Research

Automated greenhouse gas measurements

Introduction
GHG emissions from agriculture contribute substantially to Australia’s total GHG emissions and this is expected to increase with future changes in land use and management. In many agricultural systems, nitrous oxide (N₂O) emissions from soils may account for up to half of all emissions from the entire system.

To understand the implications of land use and management and the biophysical interactions controlling N₂O emissions requires the collection of long-term, high spatial and temporal resolution data. As nitrous oxide emissions are regulated by nitrate, water and carbon availability, this project will also measure the other two major greenhouse gases (carbon dioxide – CO₂ and methane – CH₄).

Equipment
QUT in collaboration with German scientists, have developed an automated continuous sampling greenhouse gas monitoring system. This unique automated sampler has the following components:

• SRI gas chromatography with ECD and FID detectors for N₂O and CH₄.
• Licor infrared gas analyser for CO₂

Measurements
Eight separate flux measurements are determined each day from each land use thus providing additional information on the influence on sub-daily climatic events on emission.

Acoustic sensors

Introduction
Acoustic sensing has the potential to provide ecologists and conservation biologists with the ability to scale environmental observations both temporally and spatially. Automated sensor systems can be used to collect data passively as they do not interfere with the behaviour of the observed species and have minimal impact on the environment. They also provide a cost effective means of collecting data (24 hrs a day, 7 days a week) and thus greatly reduce the human errors associated with instantaneous surveys.

Sounds can transmit large amounts of information quickly and efficiently over relatively long distances and the information can be detected, stored and later analysed to measure species richness and abundance, or to study the behaviour of individual species.

Data Resources
Soundscape at Samford: Audio 1 (External link)
Soundscape at Samford: Audio 2 (External link)

Carbon dioxide and water flux

Introduction
The Australian National Flux Network (OzFlux) is coordinated by CSIRO’s Marine and Atmospheric Research division based in Canberra, ACT and has multiple operators throughout Australia. The TERN Facility builds upon the current OzFlux Network and aims to establish a national network of flux sites to provide observations at regional locations to serve the land-surface and ecosystem modelling communities. QUT has established and operates one of these sites – the SEQ PU grassland site at the SERF.

A flux station (or eddy-flux covariance) measures momentum, heat, water and carbon dioxide exchanged between the grassland and the atmosphere. It also measures a range of meteorological variables such as rainfall, air temperature and humidity.

Equipment
A flux station is a custom-built observation unit that combines a series of environmental sensors. The SERF Flux station is part of the OzFlux Network (also within TERN) has the following:

• 3D Sonic Anemometer
• Licor carbon dioxide and water analyzer
• Kipp and Zonen Net Radiometer
• soil heat flux plate
• water content reflectometer
• sonic wind sensor
• rain gauge
• Vaisala barometric pressure

Measurements
The Flux Station records information at a high temporal resolution (seconds) in the determination of eddy fluxes of CO₂ and water vapour:

• air temperature, humidity at height of eddy flux instrumentation
• windspeed and direction at height of eddy flux instrumentation
• 4 radiation fluxes – incoming shortwave and longwave, outgoing shortwave and longwave radiation
• soil heat flux and soil temperature
• precipitation
• soil moisture profile (incremental)

Research objectives

• Measuring the various exchanges of carbon dioxide, water vapour and energy between the SERF grassland and the atmosphere using micrometeorological techniques.
• Quantify changes in carbon and energy balances of different land- use systems in transition from a natural dry sclerophyll forest to a peri-urban area.
• Assess the impact of Brisbane’s peri-urban development on water and greenhouse gases (carbon dioxide) on surrounding vegetation.
• Providing a database of combined canopy microclimate and photosynthetic parameters for use in large-scale modeling in conjunction with remote sensing information.

Soil water (by depth)

Introduction
Changes in water content throughout a soil profile provides information on the water use and evapotranspiration of the surrounding vegetation; and the transport of water and associated soluble compounds both on (runoff) and below (leaching and lateral flow) the soil surface.

Equipment

• Sentek Triscan
• Odyessy Green Light Red Light (GLRL) soil moisture probes
• Sentek Diviner

Measurements

• Sentek Triscan – volumetric soil water content (v/v)
• Odyessy GLRL (10, 20 50, 70, 90 cm) – volumetric soil water content (v/v)
• Sentek Diviner – volumetric soil water content (v/v)

Research objectives

• Monitor changes in surface soil water content across multiple land uses and locations (soil type x slope x land use)
• Provide calibration data for modelling soil water dynamics in response to climate events across the Samford node.
• Extrapolate the modelling of changes in soil water content across the entire Samford Valley.

Soil water chemistry

Introduction
Changes in water content and soluble compounds throughout a soil profile provides information on the efficiency of nutrient uptake of surrounding vegetation. The transport of excess amounts of carbon, nitrogen and phosphorus into waterways can lead to euthrophication, resulting in oxygen depletion with detrimental effects on aquatic organisms. Transport of salts can also lead to changes in salinity and pH.

Equipment

• Sentek Triscan
• Sentek Solu Sampler

Measurements

• Sentek Triscan – electrical conductivity
• Sentek Solu Sampler – nitrate, dissolved organic carbon (DOC)

Research objectives

• To monitor changes in soil water chemistry (DOC, electrical conductivity and nitrate) across multiple land uses and locations (soil type x slope x land use)
• Provide calibration data for modelling soil water chemistry in response to climate events and urbanization across the Samford node.
• Extrapolate the modelling of changes in soil and stream chemistry across the entire Samford Valley.

Net primary production (NPP)

Introduction
The amount of organic carbon in the soil is partly determined by the amount of organic matter added from vegetation and the rate of decomposition of the organic material. NPP is a measurement of the annual production of carbon in both above and below ground biomass.

Equipment

• Manual sampling
• Satellite remote sensing

Measurements

• Manual sampling of biomass on a monthly basis from quadrants within grassland and woodland land uses.
• High resolution NDVI

Research objectives

• Quantify changes in vegetative growth (and carbon stocks) of both woodland and grassland communities in response to climate events across the Samford node.
• Provide calibration data for modelling the uptake of nutrients by representative vegetation in the Samford Valley using an integrated terrestrial carbon, nitrogen and water cycling model (e.g. SWAT).
• Extrapolate the calibrated model of vegetative growth in response to soil water and nutrient changes to assess the impact of urbanization across the entire Samford Valley.

Stream flow and chemistry

Introduction
The quality of stream water is a good integrator of the overall health of the surrounding landscape and ecosystems. The quantity of soluble compounds in a stream provides information on the efficiency of surrounding vegetation and soils to store and retain nutrients. Changes in the volume of water and/or the level of certain compounds could indicate major shifts in the biogeochemistry of local ecosystems which ultimately will impact on human, animal and plant populations.

Equipment

• Sontek Argonaut
• YSI Sonde

Measurements

• Sontek Argounauts - flow (velocity) and depth every 1 minute (10 min average).
• YSI Sonde with ROX Optical Dissolved Oxygen sensor and YSI6136 Turbidity sensor – electrical conductivity, stream temperature, turbidity and dissolved oxygen (10 minutes).

Research objectives

• Quantify changes in stream volume and chemistry as a function of land use and climate events across the Samford node.
• Provide calibration data for modelling stream flow and quality for the Samford node using an integrated terrestrial carbon, nitrogen and water cycling model (e.g. SWAT).
• Extrapolate the calibrated model of vegetative growth, soil and stream chemistry to assess the impact of urbanization across the entire Samford Valley.