Factors behind the variability of phosphorus accumulation in Finnish lakes
Laen...
Kuupäev
2018
Kättesaadavus
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Springer
Abstrakt
Purpose Phosphorus retention (TPacc) is one of the major water quality regulators in lakes. The current study aimed at ascer-
taining the specific lake characteristics regulating TP acc . Moreover, we were interested whether NAO (North Atlantic
Oscillation), a proxy of climatic forcing, can explain variability in TPacc, additionally to that ascribed to lake characteristics.
Materials and methods Sediment cores were obtained from 21 Finnish lakes, subject to radiometric dating and measurements of
TP concentrations. Principal components (PCs) were generated using lake characteristics that are usually included into the
modelling of TPacc (e.g. lake area, lake depth, catchment area, P inflow) but also the parameters that the classical models usually
missed (e.g. anoxic factor). We used significant principal components (PCs), specific combinations of lake characteristics and
monthly NAO values as predictors of TPacc.
Results and discussion Lake characteristics explained the bulk of TPacc variability. The most influential factors (positive drivers)
behind TPacc included PC1 (representing mainly deep lakes), PC2 (small lakes with high levels of anoxia and water column
stability), PC3 (productive lakes with large catchment area and short water residence time), PC4 (lakes with high water column
stability, low anoxic factor and relatively high sediment focusing) and PC5 (lakes with high levels of P inflow, anoxia and long
water residence time). Additionally, we found a potential negative effect of NAO in October on the annual TPacc. This NAO was
significantly positively related to temperatures in surface and near-bottom water layer (also their difference) in autumn, suggest-
ing the possible implications for the internal P dynamics. Increased mineralization of organic matter is the most likely explanation
for the reduced TPacc associated with NAO-driven water temperature increase.
Conclusions The analysis presented here contributes to the knowledge of the factors controlling P retention. Moreover, this
spatially and temporally comprehensive sediment data can potentially be a valuable source for modelling climate change
implications.
This study was funded by the Academy of Finland (grant nr. 263365), Maa-ja vesitekniikan tuki ry (grant nr. 29159) and the City of Lahti.
This study was funded by the Academy of Finland (grant nr. 263365), Maa-ja vesitekniikan tuki ry (grant nr. 29159) and the City of Lahti.
Kirjeldus
Märksõnad
lake characteristics, lakes, NAO, phosphorus accumulation rate, phosphorus retention, articles