Graduate Students

Bryan I Torres-De Gracia (bryan.torres4@upr.edu)

Ph.D. Student

Bryan Torres is a Ph.D. student working with Dr. Bighnaraj Sarangi. His project tittle is: African Dust Radiative Forcing over Puerto Rico: A Case Study Project Description. This study examines the radiative forcing effects of Saharan dust, focusing on the 2020 “Godzilla” dust event in Puerto Rico. Using observational data and the Rapid Radiative Transfer Model (RRTM), the research compares the impacts of dust and non-dust conditions on solar irradiance and climate. It assesses shortwave and longwave radiation changes, diurnal variability, and surface radiation during dust events. By analyzing the effect of Saharan dust transported via the Saharan Air Layer, the study contributes to a better understanding of mineral dust aerosols’ influence on climate and improves climate modeling accuracy.

Ana G Rivera-Vega (ana.rivera17@upr.edu)

Ph.D. Student

Ana Rivera Vega is a Ph.D. student at the University of Puerto Rico, Río Piedras, where she conducts research under the guidance of Dr. Elvia Meléndez-Ackerman in the Tropical Plant Ecology and Urban Systems Laboratory. Her research explores the ecological and social value of urban mango trees, integrating biological data collection with sustainability and cultural relevance assessments. For her dissertation, she is studying the phenology, diversity, and environmental responses of Mangifera indica trees across an urban environment, aiming to inform urban greening strategies and community engagement around urban agriculture. Ana has been working with the Tropical Plant Ecology and Urban Systems Laboratory since beginning her doctoral studies and has collaborated on projects related to urban biodiversity, ecosystem services, and environmental education.

Abdel A. Jimenez Torres (abdel.jimenez@upr.edu)

MS. Student

Abdel Jiménez is a Master’s candidate working under the supervision of Dr. Jorge Ortiz Zayas in the Laboratory of Tropical Limnology at the University of Puerto Rico, Río Piedras Campus. Broadly, his research focuses on the production and dynamics of methane emissions in reservoirs, aimed at enhancing the understanding of greenhouse gas fluxes within tropical aquatic ecosystems. For his thesis, Abdel investigates methane emissions from Las Curias Reservoir following biological control measures implemented to manage the invasive aquatic fern, Salvinia molesta. His research integrates extensive field and laboratory analyses to evaluate how macrophyte-derived organic matter affects methane production and emission rates. Since 2019, Abdel has contributed to the Laboratory of Tropical Limnology, acquiring more than five years of experience conducting hydrological and biogeochemical analyses, coordinating extensive field campaigns, developing Quality Assurance Project Plans (QAPP), and actively engaging in community outreach initiatives to foster sustainable water resource management and climate resilience in Puerto Rico.

Edgar J. Lozada Gómez (edgar.lozada@upr.edu)

Ph.D. Student

Edgar Lozada-Gómez is a Ph.D. student working with Dr. Omar Pérez at the Aquatic Ecology Laboratory (AEL) at the University of Puerto Rico-Río Piedras Campus (UPRRP). His doctoral research focuses on the study of migratory snail species of the genus Neritina as bioaccumulators of microplastic pollution in estuaries of Puerto Rico. For his dissertation, he has been able to analyze the accumulation of microplastics in these mollusks, where he seeks to evaluate the impact of pollution in aquatic ecosystems and its potential effect on biodiversity and water quality. Edgar Lozada-Gómez has worked at AEL since 2019, before earning his master’s degree in Environmental Science in 2023 at UPRRP. His study provides key information for the conservation of native species and the development of strategies to mitigate plastic pollution in freshwater and coastal bodies; contributing to the knowledge on microplastic pollution in tropical ecosystems, an area still little explored in the Caribbean region.

Marylene Fox(marylene.fox@upr.edu)

MS. Student

Marylène Fox is pursuing an M.Sc. in Environmental Sciences. Her research focuses on studying the accumulation of a class of synthetic compounds that are commonly used in personal care products, in the sediments of the Laguna San José. The study aims to quantify their presence, map their distribution, and provide complimentary data to ongoing research investigating untreated wastewater releases into the lagoon. Originally from Vancouver, Canada, she holds a B.Sc. in Chemistry (2008) from the University of Montréal. Her background as an analytical chemist and laboratory technician includes specializing in the analysis of pesticides and pharmaceuticals in food products using instrumentation such as LC-MS/MS and GC-MS, as well as analyzing water quality parameters with various laboratory and field instruments. Currently, she works with Dr. Jorge Ortiz-Zayas at the Tropical Limnology Laboratory, UPR-RP, on projects analyzing inorganic ions in freshwater samples. Through her research, Marylène hopes to enhance our understanding of anthropogenic contaminants in the environment, particularly those that are not easily visible.

Tatiana Barreto-Vélez (tatiana.barreto@upr.edu)

MS. Student

Tatiana Barreto Vélez is pursuing an M.S. in Environmental Sciences, advised by Dr. Omar Pérez-Reyes in the Aquatic Ecology Laboratory. Her research focuses on characterizing the diversity of non-native freshwater fish, analyzing limnological parameters, and understanding spatial fish distribution in a regulating water reservoir in the northwest karst region of Isabela, Puerto Rico. Since obtaining a B.S. in Environmental Sciences in 2018, Tatiana has contributed to multiple long-term research projects in El Yunque National Forest. As a project manager and research analyst, she has gained extensive experience in both field and laboratory settings, performing aquatic and soil sampling protocols, maintaining sensor arrays, processing samples, analyzing sensor data, and supervising personnel. When Tatiana is not at UPR-RP, she is in the forest, overseeing the day-to-day operations of a forest warming experiment and searching for insects

Victor M. Prado-Marcano (victor.prado@upr.edu)

MS. Student

Victor Prado is a M.S. candidate currently working with Dr. Christopher Nytch in the Integrative Forest Ecology Laboratory at UPRRP. His research is mainly focus in ecological dynamics of Puerto Rican Amazona (Amazona vittata) in El Yunque National Forest, Rio Abajo State Forest and Maricao State Forest.

Derek H. Hillmann-Girod (derek.hillman@upr.edu)

MS. Student

Derek Hillman is a MS student in Environmental Science and is undergoing research with Dr. Bighnaraj Sarangi in the Atmospheric Chemistry and Aerosol Research laboratory in the UPR Río Piedras Campus. Currently, he’s analyzing how ground based urban aerosols can act as Cloud Condensing Nuclei and their potential condensational growth into cloud droplets. He is also working on the refurbishment of Pico del Este field station so he can study aerosol and cloud interactions using the Aerosol and Cloud Analysis System (ACAS). His interest is on meteorology and plans on doing further graduate studies in the atmospheric sciences.

Gabriela S. Hernández-Ramirez (gabriela.hernandez@upr.edu)

Ph.D. Student

Gabriela S. Hernández Ramírez is a Ph.D. student at the Department of Environmental Sciences at the University of Puerto Rico-Río Piedras. She graduated from the University of Puerto Rico-Humacao with a B.Sc in Coastal Marine Biology. As an undergraduate, she worked on various research projects that focused on photo-identification of dusky dolphins (Lagenorhynchus obscurus) and humpback whales (Megaptera novaeanglie), and on the vocal behavior of common bottlenose dolphins (Tursiops truncatus). After graduating in 2020, she went abroad and obtained a M.Sc. in Marine Mammal Science from the University of St Andrews in Scotland, where she investigated cetacean distribution in the Eastern Caribbean using passive acoustic monitoring techniques. Now she is excited to continue her research within the marine mammal science field by focusing on the foraging behavior of Greater Caribbean manatees (Trichechus manatus manatus) in Puerto Rico.

Rose D. Pierre (rose.pierre@upr.edu)

MS. Student

Rose is an MS student in Environmental Sciences at the University of Puerto Rico, Rio Piedras. She is interested in determining strategies to enhance agricultural production while reducing the anthropogenic impacts of climatic change through the agroforestry system. Her research is led by Doctor Christopher Nytch, a specialist in forest ecology. Prior to her graduate journey, she had a BS in Agroforestry and Environment at the American University of Les Cayes, Haiti, and then benefited from a scholarship to continue her educational career in Puerto Rico. She enjoys spending time playing with her daughter and listening to music.

Yeraldin Ramos-Maldonado (yeraldin.ramos1@upr.edu)

MS. Student

Yeraldin Ramos Maldonado is a master’s student in Environmental Science at the University of Puerto Rico – Río Piedras, where she is co-advised by Dr. María F. Barberena-Arias, Dr. Tamara Heartsill-Scalley, and Dr. Omar Pérez-Reyes. Her research explores how soil arthropods contribute to leaf litter decomposition and nutrient cycling in urban forests growing on artificial fill substrates. By examining the roles of arthropods across different stages of decomposition, she aims to understand how biodiversity supports soil fertility in degraded or novel ecosystems — with applications for urban farming, restoration, and sustainable land management. Originally from Trujillo Alto, Puerto Rico, Yeraldin earned her bachelor’s degree in biology from Universidad Interamericana de Puerto Rico – Recinto Metro in 2022. She has conducted research on mangrove and urban forest ecology through her work with SEAS Island Alliance, NASA’s OCEANOS project and the U.S. Forest Service. Outside the lab, Yeraldin enjoys spending time with her three-year-old, whether they’re reading books together, visiting the park, or just exploring the world one curious question at a time. She also finds joy in taking care of her chickens, walking her dog, and spending quiet moments outdoors. Yeraldin values balance between research and community, and she’s passionate about making science accessible and meaningful for the people and places she calls home.

Alondra Del Mar Norat-Pérez (alondra.norat@upr.edu)

MS. Student

Alondra Norat is pursuing an MS in Environmental Science, advised by Dr. Mei Yu. Her research focuses on environmental spatial analysis to study land cover use and land cover change patterns in Puerto Rico with a special focus on coastal wetlands. She also integrates species distribution models to understand the habitat use of shorebird species on the Island. Alondra graduated from the University of Puerto Rico Río Piedras Campus in 2022 with a BS in Environmental Science and has been part of our department since 2017. She is passionate about contributing to the conservation of coastal ecosystems and shorebird species in Puerto Rico. Outside of the lab, she collaborates with various conversation groups by leading bird surveys across the Island. She also has her own educational Instagram page (@pajareovirtual), where she shares her bird photos of Puerto Rico’s avifauna, along with information about the species, to help educate the public about the importance of bird conservation in the Caribbean.

Jason Dragoni-Rosado (jason.dragoni@upr.edu)

Ph.D. Student

Jason Dragoni Rosado is a Ph.D. student working with Dr. Clifford Louime in the C.R.E.S. Lab at the University of Puerto Rico in Río Piedras. For his dissertation, he is studying the changes in the microbiome associated with sargassum during decomposition. Since August 2024, he has been analyzing the microbiome, studying microbial succession, and identifying the presence of essential enzymes for biofuel production. Jason is dedicated to understanding the sargassum problem and its contribution to environmental sustainability.

Yazmin Conté-Gorgas (yazmin.contes@upr.edu)

Ph.D. Student

Yazmín Conté Gorgas is pursuing a Ph.D. in Environmental Science under the mentorship of Dr. José Luis Agosto Rivera. Her research focuses on the impact of light pollution on bioluminescent ecosystems in Puerto Rico, specifically examining its effects on the circadian rhythm of Pyrodinium bahamense var bahamense. She looks forward to contributing to the improvement of the night sky quality in Puerto Rico’s bioluminescent bays and lagoons. Through her work at the University of Puerto Rico at Rio Piedras campus and throughout her future endeavors, she aims to help in the conservation and preservation of bioluminescence in these ecosystems.

Carla Dumas-Vega (carla.dumas@upr.edu)

MS. Student

Carla Dumas is a researcher with a multidisciplinary background in agroenvironmental science, public health, and community-based environmental work. Their academic journey includes research at the Agroenvironmental Chemistry Lab at the University of Puerto Rico–Mayagüez Campus, where they focused on enhancing soil productivity in tropical regions through the use of cover crops. In parallel, they engaged in field work with the Puerto Rico Sea Grant College Program, leading community outreach and educational initiatives related to rural aqueducts and water security across the island. Furthering their interest in environmental health, Dumas contributed to studies on contaminant exposure and its short- and long-term effects on workers at the Environmental Health Laboratory of the UPR–Medical Sciences Campus. Their central research interest lies in developing projection models and analyzing the spatial distribution of chemical impacts on agriculture and greenhouse gas emissions. Through this lens, Dumas aims to evaluate and better understand environmental change across Puerto Rico and the broader U.S. landscape.

Addy Z. Molina (addy.molina@upr.edu)

Ph.D. Student

Addy Z Molina is a Ph.D. student working with Dr. Jorge Ortiz Zayas in the Limnology Laboratory at UPRRP. Her research theme is Human Influences on the Hydrology of the Ciénagas Las Cucharillas Basin, Cataño, Puerto Rico. Broadly speaking, her research and work in the Limnology Laboratory focus on determining the hydrological behavior of water flows as they travel from the headwaters to the mouth of San Juan Bay. This basic knowledge is necessary to analyze the effect of urbanization on water quality, focusing on trace metals and physicochemical parameters, and to offer recommendations for sustainable watershed management. She is also evaluating the impacts of urbanization in a historically intensively managed area. Addy Zahyra currently works for the Department of Defense at Fort Buchanan as a contractor for the Environmental Compliance and Restoration Program. In her spare time, she engages in domestic tourism and participates in 5k/10k running events in Puerto Rico

Angel S. Estruche Santos (angel.estruche@upr.edu)

MS. Student

Ángel Sebastián Estruche Santos is an M.S. student and NSF Graduate Research Fellow at the University of Puerto Rico-Río Piedras Campus, currently working in the Aquatic Ecology Laboratory. As an undergraduate, he conducted research on invasive cichlid feeding behavior, microplastic detection, and mark-recapture efforts. His current work centers on long-term monitoring of freshwater species, biological management, and community outreach. His research focuses on characterizing freshwater ichthyofauna communities using size- and trait-based approaches, concentrating on systems dominated by non-native species. He integrates ecological data with computer science software that specializes in organism measurement, shape analysis, and trait segmentation. This work uses novel approaches to describe population dynamics and demographics in data-limited freshwater ecosystems. Throughout his academic journey, he has explored freshwater systems across Puerto Rico and North America, gaining diverse skills in fisheries science, conservation, and ecological research. His broader academic interests include the curation, conservation, and interpretation of landscapes and natural history collections. Outside the laboratory, Ángel enjoys illustrating, gardening, and volunteering with local organizations on reforestation, species monitoring, and environmental restoration efforts.

Billy Dessalines (billy.dessalines@upr.edu)

Ph.D. Student

Billy Dessalines, originally from Haiti, is currently a doctoral student in environmental sciences, working with Dr. Christopher Nytch. He is interested in landscapes, land conservation, ecosystem services, waste management, and industrial sustainability. He is also interested in mathematical modeling and GIS. He holds a master’s degree in Environmental Sciences from the University of Puerto Rico, Rio Piedras campus, and a bachelor’s degree in industrial engineering from Quisqueya University (UniQ) in Haiti.

Pamela D. Acevedo (pamela.acevedo@upr.edu)

Ph.D. Student

Pamela Denise Acevedo Soto is a doctoral student in the Environmental Sciences program. She is passionate about understanding how microorganisms interact with the atmosphere and influence both environmental and public health. Her recent research, titled “Tracking Bioaerosol Dynamics: Spatiotemporal Patterns of Fluorescent Particles in Tropical and Temperate Environments,” was conducted at
Brookhaven National Laboratory (BNL) as part of a summer internship, in collaboration with BNL scientists. This work examined how atmospheric biological particles vary across different climates urban tropical, temperate, and coastal natural reserves and over time. She presented the results of this research at AGU 2024 in Washington, D.C. Currently, she is focusing on the characterization of bacterial bioaerosols using the WIBS-5 sensor and complementary sampling methods, with the goal of identifying airborne bacterial communities in diverse environments. In the future, she plans to integrate genomic tools and remote sensing technologies to better understand microbial transport and diversity, with a dual focus on climate implications and public health impacts, particularly in tropical regions like Puerto Rico.

Angela Whitley (angela.whitley@upr.edu)

Ph.D. Student

I am currently a PhD candidate studying Environmental Sciences under Dr. Edwin Hernandez. My focus is on Coral Reef Ecology and Coastal Resilience. I’m interested in gaining a better understanding of the current state of shallow urban coral reefs in PR to provide ideas for restoration. I’m also a personal trainer, and professional Muay Thai fighter. I’m currently the #1 ranked welterweight in the world by the World Boxing Council (WBC) and the WBC International Champion

Kevin D. López-Rivera (kevin.lopez24@upr.edu)

Ph.D. Student

Kevin López-Rivera is a Ph.D. student working under Dr. Elvira Cuevas at the EcoLab at the University of Puerto Rico, Río Piedras Campus (UPRRP). He is also working under Dr. José Dumas at the Subestación Experimental Agrícola in the Río Piedras Botanical Garden. His doctoral research focuses on the synchronization between the demand and availability of elements in two highly important crops under contrasting conditions: avocado and banana. Through a combination of greenhouse and field experiments, his work aims to understand how different soil treatments and climate variability influence nutrient uptake dynamics and soil health. Ultimately, his research seeks to inform more sustainable agricultural practices in tropical systems, support farmers across Puerto Rico, and strengthen food security and sustainability.

Durgadevi Kalirathnam (durgadevi.kalirathnam@upr.edu)

MS Student

I’m a MS student passionate in building sustainable environment for our future generation. Currently my research focus on Sargassum a part of marine ecosystem but during summer blooms and cause major distress to the pelagic ecosystem and coastal community. I’m keen in finding a balance between the economic and environmental aspect to reach truly sustainable solutions, protecting the environment by reducing the carbon emission from decaying Sargassum and benefiting the coastal community. With my engineering background in biotechnology, I explore valorization of Sargassum through biopolymers, biogas and other possibilities. I work with Dr. Clifford Louime in C.R.E.S lab studying Sargassum, effective storage and creating a biorefinery concept using Sargassum. My thesis focuses on Techno-Economic analyses of production of biopolymers from Sargassum.

Mario Rivera Bonilla (mario.rivera@upr.edu)

Ph.D. Student

Mario Rivera Bonilla is a Ph.D. candidate in Environmental Science at the University of Puerto Rico. His doctoral research focuses on the influence of soil amendments on antinutritional secondary metabolites in Phaseolus vulgaris, integrating analytical chemistry, sustainable agriculture, and plant biochemistry. Prior to his doctoral work, Mario completed all coursework for an M.D. at UPR Medical Sciences and earned a B.S. in Cellular and Molecular Biology from UPR Río Piedras, graduating Magna Cum Laude. He has contributed to public health research on transgender healthcare and hypospadias management in Puerto Rico, demonstrating a commitment to equity-focused inquiry. His academic journey reflects a dedication to interdisciplinary research, scientific rigor, and a vision for integrating environmental and health sciences to address pressing global challenges through education and evidence-based practice.

Julymar Rodríguez López (julymar.rodriguez@upr.edu)

MS. Student

Julymar R. López is an Environmental Sciences graduate student at the University of Puerto Rico–Río Piedras Campus. She graduated from the Wildlife Management Program at the University of Puerto Rico–Humacao Campus. As an undergraduate student, she focused on researching population dynamics and community ecology of flora (orchids) and fauna (reptiles, amphibians, and insects) under the guidance of various professors. She also participated in a National Science Foundation Research Experience for Undergraduates and was awarded a fellowship of the National Science Foundation Strategies for Ecology Education, Diversity, and Sustainability Partnership for Undergraduate Research of the Ecological Society of America. Her main interests include understanding how abiotic factors influence the responses of organisms, primarily those of endangered species, at population and community levels and for conservation contexts. Her long-term goal is to become a professor and contribute to bridging the science communication gaps between scientists and non-scientists. Julymar enjoys wildlife photography and writing poetry.