Geological and physiographic setting
The KCS is located in the Svecokarelian orogenic belt, which traverses
large parts of Sweden and Finland. The bedrock is dominated by
1.92-1.87 Ga old migmatised meta-greywacke or paragneiss, which consists
of metamorphosed sediments once deposited outside the Achaean Baltic
Shield. The numerous hills in the area with peaks up to 400 m are
largely derived from selective weathering of biotite-plagioclase schist
in the valleys and more resistant veined gneiss at higher altitudes.
Further inland, the meta-sediments are gradually replaced by
1.74-1.82 Ga old granite and granodiorite, which also occur as
intrusions in the KCS along with minor intrusions of mafic rocks.
The Quaternary deposits are strongly influenced by the latest
glaciation. Drumlins and crag-and-tails are aligned in a SSW direction
as the inland ice was moving from NNW. The ice retreated ca. 10,200 a BP
(Stroeven et al., 2016), leaving up to 30 m thick till in sheltered
areas, but also bare bedrock in more exposed locations. In addition, the
large Vindel River Esker passes through the lower parts of the KCS
adding large deposits of glaciofluvial material (Fig. 1c). The
Quaternary deposits are predominately of local origin, displaying a
silicate-dominated chemistry with
quartz>plagioclase>K
feldspar>amphiboles as the main minerals (Lampa et al.,
2020). In areas with low topographic relief, peat has built up generally
forming oligotrophic minerogenic mires. At the termination of the
deglaciation, approximately half of the KCS was located below the
highest postglacial coastline (situated at ca 257 m above present sea
level). This has resulted in locally >60 m deep sand and
silt sediments that now cover the lower parts of the KCS, deposited by
the Vindel River during the course of the isostatic rebound.
Long-term environmental trends
The boreal region encompassing the KCS has experienced some strong
environmental trends during the last several decades. Changes in
climate, land-use, and long-range transport of air pollutants all have
had a role to play in explaining some of these decadal changes. Despite
having a highly developed research infrastructure in place, the
co-occurrence, interaction, and synchronicity of several human
interventions complicate our efforts to disentangle the
cause-and-effects responsible for all changes that can be observed.
However, by combining long-time series, large-scale experiments, and
modeling we are now beginning to understand the role climate change,
land-use, and atmospheric pollution have had in the past and present,
and predict which roles they will have in the future.
Here we highlight some of the major trends in forest biomass growth,
lake ice extent, catchment hydrology, and water quality for the KCS
(Fig. 3). While some of the trends can be directly related to changes in
climate, such as the increasingly earlier lake ice-out, other trends are
more likely related to atomospheric pollution, namely, the decline in
stream calcium that relates to the recovery from acid deposition.
Increased forest biomass production, stream water brownification, and
increase in ET are likely caused by a combination of interacting
factors. Such interactions, and the fact that some catchments respond
while adjacent systems do not, call for the need of continued research
to disentangle these cause-and-effect mechanisms. In addition, we
urgently need to provide predictions for what these large-scale
environmental changes will mean for northern environments. These include
the direct and indirect effects on carbon and greenhouse gas (GHG)
balances, atmospheric radiative forcing, terrestrial and aquatic
biodiversity and water quality, but also for the industry and livelihood
of communities in northern regions. Living up to these goals in an
environment that is constantly changing, requires maintaining research
infrastructures that take a landscape scale perspective and include the
most important processes in the atmosphere, vegetation, soils, bedrock,
and water, as well as the interactions between them.
Research infrastructure (max 2500
words)
The ambition of KCS is to take a holistic ecosystem perspective of the
boreal landscape to understand, elucidate, and predict the role of
internal and external drivers of catchment processes across a range of
scales. In our approach, we combine state-of-the-art technology to
capture various ecosystem processes with traditional research tools and
basic environmental monitoring. This includes processes and dynamics of
living and non-living ecosystem compartments, as well as the fluxes of
energy, water, carbon, nutrients, metals, and other compounds within and
between the atmosphere, lithosphere, cryosphere, and hydrosphere. In the
KCS, we do this by combining a large, central, research facility –
namely, the ICOS research tower – with supplemental infrastructures
distributed across the entire landscape (Fig. 4). In addition to these
facilities, the KCS also offers a number of large scale and/or long-term
experimental facilities. Below we outline some of the most central of
these facilities and data.