Sunlight caused interference in outdoor N, N-diethyl-p-phenylenediamine colorimetric measurement for residual chlorine and the solution for on-site work.

Chlorination is the most common method to control water qualities, in some case on-site outdoor measurements are required to measure easily-decaying residual chlorine concentration appropriately without delay. In this study sunlight-induced unexpected colour development (UCD) of N, N-diethyl-p-phenylenediamine (DPD) colorimetric measurement was studied under several sun exposure conditions. The colour development level was evaluated with reference to chlorine concentration (mg/L) and relationships between colour development rate (mg/L min) and intensities of solar were investigated.

Cypris larvae (Cirripedia: Balanomorpha) display auto-fluorescence in nearly species-specific patterns.

The identification of balanomorph larvae plays an important role in ecological study and for protection against biofouling. However, it is difficult to identify species of cyprids (settling larvae) of balanomorph barnacles, as they show remarkably similar morphology. Some authors have suggested distinguishing cyprids of different species by carapace length, pigmentation, and fine carapace detail.