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2023

"Accelerating change to solve the water and sanitation crisis" is the theme for the World Water Day 2023. Within the SITES Water long-term measurement program, data on hydrological, physical, chemical, and biological parameters within lakes and streams across SITES stations is made openly available to the user community to address a broad range of scientific questions relevant to solving the water crisis.

In celebration of World Water Day, the AQUATIC data from LAKE ERKEN has been updated including quality controlled data for 2022. The data covers a broad range of data types on chemical and physical variables for the lake and the streams surrounding it. Extensive time series can be found under the following link:


METEOROLOGY
Meteorological data Malma Island

CHEMISTRY
Lake Chemistry
Stream Chemistry (Filter on all stream sampling points)

LAKE PROFILING
Lake Temperature Profiles (Filter on all water temperature profiles)
Lake YSI Profiles (Filter on all YSI profiles)

WATER BALANCE
Stream Inlet & Outlet discharge (Filter on discharge for In-&Outlet)
Lake Water Level

More data on AQUATIC BIOTA will follow soon, so keep yourself updated on the SITES Data Portal for new data uploads.
 
Data collected within SITES are freely available and can be used by anyone as long as the data is cited and acknowledged, following the instructions in the SITES data policy.

Ice cover on Lake Erken (Photo: Holger Villwock)

In March, it is still “low season” at Abisko Scientific Research Station. About ten researchers have been on-site during the winter, but the number will gradually increase during the spring. In May, larger groups will arrive as the field season begins in earnest. They will be at the station all summer, and thus it looks like it will be another intense field season.

Svante Zachrisson is shovelling to get into Kärkevagge cabin (Photo: Thomas Westin) Svante Zachrisson is shovelling to get into Kärkevagge cabin (Photo: Thomas Westin)

Work is underway to replace the heating system from direct electricity to geothermal heating. In the summer, three 550-meter-deep holes will be drilled from which the energy will be taken. The goal is for all indoor work to be completed by 31 March. In total, 1,900 square meters of laboratory and office space are affected in the main building. New pipes are being laid into each space, and around 200 radiators are being installed on three floors.
 
At this time of year, propane and other supplies are transported by snowmobile to the five field huts; the Mire villa in Stordalen, Latnjajaure, Kärkevagge, Jieprenkiedde, and Lullihatjårro. The transports are made by snowmobile during the winter to avoid helicopter transport during the summer. Some shovelling is required to get into the cabins (as pictured).

Browning of surface water, rivers and lakes is a major problem that affects the ecosystem and the water quality. For example, increasing browning reduces biodiversity in lakes by reducing the fish population and therewith the food web. Browning also lowers the recreational value in tourism and requires higher effort to produce clean drinking water. Due to its complexity and the relatively young research field on browning in waters, the governing processes and their interrelationship are not fully understood yet. But to mitigate the effect of browning, these processes need to be understood and suitable measures needs to be taken.

Geophysical measurement setup in the lake Bolmen area Geophysical measurement setup in the lake Bolmen area

Therefore, two research projects in the lake Bolmen area are ongoing. One is the FORMAS financed Blue innovation project with Lagan water council, Bolmen Research station and Lund University as partners. The second project is the EU Interreg North Sea region Blue transition project with 24 partners from 6 European countries, including the Swedish Geological Survey (SGU), Bolmen Research station/Sydvatten and Lund University. In both projects the purpose is to develop a toolbox for mitigation and verification of methods that have been tested to be efficient for reducing the browning of lakes. It is expected that these measures are transferrable to many other lake systems since the problem is widespread in Sweden as wells as in other countries.

One of the main aims is to establish a good communication channel between the property owners and stakeholders in the Lagan water region. That is done by organizing workshops, for example at Bolmen Research station, and regular reference group meetings with stakeholders. To understand the underground hydrogeological conditions and to adapt it on a large scale, geophysics in combination with other sensors and in-situ investigations will be used. That has been done already for reconnaissance purposes (photo above) to get information, for example, about the thickness of the soil layer and the depth of the bedrock (figure below). After identifying suitable test sites, a monitoring system will be setup to run over several years to investigate the influence of the browning on the hydrogeological system. Based on that, mitigation strategies and measures will be developed and tested in a latter step.

News item was written by Tina Martin - Researcher and project leader at  Engineering Geology at Lund University.

Example of geophysical result from the DCIP measurements, showing the resistivity distribution of the underground along an 82m long profile. Clearly, the thickness of the lower resistive soil layer (blue – yellow zones) and the variation along the profile can be seen and delimited from the higher resistive bedrock (red zones) in greater depths.

Ingrid Sassenhagen has recently started as Research Engineer at SITES Erken Laboratory! Welcome to the SITES Community, Ingrid!

Ingrid Sassenhagen Ingrid Sassenhagen

Ingrid is an aquatic ecologist and studies all things related to phytoplankton. During her PhD project at Lund University, she investigated dispersal patterns and local adaption in the freshwater raphidophyte Gonyostomum semen, the infamous Gubbslem. For the following postdoc positions, she moved to Texas and France, where she worked in the marine ecosystems of the Caribbean and the Southern Ocean. Back in Sweden, this time at Uppsala University, Ingrid worked again with freshwater phytoplankton and investigated fungal parasites that infect algal blooms.

She is excited about contributing to studies of plankton community responses to environmental change in the SITES AquaNet mesocosm facilities. She will help with coordinating the upcoming mesocosm experiments, which will run in parallel at SITES stations at Erken, Bolmen and Skogaryd. Ingrid will also help with the maintenance and installation of the sensors for the mesocosms, prepare materials and chemicals for the experiments, and analyze the resulting data. She is really looking forward to meeting all the other enthusiastic aquatic scientists that will be involved in the experiments. In her free time, she likes to dance salsa and swing, go swimming and sew clothes, but lately she has been spending a lot of time at various playgrounds with her toddler son.

The SITES 2023 Calendar theme is “Data in Focus”. The openly available data produced within SITES and stored on the SITES Data Portal is the “golden thread” of the infrastructure, allowing users access to ecosystem data that covers diverse habitats and climate zones across geographical gradients in Sweden. Each month follow along as we highlight a unique SITES dataset.  

At Svartberget Research Station, within the Krycklan catchment, hydrological and biogeochemical monitoring takes place across the watershed. The highly instrumented and monitored watershed creates a field platform for ecosystem research with the possibility to study interactions within and between the different parts of the landscape. The SITES calendar post for March displays a part of the field platform; one example of the 19 total V-Notch weirs and flumes installed across the stream network. The weirs are equipped with sensors to measure, e.g. water temperature and stage height. Additionally, water samples are manually collected at the stream locations throughout the year (i.e. twice a week during spring flood, once a month during winter conditions and every second week, during the rest of the year) for biogeochemical analysis, including chemical variables within the SITES Water Thematic Program.      

Link to data: https://meta.fieldsites.se/objects/FE1KELfYkAA3Ch8cGkSIGnfI 

Photo: Johan Westin, Graphic: Roberto Lo Monaco

The graph displays dissolved organic carbon (DOC, top line), ammonium (NH4, middle line) and phosphate (PO4, bottom line) concentrations measured at Kallkälsbäcken stream measured throughout the year in 2021. The photo shows the V-Notch weir installation at Kallkälsbäcken.

The soil organic matter (SOM) reservoir is one of the largest pools of global carbon (C), with a powerful ability to regulate atmospheric carbon dioxide (CO2) concentrations. For that reason, ‘carbon farming’, or the active regulation of SOM pools through different management practices, has become one of the most tempting solutions for climate change mitigation. While there are good reasons to expect that agricultural soils can store large amounts of C, there are also major knowledge-gaps regarding the fundamental processes governing C sequestration.

Guoxiang Niu from Lund University assessing the mineral associated organic matter fraction in the soil samples through the depth profile. Photo: Johannes Rousk. Guoxiang Niu from Lund University assessing the mineral associated organic matter fraction in the soil samples through the depth profile. Photo: Johannes Rousk.

One of the main areas of uncertainty is the fate of C in deeper layers of soil. In a recent meta-analysis, deeper soil layers hold on average 47% of agricultural soil organic C stocks. However, due to logistical challenges, deeper agricultural soil horizons below ploughing depth have rarely been studied, and most research has been restricted to the topsoil. In ecosystems dominated by perennial vegetation it has been shown that although the concentration of C is usually low in deeper soil layers, the total C stock below 20 cm often represents more than half the soil C. To date, nearly half the agricultural C stocks remain largely unassessed. Deeper soil layers contain C that has a significantly longer turnover time, in some cases up to thousands of years, whereas the topsoil mainly consists of young OM. Thus, not only do half the agricultural C stocks remain unassessed, it is also likely that they accumulate C, with power to mitigate atmospheric CO2.

Ryan Davidson from SITES Lönnstorp Research Station splitting 1 m deep soil cores into 10 cm increments. Photo: Albert Brangarí Ryan Davidson from SITES Lönnstorp Research Station splitting 1 m deep soil cores into 10 cm increments. Photo: Albert Brangarí

In a newly launched project, a group of researchers from Lund University will attempt to close many of these pressing knowledge gaps, by assessing the outcome of the different farming practices conducted in the unique availability of comparable perennial and conventional agricultural practices of the SITES Agroecological Field Experiment (SAFE) at Lönnstorp Research Station. Supported by Formas, over four years, Johannes Rousk, Lettice Hicks, Albert Brangarí and David Wårlind, will investigate the potential that agricultural practices have to increase deep soil carbon stocks, while also improving mechanistic understanding of the processes that determine soil organic matter persistence. Specifically, the team will determine how agricultural paradigms with perennial crops (Kernza), supporting deep rhizospheres, can provide a means to both store C and maintain fertility. The team sets out to test fundamental soil science theory, and will attempt to optimize the contradictive ecosystem services of mitigating climate change by storing C while maintaining soil fertility. The hypotheses to be interrogated include 1) conversion to perennial agricultural systems with deep rhizospheres will increase soil organic matter contents (via “the microbial carbon pump”), increase the retention time of organic matter (increasing its persistence), and reduce the nutrient content (N and P) locked in the stored organic matter, 2) belowground root input in perennial systems will trigger a rhizosphere priming effect, resulting in recovery of nutrients (N and P) from SOM throughout the profile (<1m). The team anticipates that perennial systems can make agricultural soils mitigate climate warming by storing C, more resilient to indirect effects of warming (drought), and maintain a nutrient supply conducive for a sustainable agricultural productivity.

News item written by Johannes Rousk (Lund University) 

To kick-off the new and third phase of SITES, Asa Research Station hosted a meeting during 8-10 of February. More than 50 persons participated physically at the meeting with several representatives from each SITES station, the Thematic Programs, the SITES Secretariat and the SITES Steering Group.

Group photo in front of Asa Herrgård. Photo: Holger Villwock

An important part of the meeting was to discuss and agree on the strategy and goals for SITES III. During the first ten years the focus within SITES has been on building the infrastructure, starting up the three Thematic Programs and making data from the stations available. The value of SITES to the science community was evident in the “Cool Science” presentations, which focused on multi-station research during SITES II related to eDNA, lake greenhouse gases and soil organic carbon decomposition.  

During SITES III, the core for SITES is to continue to have a well-functioning and sustainable infrastructure over time that supports high-quality research with easy access to the infrastructure and data from the stations. The strategic goals for SITES during phase III reflect this, categorized by three watchwords; Quality, Openly Available and Sustainable.

Discussions during the strategy and goals session. Photo: Blaize Denfeld Discussions during the strategy and goals session. Photo: Blaize Denfeld



In addition to the strategical work, the Kick-off meeting also had presentations from the stations, a session on data and user engagements, focused discussions within each Thematic Program and guest speakers to talk about SITES international engagements with LIFEPLAN, ICOS/ACTRIS and eLTER. The group also heard about the interesting history of Asa Reserach Station and toured the field station. 

A detailed summary of the SITES meeting will be featured in the March Newsletter, so stay tuned!

The SITES 2023 Calendar theme is “Data in Focus”. The openly available data produced within SITES and stored on the SITES Data Portal is the “golden thread” of the infrastructure, allowing users access to ecosystem data that covers diverse habitats and climate zones across geographical gradients in Sweden. Each month follow along as we highlight a unique SITES dataset.  

In Northern Sweden, lakes can be ice-covered for many months of the year, and although the conditions in the lake during this time are cold and dark (depending on the snow and ice conditions), biogeochemical processes in the lake continue. The SITES calendar post for February displays this, as an oxygen gradient develops in Almbergasjön as ice forms, with oxygenated surface waters and oxygen-depleted bottom waters persisting until ice melt begins at the end of May.

At Abisko Scientific Research Station, as part of the SITES Water Thematic Program, lake biogeochemistry data during winter is collected by aquatic sensors deployed under the ice as well as manually by station staff. The SITES lake water biogeochemistry monitoring in Almbergasjön began in 2017 and continues today, providing valuable data to understand how a changing climate, including lake ice-cover decline, will alter lake biogeochemical processes in the future.

Link to data: https://meta.fieldsites.se/objects/plRSfwkbopYGhj2W31TBRKul   

Photo: Niklas Rakos, Graphic: Roberto Lo Monaco
Photo: Niklas Rakos, Graphic: Roberto Lo Monaco

The graph displays sub-hourly surface (light yellow) and bottom water (dark yellow) oxygen concentrations in Almbergasjön during winter from ice formation to ice melt in 2021. The photo shows station staff at Abisko Scientific Research Station drilling a hole in the ice on Almbergasjön in order to collect water samples for the routine SITES Water sampling program. 

The year 2023 started with a new SITES period at Röbäcksdalen, but there are more new things happening at the station. From the first of January 2023, Röbäcksdalen SITES station is no longer managed under the department of Agricultural Research for Northern Sweden. After an organization change at SLU, the field station, which houses the majority of the SITES activities, is now part of the Department of Crop Production Science, while the dairy farm is part of the animal infrastructure at the Faculty of Veterinary Medicine and Animal Science.

Weather Station at Röbäcksdalen currently run by solar panles (Photo: Johanna Wallsten) Weather Station at Röbäcksdalen currently run by solar panles (Photo: Johanna Wallsten)

The SITES activities at Röbäcksdalen are continuing as usual, and soon we will have even better possibilities to collect field data. Located in Northern Sweden, the long nights, cold weather and cloudy skies in winter at the station have presented problems for the solar panels operating the weather station and the sensors on masts. This in turn, often has resulted in data missing from November to January. However, in late November 2022, Röbäcksdalen was awarded a stipend from Kempestiftelserna to support a project to install electricity to the stations infrastructures. With this effort, starting in winter 2023-2024, hopefully the weather and spectral data sets can run without interruptions throughout the whole season.

There is a need to optimize forest management in order to contribute to climate change mitigation by enhanced ecosystem carbon storage. Rotation forestry is the most common silvicultural practice in Sweden, but there is an intense debate about its ability to contribute to long-term sequestration of carbon from the atmosphere. Due to the urgent need for nature-based climate change mitigation options, there is now considerable social and scientific interest in the use of continuous cover forestry (CCF), but its effects on carbon sequestration are largely unknown and need to be quantified urgently. Ongoing and future forestry projects are taking place at the Central Forest at Skogaryd Research Catchment (SRC) to address these unknowns.

Clearcut area immediately after harvest. Photo: T. Rütting Clearcut area immediately after harvest. Photo: T. Rütting

Already this winter at SRC, a 60-year-old Norway spruce forest has seen some harvest activities, including different management techniques; clearcutting (Rotation forestry- RF), diameter-limit cutting (CCF) and unharvested with extended rotation length.

A new Formas financed project will make use of the harvested activities at SRC to study the effect of CCF on carbon fluxes and sequestration, compared to RF, by use of novel methodologies based on sap flux (trees’ water transport) and phloem stable isotopes. The goal is to determine whether, and by how much, carbon uptake capacity is sacrificed as forests grow older and if a selectively cut forest can compensate for the carbon stock lost following clearcutting by increased growth and, if so, how. The novel methodology will be compared to the time-tested eddy covariance method. Both methods estimate forest carbon uptake in photosynthesis, but the isotopic method also allows for determining how individual uncut trees respond to the selection cutting. This project will support rigorous, objective analyses of one of the most compelling social issues in Scandinavia: what is to be done with the forests?

Installed Sap-flow system for measuring the tree’ water transport . Photo: T. Rütting Installed Sap-flow system for measuring the tree’ water transport . Photo: T. Rütting

With this project forestry professionals, private forest owners, policymakers and the public will be provided with information regarding the impacts of different forest management strategies on the productivity and carbon sequestration of forests. Ultimately, this could contribute to the formulation of new ecological and economic goals, management plans and policies that guide the future use of the Swedish forests.

The SITES 2023 Calendar theme is “Data in Focus”. The openly available data produced within SITES and stored on the SITES Data Portal is the “golden thread” of the infrastructure, allowing users access to ecosystem data that covers diverse habitats and climate zones across geographical gradients in Sweden. Each month follow along as we highlight a unique SITES dataset.  
 

During the month of January most of Sweden is snow and ice-covered, although the duration and intensity of snow and ice has been declining over time due to ongoing climate change. The SITES calendar post for January displays this trend, as ice cover duration on Lake Erken over the past 80 years has been declining. At Erken Laboratory, visual observations of Lake Erken’s ice cover began in the 1940s and continues today, now with the assistance of a monitoring camera on Malma Island. This long-term ice-covered record is one of the most comprehensive in the world.  


Link to data: https://meta.fieldsites.se/objects/QLqXw2wkqxXrr0ahsxeQaWbp

Photo and graphic: Roberto Lo Monaco

The graph displays the total number of lake ice cover days, i.e. days between the start of continuous ice coverage (> 75% of lake surface ice-covered) and the ice break-up of the observed lake area, over time on Lake Erken between 1941 to 2021. The photo shows Malma Island, where the lake monitoring camera as well as other monitoring sensors are located, and with the Erken Laboratroy in the very background. 

On January 1 the SITES community not only welcomed in the New Year, but also a new, six-year funding period (2023-2028). By the time we gather for the SITES III Kick-off meeting Feb 8‑10 at Asa Station, the incoming SITES Director, Kevin Bishop, will have visited all SITES stations and the Thematic Programs. He is looking forward to kicking-off SITES III this year: 

“Getting to know this infrastructure during my three months of “inskolning” has been an eye-opener to the amazing infrastructure built up during the first decade of SITES existence. Now, with a period of stable funding ahead, SITES can focus on what it is we are here for, providing scientists with access to well documented field sites where they have superb opportunities for doing excellent ecosystem research. I am looking forward to the meeting with many of you in Asa and working together to refine the plans for the coming years of SITES.”

- Kevin Bishop (SITES incoming Director)
 

Lake outlet at Asa Research Station over winter (Photo: Niels Aagaard Jakobsen)

2023

"Accelerating change to solve the water and sanitation crisis" is the theme for the World Water Day 2023. Within the SITES Water long-term measurement program, data on hydrological, physical, chemical, and biological parameters within lakes and streams across SITES stations is made openly available to the user community to address a broad range of scientific questions relevant to solving the water crisis.

In celebration of World Water Day, the AQUATIC data from LAKE ERKEN has been updated including quality controlled data for 2022. The data covers a broad range of data types on chemical and physical variables for the lake and the streams surrounding it. Extensive time series can be found under the following link:


METEOROLOGY
Meteorological data Malma Island

CHEMISTRY
Lake Chemistry
Stream Chemistry (Filter on all stream sampling points)

LAKE PROFILING
Lake Temperature Profiles (Filter on all water temperature profiles)
Lake YSI Profiles (Filter on all YSI profiles)

WATER BALANCE
Stream Inlet & Outlet discharge (Filter on discharge for In-&Outlet)
Lake Water Level

More data on AQUATIC BIOTA will follow soon, so keep yourself updated on the SITES Data Portal for new data uploads.
 
Data collected within SITES are freely available and can be used by anyone as long as the data is cited and acknowledged, following the instructions in the SITES data policy.

Ice cover on Lake Erken (Photo: Holger Villwock)

In March, it is still “low season” at Abisko Scientific Research Station. About ten researchers have been on-site during the winter, but the number will gradually increase during the spring. In May, larger groups will arrive as the field season begins in earnest. They will be at the station all summer, and thus it looks like it will be another intense field season.

Svante Zachrisson is shovelling to get into Kärkevagge cabin (Photo: Thomas Westin) Svante Zachrisson is shovelling to get into Kärkevagge cabin (Photo: Thomas Westin)

Work is underway to replace the heating system from direct electricity to geothermal heating. In the summer, three 550-meter-deep holes will be drilled from which the energy will be taken. The goal is for all indoor work to be completed by 31 March. In total, 1,900 square meters of laboratory and office space are affected in the main building. New pipes are being laid into each space, and around 200 radiators are being installed on three floors.
 
At this time of year, propane and other supplies are transported by snowmobile to the five field huts; the Mire villa in Stordalen, Latnjajaure, Kärkevagge, Jieprenkiedde, and Lullihatjårro. The transports are made by snowmobile during the winter to avoid helicopter transport during the summer. Some shovelling is required to get into the cabins (as pictured).

Browning of surface water, rivers and lakes is a major problem that affects the ecosystem and the water quality. For example, increasing browning reduces biodiversity in lakes by reducing the fish population and therewith the food web. Browning also lowers the recreational value in tourism and requires higher effort to produce clean drinking water. Due to its complexity and the relatively young research field on browning in waters, the governing processes and their interrelationship are not fully understood yet. But to mitigate the effect of browning, these processes need to be understood and suitable measures needs to be taken.

Geophysical measurement setup in the lake Bolmen area Geophysical measurement setup in the lake Bolmen area

Therefore, two research projects in the lake Bolmen area are ongoing. One is the FORMAS financed Blue innovation project with Lagan water council, Bolmen Research station and Lund University as partners. The second project is the EU Interreg North Sea region Blue transition project with 24 partners from 6 European countries, including the Swedish Geological Survey (SGU), Bolmen Research station/Sydvatten and Lund University. In both projects the purpose is to develop a toolbox for mitigation and verification of methods that have been tested to be efficient for reducing the browning of lakes. It is expected that these measures are transferrable to many other lake systems since the problem is widespread in Sweden as wells as in other countries.

One of the main aims is to establish a good communication channel between the property owners and stakeholders in the Lagan water region. That is done by organizing workshops, for example at Bolmen Research station, and regular reference group meetings with stakeholders. To understand the underground hydrogeological conditions and to adapt it on a large scale, geophysics in combination with other sensors and in-situ investigations will be used. That has been done already for reconnaissance purposes (photo above) to get information, for example, about the thickness of the soil layer and the depth of the bedrock (figure below). After identifying suitable test sites, a monitoring system will be setup to run over several years to investigate the influence of the browning on the hydrogeological system. Based on that, mitigation strategies and measures will be developed and tested in a latter step.

News item was written by Tina Martin - Researcher and project leader at  Engineering Geology at Lund University.

Example of geophysical result from the DCIP measurements, showing the resistivity distribution of the underground along an 82m long profile. Clearly, the thickness of the lower resistive soil layer (blue – yellow zones) and the variation along the profile can be seen and delimited from the higher resistive bedrock (red zones) in greater depths.

Ingrid Sassenhagen has recently started as Research Engineer at SITES Erken Laboratory! Welcome to the SITES Community, Ingrid!

Ingrid Sassenhagen Ingrid Sassenhagen

Ingrid is an aquatic ecologist and studies all things related to phytoplankton. During her PhD project at Lund University, she investigated dispersal patterns and local adaption in the freshwater raphidophyte Gonyostomum semen, the infamous Gubbslem. For the following postdoc positions, she moved to Texas and France, where she worked in the marine ecosystems of the Caribbean and the Southern Ocean. Back in Sweden, this time at Uppsala University, Ingrid worked again with freshwater phytoplankton and investigated fungal parasites that infect algal blooms.

She is excited about contributing to studies of plankton community responses to environmental change in the SITES AquaNet mesocosm facilities. She will help with coordinating the upcoming mesocosm experiments, which will run in parallel at SITES stations at Erken, Bolmen and Skogaryd. Ingrid will also help with the maintenance and installation of the sensors for the mesocosms, prepare materials and chemicals for the experiments, and analyze the resulting data. She is really looking forward to meeting all the other enthusiastic aquatic scientists that will be involved in the experiments. In her free time, she likes to dance salsa and swing, go swimming and sew clothes, but lately she has been spending a lot of time at various playgrounds with her toddler son.

The SITES 2023 Calendar theme is “Data in Focus”. The openly available data produced within SITES and stored on the SITES Data Portal is the “golden thread” of the infrastructure, allowing users access to ecosystem data that covers diverse habitats and climate zones across geographical gradients in Sweden. Each month follow along as we highlight a unique SITES dataset.  

At Svartberget Research Station, within the Krycklan catchment, hydrological and biogeochemical monitoring takes place across the watershed. The highly instrumented and monitored watershed creates a field platform for ecosystem research with the possibility to study interactions within and between the different parts of the landscape. The SITES calendar post for March displays a part of the field platform; one example of the 19 total V-Notch weirs and flumes installed across the stream network. The weirs are equipped with sensors to measure, e.g. water temperature and stage height. Additionally, water samples are manually collected at the stream locations throughout the year (i.e. twice a week during spring flood, once a month during winter conditions and every second week, during the rest of the year) for biogeochemical analysis, including chemical variables within the SITES Water Thematic Program.      

Link to data: https://meta.fieldsites.se/objects/FE1KELfYkAA3Ch8cGkSIGnfI 

Photo: Johan Westin, Graphic: Roberto Lo Monaco

The graph displays dissolved organic carbon (DOC, top line), ammonium (NH4, middle line) and phosphate (PO4, bottom line) concentrations measured at Kallkälsbäcken stream measured throughout the year in 2021. The photo shows the V-Notch weir installation at Kallkälsbäcken.

The soil organic matter (SOM) reservoir is one of the largest pools of global carbon (C), with a powerful ability to regulate atmospheric carbon dioxide (CO2) concentrations. For that reason, ‘carbon farming’, or the active regulation of SOM pools through different management practices, has become one of the most tempting solutions for climate change mitigation. While there are good reasons to expect that agricultural soils can store large amounts of C, there are also major knowledge-gaps regarding the fundamental processes governing C sequestration.

Guoxiang Niu from Lund University assessing the mineral associated organic matter fraction in the soil samples through the depth profile. Photo: Johannes Rousk. Guoxiang Niu from Lund University assessing the mineral associated organic matter fraction in the soil samples through the depth profile. Photo: Johannes Rousk.

One of the main areas of uncertainty is the fate of C in deeper layers of soil. In a recent meta-analysis, deeper soil layers hold on average 47% of agricultural soil organic C stocks. However, due to logistical challenges, deeper agricultural soil horizons below ploughing depth have rarely been studied, and most research has been restricted to the topsoil. In ecosystems dominated by perennial vegetation it has been shown that although the concentration of C is usually low in deeper soil layers, the total C stock below 20 cm often represents more than half the soil C. To date, nearly half the agricultural C stocks remain largely unassessed. Deeper soil layers contain C that has a significantly longer turnover time, in some cases up to thousands of years, whereas the topsoil mainly consists of young OM. Thus, not only do half the agricultural C stocks remain unassessed, it is also likely that they accumulate C, with power to mitigate atmospheric CO2.

Ryan Davidson from SITES Lönnstorp Research Station splitting 1 m deep soil cores into 10 cm increments. Photo: Albert Brangarí Ryan Davidson from SITES Lönnstorp Research Station splitting 1 m deep soil cores into 10 cm increments. Photo: Albert Brangarí

In a newly launched project, a group of researchers from Lund University will attempt to close many of these pressing knowledge gaps, by assessing the outcome of the different farming practices conducted in the unique availability of comparable perennial and conventional agricultural practices of the SITES Agroecological Field Experiment (SAFE) at Lönnstorp Research Station. Supported by Formas, over four years, Johannes Rousk, Lettice Hicks, Albert Brangarí and David Wårlind, will investigate the potential that agricultural practices have to increase deep soil carbon stocks, while also improving mechanistic understanding of the processes that determine soil organic matter persistence. Specifically, the team will determine how agricultural paradigms with perennial crops (Kernza), supporting deep rhizospheres, can provide a means to both store C and maintain fertility. The team sets out to test fundamental soil science theory, and will attempt to optimize the contradictive ecosystem services of mitigating climate change by storing C while maintaining soil fertility. The hypotheses to be interrogated include 1) conversion to perennial agricultural systems with deep rhizospheres will increase soil organic matter contents (via “the microbial carbon pump”), increase the retention time of organic matter (increasing its persistence), and reduce the nutrient content (N and P) locked in the stored organic matter, 2) belowground root input in perennial systems will trigger a rhizosphere priming effect, resulting in recovery of nutrients (N and P) from SOM throughout the profile (<1m). The team anticipates that perennial systems can make agricultural soils mitigate climate warming by storing C, more resilient to indirect effects of warming (drought), and maintain a nutrient supply conducive for a sustainable agricultural productivity.

News item written by Johannes Rousk (Lund University) 

To kick-off the new and third phase of SITES, Asa Research Station hosted a meeting during 8-10 of February. More than 50 persons participated physically at the meeting with several representatives from each SITES station, the Thematic Programs, the SITES Secretariat and the SITES Steering Group.

Group photo in front of Asa Herrgård. Photo: Holger Villwock

An important part of the meeting was to discuss and agree on the strategy and goals for SITES III. During the first ten years the focus within SITES has been on building the infrastructure, starting up the three Thematic Programs and making data from the stations available. The value of SITES to the science community was evident in the “Cool Science” presentations, which focused on multi-station research during SITES II related to eDNA, lake greenhouse gases and soil organic carbon decomposition.  

During SITES III, the core for SITES is to continue to have a well-functioning and sustainable infrastructure over time that supports high-quality research with easy access to the infrastructure and data from the stations. The strategic goals for SITES during phase III reflect this, categorized by three watchwords; Quality, Openly Available and Sustainable.

Discussions during the strategy and goals session. Photo: Blaize Denfeld Discussions during the strategy and goals session. Photo: Blaize Denfeld



In addition to the strategical work, the Kick-off meeting also had presentations from the stations, a session on data and user engagements, focused discussions within each Thematic Program and guest speakers to talk about SITES international engagements with LIFEPLAN, ICOS/ACTRIS and eLTER. The group also heard about the interesting history of Asa Reserach Station and toured the field station. 

A detailed summary of the SITES meeting will be featured in the March Newsletter, so stay tuned!

The SITES 2023 Calendar theme is “Data in Focus”. The openly available data produced within SITES and stored on the SITES Data Portal is the “golden thread” of the infrastructure, allowing users access to ecosystem data that covers diverse habitats and climate zones across geographical gradients in Sweden. Each month follow along as we highlight a unique SITES dataset.  

In Northern Sweden, lakes can be ice-covered for many months of the year, and although the conditions in the lake during this time are cold and dark (depending on the snow and ice conditions), biogeochemical processes in the lake continue. The SITES calendar post for February displays this, as an oxygen gradient develops in Almbergasjön as ice forms, with oxygenated surface waters and oxygen-depleted bottom waters persisting until ice melt begins at the end of May.

At Abisko Scientific Research Station, as part of the SITES Water Thematic Program, lake biogeochemistry data during winter is collected by aquatic sensors deployed under the ice as well as manually by station staff. The SITES lake water biogeochemistry monitoring in Almbergasjön began in 2017 and continues today, providing valuable data to understand how a changing climate, including lake ice-cover decline, will alter lake biogeochemical processes in the future.

Link to data: https://meta.fieldsites.se/objects/plRSfwkbopYGhj2W31TBRKul   

Photo: Niklas Rakos, Graphic: Roberto Lo Monaco
Photo: Niklas Rakos, Graphic: Roberto Lo Monaco

The graph displays sub-hourly surface (light yellow) and bottom water (dark yellow) oxygen concentrations in Almbergasjön during winter from ice formation to ice melt in 2021. The photo shows station staff at Abisko Scientific Research Station drilling a hole in the ice on Almbergasjön in order to collect water samples for the routine SITES Water sampling program. 

The year 2023 started with a new SITES period at Röbäcksdalen, but there are more new things happening at the station. From the first of January 2023, Röbäcksdalen SITES station is no longer managed under the department of Agricultural Research for Northern Sweden. After an organization change at SLU, the field station, which houses the majority of the SITES activities, is now part of the Department of Crop Production Science, while the dairy farm is part of the animal infrastructure at the Faculty of Veterinary Medicine and Animal Science.

Weather Station at Röbäcksdalen currently run by solar panles (Photo: Johanna Wallsten) Weather Station at Röbäcksdalen currently run by solar panles (Photo: Johanna Wallsten)

The SITES activities at Röbäcksdalen are continuing as usual, and soon we will have even better possibilities to collect field data. Located in Northern Sweden, the long nights, cold weather and cloudy skies in winter at the station have presented problems for the solar panels operating the weather station and the sensors on masts. This in turn, often has resulted in data missing from November to January. However, in late November 2022, Röbäcksdalen was awarded a stipend from Kempestiftelserna to support a project to install electricity to the stations infrastructures. With this effort, starting in winter 2023-2024, hopefully the weather and spectral data sets can run without interruptions throughout the whole season.

There is a need to optimize forest management in order to contribute to climate change mitigation by enhanced ecosystem carbon storage. Rotation forestry is the most common silvicultural practice in Sweden, but there is an intense debate about its ability to contribute to long-term sequestration of carbon from the atmosphere. Due to the urgent need for nature-based climate change mitigation options, there is now considerable social and scientific interest in the use of continuous cover forestry (CCF), but its effects on carbon sequestration are largely unknown and need to be quantified urgently. Ongoing and future forestry projects are taking place at the Central Forest at Skogaryd Research Catchment (SRC) to address these unknowns.

Clearcut area immediately after harvest. Photo: T. Rütting Clearcut area immediately after harvest. Photo: T. Rütting

Already this winter at SRC, a 60-year-old Norway spruce forest has seen some harvest activities, including different management techniques; clearcutting (Rotation forestry- RF), diameter-limit cutting (CCF) and unharvested with extended rotation length.

A new Formas financed project will make use of the harvested activities at SRC to study the effect of CCF on carbon fluxes and sequestration, compared to RF, by use of novel methodologies based on sap flux (trees’ water transport) and phloem stable isotopes. The goal is to determine whether, and by how much, carbon uptake capacity is sacrificed as forests grow older and if a selectively cut forest can compensate for the carbon stock lost following clearcutting by increased growth and, if so, how. The novel methodology will be compared to the time-tested eddy covariance method. Both methods estimate forest carbon uptake in photosynthesis, but the isotopic method also allows for determining how individual uncut trees respond to the selection cutting. This project will support rigorous, objective analyses of one of the most compelling social issues in Scandinavia: what is to be done with the forests?

Installed Sap-flow system for measuring the tree’ water transport . Photo: T. Rütting Installed Sap-flow system for measuring the tree’ water transport . Photo: T. Rütting

With this project forestry professionals, private forest owners, policymakers and the public will be provided with information regarding the impacts of different forest management strategies on the productivity and carbon sequestration of forests. Ultimately, this could contribute to the formulation of new ecological and economic goals, management plans and policies that guide the future use of the Swedish forests.

The SITES 2023 Calendar theme is “Data in Focus”. The openly available data produced within SITES and stored on the SITES Data Portal is the “golden thread” of the infrastructure, allowing users access to ecosystem data that covers diverse habitats and climate zones across geographical gradients in Sweden. Each month follow along as we highlight a unique SITES dataset.  
 

During the month of January most of Sweden is snow and ice-covered, although the duration and intensity of snow and ice has been declining over time due to ongoing climate change. The SITES calendar post for January displays this trend, as ice cover duration on Lake Erken over the past 80 years has been declining. At Erken Laboratory, visual observations of Lake Erken’s ice cover began in the 1940s and continues today, now with the assistance of a monitoring camera on Malma Island. This long-term ice-covered record is one of the most comprehensive in the world.  


Link to data: https://meta.fieldsites.se/objects/QLqXw2wkqxXrr0ahsxeQaWbp

Photo and graphic: Roberto Lo Monaco

The graph displays the total number of lake ice cover days, i.e. days between the start of continuous ice coverage (> 75% of lake surface ice-covered) and the ice break-up of the observed lake area, over time on Lake Erken between 1941 to 2021. The photo shows Malma Island, where the lake monitoring camera as well as other monitoring sensors are located, and with the Erken Laboratroy in the very background. 

On January 1 the SITES community not only welcomed in the New Year, but also a new, six-year funding period (2023-2028). By the time we gather for the SITES III Kick-off meeting Feb 8‑10 at Asa Station, the incoming SITES Director, Kevin Bishop, will have visited all SITES stations and the Thematic Programs. He is looking forward to kicking-off SITES III this year: 

“Getting to know this infrastructure during my three months of “inskolning” has been an eye-opener to the amazing infrastructure built up during the first decade of SITES existence. Now, with a period of stable funding ahead, SITES can focus on what it is we are here for, providing scientists with access to well documented field sites where they have superb opportunities for doing excellent ecosystem research. I am looking forward to the meeting with many of you in Asa and working together to refine the plans for the coming years of SITES.”

- Kevin Bishop (SITES incoming Director)
 

Lake outlet at Asa Research Station over winter (Photo: Niels Aagaard Jakobsen)

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