José A. Vargas

Reconnaissance of selected PPCP compounds in Costa Rican surface waters.

Eighty-six water samples were collected in early 2009 from Costa Rican surface water and coastal locations for the analysis of 34 pharmaceutical and personal care product compounds (PPCPs). Sampling sites included areas receiving treated and untreated wastewaters, and urban and rural runoff. PPCPs were analyzed using a combination of solid phase extraction and liquid chromatography tandem mass spectrometry. The five most frequently detected compounds were doxycycline (77%), sulfadimethoxine (43%), salicylic acid (41%), triclosan (34%) and caffeine (29%). Caffeine had the maximum concentration of 1.1 mg L(-1), possibly due to coffee bean production facilities upstream. Other compounds found in high concentrations include: doxycycline (74 μg L(-1)), ibuprofen (37 μg L(-1)), gemfibrozil (17 μg L(-1)), acetominophen (13 μg L(-1)) and ketoprofen (10 μg L(-1)). The wastewater effluent collected from an oxidation pond had similar detection and concentrations of compounds compared to other studies reported in the literature. Waters receiving runoff from a nearby hospital showed higher concentrations than other areas for many PPCPs. Both caffeine and carbamazepine were found in low frequency compared to other studies, likely due to enhanced degradation and low usage, respectively. Overall concentrations of PPCPs in surface waters of Costa Rica are inline with currently reported occurrence data from around the world, with the exception of doxycycline.

The estuarine character of the Gulf of Nicoya, an embayment on the Pacific coast of Central America

Hydrography and exchange processes in a tropical estuary, the Gulf of Nicoya, Costa Rica, are described from data collected in 1979 and 1980. The measurements and analyses were made in both the dry season and wet season and include temperature, salinity, and density at twenty locations in the gulf and currents (over a semi-diurnal tidal cycle) at five locations. These new results enlarge on the early study by Peterson (1958). Circulation in the lower gulf shows a marked east-west asymmetry due to the predominant runoff along its eastern shore from Rio Barranca and Tarcoles. The freshened surface water from the upper gulf combines with the runoff from these rivers and flows southward along the eastern side of the lower gulf. This flow is compensated by a northward flow of more saline water on the western side at all depths and on the eastern side along the bottom. The boundary between the southward and northward surface flow is marked by a strong salinity front in the rainy season. There is a rapid increase in tidal energy density toward the shoaling northern reaches of the lower gulf, between San Lucas Island and Puntarenas Peninsula. Enhanced mixing must accompany this increase, and direct measurements in the constriction between San Lucas and Puntaneras show that tidal mixing is dominant in transporting salt into the upper gulf against the freshwater runoff.

Phenetic discrimination of biometric simpletons: Paleobiological implications of morphospecies in the lingulide brachiopod Glottidia

The extreme morphological simplicity of lingulide brachiopod shells makes them particularly useful for investigating the species-level taxonomic resolution of the fossil record as well as the relationships between taxonomy, morphological complexity, and evolutionary rates. Lingulides have undergone little change in shell morphology and have had low taxonomic diversity since the Paleozoic. Is this pattern an evolutionary phenomenon or an artifact of the shell9s simplicity? Multivariate methods were used to establish morphogroups among seven populations of four extant species of Glottidia. Six characters (three shell dimensions and three internal septa) were measured for 162 specimens from field and museum collections. All populations follow similar allometric trajectories: internal septa display positive allometry and shell dimensions display negative allometry. The allometric pattern may reflect D9Arcy Thompson9s Principle of Similitude. Principal component analysis does not reveal any distinct clusters in Glottidia morphospace but suggests that some differences independent from ontogeny exist among the populations. Size-free canonical variate analysis indicates the presence of five size-invariant groups that are statistically distinct. Bootstrap-corrected error rates indicate that four specimens are enough to classify a sample correctly at alpha = 0.05 and eight specimens at alpha = 0.01. The groups are consistent with neontological classification with the exception of two populations of G. pyramidata identified by discriminant analysis as two distinct groups. The size-free morphogroups reflect geographic separation rather than ontogenetic or substrate differences among the populations. Despite the morphological simplicity of the shell, size-free multivariate analysis of Glottidia delineates groups that offer taxonomic resolution comparable with the neontological classification. The method offers a promising tool for identifying natural morphogroups on the basis of few morphological characters. Moreover, the agreement between neontological taxonomy and the morphogroups suggests that the size-free approach can be applicable for evaluating the reality of the low diversity and turnover rates observed in the fossil record of lingulide brachiopods (= Family Lingulidae). Assuming that the neontological species of Glottidia are biologically meaningful, this study shows that morphological simplicity of lingulides does not necessarily result in taxonomic underresolution. Our analysis, as well as several previous case studies, suggests that taxonomic diversity and turnover rates do not have to be dependent on the morphological complexity of preservable parts. In many cases, when rigorous quantitative methods are employed, the differences in the rates of morphological evolution may be a real evolutionary phenomenon and not artifacts of morphological complexity.

The Gulf of Nicoya Estuary, Costa Rica: Past, present, and future cooperative research

The Gulf of Nicoya is a tectonic estuary on the Pacific coast of Costa Rica (10°N–85°W), extending about 100 km from the Tempisque river to the 500 m isobath. A dry season (December–April) and a rainy season (May–November) exert a significant impact on its water characteristics. The estuary is the most important fishing ground of Costa Rica, and the main Pacific ports are located within it. Coastal zone development has increased in recent years. In 1979 a research programme to study the Gulf was established at the University of Costa Rica, and foreign scientists were invited to work jointly with local experts to achieve the goals of the evaluation. More than 80 papers have been published to date, making the Gulf one of the best known tropical estuaries. The study of soft-bottom communities is an important component of this research programme. Past benthic research focused on the description of the structure of communities, while future efforts will find an unexplored field in the study of energy flow and community interactions. More than 200 species of fish, and 400 of benthic invertebrates have been identified. Future cooperative research is most welcome in larval ecology, interactions between size groups, and physiological tolerances. Considerable experience has been accumulated in the experimental manipulation of soft-bottom communities of high latitudes. This branch of ecology, however, remains little explored in the tropics. Future cooperative efforts in the Gulf of Nicoya will be established on solid ground, formed by a data base that has been improved since 1979, the existence of a marine research centre and a group of active, local scientists who have experience in working together with foreign expertise.

Distribution and transport of sediment-bound metal contaminants in the rio grande de tarcoles, costa rica (Central America)

Abstract A reconnaissance survey of the extent of metal contamination in the Rio Grande de Tarcoles river system of Costa Rica indicated high levels of chromium (Cr) in the fine-grain bed sediments ( μ m) of tributaries downstream from leather tanneries (50–83 times Cr background or 3000–5000 μg/g). In the main channel of the river downstream of the San Jose urban area, Cr contamination in sediments was 4–6 times background and remained relatively constant over 50 km to the mouth of the river. Sediments from a mangrove swamp at the river mouth had Cr levels 2–3 times above background. Similar patterns of dilution were observed for lead (Pb) and zinc (Zn) sediment contamination, although the contamination levels were lower. The high affinity of Cr towards particulate phases, probably as Cr(III), allows the use of Cr contamination levels for delineating regions of deposition of fine-grained sediments and dilution of particle associated contaminants during transport and deposition.

Tropical Tidal Flat Benthos Compared Between Australia and Central America

At all latitudes, tidal flats occur along the shorelines of the world’s oceans, covering areas up to thousands of square kilometers (Veenstra 1976; Mathieson and Nienhuis 1991). These soft-sediment environments provide habitat for a species-rich and abundant benthic fauna. As an ecotone between the land and the sea, tidal flats often function as a turntable, both for certain life stages of various organisms, as well as for energy and matter (Reise 1985; Gatje and Reise 1998). From decades of intensive ecological studies, an understanding has grown of the processes that structure benthic communities in temperate tidal flats (Wolff 1983; Reise 1985). Yet, how universal are these processes and do they playa comparable role in tidal flats in tropical environmental settings?

Benthic invertebrates of a tropical estuary: Gulf of Nicoya, Costa Rica

Summary Crustaceans showed considerable differential distribution in response to a variety of features. Portunid crabs may be responding to salinity gradients, peak abundance of shrimp may be associated with detritus from rivers flowing into the Gulf and mantis shrimp may be influenced by sediment type and biotic interactions. Because of the ecologic and economic value of crustaceans these findings are significant in terms of red tides (Hargraves and Viquez 1981) and potential perturbations in the Gulf of Nicoya. Differences between shallow tropical marine ecosystems and temperate counter-parts concern chemical and physical characteristics (temperature, light, rainfall, nutrients), community structure (species diversity, population density, biomass), and biological functions (primary productivity, growth rates, resource sharing) (Johannes and Betzer 1975). Spight (1977) posed some generalizations concerning differences between tropical marine and temperate communities. These generalizations included: (1) ...