Consequences for pelagic energy mobilisation of a sudden browning episode without a clear increase in DOC concentration - a case of a boreal pristine lake.

Tutkimustuotos: ArtikkelijulkaisuArtikkeliTieteellinenvertaisarvioitu

Kuvaus

In the boreal zone, episodes of heavy rains are among the most conspicuous events disturbing aquatic ecosystems. Due to climate change they are predicted to become more frequent and intense, leading on browning of lakes. We assessed the possible effects of heavy rains to DOC concentration and water colour and resulting impacts on functioning of a headwater lake with naturally high water colour and concentration of allochthonous DOC. The weekly measurements were carried out in summers 2002-2004; the first 2 years had normal and the last year very high summer precipitation. The rains resulted in rapid increase in water colour, but not in DOC. We hypothesised that due to browning, irrespective of whether it stems from an increase in brownish DOC or other coloured substances, photosynthesis decreases, bacterial activity increases, and the lake becomes more heterotrophic. We also anticipated that due to strengthened heterotrophy, the period with apparent net autotrophy and CO2 flux onto the lake would disappear. To test our hypothesis, we measured autotrophic inorganic carbon uptake of photosynthetic organisms as well as dark fixation of inorganic carbon, community respiration and leucine uptake. Finally, we compared the results to CO2 flux measurements with an eddy covariance technique. Our hypotheses were only partly supported since there were no drastic changes in any of the metabolic processes measured. Although the lake ecosystem became slightly more heterotrophic, primary production was still occasionally higher than community respiration and the lake could act as a sink of CO2. Thus regarding metabolic processes, the ecosystem of this pristine lake was not strongly disturbed by the sudden browning episode.
Alkuperäiskielienglanti
LehtiAquatic Sciences
Vuosikerta78
Numero4
Sivut627-639
Sivumäärä13
ISSN1015-1621
DOI - pysyväislinkit
TilaJulkaistu - lokakuuta 2016
OKM-julkaisutyyppiA1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä, vertaisarvioitu

Tieteenalat

  • 1172 Ympäristötiede

Lainaa tätä

@article{2dbf323b4f4d496f8640e27975555143,
title = "Consequences for pelagic energy mobilisation of a sudden browning episode without a clear increase in DOC concentration - a case of a boreal pristine lake.",
abstract = "In the boreal zone, episodes of heavy rains are among the most conspicuous events disturbing aquatic ecosystems. Due to climate change they are predicted to become more frequent and intense, leading on browning of lakes. We assessed the possible effects of heavy rains to DOC concentration and water colour and resulting impacts on functioning of a headwater lake with naturally high water colour and concentration of allochthonous DOC. The weekly measurements were carried out in summers 2002-2004; the first 2 years had normal and the last year very high summer precipitation. The rains resulted in rapid increase in water colour, but not in DOC. We hypothesised that due to browning, irrespective of whether it stems from an increase in brownish DOC or other coloured substances, photosynthesis decreases, bacterial activity increases, and the lake becomes more heterotrophic. We also anticipated that due to strengthened heterotrophy, the period with apparent net autotrophy and CO2 flux onto the lake would disappear. To test our hypothesis, we measured autotrophic inorganic carbon uptake of photosynthetic organisms as well as dark fixation of inorganic carbon, community respiration and leucine uptake. Finally, we compared the results to CO2 flux measurements with an eddy covariance technique. Our hypotheses were only partly supported since there were no drastic changes in any of the metabolic processes measured. Although the lake ecosystem became slightly more heterotrophic, primary production was still occasionally higher than community respiration and the lake could act as a sink of CO2. Thus regarding metabolic processes, the ecosystem of this pristine lake was not strongly disturbed by the sudden browning episode.",
keywords = "1172 Environmental sciences, DOC , Primary production , Community respiration , Leucine uptake , Priming effect , Extreme event , DISSOLVED ORGANIC-CARBON , STRATIFIED HUMIC LAKE , MICROBIAL FOOD-WEB , SMALL FOREST LAKES , BACTERIAL PRODUCTION , MARINE-BACTERIA , SURFACE WATERS , PHYTOPLANKTON , CLIMATE , VARIABILITY",
author = "Peltomaa, {Elina Talvikki} and Ojala, {Anne Kristiina}",
year = "2016",
month = "10",
doi = "10.1007/s00027-015-0452-1",
language = "English",
volume = "78",
pages = "627--639",
journal = "Aquatic Sciences",
issn = "1015-1621",
publisher = "SPRINGER BASEL AG",
number = "4",

}

Consequences for pelagic energy mobilisation of a sudden browning episode without a clear increase in DOC concentration - a case of a boreal pristine lake. / Peltomaa, Elina Talvikki; Ojala, Anne Kristiina.

julkaisussa: Aquatic Sciences, Vuosikerta 78, Nro 4, 10.2016, s. 627-639.

Tutkimustuotos: ArtikkelijulkaisuArtikkeliTieteellinenvertaisarvioitu

TY - JOUR

T1 - Consequences for pelagic energy mobilisation of a sudden browning episode without a clear increase in DOC concentration - a case of a boreal pristine lake.

AU - Peltomaa, Elina Talvikki

AU - Ojala, Anne Kristiina

PY - 2016/10

Y1 - 2016/10

N2 - In the boreal zone, episodes of heavy rains are among the most conspicuous events disturbing aquatic ecosystems. Due to climate change they are predicted to become more frequent and intense, leading on browning of lakes. We assessed the possible effects of heavy rains to DOC concentration and water colour and resulting impacts on functioning of a headwater lake with naturally high water colour and concentration of allochthonous DOC. The weekly measurements were carried out in summers 2002-2004; the first 2 years had normal and the last year very high summer precipitation. The rains resulted in rapid increase in water colour, but not in DOC. We hypothesised that due to browning, irrespective of whether it stems from an increase in brownish DOC or other coloured substances, photosynthesis decreases, bacterial activity increases, and the lake becomes more heterotrophic. We also anticipated that due to strengthened heterotrophy, the period with apparent net autotrophy and CO2 flux onto the lake would disappear. To test our hypothesis, we measured autotrophic inorganic carbon uptake of photosynthetic organisms as well as dark fixation of inorganic carbon, community respiration and leucine uptake. Finally, we compared the results to CO2 flux measurements with an eddy covariance technique. Our hypotheses were only partly supported since there were no drastic changes in any of the metabolic processes measured. Although the lake ecosystem became slightly more heterotrophic, primary production was still occasionally higher than community respiration and the lake could act as a sink of CO2. Thus regarding metabolic processes, the ecosystem of this pristine lake was not strongly disturbed by the sudden browning episode.

AB - In the boreal zone, episodes of heavy rains are among the most conspicuous events disturbing aquatic ecosystems. Due to climate change they are predicted to become more frequent and intense, leading on browning of lakes. We assessed the possible effects of heavy rains to DOC concentration and water colour and resulting impacts on functioning of a headwater lake with naturally high water colour and concentration of allochthonous DOC. The weekly measurements were carried out in summers 2002-2004; the first 2 years had normal and the last year very high summer precipitation. The rains resulted in rapid increase in water colour, but not in DOC. We hypothesised that due to browning, irrespective of whether it stems from an increase in brownish DOC or other coloured substances, photosynthesis decreases, bacterial activity increases, and the lake becomes more heterotrophic. We also anticipated that due to strengthened heterotrophy, the period with apparent net autotrophy and CO2 flux onto the lake would disappear. To test our hypothesis, we measured autotrophic inorganic carbon uptake of photosynthetic organisms as well as dark fixation of inorganic carbon, community respiration and leucine uptake. Finally, we compared the results to CO2 flux measurements with an eddy covariance technique. Our hypotheses were only partly supported since there were no drastic changes in any of the metabolic processes measured. Although the lake ecosystem became slightly more heterotrophic, primary production was still occasionally higher than community respiration and the lake could act as a sink of CO2. Thus regarding metabolic processes, the ecosystem of this pristine lake was not strongly disturbed by the sudden browning episode.

KW - 1172 Environmental sciences

KW - DOC

KW - Primary production

KW - Community respiration

KW - Leucine uptake

KW - Priming effect

KW - Extreme event

KW - DISSOLVED ORGANIC-CARBON

KW - STRATIFIED HUMIC LAKE

KW - MICROBIAL FOOD-WEB

KW - SMALL FOREST LAKES

KW - BACTERIAL PRODUCTION

KW - MARINE-BACTERIA

KW - SURFACE WATERS

KW - PHYTOPLANKTON

KW - CLIMATE

KW - VARIABILITY

U2 - 10.1007/s00027-015-0452-1

DO - 10.1007/s00027-015-0452-1

M3 - Article

VL - 78

SP - 627

EP - 639

JO - Aquatic Sciences

JF - Aquatic Sciences

SN - 1015-1621

IS - 4

ER -