Oscillation warming event. In January 1984 a survey around the island showed a mean live and death coral cover of 5.4% and... more
Resumen: The coral reefs at Isla del Caño, Costa Rica, were apparently affected by the 1982/83 El Niño Southern Oscillation warming event. In January 1984 a survey around the island showed a mean live and death coral cover of 5.4% and 30.26% respectively. Based ...
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FIGURE 10. Eugorgia multifida (YPM 4605), coenenchymal sclerites.
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The species of the genus Psammogorgia Verrill, 1868 from the shallow waters of the tropical eastern Pacific were mainly described from 1846 to 1870. Very few contributions were published subsequently. Recently, the genus was revisited... more
The species of the genus Psammogorgia Verrill, 1868 from the shallow waters of the tropical eastern Pacific were mainly described from 1846 to 1870. Very few contributions were published subsequently. Recently, the genus was revisited with the addition of two new species. However, a comprehensive generic study is still missing for the eastern Pacific. Psammogorgia is characterised by having axes cores without mineralisation, mainly coarse irregular spindles and thorny, leafy or tuberculate clubs coenenchymal sclerites and the anthocodial armature with distinct collaret and points arrangements. Herein a taxonomic revision of the genus is presented based on type material which was morphologically analysed and illustrated using optical and scanning electron microscopy. Comparative character tables are provided for comparison among species in the genus, along with a taxonomic key. Moreover, the taxonomic status of each species was analysed. The genus Psammogorgia comprises six valid spe...
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En estudios anteriores se encontró que el área protegida del Parque Nacional M arino de Isla B astimentas (PNMIB) no albergaba arrecifes en buen estado de conservación, desarrollo y diversidad, n:comcndándosc ampliar el reconocimiento de... more
En estudios anteriores se encontró que el área protegida del Parque Nacional M arino de Isla B astimentas (PNMIB) no albergaba arrecifes en buen estado de conservación, desarrollo y diversidad, n:comcndándosc ampliar el reconocimiento de arrecifes a otras áreas del archipiélago de Bocas del Toro, en particular el sector oriental del parque marino. En el presente estudio, se hizo un reconocimiento - ca. J 07 .5 km en total - detallado de la zona costera insular de islas Pastores, Cristóbal . Popa y Cayo Agua, donde se evalu ó la distribución de los arrecifes coralinos. Se describieron un total de 24 arrecifes, los cuales representan las formaciones típicas para l as distintas localidades. Se define por primera vez para el archipiélago el centro de mayor diversidad de organismos sésiles, que son importantes constructores de arrecies coralinos. El número de especies de corales escleractínidos para todo el archipiélago de Bocas del Toro aumentó a 57 y se actualizan también los registros...