TY - JOUR
T1 - Role of groundwater-borne geogenic phosphorus for the internal P release in shallow lakes
AU - Nisbeth, Catharina S.
AU - Jessen, Søren
AU - Bennike, Ole
AU - Kidmose, Jacob
AU - Reitzel, Kasper
N1 - Publisher Copyright:
© 2019 by the authors.
PY - 2019
Y1 - 2019
N2 - This study explores the under-investigated issue of groundwater-borne geogenic phosphorus (P) as the potential driving factor behind accumulation of P in lake sediment. The annual internally released P load from the sediment of the shallow, hypereutrophic and groundwater-fed lake, Nørresø, Denmark, was quantified based on total P (TP) depth profiles. By comparing this load with previously determined external P loadings entering the lake throughout the year 2016-2017, it was evident that internal P release was the immediate controller of the trophic state of the lake. Nevertheless, by extrapolating back through the Holocene, assuming a groundwater P load corresponding to the one found at present time, the total groundwater P input to the lake was found to be in the same order of magnitude as the total deposit P in the lake sediment. This suggests that groundwater-transported P was the original source of the now internally cycled P. For many lakes, internal P cycling is the immediate controller of their trophic state. Yet, this does not take away the importance of the external and possibly geogenic origin of the P accumulating in lake sediments, and subsequently being released to the water column.
AB - This study explores the under-investigated issue of groundwater-borne geogenic phosphorus (P) as the potential driving factor behind accumulation of P in lake sediment. The annual internally released P load from the sediment of the shallow, hypereutrophic and groundwater-fed lake, Nørresø, Denmark, was quantified based on total P (TP) depth profiles. By comparing this load with previously determined external P loadings entering the lake throughout the year 2016-2017, it was evident that internal P release was the immediate controller of the trophic state of the lake. Nevertheless, by extrapolating back through the Holocene, assuming a groundwater P load corresponding to the one found at present time, the total groundwater P input to the lake was found to be in the same order of magnitude as the total deposit P in the lake sediment. This suggests that groundwater-transported P was the original source of the now internally cycled P. For many lakes, internal P cycling is the immediate controller of their trophic state. Yet, this does not take away the importance of the external and possibly geogenic origin of the P accumulating in lake sediments, and subsequently being released to the water column.
KW - Geogenic phosphorus
KW - Groundwater-borne phosphorus
KW - Groundwater-surface water interaction
KW - Internal phosphorus release
KW - Phosphorus cycling
UR - http://www.scopus.com/inward/record.url?scp=85071376206&partnerID=8YFLogxK
U2 - 10.3390/w11091783
DO - 10.3390/w11091783
M3 - Article
VL - 11
JO - Water (Switzerland)
JF - Water (Switzerland)
SN - 2073-4441
IS - 9
M1 - 1783
ER -