Research

I am a marine biogeochemist, specializing in environmental tracers and biogeochemical hotspots for nitrogen cycling. My research studies the processes affecting the transport, fate, and impact of chemical species, including contaminants, in aquatic ecosystems. The goal is to understand the functional plasticity of ecosystems to anthropogenic pressure, climate change and biological activity, leading to increased knowledge on the functional resilience of marine systems to environmental change.

Projects

iCrag (Irish Centre for Applied Geosciences) / Trinity Environmental Tracer and Forensics Laboratory

This laboratory will employ state of the art isotope tracing techniques to identify sources and transfer pathways, track flows, and pinpoint storage locations for carbon, nitrogen, and water moving through soil and across the soil/atmosphere, the land/ocean and ocean/atmosphere interfaces as well as identifying mixing and transformative processes and rates affecting natural storage and mobilization potential for carbon and nitrogen. This analytical capacity is unique in Ireland. Equipment includes state of the art CRDS systems, radon, and radium isotope analysers, as well as the more traditional hydrochemistry techniques. This significant analytical power will play a key role in developing the future sustainable and circular economy (Negative carbon drive, UN sustainability goals, EU Blue Growth, inter-alia).

GRoundwater Age DistributionS for the Sustainable MAnagement of gRoundwaTer reSources in Ireland (GRADS & SMARTS), EPA Ref: 2021-NE-1045.

This project (~500 kEuro) is funded in equal parts by the EPA and the GSI. Its purpose is threefold: 1) to provide the first quantitative assessment of average groundwater residence times (GRTs) and mean groundwater travel times (GTTs) in selected Irish catchments, 2) to use such GRTs and GTTs to gain insights into the fate and transport of nitrate (NO3-) in catchments particularly at risk from such contamination and 3) to present the first isoscape (isotopic landscape) of the water cycle in Ireland, from recharge to discharge. The first and second aims will facilitate the sustainable management of groundwater, particularly with respect to anthropogenic contamination and especially with regards to nitrate (fertilizer) pollution, while the third will advance the quantification and monitoring of climate and environmental change impacts on the local water cycle, help understand regional ecology and biodiversity and support environmental forensics seeking to understand sources, pathways and timing of contaminant flows, including nitrate, through groundwater bodies to receptor ecosystems.

Students

Eimear Prendergast

Eimear graduated with a BA in Earth Sciences from Trinity in 2021 and is part of the GRoundwater Age DistributionS for the Sustainable MAnagement of gRoundwaTer reSources in Ireland (GRADS & SMARTS, EPA Ref: 2021-NE-1045) research team. Her PhD project explores the combined use of stable isotopes in water (ẟ18O and ẟ2H) and other environmental tracers, including 222Rn and Cl-, to quantify young water fractions in Irish catchments, and help assess nitrate lag times for the sustainable management of water resources. GRADS & SMARTS is funded by the Irish Environmental Protection Agency (EPA) and the Geological Survey Ireland (GSI)

Conor Smith

Conor graduated with a BSc (Hons) in Analytical Chemistry from TU Dublin in 2022 and is part of the GRoundwater Age DistributionS for the Sustainable MAnagement of gRoundwaTer reSources in Ireland (GRADS & SMARTS, EPA Ref: 2021-NE-1045) research team. His PhD project explores the combination of stable isotope signatures of solutes in groundwater (ẟ13C in DIC, CO2 and CH4 and ẟ15N in NO3- and N2O) with traditional water age indicators (CFCs, SF6, 3H, 3H/3He and 14C) to resolve kinetic and biogeochemical controls over nitrate lag times in Irish catchments. GRADS & SMARTS is funded by the Irish Environmental Protection Agency (EPA) and the Geological Survey Ireland (GSI).

Teaching

GLU33002 Blue Earth: Understanding the function of Marine Ecosystems

Publications

2022

Calvo-Martin, Elisa, Eva Teira, Xosé Antón Álvarez-Salgado, Carlos Rocha, Shan Jiang, Maider Justel-Díez, and Juan Severino Pino Ibánhez. 2022. ‘On the Hidden Diversity and Niche Specialization of the Microbial Realm of Subterranean Estuaries’. Environmental Microbiology n/a (n/a). https://doi.org/10.1111/1462-2920.16160.

O’Connell, D. W., C. Rocha, E. Daly, R. Carrey, M. Marchesi, M. Caschetto, N. Ansems, J. Wilson, C. Hickey, and L. W. Gill. 2022. ‘Characterization of Seasonal Groundwater Origin and Evolution Processes in a Geologically Heterogeneous Catchment Using Geophysical, Isotopic and Hydro-Chemical Techniques (Lough Gur, Ireland)’. Hydrological Processes 36 (10): e14706. https://doi.org/10.1002/hyp.14706.

Rocha, Carlos, Henry Bokuniewicz, Clare E. Robinson, Isaac R. Santos, and Hannelore Waska. 2022. ‘To Study the Invisible: Hydraulics, Biogeochemistry, and Life in Subterranean Estuaries [Editorial: Subterranean Estuaries]’. Frontiers in Environmental Science 10. https://www.frontiersin.org/articles/10.3389/fenvs.2022.988723.

Rocha, Carlos, Shan Jiang, J. S. P. Ibánhez, Qiang Yang, Katerina Mazi, and Antonis D. Koussis. 2022. ‘The Effects of Subterranean Estuary Dynamics on Nutrient Resource Ratio Availability to Microphytobenthos in a Coastal Lagoon’. Science of The Total Environment 851: 157522. https://doi.org/10.1016/j.scitotenv.2022.157522.

2021

Jiang, S., Kavanagh, M., Ibánhez, J.S.P., Rocha, C., 2021. Denitrification-nitrification process in permeable coastal sediments: An investigation on the effect of salinity and nitrate availability using flow-through reactors. Acta Oceanol. Sin. 40, 1–12. https://doi.org/10.1007/s13131-021-1811-5

Ibánhez, J.S.P., Álvarez‐Salgado, X.A., Nieto‐Cid, M., Rocha, C., 2021. Fresh and saline submarine groundwater discharge in a large coastal inlet affected by seasonal upwelling. Limnology & Oceanography 66: 2141–2158. https://doi.org/10.1002/lno.11733

Ibánhez, J.S.P., Álvarez-Salgado, X.A., Rocha, C., 2021. Does Nitrate Enrichment Accelerate Organic Matter Turnover in Subterranean Estuaries? Frontiers in Marine Science, 8: 661201. https://doi.org/10.3389/fmars.2021.661201

Jiang, S., Jin, J., Wu, Y., Zhang, Y., Wei, Y., Rocha, C., Ibánhez, J.S.P., Zhang, J., 2021. Response of Nitrate Processing to Bio-labile Dissolved Organic Matter Supply Under Variable Oxygen Conditions in a Sandy Beach Seepage Face. Frontiers in Marine Science, 8: 642143. https://doi.org/10.3389/fmars.2021.642143

Savatier, M., Rocha, C., 2021. Rethinking tracer-based (Ra, Rn, salinity) approaches to estimate point-source submarine groundwater discharge (SGD) into coastal systems. Journal of Hydrology, 598: 126247. https://doi.org/10.1016/j.jhydrol.2021.126247

Rocha C, CE Robinson, IR Santos, H Waska, HA Michael, HJ Bokuniewicz 2021. A place for subterranean estuaries in the coastal zone. Estuarine, Coastal and Shelf Science, 250: 107167. https://doi.org/10.1016/j.ecss.2021.107167

Savatier M, MT Guerra, JE Murphy, C Rocha 2021. Radium isotopes as tools to characterise nutrient dynamics in a variably stratified temperate fjord. Marine Chemistry, 231: 103934. https://doi.org/10.1016/j.marchem.2021.103934

Calvo-Martin E, XA Álvarez-Salgado, C Rocha, JSP Ibánhez 2021. Reactive solute transport through two contrasting subterranean exit sites in the Ria de Vigo (NW Iberian Peninsula). Frontiers in Marine Science, 8: 626813. https://doi.org/10.3389/fmars.2021.626813

Aghdam MM, Q Crowley, C Rocha, V Dentoni, S Da Pelo, S Long, M Savatier 2021. A study of natural radioactivity levels and Radon/Thoron release potential of bedrock and soil in south-eastern Ireland. International Journal of Environmental Research and Public Health, 18(5): 2709. https://doi.org/10.1016/ijerph18052709