Sunlit surface waters : exploring the photochemical reactivity of dissolved organic carbon
In surface waters, solar radiation can photochemically mineralise the dissolved
organic carbon (DOC, a measure of dissolved organic matter, DOM) to
dissolved inorganic carbon (DIC). This DIC photoproduction constitutes an
essential yet vague flux in the aquatic carbon cycling. The present thesis is
based on the empirical assessment of the DOC photochemical reactivity, which
was determined as the spectral apparent quantum yields (AQY) for DIC
photoproduction. First, AQYs were determined in DOM solutions to quantify
the impact of pH and DOM-associated iron. Then boreal lake waters were used
for assessing the alteration of DOC photoreactivity due to water quality and
catchment property. By simulating DIC production, further, AQYs were used to
approximate the photomineralisation of terrigenous DOC (tDOC) in coastal
waters. Finally, the experimental protocols determining AQY were compared
by four laboratories. The results demonstrated the variation of AQYs triggered
by the laboratory-specific procedures was less than that across the examined
inland waters. Up to 86 % of the DIC photoproduction in DOM solutions can be
justified by iron-stimulated photoreactions with acidic pH, while the effect was
negligible at pH > 7. This interaction between iron and acidity was similarly
influential on DOC photoreactivity in boreal lake waters. Across lakes, the DOC
photoreactivity was varied relevant to the water quality and catchment land use
patterns. A high DOC photoreactivity can be expected when the contents of
DOC and chromophoric DOM are high, more so in small lakes enriched by
peaty soils. Although DOC photoreactivity in lakes was higher, the estimates
revealed that solar radiation mineralised far more tDOC in marine waters,
which may be attributed to the extensive spreading of tDOC during mixing
over the coastal ocean.
...
Publisher
University of JyväskyläISBN
978-951-39-7252-3ISSN Search the Publication Forum
1456-9701Keywords
Metadata
Show full item recordCollections
- Väitöskirjat [3559]
License
Related items
Showing items with similar title or keywords.
-
Coupling of iron and dissolved organic matter in lakes–selective retention of different size fractions
Riise, Gunnhild; Haaland, Ståle Leif; Xiao, Yihua (Springer, 2023)Increasing concentration of iron (Fe) is observed in many boreal lakes, such as for the present study in Oslo Østmark, SE-Norway (1983–2018). As Fe-regulating processes are complex and dynamic, the link between mobilizing ... -
Periphyton as a key diet source of essential fatty acids for macroinvertebrates across a nutrient and dissolved organic carbon gradient in boreal lakes
Vesterinen, Jussi; Strandberg, Ursula; Taipale, Sami J.; Kainz, Martin J.; Kankaala, Paula (Wiley; Association for the Sciences of Limnology and Oceanography, 2022)We studied how physiologically important long-chain polyunsaturated fatty acids (PUFA) in benthic macroinvertebrates (Asellus aquaticus, Chironomidae, and Oligochaeta) were related to those in periphyton and terrestrial ... -
Inter‐laboratory differences in the apparent quantum yield for the photochemical production of dissolved inorganic carbon in inland waters and implications for photochemical rate modeling
Koehler, Birgit; Powers, Leanne C.; Cory, Rose M.; Einarsdóttir, Karólína; Gu, Yufei; Tranvik, Lars J.; Vähätalo, Anssi V.; Ward, Collin P.; Miller, William L. (John Wiley & Sons, 2022)Solar radiation initiates photochemical oxidation of dissolved organic carbon (DOC) to dissolved inorganic carbon (DIC) in inland waters, contributing to their carbon dioxide emissions to the atmosphere. Models can determine ... -
Photochemical mineralization of terrigenous DOC to dissolved inorganic carbon in ocean
Aarnos, Hanna; Gélinas, Yves; Kasurinen, Ville; Gu, Yufei; Puupponen, Veli-Mikko; Vähätalo, Anssi (American Geophysical Union, 2018)When terrigenous dissolved organic carbon (tDOC) rich in chromophoric dissolved organic matter (tCDOM) enters the ocean, solar radiation mineralizes it partially into dissolved inorganic carbon (DIC). This study addresses ... -
Carbon budget and molecular structure of natural organic matter in bank infiltrated groundwater
Jylhä‐Ollila, Maija; Laine‐Kaulio, Hanne; Schilder, Jos; Niinikoski‐Fuβwinkel, Paula; Kekäläinen, Timo; Jänis, Janne; Koivusalo, Harri (Wiley-Blackwell, 2021)Managed aquifer recharge (MAR) provides means to remove natural organic matter (NOM) from surface waters. Recent studies have explored the degree of NOM removal in groundwater. In this study, we further elaborate the NOM ...