Hyodo, Fujio
- 総合地球環境学研究所
Sammanfattning
We measured stable nitrogen (N) and carbon (C) isotope ratios, lignin-derived phenols, and fossil pigments in sediments of known ages to elucidate the historical changes in the ecosystem status of Lake Biwa, Japan, over the last 100 years. Stable N isotope ratios and algal pigments in the sediments increased rapidly from the early 1960s to the 1980s, and then remained relatively constant, indicating that eutrophication occurred in the early 1960s but ceased in the 1980s. Stable C isotope ratios of the sediment increased from the 1960s, but decreased after the 1980s to the present. This decrease in stable C isotope ratios after the 1980s could not be explained by annual changes in either terrestrial input or algal production. However, when the C isotope ratios were corrected for the Suess effect, the shift to more negative isotopic value in atmospheric CO2 by fossil fuel burning, the isotopic value showed a trend, which is consistent with the other biomarkers and the monitoring data. The trend was also mirrored by the relative abundance of lignin-derived phenols, a unique organic tracer of material that originated from terrestrial plants, which decreased in the early 1960s and recovered to some degree in the 1980s. We detected no notable difference in the composition of lignin phenols, suggesting that the terrestrial plant composition did not change markedly. However, we found that lignin accumulation rate increased around the 1980s. These results suggest that although eutrophication has stabilized since the 1980s, allochthonous organic matter input has changed in Lake Biwa over the past 25 years. (C) 2008 Elsevier B.V. All rights reserved.
Nyckelord
stable carbon and nitrogen isotopes; lignin-derived phenol; fossil pigments; eutrophication; land transformation; Suess effect; Lake Biwa
Publicerad i
Science of the Total Environment
2008, volym: 403, nummer: 1-3, sidor: 139-147
Utgivare: ELSEVIER SCIENCE BV
SLU författare
Globala målen (SDG)
SDG6 Rent vatten och sanitet för alla
SDG15 Ekosystem och biologisk mångfald
UKÄ forskningsämne
Miljö- och naturvårdsvetenskap
Publikationens identifierare
- DOI: https://doi.org/10.1016/j.scitotenv.2008.05.010
Permanent länk till denna sida (URI)
https://res.slu.se/id/publ/19520