RESEARCH FELLOWS
Chris T. Wood
Email: ctwood@uci.edu
I’m Chris, and I am currently finishing a PhD in Earth System Science at the University of California, Irvine, after which I plan to join the Waikato Environmental Geochemistry group in January 2020 as a research fellow. My research, under the supervision of Dr. Kathleen Johnson, has focused on developing stalagmite records of paleoclimate from mainland Southeast Asia. Specifically, I have been investigating how trace elements and radiocarbon may act as hydrologic proxies in a speleothem record over the last deglaciation and Holocene with a focus on abrupt, global climate events. These projects have involved field work and cave monitoring in Laos and Vietnam as well as extensive lab work using ICP-MS and AMS techniques. I plan to apply my interests and experience to new projects in the South Pacific and New Zealand while continuing to explore the geochemistry of karst and cave environments. I also hope to contribute to the community in and around the University of Waikato through mentorship, service, and collaborations.
Dorisel Torres-Rojas
Email: dt273@cornell.edu
Hi, I am Dori and I am excited to join the WaiBER and WEG group as a Postdoctoral Research Fellow. I completed my PhD in Soil Science at Cornell University and I have a background in Engineering. My PhD research focused on the study of thermal and biological transformations of organic N in plant residue and their effect on the persistence of pyrogenic C in terrestrial ecosystems. This work sparked my interest in understanding the mechanistic interactions that govern N removal, retention, and sequestration in agricultural and natural ecosystems.
As a Research Fellow, I will be working on increasing bioreactor nitrate removal rates by activating media surface and controlling redox conditions to promote denitrification. I look forward to collaborating and learning from an incredible group of scientists while applying my expertise in soil biogeochemistry and engineering to the design of more efficient bioreactors.
I am a geek at heart and I love the challenge of understanding mechanistic processes but also finding a practical solution to real world problems.
PhD RESEARCHERS
Sebastian Höpker
Email: seb.hoepker@gmail.com
Hi, I’m Seb. I obtained my undergraduate degree in Marine Science (BMarSc) at James Cook University, Australia, with a focus on physical and geochemical processes in the ocean and tropical coral reef systems.
My studies continued closer to home in northern Germany, where I completed my MSc in Marine Geosciences at the University of Bremen. I had the opportunity to carry out some exciting field and lab work throughout my studies, during which I developed a particular interest in looking at past and present climate variability based on the chemical composition of biogenic carbonates. In my MSc thesis I assessed the use of strontium isotopes in modern and archaeological bivalve shells and fish otoliths as a tracer for freshwater discharge in NW African estuaries, yielding new insights into the activity of the West African Monsoon System over the last 6,000 years.
For my PhD, supervised by Dr. Adam Hartland and Dr. Megan Grainger, I am now looking at developing a new speleothem hydroclimate proxy based on the interactions of trace metals in dripwater with organic ligands. The project will involve the establishment of cave monitoring programs in New Zealand and islands of the South Pacific, as well as carbonate growth experiments mimicking cave conditions in the lab at UoW. This novel type of proxy aims to allow for quantitative estimates of past cave drip rates derived from measured trace metal concentrations in speleothems, ultimately providing new information on recent and Holocene changes in the New Zealand and South Pacific hydroclimate. I’m excited to join this growing field of research, and am looking forward to exploring the stunning NZ outdoors in my spare time.
Huma Saeed
Email: huma.saeed@waikato.ac.nz
My PhD project focuses on the interaction between iron nanoparticles and phosphorus in lake systems with high internal loadings of iron. The objective is to understand how iron influences the bioavailability of P to autotrophs. My studies are supported by a Waikato University Environmental Research Institute Scholarship.
Amir Mohammadi
Email: amir.mohammadi21@gmail.com
My journey in Environmental Studies started in Iran, where I completed my MSc in Environmental Engineering at Iran University of Science and Technology. I have a strong interest in the fate and transport of contaminants in soils and aquifers. My PhD thesis is entitled “From soil to groundwater: assessing the leaching potential of cadmium across gradients of soil type and land-use”. In this study, I aim to deploy Diffusive gradients in thin films (DGT) solution probes in groundwater piezometers to monitor the concentration of Cd. This approach will be extended by measurement of the Cd isotope composition in order to characterise the Cd source(s) and biogeochemical processes affecting Cd mobilisation. I am supported by the Waikato University Doctoral Scholarship and supervised by Dr Adam Hartland and Prof. Louis Schipper. Aside from my academic interests, I enjoy exercising, camping, sport fishing and cooking!
Cinthya Nava Fernandez
Email: cinthya.navafernandez@rub.de
I’m Cinthya 
Nava Ph.D. student at Ruhr University Bochum. Through research, I am exploring the variability of the El Niño Southern Oscillation ENSO during the mid-Holocene. For this we are using oxygen and carbon stable isotope ratios and LA-ICP-MS analysis as a proxy of the past climate in the south tropical Pacific using a stalagmite from Niue Island. Another amazing chapter of my thesis involves cave monitoring at Waipuna Cave, New Zealand. During each visit we take dripwater samples and microclimate measurements in order to test the sensitivity of the cave to record external environment conditions as well as climate anomalies such El Niño and La Niña events. This research is framed by project QUEST formed by the collaboration of my supervisors Dr. Sebastian Breitenbach from RUB and Dr. Adam Hartland, who kindly hosts me at Waikato University, an extraordinary place to carry on the fieldwork and joyfully develop my project together with WEG friends.
Gimhani Perera
Email: gimhani.perera@niwa.co.nz
Hi, I’m Gimhani and I am excited to be a part of the WEG group. I recently graduated with my masters in Environmental Sciences from the Chinese Academy of Sciences, Chongqing Institute of Green and Intelligent Technology. My studies focused on advanced membrane fabrication and the application of membrane-based desalination in understanding membrane fouling mechanisms and developing novel desalination technology. I obtained my BSc in Mineral resources and technology (sp. water science) at Uva Wellassa University, Sri Lanka. Here I will continue within the same themes, but also mainly focusing on the bioreactor project the group already has ongoing.
I am currently fortunate enough to be provided with the opportunity to work hand in hand with UoW and NIWA across various sectors of study. Under the supervision of Dr. Adam Hartland, Professor Louis Schipper, Dr. Dorrisel Torres-Rojas, and Dr. Rupert Craggs, I am undertaking a Ph.D. research project which aims to enhance phosphorous removal from agricultural subsurface drainage by activated bio media. This study will provide new perspectives on the biogeochemistry of denitrifying bioreactors by examining the interplay of redox processes which may affect P and it’s interaction with introduced biomedia.
I’ve long been involved in various science projects and research experiments, and I am passionate about traveling in my spare time. I’m pretty excited to soak up all I can from this experience and make some new friends along my Ph.D. journey.
ALUMNI
PhD
Thomas Corbett
Email: corbett.tdw@gmail.com
Thesis: Quantification of Nitrate Concentrations and Determination of Flow Rates in Freshwater: Enhancement of the ‘Diffusive Gradients in Thin-films’ Methodology
Current position: Postdoc, Uppsala University
Andrew Pearson
Email: apearson181@gmail.com
Current position: Groundwater Quality Scientist, Environment Canterbury
MSc
Ingrid Lindeman
Email: ilindemannz@gmail.com
Thesis: Effects of Organic Matter Complexation on Partitioning of First Row Transition Metals Into Calcite: Cave-Analogue Crystal Growth Studies
Current position: Research Associate at Plant and Food Research
Chris Eager
Email: chris.eager@niwa.co.nz
Thesis: Biogeochemical Characterisation of an Alum Dosed Stream:
Implications for Phosphate Cycling in Lake Rotoehu (2017)
Current position: Coastal Technician, NIWA
BSc (Hons)
Jackson White
Email: jacksonwhite704@gmail.com
Dissertation: Quantifying condensation corrosion in the Glowworm Cave, Waitomo (2019)
Current position: PhD candidate, University of Queensland
Summer research project students
Ben Scarlet (2014), Jain Abraham (2015), Amy Shen (2016)
Undergraduate Research Students
Jackson White (2016), Katie O’Reilly (2017)
International Internship Students
Pierre Oesterle (2013)
Katrin Hattig, University of Bremen (PROMOS, 2018)
VISITORS
Martin Andersen, UNSW Connected Waters Initiative Research Centre. November-December 2014.
John Hellstrom, University of Melbourne, November 2015.
Chaoyong Hu, China University of Geosciences, January-July 2016.
Niklas Lehto, Lincoln University, April 2016.
Sebastian Breitenbach, Ruhr-Universität Bochum, September-October 2016.
Tihana Vujinovic, Lincoln University, June and October 2017.
Dharshika Welikala, Lincoln University, June 2017.
Mirona Chirienco, Okinawa Institute of Science & Technology, May-June 2017.
Andreas Holbach, Karlsruhe Institute of Technology (KIT), October – December 2017
Ry Farley, Vassar College, Poughkeepsie, New York, October – December 2017
Inken Heidke, Johannes Gutenberg University Mainz, December 2017 – January 2018
David Dominguez-Villar, Ruđer Bošković Institute, Zagreb, January- February 2018
Maximilian Hansen, Johannes Gutenberg University Mainz, April – May 2018
Bedartha Goswami, Potsdam Institute for Climate Impact Research, Sept – Nov 2018
Hauke Kraemer, Potsdam Institute for Climate Impact Research, Nov – Dec 2018
Sebastian Breitenbach & Ola Kwiecien, Ruhr-Universität Bochum, December 2018 -January 2019
Cinthya Nava Fernandez, Ruhr-Universität Bochum, January- March 2019
John Hellstrom, University of Melbourne, April 2019.
Anja Beschnitt, Johannes Gutenberg University Mainz, August-October 2019.
Marco Roth, Ruhr-Universität Bochum, October – November 2019.
Alena Giesche, University of Cambridge, October – December 2019.
Slide show of some of the visitors and students in our group
Waikato Environmental GEOCHEMistry 