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NASA NTRS2012

Snow Cover and Precipitation Impacts on Dry Season Streamflow in the Lower Mekong Basin

Climate change impacts on dry season streamflow in the Mekong River are relatively understudied, despite the fact that water availability during this time is critically important for agricultural and ecological systems. Analyses of two gauging stations (Vientiane and Kratie) in the Lower Mekong Basin (LMB) show significant positive correlations between dry season (March through May, MAM) discharge and upper basin snow cover and local precipitation. Using snow cover, precipitation, and upstream discharge as predictors, we develop skillful regression models for MAM streamflow at Vientiane and Kratie, and force these models with output from a suite of general circulation model (GCM) experiments for the twentieth and twenty-first centuries. The GCM simulations predict divergent trends in snow cover (decreasing) and precipitation (increasing) over the twenty-first century, driving overall negligible long-term trends in dry season streamflow. Our study demonstrates how future changes in dry season streamflow in the LMB will depend on changes in snow cover and precipitation, factors that will need to be considered when assessing the full basin response to other climatic and non-climatic drivers.

Cook, Benjamin I.↗

NASA NTRS2014

Performance of Silica Gel in the Role of Residual Air Drying

Removal of carbon dioxide (CO2) is a necessary step in air revitalization and is often accomplished with sorbent materials. Since moisture competes with CO2 in sorbent materials, it is necessary to remove the water first. This is typically accomplished in two stages: bulk removal and residual drying. Silica gel is used as the bulk drying material in the Carbon Dioxide Removal Assembly (CDRA) in operation on ISS. There has been some speculation that silica gel may also be capable of serving as the residual drying material. This paper will describe test apparatus and procedures for determining the performance of silica gel in residual air drying.

air revitalization↗

NASA NTRS2016

Simultaneous Water Vapor and Dry Air Optical Path Length Measurements and Compensation with the Large Binocular Telescope Interferometer

The Large Binocular Telescope Interferometer uses a near-infrared camera to measure the optical path length variations between the two AO-corrected apertures and provide high-angular resolution observations for all its science channels (1.5-13 microns). There is however a wavelength dependent component to the atmospheric turbulence, which can introduce optical path length errors when observing at a wavelength different from that of the fringe sensing camera. Water vapor in particular is highly dispersive and its effect must be taken into account for high-precision infrared interferometric observations as described previously for VLTI/MIDI or the Keck Interferometer Nuller. In this paper, we describe the new sensing approach that has been developed at the LBT to measure and monitor the optical path length fluctuations due to dry air and water vapor separately. After reviewing the current performance of the system for dry air seeing compensation, we present simultaneous H-, K-, and N-band observations that illustrate the feasibility of our feed forward approach to stabilize the path length fluctuations seen by the LBTI nuller uses a near-infrared camera to measure the optical path length variations between the two AO-corrected apertures and provide high-angular resolution observations for all its science channels (1.5-13 microns). There is however a wavelength dependent component to the atmospheric turbulence, which can introduce optical path length errors when observing at a wavelength different from that of the fringe sensing camera. Water vapor in particular is highly dispersive and its effect must be taken into account for high-precision infrared interferometric observations as described previously for VLTI MIDI or the Keck Interferometer Nuller. In this paper, we describe the new sensing approach that has been developed at the LBT to measure and monitor the optical path length fluctuations due to dry air and water vapor separately. After reviewing the current performance of the system for dry air seeing compensation, we present simultaneous H-, K-, and N-band observations that illustrate the feasibility of our feed forward approach to stabilize the path length fluctuations seen by the LBTI nuller.

which can introduce optical path length errors whe↗

NASA NTRS2016

Performance of Silica Gel in the Role of Residual Air Drying. Part II.

Removal of carbon dioxide (CO2) is a necessary step in air revitalization and is often accomplished with sorbent materials. Since moisture competes with CO2 in zeolite sorbent materials, it is necessary to remove the water first. This is typically accomplished in two stages: “bulk” removal and “residual” drying. Silica gel is used as the bulk drying material in the Carbon Dioxide Removal Assembly (CDRA) in operation on the ISS (International Space Station). There has been some speculation that silica gel may also be capable of serving as both bulk and residual drying material to reduce system mass and Foreign Object Debris (FOD). Previous research tested silica gel alone as drying material. However, the silica gel volume used was not comparable to the current amount used on the CDRA. Therefore, the tests were repeated with the new silica gel volume. This paper discusses the fabrication and assembly of the modified canister to accommodate the new volume, the testing, and the evaluation of the test results.

Air Revitalization↗

NASA NTRS2019

Dynamics and Variability of the Spring Dry Season in the United States Southwest as Observed in AmeriFlux and NLDAS-2 Data

The spring dry season occurring in an arid region of the Southwest United States, which receives both winter storm track and summer monsoon precipitation, is investigated. Bimodal precipitation and vegetation growth provide an opportunity to assess multiple climate mechanisms and their impact on hydroclimate and ecosystems.We detect multiple shifts from wet to drier conditions in the observational record and land surface model output. Focusing on the recent dry period, a shift in the late 1990s resulted in earlier and greater spring soil moisture draw down, and later and reduced spring vegetation green-up, compared to a prior wet period (1979 - 1997). A simple soil moisture balance model shows this shift is driven by changes in winter precipitation.The recent post-1999 dry period, as well as an earlier one from 1948 - 1966, are both related to the cool tropics phase of Pacific decadal variability which influences winter precipitation. In agreement with other studies for the Southwest United States, we find the recent drought cannot be explained in terms of precipitation alone, but also is due to the rising influence of temperature, thus highlighting the sensitivity of this region to warming temperatures. Future changes in the spring dry season will therefore be affected by how tropical decadal variability evolves, and also by emerging trends due to human-driven warming.

Pascolini-Campbell, Madeleine↗

NASA NTRSDate not supplied

Efficacy of Dried Plum to Countermeasure Simulated Spaceflight Exposure

Human exploration of the space environment has been a topic of interest for decades; however, the threat to physiological health posed by ionizing radiation and microgravity effects remains a concern. Previous research utilizing combined hindlimb unloading and irradiation to simulate spaceflight effects found that a dried plum diet can mitigate adverse effects of simulated spaceflight on skeletal health. Though the mechanism is not fully understood we believe this protective effect is due to its high antioxidant capacity and polyphenolic content. This study seeks to extend these findings to investigate if dried plum is an effective countermeasure in other tissues relating to aging and neurotoxicity. Male C57BL/6 J mice were assigned to one of eight groups (n = 10/group) and were fed either a controlled diet or dried plum diet, underwent normal loading or hindlimb unloading as well as exposure 2 Gy gamma radiation or sham exposure. At the end of the experiment, mice were euthanized, and RNA was extracted from brain and bone marrow tissue and PCR was employed to analyze significant changes in gene expression profiles. Analysis of five house-keeping genes revealed genes B2M (neurotoxicity) and GUSB (aging) to be the most stable genes across all treatments and were used to find the fold change within our genes of interest. Through this, and analysis via ANOVA, we were able to identify genes with significant altered expression levels within brain and bone marrow tissues related to neurotoxicity and aging. Considering previous research, we hypothesize that the dried plum diet’s antioxidative properties ameliorated the oxidative stress from irradiation and microgravity via altered levels of gene expression. Identified expression changes will provide insights into molecular mechanisms behind the observed protective effects. These findings present potential avenues for future interventions to alleviate negative impacts of spaceflight on astronaut health.

Faisal Ahmad↗

NASA NTRSDate not supplied

The Efficacy of Dried Plum to Counter Spaceflight Microgravity and Radiation

Faisal Ahmad↗

NASA NTRSDate not supplied

Cleanroom Microbes Survive Drying, Vacuum, and Proton Irradiation

Introduction : The goal of planetary protection at NASA is to mitigate the risk of contaminating sensitive target bodies with biological life. While many cleaning procedures have been put in place to reduce bioburden on spacecraft, microbes are experts at evolving to survive harsh conditions. Specifically, the dry, low-nutrient environment of a cleanroom (commonly used for assembly of spacecraft) can represent an environment where extremophiles can survive. Methods : Scientists at NASA MSFC wished to gather a snapshot of the microbial population within a variety of cleanrooms on site. A study was undertaken to collect air, surface, and floor samples from clean-rooms and isolate unique morphologies. From this study, 95 isolates were collected and saved in a microbial library. About 86% of these were identified at least to a genus level. Following identification, 24 microbes were selected, based on a literature review, as potential extremophiles. These were grown in liquid cultures, diluted to a set optical density, washed with water, and then applied to a sterilized Kapton coupon. Droplets were allowed to dry overnight in a biosafety cabinet. Coupons were then installed in a pelletron and pumped down to high vacuum (~1E-6 Torr). Samples were then subjected 100 keV protons at a fluence of 2x10 15 p+/cm 2 up to 4x10 15 p+/cm 2 . Following exposure, samples were returned to the microbiology lab where they were pro-cessed by submerging in water, vortexing, and then plating either droplets or spread plates. Recovery data collected was qualitative with a ranking or +, minor, or – for growth. Some selected radiotolerant strains were sequenced using the Illumina sequencing platform. The resulting genomes were annotated with the Rapid Annotations using Subsystems Technology (RAST) server and analyzed for conserved and unique stress response relevant genomic signatures to identify clues related to specific tolerances. Results and Discussion : After five rounds of proton radiation, we narrowed our isolates to five, non-spore forming bacteria that demonstrated survival: Arthrobacter koreensis, Paenarthrobacter nitroguajacolicus, Mycetocola manganoxydans , and an Erwinia sp. Furthermore, we exposed these four microbes to 254 nm wavelength light at an intensity of 80 W/m 2 at a distance of ~18 cm for 10 minutes. Only A. koreensis demonstrated survival following UV exposure. Finally, we performed whole genome sequencing on the four strains to look for genetic markers of stress resistance. When we compared the genomes of the four strains, we found that genes coding for GGDEF and EAL domains with PAS/PAC sensors were only found in A. koreensis . These domains, modulated by PAS/PAC sensors, are hypothesized to facilitate survival under drying, desiccation, and proton irradiation. Drying and Desiccation : PAS domains sense hydration changes and modulate GGDEF and EAL domain activity to adjust c-di-GMP levels, enhancing resistance to desiccation. For instance, in Pseudomonas aeruginosa , the PAS domain of RbdA modulates activity under varying hydration conditions, affecting stress responses [1]. Proton Irradiation : Proton irradiation causes oxidative stress, leading to ROS generation. PAS domains detect this stress and modulate GGDEF and EAL domains to manage oxidative stress responses. In Shewanella , EAL domain proteins modulated by PAS sensors help bacteria adapt to extreme conditions [2]. These genes upregulate other stress response genes, protecting membrane function, protein stability, DNA repair, and antioxidant defenses. The modulation of c-di-GMP by PAS domains is crucial for bacterial adaptation to stress conditions, enabling dynamic physio-logical adjustments [3]. Understanding these mechanisms provides insights into bacterial stress responses and strategies for controlling bacterial growth [4]. Conclusions : These findings indicate that clean-rooms harbor extremophile microbes that may be able to survive conditions in deep space. Furthermore, while we identified certain stress-response genes that may be at least partly responsible for the phenotypes observed in this study, there are likely unidentified genes or characteristics about A. koreensis , and other bacteria, that may allow them to survive in harsh environments. Future studies will focus on identifying these unknown genes and characteristics, further elucidating the mechanisms of extremophile survival and potentially informing the development of new biotechnologies for space exploration and other extreme environments.

Chelsi Cassilly↗

DOE OSTI2025

Considerations for Thermal Annealing of Zr-Alloy Cladding During Dry Storage

In January 2025, the U.S. Department of Energy (DOE) sponsored a technical workshop with fuel vendors that provided a forum for increased collaboration on backend fuel cycle research. The workshop reviewed observations of thermal annealing of irradiated zirconium alloys in simulated dry storage conditions and discussed implications to the industry’s interest in reducing wet storage to optimize operational flexibility and the expected trend of increasing discharge burnup (and decay heats), which could lead to an increase in dry storage temperatures. One approach to accommodate increased decay heats in dry storage is to increase the regulatory temperature limit during dry storage, which is now 400°C. However, this could lead to thermal annealing of the cladding, which will tend to increase creep rates, creep strains, and ductility while decreasing yield strength. These considerations are compounded by bonding between the pellet and cladding at high burnup, which results in the pellet carrying more load during fuel rod deformations, especially in bending, which is the dominant deformation phenomenon in canister drop analyses. Because the U.S. Nuclear Regulatory Commission (NRC) recommends yield strength as a primary failure criterion for accident analyses in storage and transportation, particularly for canister drop scenarios, the purpose of the workshop was to develop options for alternative failure criterion that could replace yield strength in canister drop analyses. Topics discussed were (1) the regulatory framework, (2) the effect of thermal annealing on microhardness and tensile properties of cladding materials, (3) the effect of thermal annealing on fuel rod failure during bending, bending fatigue, and pinch loading, and (4) an alternative failure criterion for canister drop analyses. This paper provides a summary of the key discussions and outcomes of the workshop

Cantonwine, Paul [ORNL] (ORCID:0009000522247033)↗

DOE OSTI2025

Toward integrating high-fidelity CFD approaches in the thermal-hydraulic analysis of turbulent dry cask systems

Nuclear power plants have been supplying resilient and reliable electricity for decades, contributing to energy independence of the U.S.. However, nuclear waste management remains one of the most significant challenges in the industry. The safety of dry cask storage systems relies heavily on their thermal-hydraulic performance. Computational Fluid Dynamics (CFD) simulations are often used to demonstrate this performance and ensure that the system design meets safety standards. This study presents reduced numerical models for various types of dry cask systems. These numerical models can produce efficient and fast results based on the employed modeling strategies. Additionally, the study uses a novel approach to high-fidelity simulations to evaluate modeling assumptions in dry cask modeling. Large Eddy Simulations (LES) are used for this purpose, particularly in regions where fluid velocity is relatively high and the turbulence characteristics become important. Furthermore, the results of these high-fidelity simulations will enhance the interpretation of outcomes produced from a lower-fidelity CFD model.

CFD↗

DOE OSTI2021

Grafted nickel-promoter catalysts for dry reforming of methane identified through high-throughput experimentation

High-throughput synthesis of a series of monometallic and bimetallic catalysts (45 bimetallic and 50 monometallic samples) consisting of nickel and one of nine different metal promoters (B, Co, Cu, Fe, Mg, Mn, Sn, V and Zn) supported on one of six different metal oxides alumina, ceria, magnesia, silica and titania) is carried out via organometallic grafting using a robotic platform. The catalysts are evaluated for their activity and selectivity for the dry reforming of methane at a feed ratio of CH 4 :CO 2 of 1 at 650–800 °C in a parallel flow reactor system. The type of oxide support prevails over the type of additive for both catalyst activity and stability. On Al 2 O 3 and MgO, Fe was found to be the best promoter; on SiO 2 , Cu is the best promoter at 700 °C and higher, while on TiO 2 , Mn is found to enhance the conversion at 800 °C. On CeO 2 , all additives except Fe have beneficial effects. Twenty-five catalysts show > 90% methane conversion with ten catalysts showing > 95% conversion at 800 °C with the H 2 :CO ratios ranging from 0.8 to 1.2. Amongst the ten highest performers, NiFe/Al 2 O 3 and NiFe/MgO are more active than Ni/Al 2 O 3 and Ni/MgO, respectively and were stable over a period of 25 h at 800 °C. Characterization on the as-prepared samples reveals highly dispersed phase, while after reduction in H 2 , highly dispersed and reduced nickel particles up to 10 nm are formed. The particles do not increase in size under dry reforming reaction conditions at 800 °C. An increased hydrogen consumption observed during H 2 -TPR of the nickel particles is positively correlated with methane conversion for Al 2 O 3 -based catalysts. The resistance to deactivation by coking and variation in coke structure are investigated by spectroscopic and microscopic methods to identify the relationship between metal promoters, alloy formation, and type of surface carbon deposits. Carbon whiskers were observed on the ten selected spent samples and are preferentially deposited on Ni rather than on the promoters. Carbon nanotube formation and metal particle removal from support were not observed to cause deactivation while amorphous carbon formation was clearly linked to catalyst deactivation, as amorphous carbon could encapsulate nickel, either on the support or at the end of the carbon nanotube. Furthermore, the organometallic grafting technique is an efficient and suitable technique for synthesizing highly dispersed and homogeneous phases which lead to high conversion and high durability for dry reforming of methane.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

The adsorption of As(V) on poorly crystalline Fe oxyhydroxides, revisited: Effect of the reaction media and the drying treatment

Arsenic (As) adsorbed on Fe oxyhydroxides (adsorbent) is widely occurring in many environmental settings such as in acid mine drainage systems or in the hydrometallurgical operations to form Fe-As coprecipitates. However, the influence of the reaction media and the drying treatment on the microstructure of the directly formed adsorbents at various pHs was still not fully understood. In this work, As adsorption behaviors on various forms of Fe oxyhydroxides were systematically investigated by using XRD, FTIR, Raman, XANES, and HRTEM. Overall, the results revealed that at weak acidic pH, more As could adsorbed on the suspension adsorbent formed in sulfate and chloride media than that in nitrate media, possibly due to the microstructure alteration of the adsorbent in the presence of sulfate and chloride. Besides, the increasing crystallinity of the Fe oxyhydroxides and the aggregation effect after drying were the major reasons why less As could be hold by the dried adsorbents than that of the corresponding suspension adsorbents. These findings could shed more light on the nature of the Fe oxyhydroxides which may be helpful for more precisely predicting the fate of some toxic metal(loid)s in the environment.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

The Impact of Slantwise Descending Dry Intrusions on the Marine Boundary Layer and Air-Sea Interface Over the ARM Eastern North Atlantic Site

Dry intrusions (DIs) are synoptic-scale slantwise descending airstreams from the midlatitude upper troposphere toward the boundary layer at lower latitudes. Typically occurring behind cold fronts, such intrusions of dry air often reach the boundary layer and cause its deepening, thereby affecting boundary-layer clouds. Although subsidence is generally an inherent feature of the subtropical marine boundary layer (MBL), it is unclear how the MBL reacts to the transient, dynamically distinct DI. In this study, reanalysis data were combined with observations from the Atmospheric Radiation Measurement Eastern North Atlantic (ENA) site (39.1 degrees N,28.0 degrees W) to characterize the impact of DIs on MBL characteristics and clouds. Specifically, an objective criterion is applied to the observations made during the winter months of 2016-2018 to identify the DI days from those before and following DIs, and reference periods without DIs. The analyses suggest substantial deepening of the well-mixed boundary layer accompanied by changes in the cloud, precipitation and thermodynamic properties during the DI events. During the DI, the lower troposphere cooled and dried substantially thereby inducing strong surface sensible and latent heat fluxes. All while a strong inversion builds up at the elevated MBL top affecting cloud occurrence. The results show DIs to affect the boundary layer and cloud structure at the ENA site similar to 21% of the time in winter months, with the response of the cloud fields to the DI-fronts substantially different than that to the non-DI fronts. Hence, the DI events should be considered while studying boundary layer and cloud processes in the region.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2022

Adjoint sensitivity analysis and data assimilation for verification of dry storage cask contents

Dry cask storage is a method for interim storage of spent fuel assemblies which contain fissile isotopes of uranium and plutonium. These can present a proliferation concern and consequently there is a need for non-destructive testing methods to verify a dry cask's contents for proliferation protection. We present an application of adjoint sensitivity analysis and data assimilation to a multigroup diffusion model of dry cask storage. Adjoint sensitivity analysis allows the efficient calculation of sensitivities for use in data assimilation to calibrate imprecisely known parameter values and data consistency tests to detect diversion scenarios. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2026

The Interactions Between Shading and Organic Fertilizer Application on Dry-farmed Tomato Grown Between Photovoltaic Panels

Agrivoltaic systems are mixed systems of solar photovoltaic (PV) panels and agricultural production, where shade from the panels can result in lower evapotranspiration for crops, which is of particular interest for dryland agriculture. Dry-farmed tomato (Solanum lycopersicum) production in the Willamette Valley of Oregon has lower total yields and higher rates of blossom-end rot (BER) than irrigated tomato production, resulting in reduced marketable yields. To determine how dry-farmed ‘Early Girl’ tomato performed in an agrivoltaics system, a trial was conducted at the Valley Creek Solar Project (Salem, OR, USA) in 2020, using three different amendment treatments and three levels of shading from the panels. Amendment treatments were 0N (receiving no fertilizer), 84N (receiving 84 kg·ha −1 N), and 168N (receiving 168 kg·ha −1 N), applied as processed chicken manure. Plants were estimated to receive an irradiance factor of 30%, 76%, and 89% for full-shade, partial-shade, and full-sun treatments respectively. There was an interaction between amendment treatments and shading treatments in their effects on unblemished yield (yield of fruit without BER or sunscald). The optimum fertilizer application for full-shade and partial-shade rows was 84N, the optimum for full-sun rows was 0N. Fertilizing these rows at these rates resulted in an unblemished yield for the aisle of 11.1 t·ha −1 , which was lower than unblemished yields reported in previous experiments and trials in open fields. However, these results are from a single location and a single year, and other solar sites may behave more similar to open-field conditions. Shading from the panels increased average fruit weight and decreased incidence of BER and sunscald, suggesting that crops were less drought stressed. This resulted in similar unblemished yields for the full-shade and full-sun plots at 84N and 168N. Applying fertilizer resulted in higher total yields, smaller average fruit weight, increased BER incidence, and decreased sunscald incidence. The results suggest a possible synergy between dry-farmed tomato production and agrivoltaics, although several concerns remain, including difficulties managing the vegetation under panels, rules restricting PVs on high-value agricultural soils, and the possibility of soil compaction during PV installation.

14 SOLAR ENERGY↗

DOE OSTI2023

Preheating of Cold, High Moisture Particulate Biomaterials to Reduce Drying Time

Forest Concepts led a two-year project to reduce fossil fuel consumption and improve the energy efficiency of dryers through the application of radio frequency (RF) energy impartation to preheat cold-wet bulk particulate biomass materials. A comprehensive biomass heating and drying mathematical model was developed that enables simulation of drying systems for biomass as well as most other bulk porous particulate materials. Experimental and modeling results conclude that energy consumption for both RF preheating and hot-air preheating are essentially equal for cold, high-moisture feedstocks that are above fiber saturation and therefore not economically beneficial for those conditions. Further results suggest that RF heating may have a direct energy consumption benefit in the late stages of drying and in case of preheating biomass that has a moisture content below fiber saturation. This work was funded in part by the US Department of Energy under contact DE-EE0009130.

09 BIOMASS FUELS↗

DOE OSTI2022

Melting Behavior of Conventional and Hydrogen-Reduced DRI in a Simulated EAF Steel Bath

The melting behavior of carbon-free direct reduced iron (DRI) produced by hydrogen reduction has been investigated in a simulated electric arc furnace (EAF) melting environment. A testing apparatus was created to document the melting rates under various bath conditions in slag and steel. This investigation is specific to pellets melted in a steel bath. A model was developed to simulate the shell growth and melting rate of a non-reactive DRI pellet in molten steel. Data acquired from preliminary experiments are utilized to validate the model. This investigation sheds light on the potential effects of melting hydrogen-reduced DRI in the EAF.

36 MATERIALS SCIENCE↗

DOE OSTI2021

Taxonomic and Functional Diversity of Aquatic Macroinvertebrate Assemblages and Water Quality in Rivers of the Dry Tropics of Costa Rica

One of Costa Rica’s driest areas is the province of Guanacaste, in the Pacific Northwest, with almost no rain during the dry season from November to April. Due to this marked seasonality, the area is covered by dry tropical deciduous forest, considered the most threatened and least known tropical ecosystem in this area. This study analyzes and characterizes the assemblages of aquatic macroinvertebrates in water bodies within the Tempisque basin. Biological water quality was measured using the BMWP′-CR index. Macroinvertebrate assemblages were analyzed using abundance, richness, and functional feeding group approaches (FFG). Partial least square (PLS) analyses were performed, and the relationships between environmental factors and macroinvertebrate assemblages are also discussed. Macroinvertebrate assemblages were dominated numerically by mayflies, caddisflies, flies, and beetles. The BWMP′-CR index showed varying biological water quality, ranging from “very bad” to “excellent,” depending on rainfall and site management. Results suggest that tropical Mesoamerican rivers contradict the “river continuum concept” because predators and scrapers displace shredders in numbers. On the other hand, the study area shows a notable high richness of the Coleoptera genera. The class Rhynchocoela (Nemertea) is reported for the first time in Central America. The results indicate that the dry forest river ecosystem shows staggering biodiversity despite the surrounding agricultural land use, probably because of their older origin concerning tropical rain forests in Central America.

54 ENVIRONMENTAL SCIENCES↗