Doctoral Studies

Supervisor: Evelyn Uuemaa

Growing human population needs to increase food production without more negative impact on the environment. This situation has created a need for “sustainable intensification”: increasing agricultural yields while simultaneously decreasing environmental impacts. Nature-based solutions (NbS) such as riparian buffer strips and wetlands have been proven to be an effective measure at retaining sediments and nutrients leached from upslope agricultural areas, and in increasing carbon storage. However, in agricultural regions, riparian buffer zones and wetlands have been rather reduced in extent, or removed entirely to maximize arable cropland. To restore or create wetlands and riparian buffer strips is costly and therefore the potential restoration/creation sites must be selected carefully by considering site-specific conditions. Traditionally, such large-scale planning efforts are accompanied by extensive fieldwork, which reduces its applicability on larger scale.  The aim of this PhD project is to identify the feasible and potentially most effective areas for wetlands and riparian buffer strips to reduce the nutrient runoff and increase carbon storage at regional (European) and national (Estonian) scales using remotely sensed data and novel spatial analysis methods.

More info: https://landscape-geoinformatics.ut.ee/calls/phd-wetland-riparian/

If interested, please contact eveyn.uuemaa@ut.ee

Supervisors: Anto Aasa

Mobile and GPS positioning has been acknowledged as valuable data sources for mobility studies for several decades. Both methods have proven to be high-quality and cost-effective alternatives to traditional data collection methods. Using mobile positioning data as input to produce official tourism statistics is a well-known success story. Therefore, governmental statistical offices are mapping possibilities to use mobile positioning data as one possible data source to replace traditional census.

Statistics covering the entire population is usually quite general in detail. Surveys are used to gather information in more detail (household, individual) about the target population. Conducting surveys is expensive. Therefore, the sample size is relatively small, and the studied period is very short.

Among other surveys, Eurostat is responsible for Harmonised European Time Use Surveys. The Harmonised European Time Use Surveys (HETUS) are national surveys conducted in European countries to quantify how much time people spend on various activities. The main survey instruments are a household questionnaire, an individual questionnaire, and a time-use diary in which respondents are asked to record their daily activities in 10-minute time slots (Eurostat).

All this could be done with the help of mobile phones. Mobile phones can be used as sensors to collect more detailed survey data. Most mobile phones are equipped with GPS and other sensors, which are used to collect locational information about phone carriers. GPS data can be used to analyze mobility patterns and detect places the respondent visits. Overlaying derived mobility statistics with spatial context (land use, population register, buildings register, business register, services, etc.) can answer why the specific place was visited. And what was the activity there? As the starting platform, the data collection application “MobilityLog” will be used (link).

Mobile phones can be used as sensors to gather more detailed survey data. Most mobile phones with GPS and other sensors can collect locational information about the phone carrier, providing valuable data about mobility patterns and places the respondent visits. By overlaying derived mobility statistics with spatial contexts such as land use, population register, building register, business register, services, and more, researchers can better understand why a specific place was visited and what activities occurred there.

The key innovation of this PhD thesis is a systematic development of methodological framework based on GPS-data to get answers to the questions asked during time use surveys.

If interested, please contact anto.aasa@ut.ee

Supervisors: Kadri Leetmaa,  Kairi Kreegipuu, Bianka Plüschke-Altof

Our broader mission is to pioneer connecting research in ‘smartification’ and exclusion. We focus on ’smart rurality’ and the elderly typically disadvantaged spaces and social group in terms of the newest smart solutions. We will study the individual- and place-level enablers and barriers to smartification and carefully unpack the digital innovation biographies of four model localities in rural Estonia. We will apply the bottom-up strategy to explore the needs of smartification in double-excluded (rural, aging) localities in order to co-create the adjusted smartification process. The specific learning experiment (intervention) will be prepared and carried out to create smart data in the data-poor environment (rural localities) for the typically data-poor social group (elderly). The community researchers’ approach will be applied to facilitate the learning experiment. The participative qualitative methods will be combined with quantitative research design. This is followed by the systematic observations of the social innovation process. The candidate for the PhD-project is expected to actively participate in the planned fieldworks in close collaboration of the -years research project “Rethinking smartification from the margins: Co-creating Smart Rurality with and for an Aging Population” (PI K.Leetmaa, funded by Estonian Research Council).

If interested, please contact kadri.leetmaa@ut.ee

Supervisor: Kuno Kasak

Restoring degraded peat soils is an attractive, but largely untested climate change mitigation approach. Drained peat soils used for agriculture or for peat extraction are often large greenhouse gas sources. Restoring subsided peat soils to managed, impounded wetlands can turn these sources into carbon sinks. However, at present, the amount of scientific information available to guide such restoration decisions and assess the impact of these actions is still sparse and restoration outcome can be low carbon uptake and high methane emissions. Therefore, the overarching objective of this study is to provide an experimental and theoretical understanding how to restore wetlands with minimized methane and nitrous oxide emissions and maximized carbon uptake. The current study focuses on the spatial heterogeneity of methane, nitrous oxide, and carbon dioxide emission from restored wetlands using micrometeorological and field-based techniques. The research will be carried out in three restored wetland ecosystems in Estonia but with strong collaboration with international partners in Europe, Korea, and USA.

More info: https://sisu.ut.ee/ecotech/opportunities

If interested, please contact kuno.kasak@ut.ee

Supervisors: Margit Kõiv-Vainik, Kuno Kasak

Intensive forest management and agricultural activities cause diffuse pollution, which is harmful to freshwater ecosystems. Nature-based solutions for water conservation and pollution mitigation, such as sedimentation ponds and treatment wetlands, are effective solutions for cleaning polluted water from various sources. However, there is still too little scientific information to choose the optimal measures, especially in cold climate conditions. For an effective water treatment, it is necessary to develop site-specific treatment methods by enhancement of existing technological solutions and by conducting in-depth process-based research to identify different treatment processes and other factors influencing their performance. The PhD research will be conducted on full-scale treatment systems built to remove diffuse pollution from peatland forests and agricultural fields.

More info: https://sisu.ut.ee/ecotech/opportunities

If interested, please contact kuno.kasak@ut.ee

Supervisors: Kaido Soosaar, Jüri-Ott Salm

Wetlands cover 5-8% of the world's land area and have a tremendous capacity to sequester carbon (C) from the atmosphere. Natural wetlands effectively accumulate C effectively due to water-logged conditions promoting highly stable C content. Currently, there is still a great deal of uncertainty regarding the spatial extent of restored wetlands and the extent of C sinks, as well as source estimates and sustainable restoration alternatives. In addition, there are uncertainties related to the impacts of climate change on greenhouse gas fluxes, particularly for extreme weather events such as droughts and floods. Currently, there is a lack of national emission factors to account for GHG fluxes from restored wetlands, especially as it relates to CH₄ fluxes. These issues hinder the efficient use of wetlands for GHG mitigation and adaptation in the context of other LULUCF mitigation options.

The dissertation will add to the current state of knowledge on wetlands, their use and degradation in Europe. Several new experimental data on ecosystem responses to wetland management and restoration under different land uses will be collected and summarised in relation to biodiversity and other ecosystem services.

This work will be based on the data obtained from the ALFAwetlands project joint database (27 sites in Europe): soil CO₂, CH₄ and N₂O fluxes, automated and periodic environmental parameters, including precipitation, soil temperature, water table and topsoil moisture, data collected over a two-year period. To establish the soil carbon balance, C transfer in litter, C stocks in above- and below-ground biomass, and C turnover in litter decomposition are quantified by synthesising high-quality research data and data from field studies. GHG flux data from the database will be linked to detailed information on peat composition, soil and water biogeochemistry to improve process-based modelling of peatland GHG emissions.

If interested, please contact kaido.soosaar@ut.ee

Supervisors: Alisa Krasnova, Kaido Soosaar, Ülo Mander

Forest ecosystems play an important role in carbon (C) and water cycles by acting as C sinks and as sources of water vapor via evapotranspiration. In recent decades, climate extremes have increased and significantly changed forest ecosystems' C cycle and water regime. For instance, a severe heatwave in the summer of 2018 switched some Estonian forests from net C sink during the vegetation season of 2017 to net C source in 2018. However, only a few studies compare several forest ecosystem types within temperate and boreal zones regarding their long-term dynamics of C and water fluxes and characterizing their differences in tolerance to climate extremes.

This PhD project will analyze temporal and spatial dynamics of C and water fluxes (evapotranspiration) and water use efficiency (WUE) in temperate and boreal forest ecosystems. Long-term datasets from several Estonian stations, FLUXNET, and ICOS (Integrated Carbon Observation System) stations (regional to global networks of eddy covariance flux measurements) in Scandinavia will be used for the analysis. The proposed thesis will link the dynamics of C fluxes with water exchange in various forest ecosystems of temperate and boreal zones. Specific research aims are: (1) to analyze the dynamics of C and water fluxes, and water use efficiency of various temperate and boreal forests, (2) to clarify the impact of climate extremes on these dynamics.

If interested, please contact ulo.mander@ut.ee