Impacts of multiple environmental disturbances on ecosystem metabolic rates inferred from high frequency sensor monitoring

Application
The project is open for application of Master candidates with strong motivation on disturbance ecology and statistical modelling. Please contact Silke Langenheder (silke.langenheder@ebc.uu.se) or Pablo Urrutia Cordero (pablo.urrutiacordero@ebc.uu.se) from Uppsala University (Limnology Unit) for further information.
 
Background and project description
The project aims to determine the impacts of multiple environmental disturbances on ecosystem metabolic rates (gross primary production, ecosystem respiration and net ecosystem production). The candidate will use an extensive and unique database generated with a modularized experiment conducted along a latitudinal gradient in Scandinavian lakes (see one of the sites in the picture below). Data will be analyzed using developed R packages for handling high frequency sensor data and calculating ecosystem metabolic rates from dial oxygen measurements. We are therefore seeking a highly motivated candidate with an interest in technical and statistical methodology and an affinity for data analysis in R. The knowledge generated within the project will be highly valuable for anticipating potential changes in lake functioning in response to environmental disturbances. The project also aims to publish the results in a high-impact scientific journal.
 

Last week, Holger Villwock from the SITES Secretariat took the chance for a short summer break from the office work to visit the SITES station in Skogaryd. The goal was to better understand the installations behind the data which are currently structured for uploading on the SITES Data Portal and also to work on data to prepare the upload. Leif Klemedtsson the station manager and thematic programme coordinator of SITES Water provided a guided tour through all installations and informed in depth about the monitoring infrastructure and historical background.

The research focus of the station is on greenhouse gas emission from different ecosystem types including lakes, streams, mires, forests and restructured sites in transition phases. The purpose is to better understand ecosystem processes within a catchment and how anthropogenic habitat alteration effects the biogeochemical cycles.

Even though Skogaryd is the youngest among the nine SITES stations (officially announced as a research station in 2013), it already has a well-established variety of installations on a catchment scale level.

Overview of the Skogaryd Research Catchment with its sub-catchments.
Creator: Haldor Lorimer-Olsson.

The tour followed along the different ecosystems and the monitoring installations, which are explained in more detail in the following paragraphs. The starting point was Skogaryd 800 (address to use for a google search), which served as the base camp during the stay.

Skogaryd 800 – the so called “Torpet” house, one of two accommodations on site. Photographer: HV

The main research catchment is divided in six sub-catchment with unique features – one of which is Följesjön, the first visit during the stay. This sub-catchment is mainly represented by a lake which is in progress of siltation. On site installations monitor plant succession with phenology cameras and the biogeochemical fluxes with eddy covariance towers.

Siltation processes ongoing at Följesjön. The eastern part of the lake still has open water patches, while the western part is already fully overgrown. Photographer: HV

 
One unique feature of the installations at Lake Följesjön is a 3D-Skygas equipment, which can measure greenhouse gas fluxes in 3 dimensions across an approximately 500 square meter large area over Följesjön. The system is developed by a research group at the University of York (Great-Britain) and is the only one in existence on that scale.

3D-Skygas equipment functioning like a birds-eye soccer stadium camera to monitor greenhouse gas fluxes across a 500 square meter transect. Photographer: HV

Another unique monitoring site is Följemaden which is connected to the runoff from Följesjön and served as the second stop during the tour. The former forest site with highly fertile soil from historical agricultural land use has been clear cut. One part will be rewetted and planted with alder and birch trees this year, the other drained part will be reforested with spruce trees. Micrometeorological flux towers will measure greenhouse gas emissions throughout this process.

Creative installation at Följemaden, a clear-cut site getting prepared for a control-impact monitoring campaign. Photographer: HV

The last site visited on the first day was the Central sub-catchment with its installation of a 38 meter high flux tower monitors meteorological and biogeochemical parameters at several different heights in a spruce forest on mineral soil. Future planning also includes a control-impact concept for this site. An opportunity to harvest and re-forest parts of the sub-catchment is provided by the land owner. This is a great chance to test and monitor different forest types at Skogaryd Research Catchment in the future.

Picture 6 Flux tower at the Central sub-catchment monitoring meteorological and biogeochemical processes in a 60 year old spruce forest. Photographer: HV

On the south eastern side of Skogaryd the mire “Mycklemossen” shows processes of forest succession. Man-made drainage of the ecosystem leads to forest growth on highly fertile soils. Mires are considered to be net CO2 sinks, thus the loss of the mire can lead to large carbon emissions for the atmosphere. An additional negative effect is the loss of species associated with the mire ecosystem, e.g. bird species adapted to open landscape of the mire, will be outcompeted by birds of prey which use the growing trees as observation points. This exciting site in a visual transition phase served as the first stop on the second day.

Eddy-covariance system measuring greenhouse gas fluxes over the mire Mycklemossen. Bushes and first pine trees indicated the beginning of forestation which is based on man-made drainage of the area. Photographer: HV

 
Along several discharge monitoring installations across the whole catchment, Erssjön resembles the main part of the SITES Water programme at Skogaryd. Here, several monitoring campaigns run simultaneously to observe chemical, physical and biological parameters of the limnic systems. The lake can easily be reached from the Mycklemossen mire and was visited as a second stop on the second day.

Floating platform at Erssjön equipped with a spectral mast to monitor above surface mechanisms and sub-surface profile installations to observe the limnological processes. Photographer: HV

 
Like all other SITES Station, Skogaryd Research Catchment is open to use for researchers and the team around the station manager Leif Klemedtsson welcomes everyone to visit the unique infrastructure. The SITES Secretariat can strongly recommend a guided tour by one of the staff members :) !

The SITES team around Gunhild ‘Ninis’ Rosqvist and Pia Eriksson has successfully finished the recent monitoring campaign near the Kebnekaise massif at Tarfala Research Station.  

View towards the Kebnekaise summits from a helicopter. Photographer: Gunhild Rosqvist.
 

During four weeks of field work, the group has been blessed with mostly sunny weather thanks to Freyr the Norse God of rain and sunshine - a great opportunity to maintain the long-term monitoring stations for SITES Spectral and SITES Water. As an example, the spectral masts have been maintained to continue the long-term monitoring of terrestrial primary production at Laevasvagge. An additional weather station at the location measures complementing meteorological parameters to monitor the local weather and climate and potential changes in the future.
 

SITES installations at Laevasvagge consisting of two spectral masts with an additional weather station in close vicinity. Photographer: Gunhild Rosqvist

The team further conducted several discharge campaigns aiming to cover the higher water levels during the spring flood to validate the stream water level monitoring in Tarfalajokk. The measurements of higher discharges from the snow melt are extremely valuable. When these points are added to the calculation of the water level-discharge function the rating curve will become more precise. The deviation of the high discharge points from the curve is larger than the points for medium and minimum events in descending order. More data points for the high discharge events increase the precision of the rating curve to calculate the runoff from the Tarfalajokk catchment area.

Usually, it is difficult to cover such high discharge events as the snow melt happens earlier in the season when the station is still closed. However, this year the team was lucky and valuable validation points could be added to the overall discharge equation.

View towards Tarfala Research Station and Tarfaladalen with Tarfalajokk running through it. Photographer: Gunhild Rosqvist

Not only the Tarfala SITES team, but also the vegetation in the Swedish mountains is in Freyr´s hands and the unpredictable and sometimes rough weather conditions. One example is the beautiful specimen of Silene acaulis (Swed. Fjällglim). The pink flower is a common resident in alpine and arctic zones and with its cushion forming habitus perfectly adapted to high UV radiation, strong winds and low temperatures. Silene acaulis is also called “compass plant” as the first flowers often appear on the South-oriented part of the cushion (Ref 1).

Ref 1: Link here.

Silene acaulis (Swed. Fjällglim) at the base of the Kebnekaise massif – a common and well-adapted species in the alpine landscape. Photographer: Gunhild Rosqvist.