Methane emissions from tropical freshwater wetlands located in different climatic zones of Costa Rica

Wetlands are the largest natural source of the greenhouse gas methane to the atmosphere. Despite the fact that a large percentage of wetlands occur in tropical latitudes, methane emissions from natural tropical wetlands have not been extensively studied. The objective this research was to compare methane emissions from three natural tropical wetlands located in different climatic and ecological areas of Costa Rica. Each wetland was within a distinct ecosystem: (1) a humid flow‐through wetland slough with high mean annual temperatures (25.9 °C) and precipitation (3700 mm yr^?1); (2) a stagnant rainforest wetland with high mean annual temperatures (24.9 °C) and precipitation (4400 mm yr^?1); or (3) a seasonally wet riverine wetland with very high mean annual temperatures (28.2 °C) and lower mean annual precipitation (1800 mm yr^?1). Methane emission rates were measured from sequential gas samples using nonsteady state plastic chambers during six sampling periods over a 29‐month period from 2006 to 2009. Methane emissions were higher than most rates previously reported for tropical wetlands with means (medians) of 91 (52), 601 (79), and 719 (257) mg CH₄‐C m^?2 day^?1 for the three sites, with highest rates seen at the seasonally flooded wetland site. Methane emissions were statistically higher at the seasonally wet site than at the humid sites (P<0.001). Highest methane emissions occurred when surface water levels were between 30 and 50 cm. The interaction of soil temperature, water depth, and seasonal flooding most likely affected methanogenesis in these tropical sites. We estimate that Costa Rican wetlands produce about 0.80 Tg yr^?1 of methane, or approximately 0.6% of global tropical wetland emissions. Elevated methane emissions at the seasonally wet/warmer wetland site suggest that some current humid tropical freshwater wetlands of Central America could emit more methane if temperatures increase and precipitation becomes more seasonal with climate change.     

A comparison of soil carbon pools and profiles in wetlands in Costa Rica and Ohio

Wetlands are large carbon pools and play important roles in global carbon cycles as natural carbon sinks. This study analyzes the variation of total soil carbon with depth in two temperate (Ohio) and three tropical (humid and dry) wetlands in Costa Rica and compares their total soil C pool to determine C accumulation in wetland soils. The temperate wetlands had significantly greater (P < 0.01) C pools (17.6 kg C m⁻²) than did the wetlands located in tropical climates (9.7 kg C m⁻²) in the top 24 cm of soil. Carbon profiles showed a rapid decrease of concentrations with soil depth in the tropical sites, whereas in the temperate wetlands they tended to increase with depth, up to a maximum at 18–24 cm, after which they started decreasing. The two wetlands in Ohio had about ten times the mean total C concentration of adjacent upland soils (e.g., 161 g C kg⁻¹ were measured in a central Ohio isolated forested wetland, and 17 g C kg⁻¹ in an adjacent upland site), and their soil C pools were significantly higher (P < 0.01). Among the five wetland study sites, three main wetland types were identified – isolated forested, riverine flow-through, and slow-flow slough. In the top 24 cm of soil, isolated forested wetlands had the greatest pool (10.8 kg C m⁻²), significantly higher (P < 0.05) than the other two types (7.9 kg C m⁻² in the riverine flow-though wetlands and 8.0 kg C m⁻² in a slowly flowing slough), indicating that the type of organic matter entering into the system and the type of wetland may be key factors in defining its soil C pool. A riverine flow-through wetland in Ohio showed a significantly higher C pool (P < 0.05) in the permanently flooded location (18.5 kg C m⁻²) than in the edge location with fluctuating hydrology, where the soil is intermittently flooded (14.6 kg C m⁻²).     

Carbon storage dynamics of temperate freshwater wetlands in Pennsylvania

Healthy wetlands play a significant role in climate change mitigation by storing carbon that would otherwise contribute to global warming, leading to the reduction of water and food resources as well as more extreme weather phenomena. Investigating the magnitude of carbon storage potential of different freshwater wetland systems using multiple ecological indicators at varying spatial scales provides insight and justification for selective wetland restoration and conservation initiatives. We provide a holistic accounting of total carbon values for 193 wetland sites, integrating existing carbon algorithms to rapidly assess each of the following carbon pools: above-ground, below-ground, soil, woody debris, shrub cover, and herbaceous cover. Aspects of soil, vegetation, and ecosystem characteristics and stressors were measured to obtain an overall understanding of the ecosystems ability to store carbon (long-term) along a gradient of human disturbance. Based on a review of the literature, methods were prioritized based on the initial data available from field measurements as well as their practicality and ease in replicating the process in the future. Lacustrine human impounded (88.7?±?18.0 tC/ha), riverine beaver impounded (116.2?±?29.4 tC/ha), riverine upper perennial (163.3?±?11.8 tC/ha), riverine lower perennial (199.2?±?24.7 tC/ha), riverine headwater complex (159.5?±?22.2 tC/ha), perennial/seasonal depression (269.6?±?42.4 tC/ha), and slope (162.2?±?14.6 tC/ha) wetland types were compared. Overall results showed moderate variability (9.33–835.95 tC/ha) for total carbon storage values across the wetland types, with an average total carbon storage of 174.6?±?8.8 tC/ha for all wetlands. Results show that carbon storage was significantly higher (p?=?0.002) in least disturbed wetland sites. Apart from perennial/seasonal depression wetlands, all reference standard wetlands had greater carbon storage, less disturbance impact, and a greater extent of forest cover than non-reference wetlands. Carbon storage values calculated were comparable to published literature.     

The dystrophinopathies in Costa Rica

A five-years long study aiming to describe the basic genetic epidemiology of the dystrophinopathies in Costa Rica recruited 31 patients with clinical symptoms of DMD/BMD at the National Children's Hospital (HNN). This center is the obligate reference hospital of the national health system for genetic diseases, however, the geographic origin of the patients, a low percentage of deletions and a high proportion of de novo mutations found among them indicate that a significant ascertainment bias impedes a substantial scientific approach to confront and alleviate the problems posed by these severe diseases in Costa Rica.     

Managing agricultural grazing to enhance the carbon sequestration capacity of freshwater wetlands

Wetlands Ecology and Management - Freshwater wetlands are important carbon sinks with an estimated?~?450 gigatons of carbon stored in their sediments. However, when disturbed they can...     

Changes in Soil Carbon and Nitrogen after Contrasting Land-use Transitions in Northeastern Costa Rica

Northeastern Costa Rica is a mosaic of primary and secondary forests, tree plantations, pastures, and cash crops. Many studies have quantified the effects of one type of land-use transition (for example, deforestation or reforestation) on soil properties such as organic carbon (C) storage, but few have compared different land-use transitions simultaneously. We can best understand the effects of land-use change on regional and global ecosystem processes by considering all of the land-use transitions that occur in a landscape. In this study, I examined the changes in total soil C and nitrogen (N) pools (to 0.3 m) that have accompanied different land-use transitions in a 140,000-ha region in northeastern Costa Rica. I paired sites that had similar topography and soils but differed in recent land-use history. The following land-use transitions were represented: 12 conversions of primary forests to banana plantations, 15 conversions of pastures to cash crops, and four conversions of pastures to Vochysia guatemalensis tree plantations. The conversion of forests to bananas decreased soil C concentrations and inventories (Mg C ha^–1) in the surface soil by 37% and 16.5%, respectively. The conversion of pastures to cash crops reduced soil C concentrations and inventories to the same extent that forest-to-banana cropping did. Furthermore, young Vochysia plantations do not appear to increase soil C storage, at least over the 1st decade. When data from all land-use transitions were pooled, the difference in root biomass and leaf litter pools between land-use pairs explained 50% of the differences in soil C concentrations and 36% of the differences in soil C inventories. Thus, reduced productivity or C inputs to the soil is one mechanism that could explain the losses in soil C pools with land-use change. In this landscape, losses of soil C due to cultivation are rapid, whereas re- accumulation rates are slow. Total soil N pools (0–10 cm) were also reduced after the conversion of forests to banana plantations or the conversion of pastures to crops, despite fertilization of the cropped soils. This suggests that the added N fertilizer is not retained but instead is exported via produce, N gas emissions, and hydrologic processes.     

Soil Carbon and Nutrient Changes Associated with Deforestation for Pasture in Southern Costa Rica

We assessed the effects of deforestation on soil carbon (C) and nutrient stocks in the premontane landscape near Las Cruces Biological Station in southern Costa Rica, where forests were cleared for pasture in the mid‐1960s. We excavated six soil pits to a depth of 1 m in both pasture and primary forest, and found that C stocks were ~20 kg C/m² in both settings. Nevertheless, soil δ¹³C suggests ~50 percent of the forest‐derived soil C above 40 cm depth has turned over since deforestation. Soil nitrogen (N) and phosphorus (P) stocks derived from the soil pits were not significantly different between land uses (P = 0.43 and 0.61, respectively). At a larger spatial scale, however, the ubiquity of ruts produced by cattle‐induced erosion indicates that there are substantial soil effects of grazing in this steep landscape. Ruts averaged 13 cm deep and covered ~45 percent of the landscape, and thus are evidence of the removal of 0.7 Mg C/ha/yr, and 70, 9 and 40 kg/ha/yr of N, P and potassium (K), respectively. Subsoils in this region are ~10 times less C‐ and N‐rich, and ~2 times less P‐ and K‐rich than the topsoil. Thus, rapid topsoil loss may lead to a decline in pasture productivity in the coming decades. These data also suggest that the soil C footprint of deforestation in this landscape may be determined by the fate of soil C as it is transported downstream, rather than C turnover in situ.     

The freshwater Copepoda (Crustacea) of Costa Rica with notes on some species

Sixteen species of Copepoda were recorded in this first detailed study of Costa Rican zooplankton. Two of these species are halophile. Notes are given on some of the species and their distribution. One new species found will be described elsewhere. The Costa Rican fauna resembles in composition the fauna of other Central American and Caribbean regions. Relatively few species were recorded. This is partly due to a low intensity of sampling but also to the paucity of lentic habitats. The occurrence of two circumtropical species of Mesocyclops is interesting.

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Résumé 16 espèces de Copépodes ont été inventoriées au cours d'une première étude détaillée du zooplankton dulcaquicole de Costa Rica. Deux des espèces trouvées sont halophiles. Des remarques sont faites a propos de quelques espèces et de leur répartition. Une nouvelle espèce est nouvelle — elle sera décrite par ailleurs. La fauna de Costa Rica ressemble par sa composition à celle des autres pays d'Amérique centrale et des îles caraibes. Relativement peu d'espèces sont notées. La faible intensité de l'échantillonnage mais aussi la pauvreté en habitats limniques en sont responsables. La présence de deux espèces circumtropicales de Mesocyclops est intéressante.

     

Carbon stocks,sequestration, and emissions of wetlands in south eastern Australia

Nontidal wetlands are estimated to contribute significantly to the soil carbon pool across the globe. However, our understanding of the occurrence and variability of carbon storage between wetland types and across regions represents a major impediment to the ability of nations to include wetlands in greenhouse gas inventories and carbon offset initiatives. We performed a large‐scale survey of nontidal wetland soil carbon stocks and accretion rates from the state of Victoria in south‐eastern Australia—a region spanning 237,000 km² and containing >35,000 temperate, alpine, and semi‐arid wetlands. From an analysis of >1,600 samples across 103 wetlands, we found that alpine wetlands had the highest carbon stocks (290 ± 180 Mg C_org ha^?1), while permanent open freshwater wetlands and saline wetlands had the lowest carbon stocks (110 ± 120 and 60 ± 50 Mg C_org ha^?1, respectively). Permanent open freshwater sites sequestered on average three times more carbon per year over the last century than shallow freshwater marshes (2.50 ± 0.44 and 0.79 ± 0.45 Mg C_org ha^?1 year^?1, respectively). Using this data, we estimate that wetlands in Victoria have a soil carbon stock in the upper 1 m of 68 million tons of C_org, with an annual soil carbon sequestration rate of 3 million tons of CO₂ eq. year^?1—equivalent to the annual emissions of about 3% of the state's population. Since European settlement (~1834), drainage and loss of 260,530 ha of wetlands may have released between 20 and 75 million tons CO₂ equivalents (based on 27%–90% of soil carbon converted to CO₂). Overall, we show that despite substantial spatial variability within wetland types, some wetland types differ in their carbon stocks and sequestration rates. The duration of water inundation, plant community composition, and allochthonous carbon inputs likely play an important role in influencing variation in carbon storage.     

Cystic fibrosis mutations in Costa Rica

Using polymerase chain reaction amplification of DNA in dried blood spots and a nonisotopic reverse dot blot hybridization method, we performed molecular genetic analysis for 6 and for 16 of the most common mutations of the cystic fibrosis transmembrane conductance regulator gene (CFTR) in 24 unrelated Costa Rican individuals with cystic fibrosis (CF). While many countries and ethnic groups have been surveyed for CF mutations since the cloning of CFTR, Costa Rica has not heretofore been studied. Moreover, Costa Rica represents an especially intriguing population because of its mixed European-African-Amerindian origins and the existence of a detailed historical record of the founding Spanish families. Thus, such a study may reveal not only the population frequencies of various mutant alleles in this country, but also something about their geographic migrations and ethnic founder effects. The most common CF mutation in Caucasians, deltaF508, was found in only 11 (23%) of the CF chromosomes studied, while the G542X mutation, relatively rare in the general population but more common in southern Europe, was observed in 12 (25%). None of the other mutations tested was found in any of the subjects. We failed to detect the second mutant allele in 17 subjects and could not detect either allele in 4 subjects. The high prevalence of the G542X mutation in our cohort, which exceeds that of both the general Caucasian population and the American Hispanic population, reflects the strong genetic influence of the original Spanish founding families of Costa Rica. These results highlight important differences in Costa Rican CF genotypes as compared both to other North American and European populations and to American Hispanics, raising important implications about isolated founder effects and strategies for population screening in that country.     

Rare hemoglobinopathies in Costa Rica]

Among the rare hemoglobinopathies found in Cost Rica are those of the Alfa, Beta, and Delta chains. Among these, Hb Cubujuquí, an undescribed variant, is of special interest. There was an association between the different thalassemic syndromes and their combinations with abnormal hemoglobins.     

Diversity of the free-living marine and freshwater Copepoda (Crustacea) in Costa Rica: a review

The studies on marine copepods of Costa Rica started in the 1990’s and focused on the largest coastal-estuarine systems in the country, particularly along the Pacific coast. Diversity is widely variable among these systems: 40 species have been recorded in the Culebra Bay influenced by upwelling, northern Pacific coast, only 12 in the Gulf of Nicoya estuarine system, and 38 in Golfo Dulce, an anoxic basin in the southern Pacific coast of the country. Freshwater environments of Costa Rica are known to harbor a moderate diversity of continental copepods (25 species), which includes 6 calanoids, 17 cyclopoids and only two harpacticoids. Of the +100 freshwater species recorded in Central America, six are known only from Costa Rica, and one appears to be endemic to this country. The freshwater copepod fauna of Costa Rica is clearly the best known in Central America. Overall, six of the 10 orders of Copepoda are reported from Costa Rica. A previous summary by 2001 of the free-living copepod diversity in the country included 80 marine species (67 pelagic, 13 benthic). By 2009, the number of marine species increased to 209: 164 from the Pacific (49% of the copepod fauna from the Eastern Tropical Pacific) and 45 from the Caribbean coast (8% of species known from the Caribbean Basin). Both the Caribbean and Pacific species lists are growing. Additional collections of copepods at Cocos Island, an oceanic island 530 km away of the Pacific coast, have revealed many new records, including five new marine species from Costa Rica. Currently, the known diversity of marine copepods of Costa Rica is still in development and represents up to 52.6% of the total marine microcrustaceans recorded in the country. Future sampling and taxonomic efforts in the marine habitats should emphasize oceanic environments including deep waters but also littoral communities. Several Costa Rican records of freshwater copepods are likely to represent undescribed species. Also, the biogeographic relevance of the inland copepod fauna of Costa Rica requires more detailed surveys.     

Nutrient-poor freshwater wetlands

Until the introduction of fertilizers in the 19th century nutrient-poor conditions prevailed in the larger part of The Netherlands. Freshwater wetlands consequently were of nutrient-poor nature. During the first half of the 20th century many surface waters gradually eutrophied, but most waters in the Pleistocene area and even some polders in the Holocene area kept their nutrient-poor conditions. Only during the last decades virtually all waters became eutrophied or polluted. The main sources of nutrients are agriculture, precipitation and water from the large rivers.     

Current estate of biotechnology in Costa Rica

A study was carried out on the construction of indicators in biotechnology in Costa Rica as part of the project "SYMBIOSIS, Cooperative Program for the Construction of Indicators in Biotechnology adapted to Latin American and Caribbean countries, to motivate the application and transference of industrial technologies". The study focused on two units: researchers and research projects developed in Costa Rica, between 1998 and 2002. For researchers, information was collected about indicators related to sex, age, teaching activities, number of projects, academic degree, area of speciality and number of publications. For research projects we obtained information about: speciality, sector of application, duration of projects and number of researchers per project. Very interesting results include the high participation of the women in this area of investigation (54%); the low participation of young researchers (13% younger than 30), and a high proportion of the investigators that are responsible for 4 or more projects (42%). With relation to the specialities of the projects, the majority are in the category Bio-Agro (39%) whereas in Acuaculture only 1% was found. The sectors of application with the most number of projects are: Agriculture and Livestock (37%) and Human Health (35%). The main strengthts and limitatations for the development of biotechnology in Costa Rica are discussed.     

History of leukemia research in Costa Rica

A review of leukemia worldwide is discussed, focusing on etiology, diagnosis and treatment. The history of research of this type of cancer in Costa Rica is presented through the first hospital diagnosis, the arrival of clinical and laboratory hematologists, the establishment of specialized laboratories, the local hematology teaching programs and the voluntary associations that help patients with leukemia. A brief review of Costa Rican publications in this area and the future of this problem in our country is also shown.     

Glaucoma in Costa Rica. Initial approaches

Glaucoma is the second most frequent cause of irreversible blindness worldwide. Genetic factors have been implicated in the development of the disease. So far six loci (GLC1A-GLC1F) and two genes (TIGR/MYOC and OPTN) are involved in the development of juvenile (JOAG) and adult onset or chronic primary open angle glaucoma (COAG), while two loci (GLC3A,GLC3B) and one gene (CYP1B1) are known for primary congenital glaucoma (PCG). Here we summarize the results of the first genetic studies of glaucoma in Costa Rica. Nine families: 1 with JOAG, 1 with PCG and 7 with COAG were screened for mutations at the known genes. A 10 bp duplication, 1546-1555dupTCATGCCACC, at the CYP1B1 gene, causes, in homozygous state, glaucoma in the consanguineous PCG family. This mutation has been found in different countries and generates an early stop codon that termitates protein synthesis 140 amino acids earlier than the normal allele. In exon 1 of the T1GR/MYOC the innocuous Arg76Lys variant was found in two of the COAG families. In the OPTN gene two variants in the coding region (Thr34Thr, Met 98Lys) and 7 intronic changes were found in other Costa Rican glaucoma patients. One of the COAG families was chosen for a genome scan with 379 microsatellite markers and linkage analysis. LOD scores "suggestive" of linkage were obtained for several chromosomal regions. Evidence indicates that hereditary glaucoma in Costa Rica is highly heterogeneous and that further studies in the country will probably disclose some up to now unknown genes responsible for the disease.     

Tropical wetlands for climate change research, water quality management and conservation education on a university campus in Costa Rica

EARTH University is a small agronomic university with a theme of sustainability in eastern Costa Rica. Several natural and constructed wetlands on its campus are used for research, water quality improvement, and higher education. It has become an important location for research and teaching on humid tropical wetland ecology and management. A 112-ha flow-through Raphia taedigera (Arecaceae) forested wetland is being used for climate change research, focusing on carbon sequestration and methane generation. Methane emissions are measured seasonally and are comparable to rates in tropical wetlands published elsewhere. Carbon sequestration by the wetland appears to be substantially higher than similar flow-through temperate zone wetlands. Treatment wetlands are used on campus to improve water quality of effluents from an animal farm, a dairy plant, a landfill, and a banana paper plant. Water quality was substantially improved in all of these wetlands except the landfill leachate wetland. All of these campus wetlands have been integrated into the four-year education program of EARTH University and 22 undergraduate projects have been completed on wetlands over the past 14 years.