Abstract
The dynamics of fluorescent dissolved organic matter (FDOM) in the large monomictic freshwater Lake Biwa (surface area 675 km2, maximum depth 104 m) was studied from December 2010 to December 2011. The protein-like FDOM (FDOMT) and dissolved organic carbon (DOC) showed epilimnetic accumulation (FDOMT from 4.42 ± 0.22 quinine sulfate units [QSU] to 6.30 ± 0.04 QSU; DOC from 80.8 ± 2.7 μmol L-1 to 102.7 ± 3.5 μmol L-1) between nutrient-replete winter mixing to nutrient-depleted stratified periods. This accumulation is attributed to the reduced heterotrophic activity following severe P-limitation. The positive correlation between accumulated DOC and FDOMT in the epilimnion and their uniform reduction in the hypolimnion (~ 9%) suggest FDOMT as a proxy for semi-labile DOM. The humic-like FDOM (FDOMM) generally increased with depth, a pattern similar to nutrients and total carbon dioxide (TCO2), but adverse to dissolved oxygen. The significant positive correlations of FDOMM with apparent oxygen utilization (r = 0.86, p < 0.001), TCO2 (r = 0.91, p < 0.001), nitrate (r = 0.83, p < 0.001), and phosphate (r = 0.76, p < 0.001) in the deeper layers suggest that FDOMM is formed during hypolimnetic mineralization. We estimated that ~ 8% of the organic carbon degraded in the hypolimnion is transferred into humic substances. The minor contribution of DOC (6.4%) to hypolimnetic mineralization suggests that production of humic substances is mainly fueled by the mineralization of sinking biogenic particles. The production and consumption of FDOM in freshwater lakes may influence the quality and bioavailability of carbon exported from these systems.
| Original language | English |
|---|---|
| Pages (from-to) | 2262-2278 |
| Number of pages | 17 |
| Journal | Limnology and Oceanography |
| Volume | 58 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 2013 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Oceanography
- Aquatic Science
Cite this
Biogeochemical control on fluorescent dissolved organic matter dynamics in a large freshwater lake (Lake Biwa, Japan). / Thottathil, Shoji D.; Hayakawa, Kazuhide; Hodoki, Yoshikuni; Yoshimizu, Chikage; Kobayashi, Yuki; Nakano, Shin Ichi.
In: Limnology and Oceanography, Vol. 58, No. 6, 2013, p. 2262-2278.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Biogeochemical control on fluorescent dissolved organic matter dynamics in a large freshwater lake (Lake Biwa, Japan)
AU - Thottathil, Shoji D.
AU - Hayakawa, Kazuhide
AU - Hodoki, Yoshikuni
AU - Yoshimizu, Chikage
AU - Kobayashi, Yuki
AU - Nakano, Shin Ichi
PY - 2013
Y1 - 2013
N2 - The dynamics of fluorescent dissolved organic matter (FDOM) in the large monomictic freshwater Lake Biwa (surface area 675 km2, maximum depth 104 m) was studied from December 2010 to December 2011. The protein-like FDOM (FDOMT) and dissolved organic carbon (DOC) showed epilimnetic accumulation (FDOMT from 4.42 ± 0.22 quinine sulfate units [QSU] to 6.30 ± 0.04 QSU; DOC from 80.8 ± 2.7 μmol L-1 to 102.7 ± 3.5 μmol L-1) between nutrient-replete winter mixing to nutrient-depleted stratified periods. This accumulation is attributed to the reduced heterotrophic activity following severe P-limitation. The positive correlation between accumulated DOC and FDOMT in the epilimnion and their uniform reduction in the hypolimnion (~ 9%) suggest FDOMT as a proxy for semi-labile DOM. The humic-like FDOM (FDOMM) generally increased with depth, a pattern similar to nutrients and total carbon dioxide (TCO2), but adverse to dissolved oxygen. The significant positive correlations of FDOMM with apparent oxygen utilization (r = 0.86, p < 0.001), TCO2 (r = 0.91, p < 0.001), nitrate (r = 0.83, p < 0.001), and phosphate (r = 0.76, p < 0.001) in the deeper layers suggest that FDOMM is formed during hypolimnetic mineralization. We estimated that ~ 8% of the organic carbon degraded in the hypolimnion is transferred into humic substances. The minor contribution of DOC (6.4%) to hypolimnetic mineralization suggests that production of humic substances is mainly fueled by the mineralization of sinking biogenic particles. The production and consumption of FDOM in freshwater lakes may influence the quality and bioavailability of carbon exported from these systems.
AB - The dynamics of fluorescent dissolved organic matter (FDOM) in the large monomictic freshwater Lake Biwa (surface area 675 km2, maximum depth 104 m) was studied from December 2010 to December 2011. The protein-like FDOM (FDOMT) and dissolved organic carbon (DOC) showed epilimnetic accumulation (FDOMT from 4.42 ± 0.22 quinine sulfate units [QSU] to 6.30 ± 0.04 QSU; DOC from 80.8 ± 2.7 μmol L-1 to 102.7 ± 3.5 μmol L-1) between nutrient-replete winter mixing to nutrient-depleted stratified periods. This accumulation is attributed to the reduced heterotrophic activity following severe P-limitation. The positive correlation between accumulated DOC and FDOMT in the epilimnion and their uniform reduction in the hypolimnion (~ 9%) suggest FDOMT as a proxy for semi-labile DOM. The humic-like FDOM (FDOMM) generally increased with depth, a pattern similar to nutrients and total carbon dioxide (TCO2), but adverse to dissolved oxygen. The significant positive correlations of FDOMM with apparent oxygen utilization (r = 0.86, p < 0.001), TCO2 (r = 0.91, p < 0.001), nitrate (r = 0.83, p < 0.001), and phosphate (r = 0.76, p < 0.001) in the deeper layers suggest that FDOMM is formed during hypolimnetic mineralization. We estimated that ~ 8% of the organic carbon degraded in the hypolimnion is transferred into humic substances. The minor contribution of DOC (6.4%) to hypolimnetic mineralization suggests that production of humic substances is mainly fueled by the mineralization of sinking biogenic particles. The production and consumption of FDOM in freshwater lakes may influence the quality and bioavailability of carbon exported from these systems.
UR - http://www.scopus.com/inward/record.url?scp=84887480804&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84887480804&partnerID=8YFLogxK
U2 - 10.4319/lo.2013.58.6.2262
DO - 10.4319/lo.2013.58.6.2262
M3 - Article
AN - SCOPUS:84887480804
VL - 58
SP - 2262
EP - 2278
JO - Limnology and Oceanography
JF - Limnology and Oceanography
SN - 0024-3590
IS - 6
ER -