Phytoplankton community reorganization driven by eutrophication and warming in Lake Biwa

Abstract We compiled and analyzed long-term data, including chemical, physical and phytoplankton community data, for the Lake Biwa ecosystem from 1962 to 2003. Analyses on environmental data indicate that Lake Biwa had experienced intensified eutrophication (according to total phosphorus concentration) in the late 1960s and returned to a less eutrophic status around 1985, and then exhibited rapid warming and thus increased water column stability since 1990. Total phytoplankton cell volume largely followed the trend of total phosphorus concentration, albeit short-term fluctuations existed. However, phytoplankton community shifted dramatically in response to those changes of environmental states. These shifts were cause by changes in trophic status driven by phosphorus loadings and physical properties in the water column driven by warming. Moreover, most phytoplankton species did not show a strong linear correlation with environmental variables, suggesting nonlinear transitions among different states

Appendix B. The truncation of left-hand tail of species abundance distribution in phytoplankton community appeared in four seasons.

The truncation of left-hand tail of species abundance distribution in phytoplankton community appeared in four seasons

Appendix C. Distinguishing temporal variation of species abundance distribution from sampling and statistical artifacts.

Distinguishing temporal variation of species abundance distribution from sampling and statistical artifacts

Appendix F. Multivariate linear model analyses for testing littoral ratio responses to environmental factors.

Multivariate linear model analyses for testing littoral ratio responses to environmental factors

Appendix H. Exploring the water warming-induced size-selection hypothesis.

Exploring the water warming-induced size-selection hypothesis

Appendix D. Using species traits to partition species abundance distribution.

Using species traits to partition species abundance distribution

Appendix E. Time series analysis of phytoplankton littoral ratio and species richness responses to environmental factors.

Time series analysis of phytoplankton littoral ratio and species richness responses to environmental factors

Utilization of transposable element mPing as a novel genetic tool for modification of the stress response in rice.

Transposable elements (TEs) are DNA fragments that have the ability to move from one chromosomal location to another. The insertion of TEs into gene-rich regions often affects changes in the expression of neighboring genes. Miniature Ping (mPing) is an active miniature inverted-repeat TE discovered in the rice genome. It has been found to show exceptionally active transposition in a few japonica rice varieties, including Gimbozu, where mPing insertion rendered adjacent genes stress-inducible. In the Gimbozu population, it is highly possible that several genes with modified expression profiles are segregating due to the de novo mPing insertions. In our study, we utilized a screening system for detecting de novo mPing insertions in the upstream region of target genes and evaluated the effect of mPing on the stress response of the target genes. Screening for 17 targeted genes revealed five genes with the mPing insertion in their promoters. In most cases, the alteration of gene expression was observed under stress conditions, and there was no change in the expression levels of those five genes under normal conditions. These results indicate that the mPing insertion can be used as a genetic tool to modify an expression pattern of a target gene under stress conditions without changing the expression profiles of those under natural conditions