Leeza Speranskaya completed an MSc thesis working with Dave Campbell, on peatland hydrological processes, with a focus on quantifying interception loss for the dominant vegetation type at Kopuatai bog
– Empodisma robustum and understanding evaporation partitioning under wet and dry canopy conditions. She also examined a 10-year eddy covariance evaporation dataset to identify patterns and key variables influencing evaporation and published her findings here.
Reza Moghaddam. The Reza’s PhD project was “carbon dosing of denitrifying woodchip bioreactors”. He investigated whether and to what extent, the dosing of denitrifying bioreactors with an added soluble source of carbon, particularly methanol, stimulated nitrogen removal from agricultural runoff. The project also encompassed assessing the leaching risk of the added methanol either in field and mesocosm scale bioreactors. He published three papers from his thesis, including:
Moghaddam, R., Torres-Rojas, D., Schipper, L. (2022). Enhanced nitrate removal and side effects of carbon dosing in denitrifying bioreactors. Ecological Engineering 185: 106818.
Jordan Goodrich interests span ecosystem-atmosphere interactions and the climate and management patterns that govern them. Some common threads of his research and background include ecosystem responses to environmental variability, characterizing uncertainty, and improving mechanistic knowledge through novel data analysis. During his PhD, Jordan worked on New Zealand’s unique restiad bogs, exploring carbon and methane fluxes with eddy covariance. As a research fellow he explored the agricultural realm investigating tower-based fluxes of nitrous oxide, methane, and CO2 from pasture systems with the aim of mitigating greenhouse gas emissions and limiting carbon losses. Google scholar papers
Dori Torres-Rojas joined the WaiBER and WEG group as a Postdoctoral Research Fellow. She completed her PhD in Soil Science at Cornell University and I have a background in Engineering. Her 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 an interest in understanding the mechanistic interactions that govern N removal, retention, and sequestration in agricultural and natural ecosystems. As a Research Fellow, Dori worked on increasing bioreactor nitrate removal rates by activating media surface and controlling redox conditions to promote denitrification. Google scholar papers
Charlotte Alster was a Research Fellow interested in the temperature sensitivity of soil microbial communities. Her work uses trait-based ecological approaches to link microbial physiological responses to ecosystem function as a tool to improve understanding of microbial responses to climate change. During my PhD, she used Macromolecular Rate Theory (MMRT) to develop a novel theoretical framework for characterizing temperature sensitivity as a microbial trait. at the University of Waikato, Charlotte built on this work as part of the larger Marsden funded project, “MMRT and the temperature-dependence of the terrestrial biosphere over time and space”, by exploring temperature traits from soil microbial communities from across New Zealand. Website: http://charlottealster.weebly.com/ Google Scholar
Graham Sparling is a long time collaborator, who focused on fractionation of soil carbon, dissolved organic matter, worms, changes in soil C as forest are converted to pastures, Cd and U accumulation with P fertiliser application and soil quality. He also contributed to educational articles and helps graduates turn their thesis into journal papers.
Helena Layton examined the differences in drained peat properties, historical and current land uses and drained peat developmental history on peat shrinkage. She worked at paired PSO sites across the Hauraki and Waikato regions. This, coupled with soil samples will be used to begin developing a regional picture of how spatial variation in properties and land use are linked to spatial variations in shrinkage. A comparison between land uses was made through data collected at paired blueberry and dairy farms as well as an additional dry stock site. The main remnant peat areas of interest included Rukuhia, Komokorau, Torehape and Moanatuatua. These sites have been set up as part of a region monitoring system set out by the Waikato Regional Council. Helena was supervised by Dave Campbell.
Tsitsi Chiwetu was an MSc research student with Louis Schipper. Her project focused on an analysis of the potential of phosphate to extract carbon from soil organic matter (SOM). She determined the extractability of SOM from sieved and unsieved soils from 22 different sites as well as comparing how much carbon is extracted using different concentrations of phosphate. In the end, only high concentrations of added phosphate extracted carbon from soil.
Allycia van de Laar completed her MSc (Research) thesis investigating the temperature dependence of soil respiration and priming. Her research 1) develop an automated method for measuring the temperature dependence of soil priming and 2) the temperature dependence of soil respiration and added glucose along a natural geothermal gradient. Ally’s research used 13 C isotopes and principles of macromolecular rate theory principles. Allycia worked with Louis Schipper as her supervisor.
After completing her MSc, Ally provided research support to Charlotte Alster on a wide range of research projects focussing on temperature response.
Thomas Corbett completed a PhD research project developing a Diffusive Gradients in Thin-Films (DGT) sensor, integrating colourimetry to quantify nitrate in fresh water. He also developed approaches for using DGTs to determine total loads when coupled to bromide tracers. The long-term goal aim is to develop a sensor that is easy to use, accurate, and very affordable. The project was supervised by Louis Schipper, Adam Hartland, Bill Henderson and Gerald Rys (MPI).
Alice Wheatley-Wilson investigated the temperature dependence of methane production from peat and drained peat soils as part of her MSc (Research). Temperature response is poorly constrained in peat ecosystem models, so Alice collected data on the response across a larger temperature range to capture the full curvature. The sites of interest for this research included peat domes; Kopuatai and Moanatuatua as well as drained peat soil sites; Moanaleas and Gamma farm. Alice was supervised by Jordan Goodrich, Dave Campbell, and Louis Schipper.
Georgie Glover-Clark investigated the controls on the spatial variation of hydrology in drained agricultural peatlands, and how these controls controlled pasture production and greenhouse gas emission for her Master’s thesis project. Her research utilized measurements from detailed hydrological transects and eddy covariance flux towers, at two sites with contrasting drainage designs and similar management practices. The research was supervised by Dave Campbell and contributed to the PEATWISE project. Georgie also joined the team on a short-term contract supporting Dave Campbell’s peat work.
Jasmine Robinson completed a PhD that examined the stability of newly incorporated plant matter in soil. This project is in collaboration with Mike Beare (Plant and Food), Tim Clough (Lincoln Uni) and Pete Millard (Landcare Research) supported by funds from the Global Research Alliance. Jasmine previously completed an MSc project that examined whether the temperature response of soil respiration changed between soil types, through seasons and with long term incubation at different temperatures. She applied macromolecular rate theory (MMRT) in her to calculate temperature response of soil respiration.
Anne Wecking. The core of Anne’s PhD focused on the understanding and management of nitrous oxide (N2O) emissions from grazed pastoral land. Data for her work was collected using an eddy covariance flux tower coupled to a quantum cascade laser to identify the response of N2O emissions to fertilisation, grazing intensity and sward diversity. The approach included considerations on farm scale aiming to support New Zealand’s greenhouse gas inventory and potential mitigation approaches. Anne holds a MSc in Landscape Sciences from Leibniz University Hannover, Germany, and was supervised by Louis Schipper and Dave Campbell. Her website can be found here.
Kristyn Numa completed her Masters thesis examining the controls of soil respiration. In particular, she looked at the temperature dependence of respiration with different added carbon compounds (e.g. glucose) in soils. This research involved incubating soils across a temperature gradient, measuring the carbon dioxide respired and used 13C labelled carbon compounds to help partition the temperature responses. She applied the macromolecular rate theory (MMRT) to calculate these temperature responses. This research was supervised by Louis Schipper. Kristyn subsequently joined the team on a short-term contract supporting Louis’ research and teaching.
Emily McKay investigated the effect of different intensity cultivation/tillage on soil physical properties supervised by Tanya O’Neill. Her project was with Foundation for Arable Research (FAR) with a trial site with three different treatments – full cultivation, strip-till, and no-tillage. She tested for a range of soil properties such as aggregate stability, carbon and nitrogen stocks to depth, bulk density, penetrometer resistance, the remaining soil quality indicators, along with visual soil assessments. This projects aimed to provide an understanding of the potential benefits of reduced cultivation for New Zealand growers and farmers.
Ingrid Lindeman completed a Masters thesis in speleothem science under the supervision of Dr Adam Hartland. Her research involved growing calcite under cave-analogue conditions in the laboratory and studying the partitioning behaviour of trace elements into calcite in the presence of organic ligands. This research has the potential to help improve the use of trace elements as paleoclimate proxies during climate reconstructions from speleothem archives.
Joss Ratcliffe completed a PhD studying carbon accumulation and decay rates in pristine and disturbed Waikato peatlands. He reconciled contemporary GHG flux data with paleoecological records in order to assess the stability of the carbon store and reveal the future trajectory of carbon storage. Joss previously completed an MSc from the University of Highlands and Islands, Scotland and was supervised by Dave Campbell with co-supervision by Louis Schipper and David Lowe.
Noel Bates was a technician in the Earth Sciences department and manager of the E.1.06 Soil Ecology Lab. He was a recent University of Waikato graduate (2018 MSc in Earth Sciences with First Class Honours). His primary role was to facilitate the research activities of soil and environmental science graduate students as well as to accommodate undergraduate teaching labs.
Susan Schwinning is a Professor and visited the WaiBER groups during a sabbatical leave from Texas State University in San Marcos. Susan earned her PhD in Ecology and Evolutionary Biology from the University of Arizona at Tucson in 1994. She has been affiliated with the Department of Biology at Texas State University since 2005, where she teaches General Ecology, Plant Ecology, Plant Water Relations and Introduction to Ecological Modeling. Her research focus is in ecohydrology and the ecology of plant recruitment. She is here to invigorate her long-term research interest in modeling plant-soil-animal interactions in grazing systems.
Olivia Adamson was recent graduate in Environmental Sciences undertaking a summer research project looking at the differences in the natural abundance of 13C in C3 and C4 plants to understand the impacts of land use change — particularly from pasture to maize cropping– on the dynamics of soil organic carbon. This technique can give insight into the rates at which the new vegetation adds C to the soil, if and at what rate the old C is being lost, and hence the stability and turnover rates of different types and pools of soil organic carbon. I am interested in the intersections between soils, food production and climate change and soon hope to begin masters study in this area.
Charlotte Roberston’s MSc thesis’ aimed to define management solutions that reduced nitrogen leaching by 20% in a cost-effective manner. Charlotte’s work was aligned to the ‘Forages for Reduced Nitrate Leaching’ programme that has demonstrated that fodder beet, oats and plantain can significantly reduce nitrogen leaching, especially when managed together. Her thesis explored the environmental/economic trade-offs of reducing nitrate leaching with profitability by modelling real farms in Farmax and OVERSEER®. Supervised by Louis Schipper, from DairyNZ Álvaro Romera and Graeme Doole.
Hannah Dougherty was a Fulbright US Graduate working on a Diffusive Gradients in Thin-Films (DGT) sensors with Thomas Corbett (PhD candidate). She used DGT as an updated more cost-effective way to measure nitrate removal in denitrifying bioreactors compared to existing sampling methods. Hannah holds a MSc in Crop Sciences from the University of Illinois Urbana-Champaign, USA and was supervised by Louis Schipper.
Jacob Hamill’s MSc determined the magnitude of methane emissions from a drained peatland under dairy grazing and where and when these emissions occur throughout the year. In particular, he looked for methane emission hotspots as there is a high degree of temporal and spatial variability in the methane flux as a result of drainage ditches. The project was supervised by Dave Campbell.
Femke Rambags completed a PhD on the use of denitrifying bioreactors for improving the performance of on-site decentralised wastewater management in collaboration with NIWA’s programme She showed that these bioreactors not only remove nitrate from wastewater but also effectively reduced pathogens (both E. coli and viruses) and, surprisingly, ammonium through the microbial process of ANAMMOX. She was supervised by Louis and Chris Tanner from NIWA.
Yuan Liu was a visiting PhD student from Institute of Geographic Sciences and Natural Resources Research of Chinese Academy of Sciences. He investigated the response of soil respiration to changing temperature in Chinese soils during his PhD. Yuan used the temperature block technique we established for measuring temperature dependence of soil respiration under aerobic and anaerobic conditions. He applied macromolecular rate theory (MMRT) to calculate temperature response of soil respiration and derive important temperature parameters. Yuan is broadly interested in the response of carbon and nitrogen (N) cycle and their interactions to global change factors (e.g., warming, N deposition, precipitation change, drought).
Connie Daws conducted a Masters thesis focusing on the present day hydrology of a remnant peatland in the Waikato (Moanatuatua) surrounded by drained pet used for animal grazing. She looked to establish whether the deep border drains or the late successional/shrub-dominated vegetation maintains the unnaturally low water table across the bog. Connie used data obtained from a hydrological transect across the bog coupled to eddy covariance measurements of evaporation. She sought to identify appropriate management strategies that could return this peatland to a more natural and resilient condition. Connie was supervised by Dave Campbell.
Callum Douglas conducted a MSc thesis, supervised by Dave Campbell, investigating the ecohydrology of the Otakairangi wetland in Northland. The research attempted to demonstrate the current recovery pathway this degraded remnant is currently following. He meausred the annual hydrological regime and analysed how a central drain through the wetland altered the environment and dominant surface vegetation.
Bryan Maxwell visited from the US to monitor water quality in a woodchip bioreactor treating drainage from dairy pasture. As part of his PhD at North Carolina State University, he has been developing high-frequency, multi-point sampling methods to help better understand nitrate removal in woodchip bioreactors. Louis was one of his cosupervisors. Bryan successfully defended his PhD at the very beginning of 2019.
Sheree Balvert’s PhD thesis investigated naturally-occurring inhibitors of nitrous oxide production and emissions from farm soils. Sheree was particularly interested in compounds found in brassicas and dairy cow urine and carried out this research in collaboration with AgResearch with funding from the New Zealand Agricultural Greenhouse Gas Research Centre. She speaks about her work here starting at 2.4 minutes. Sheree’s main supervisors were Louis Schipper, Jiafa Luo (AgResearch) and Dave Campbell.
Jonno Rau completed a MSc analysing land suitability analysis of the Wairoa District, Hawkes Bay to identify areas with potential for horticultural development. Other objectives included using MODIS satellite imagery to identify areas prone to frost and calculating crop irrigation needs by determining each soil types available water holding capacity. Jonno was supervised by Megan Balks with co-supervision by Dave Campbell.
Jamie Millar conducted a MSc thesis investigating whether irrigation of grazed pasture growing on pumice soils resulted in losses of soil carbon and nitrogen. Turns out that there was a loss of about 6 T C per hectare in line with previous work conducted in collaboration with Landcare Research and AgResearch that found for other soils, on average, lower organic matter stocks under irrigation . Jamie was co-supervised by Paul Mudge (Landcare Research) and Tanya O’Neill.
Janine Ryburn
Janine Ryburn was the technician in charge of the soil ecosystems lab in the Earth and Ocean Science department. She ensured all the undergraduate labs ran smoothly, trained graduate students, maintained equipment and the soil archive and coped generally with the impossible demands of academics. She contributed to a wide range of soil and water research supporting students and academics.
Liyin Liang was a research fellow who came to work with us from UC Riverside. Liyin led our efforts to develop eddy covariance measurements of nitrous oxide fluxes from grazed pastures. While technically very challenging these methods offer the advantage of measuring fluxes at paddock scales almost continuously. He also worked on using macromolecular rate theory to successfully predict leaf respiration rates. Liang et al (2018) Macromolecular rate theory (MMRT) provides a thermodynamics rationale to underpin the convergent temperature response in plant leaf respiration. Global Change Biology. 24: 1538–1547. Liyin has moved to a scientist position at Manaaki Whenua – Landcare Research and we already have joint projects in mind.
Esther Peerlings investigated the recovery of pasture after grazing by dairy cows. Specifically she was interested in how CO2 fluxes (i.e. CO2 uptake and emission) measured with the Eddy Covariance technique can be used to determine the recovery of a paddock’s photosynthesising biomass. Her supervisors were Dave Campbell and Aaron Wall. Esther’s 4-month internship was part of her MSc Earth and Environment (specialisation in Meteorology and Air Quality) at Wageningen University, The Netherlands.
Jack Pronger completed a PhD on water use efficiency of diverse pastures that have a deeper and greater root biomass than traditional ryegrass/clover swards. He was supported by the Flower Trust, University of Waikato and DairyNZ. Jack talks about his work here (at about 5:00 minutes) and in a video on his water use efficiency here. Previously, Jack determined rates of peat subsidence in the Waikato for his BSc (Hons). He showed current rates of peat subsidence are about 2cm per year.
Mahdiyeh Salmanzadeh completed a PhD on Cd accumulation in agricultural soils. Cd has accumulative effects and is a potentially biotoxic metal. Cd is found in some fertilisers commonly used in agriculture. Mahdiyeh has a master’s degree in environmental engineering where she examined PAHs and heavy metal pollution and their ecological risk assessment in street dust of Tehran, Iran. Mahdiyeh’s main supervisor was Megan Balks and co-supervised by Adam Hartland and Louis Schipper. She received funding from University of Waikato PhD scholarship, DairyNZ and FertResearch.
Olivia Petrie conducted a MSc looking at the temperature dependence of microbial respiration in soils taken from adjacent irrigated and dryland soils. This followed on a study that demonstrated lower soil carbon stocks under irrigated soils. Olivia demonstrated respiration in irrigated soil was lower and had a temperature optimum nearly 10C higher than the adjacent dryland pasture soils. Olivia was supervised by Tanya O’Neill, Louis Schipper and Paul Mudge (Landcare Research).
Peter Lafleur (left in photo, with Joss Ratcliffe at Kopuatai bog) is a professor from Trent University School of the Environment in Ontario, Canada, specializing in ecosystem-atmosphere interactions in northern peatlands and Arctic tundra. Peter’s visit is an extension of his long-time association with Dave Campbell and their shared interest in the energy, water and carbon fluxes from peatland ecosystems. While at WaiBER during Feb. and March of 2017, Peter enjoyed occasional visits to the local research sites and many insightful discussions with Dave and others about ecosystems research. Peter presented his initial work on the long-term NEE from the Mer Bleue bog and its controlling factors, exploring 17 years of continuous CO2 flux data. The Mer Bleue peatland observatory has been a key research site for investigating northern peatland ecology and functioning since 1998.
Susanna Rutledge
Susanna was a research fellow investigating approaches for increasing soil carbon content of pasture soils using eddy covariance approaches coupled to other measures of C flux and turnover. She led work on whether higher diversity pastures can increase soil C content and the effects of pasture renewal through funding from the NZ Agricultural Greenhouse Gas Research Center. Susanna completed her PhD thesis on photodegradation.
Katharyn Duffy (a.k.a. Arizona Kate) is a Ph.D candidate at Northern Arizona University visiting on a joint National Science Foundation and Royal Society of New Zealand grant to collaborate with Vic Arcus and Louis Schipper on macro-molecular rate theory and its potential applications. Her research focuses on quantifying the sensitivity of land-atmosphere carbon exchange on a biome-to-global scale, and attributing current inter-annual variability in the land sink to discrete environmental drivers. Kate’s supervisor is Christopher Schwalm at NAU and Woods Hole.
Adrea Noyes investigated soil C,N and P recovery following landslides at Whatawhata Research Station for her MSc thesis. Aerial photographs were used to date the landslides were sampled and analysed for C, N and P to understand of soil recovery rates on Waikato Steepland soils. Adrea’s chief supervisor was Dr. Megan Balks with support of secondary supervisors Dr. Vicki Moon and Prof. David Lowe. Adrea is also an avid Roller Derby fan.
Sophie Burke was a Fulbright graduate fellow from the University of New Hampshire working with Dave Campbell and Louis Schipper on a research project involving methane flux from the Moanatuatua and Kopuatai peat bogs. For her PhD, Sophie’s research involves acoustically monitoring methane ebullitive flux from thaw ponds at a peatland site in subarctic Sweden. She enjoyed her experience with WaiBER expanding her understanding of peatland ecosystems and the threats they face due to climate change. After Waiber experience, completing a PhD at University New Hampshire.
Sam McNally
Sam completed his PhD on the contribution of roots from different pasture species in contributing to soil carbon. He is measuring root stocks and rates of roots turnover for different pasture species. Supervised by Louis Schipper, Susanna Rutledge, Daniel Laughlin, Mike Dodd (AgResearch), Johan Six (ETH Zurich). Funding support from New Zealand Agricultural Greenhouse Gas Research Centre and DairyNZ. After Waiber, took up a Postdoc at Plant and Food.
Doreen Huang
For her PhD, Doreen studied carbon storage and DNA preservation in allophanic soils and paleosols, which is part of the Marsden project aiming to test the reconstruction of environmental and climate change using genetic signal (DNA) preserved in buried paleosols. Doreen’s main supervisor is Prof David Lowe who is the leader of the Marsden project and was also supervised by Louis Schipper, Jock Churchman and Ray Cursons. After Waiber, postdoc at Umeå University, Sweden.
Electra Kalaugher completed her PhD on adaptation of New Zealand dairy farms to climate change, with support from DairyNZ and a MAF/NIWA project. Her research combined computer modelling (using the DairyNZ Whole Farm model) and social research, for six case study farms in different locations in New Zealand. After Waiber, Electra became a scientist at Landcare Research. Her chief supervisor was Dave Campbell.
Olivia Jordan investigated the effect of pasture sward mixes on root biomass in a grazed plot trial at DairyNZ’s Scott farm for her MSc thesis. Root biomass is a large contributor to soil carbon which has numerous benefits for soil stability and pasture production. Olivia measured root biomass in 14 different pasture combinations to determine whether sward can increase root biomass and soil carbon and nitrogen. Biomass ranged between 1100-24000 kg DM ha-1 across the different mixtures and swards with herb species present had a lower total root biomass (average 2240 kg DM ha-1) compared with non-herb plots (average 3560 kg DM ha-1). After Waiber, Olivia took up a position at DairyNZ. Olivia was co-supervised by Paul Mudge from Landcare Research.
Emma Bagley examined the occurrence and causes of pasture pulling under dairy farming on pumice soils in the central North Island for her MSc thesis. Pasture pulling occurs when livestock pulling whole clumps of pasture from the soil. She monitored 15 paddocks of different ages for a year and found that a number of soil characteristics contributed to pulling, including; limited rooting depth, low root density in the 5-10 cm depth, increased compaction with depth, less cohesive soil when it had low moisture, and the incidence of pasture growing in clumps. Emma’s main supervisor was Dr Megan Balks and she worked with Gina Lucci at AgResearch receiving support from AgResearch, DairyNZ, University of Waikato and she also won a C Alma Baker postgraduate scholarship.
Jordan Goodrich
Jordan investigated carbon exchange in the large and relatively pristine Kopuatai peat bog, using eddy covariance techniques for his PhD. He examined the controls on CO2 and CH4 exchange, including the reaction of the plant canopy to the fraction of diffuse light, drought and the influence of plant phenology. Jordan’s PhD research contributed towards the first multi-year wetland ecosystem carbon budget to be determined for a southern hemisphere peatland. Jordan received funding through Landcare Research. After Waiber, postdoc at San Diego State University.
Brendon Welten (PhD 2014) tested whether DCD, a nitrification inhibitor, could be orally fed to cows and subsequently excreted in urine. This approach has the potential advantage of the inhibitor being spatially and temporally targeted to the main source of nitrate leaching – the urine patch. He used a mixture of barrel lysimeter and field trials.Stewart Ledgard (AgResearch) was a co-supervisor along with Megan Balks. After his PhD, Brendon continued his work at AgResearch.
Elyn Humphreys (Associate Professor, Carleton University) and her family visited for 3 months to learn more about NZ peatlands and interact with the WaiBER team to exchange ideas and techniques for analysis and interpretation of carbon and methane flux data. This follows a sabbatical visit by Dave Campbell to Carleton in 2012.
Mark Tomer
Mark visited us on a sabbatical from USDA-ARS, Ames, Iowa after receiving funding from the New Zealand-U.S.A. Soil Science Exchange Travel Award. Mark and Louis are working on concepts of nitrogen saturation in agricultural soils. Nitrogen saturation has been of interest in New Zealand for several years. They are both interested in whether these concepts might be applied to soils in the Mississippi basin and the potential consequences.
Tim Norris trialed a new coring method to measure C and N stocks of soil in adjacent dairy and drystock pastures for his MSc. He resampling sites sampled by Alice Barnett and Amy Taylor (see below) using a hand coring technique and using equivalent mass methods to estimate stocks. His objective was to develop a more pragmatic and inexpensive approach for measuring changes in soil organic matter. Tim was partly funded by University of Waikato, Landcare Research and DairyNZ. Tim has a position at Hawkes Bay Regional Council.
Noah Fierer visited on sabbatical with his family. Noah is an Associate Professor at the University of Colorado. Noah has a very broad range of interests in microbial ecology and biogeochemistry. An interesting general article over-viewing some of his work on microbial ecology, diversity and distribution can be found here. While in New Zealand, he explored connections with the WaiBER team, Vic Arcus, Craig Cary, students and a number of others at the University of Waikato and beyond. Noah’s lab group can be found here.
Prof. Nigel Roulet, McGill University Canada, visited our group in March 2014 with his wife Kathy. Nigel’s goal was to find out about our carbon exchange and ecohydrology research in NZ peatlands, and to explore collaborative research opportunities with WaiBER and David Hamilton’s lakes research group.
Nigel is the James McGill Professor of Biogeoscience, McGill University Canada
Anna Carter (MSc candidate) Anna looked at how the rate of nitrate removal and decomposition of wood chips vary with temperature at a large denitrification bed near Karaka. This information will be used to optmise bed design for given nitrate concentration and flows rates. Anna was partially supported by DairyNZ and University of Waikato.
Alex Keyte Beattie For her MSc research Alex investigated the ecohydrology of the plant canopy dominated by Empodisma robustum at Kopuatai peat bog. This plant canopy is globally unusual for a bog because it contains a large amount of standing dead litter and completely shades the moist peat surface. Alex measured the structural properties of this canopy, its spatial variation, water balance and effect on the bog energy balance, as well as its contribution to CO2 fluxes. Alex received funding from University of Waikato and the Stella Frances trust. After Waiber, Alex took a job at Tonkin & Taylor.
Nadia’s MSc thesis topic investigated the potential for improvement of soil moisture holding capacity using soil “flipping” in the central North Island of New Zealand. Experimental soil flipping trials in Galatea showed improved pasture growth in the flipped areas compared to the control areas (undisturbed soils). Nadia talks about her work on National Radio here. Nadia’s main supervisor was Dr Megan Balks and she receives support from DairyNZ and University of Waikato. After completing her MSc, Nadia took a position at DairyNZ.
Courtney Ruffell and Staci Boyte worked with us over the summer break on controls of CO2 production from soils and litter. Staci examined temperature controls of soil respiration and Courtney investigated photodegradation of plant litter in restiad bogs. Staci and Courtney were supported by the University of Waikato.
David Zweig was a Fulbright Fellow who came to Waikato after studying at University of Georgia. He determined the Km value of nitrate reduction in denitrification beds. This information will be combined with the temperature response of nitrate removal to develop a simple model that can be used for designing denitrification beds. David describes his journey to New Zealand and project here and on a Youtube video here. After returning home, David started study at Stanford University.
Alice Barnett completed a MSc thesis measuring soil C and N of adjacent drystock and dairy farms of the Waikato. With Amy Taylor (also an MSc student), they sampled 25 paired sites to a meter. Amy measured changes in soil physical properties. Both Amy and Alice received supervision by Megan Balks. Alice showed that dairy farm topsoils had less soil C than drystock. Funded by University of Waikato, DairyNZ, and the Waikato Regional Council. We are grateful for many farmers for access to their land. Alice subsequently worked at Waikato Regional Council and Tuwharetoa Maori Trust Board.
Liz Deakin aimed to quantify ecological impacts of agricultural land use intensification on native forest fragments in the Waikato region of New Zealand, with a particular focus on plant-insect interactions. Her PhD thesis was entitled “Impacts of land-use intensification on forest remnants embedded within production landscapes”. Liz was funded through a joint Marsden Project between the University of Canterbury, University of Waikato, and Landcare Research. After her PhD, Liz worked at CIFOR – Center for International Forestry Research and then Opus International Consultants Limited.
Emma Chibnall measured the amount of dissolved organic carbon and nitrogen leaching from below pasture at a grazed dairy farm for her MSc thesis. She also demonstrated that carbon that leaches below the topsoil can be degraded to CO2 lower in the soil profile.
This data will be incorporated into a carbon budget of the dairy farm being determined by Susanna Rutledge and Aaron Wall. Emma received funding from University of Waikato, DairyNZ and a Stella Frances scholarship. Emma took a position at Auckland Regional Council.
Catherine Sturgeon
Catherine conducted an MSc study of Kopouatai peat bog to determine the magnitude of dissolved organic carbon (DOC) leaching. DOC leaching is often considered an important but poorly quantified loss of carbon from wetlands.This data will be combined with CO2 exchange data collected by Jordon Goodrich when developing a carbon budget of the bog. Catherine worked at Sinclair Knight Merz and Jacobs.
Scott Korom spent a 6 month sabbatical with Louis, Greg Barkle (AquaLinc) and John Hadfield (Waikato Regional Council). Scott helped establish methods for measuring denitrification in groundwater (tricky stuff) around Lake Taupo based on work he was leading at the University of North Dakota. Scott has been back to New Zealand several times for ongoing collaborative research.
Suzanne Lambie. One possible explanation for organic matter loss from soil is increased mobilisation of organic matter by urine patches deposited by stock. Suzanne conducted a PhD project that investigated whether urine application can increase the degradation and/or leaching of soil organic matter derived from forestry or pastures. Suzanne undertook her PhD part-time while working at Landcare Research and was jointly supervised by Megan Balks and Troy Baisden (GNS Science). Suzanne continued to work at Landcare Research after her PhD.
Paul Mudge (2008) and Dirk Wallace (2009) conducted MSc studies into how physical impacts (cultivation and pugging) alter the carbon balance of intensively-grazed pasture. They used a combination of chamber and eddy co-variance techniques at Scott farm managed by DairyNZ. The project received funding from DairyNZ and Landcare Research and the University of Waikato. On left, Dirk is thinking hard. Paul submitted his thesis PhD on the use of 15N as an indicator of past nitrogen cycling in pastures – see members page. Paul subsequently completed his PhD on the utility of soil 15N as an indicator of the past intensity of nitrogen cyling of pastures. He was co-supervised by Troy Baisden (GNS Science) and Anwar Ghani (AgResearch). Paul took a position at Landcare Research and Dirk started a PhD at Plant and Food.
Jacinta Parenzee was a soil technician in charge of the Soil Ecosystems laboratory for five years supporting teaching and training graduate students. She also supported research into changes in carbon, nitrogen, phosphorus, cadmium and uranium in long term pastures trials.
James Blyth (MSc 2012) measured a range of peat indicators along a transect at Whangamarino swamp and demonstrated the invasion of the wetland by Manuka. The Manuka was able to migrate into the swamp replacing Empodisma because of increased flooding of the adjacent river. The floods carried sediments into the swamp increasing nutrient status and allowing Manuka to become more competitive. See short news story here. James worked in Australia and then Jacobs in Auckland.
Hannah Wright conducted an undergraduate thesis on changes in Olsen P along transects running from pasture into forests as part of our Marsden work with University of Canterbury and Landcare Research. This work also contributed to Hannah’s BSc(Hons) completed at Lancaster University entitled “Spatial Variation in Plant-Available Phosphorus in Pasture and Adjacent Native Forest Fragments within the Waikato Region, New Zealand” Hannah undertook a PhD at Lancaster University.
Louise Fisk worked in the lab as an analyst on soils from the long-term research trial at Whatawhata. She examined changes in soil carbon, nitrogen, phosphorus, cadmium and uranium under a range of phosphorus loading rates applied over 24 years. Louise completed a PhD at University of Western Australia and trained as a stunt women.
Lauren Long (MPhil 2011) demonstrated that a denitrification wall is still removing nitrate from groundwater 14 years after it was construction. She measured changes in nitrate concentration in groundwater and sustained activity of denitrifiers. Lauren was funded through by a Fulbright scholarship and the University of Waikato. After Waiber, Lauren worked at Auckland Regional Council and MfE.
Soeren Warneke completed a PhD thesis on the microbial ecology of denitrification beds. He determined the environmental factors (including temperature response) that control denitrification and nitrous oxide emissions. He developed a rapid approach for assessing nitrate removal and demonstrated that denitrification was the main mechanism for nitrate removal. Soeren was funded by WaikatoLink, Hans Sauer Foundation and the University of Waikato. After his PhD, Soren took up a postdoc at CSIRO.
Stewart Cameron (GNS Science) completed a PhD thesis on the flow of effluent through denitrification beds. Stewart used a combination of field and large scale barrel trials to determine the nitrate removal and hydraulic flows in a range of carbon substrates. He demonstrated that it is possible to increase the temperature of denitrification using simple passive solar heating. Funded by GNS Science and University of Waikato. After his PhD, Stewart continued to work at GNS Science becoming a programme leader.
Natalie Watkins completed an MSc thesis in 2007 looking at whether the application of the nitrification inhibitor DCD would alter other aspects of the nitrogen cycle. She specifically measured changes in denitrification rates at Scott farm. Funding from Technology Industry Fellowship scheme, University of Waikato, DairyNZ and Landcare Research. After Waiber, Natalie took a position a AgResearch.
Note that the ideas/descriptions/opinions on these pages are ours and may not reflect those of the University of Waikato.
WaiBER 