Studies On Photosynthetic Pigments' Environmental Significance And Its Model In The Three Gorges Reservoir

This paper studied on 528 filtered samples of ultraphytoplankton collected from the Three Gorges Reservoir from 2012 to 2015.The diagnostic pigments of the characterized ultraphytoplankton in the Three Gorges Reservoir were analyzed qualitatively and quantitatively by HPLC and chemical taxonomy(CHEMTAX),thus to reveal the community composition and evolutionary succession of target ultraphytoplankton in the Three Gorges Reservoir Area by CHEMTAX,and to initially discuss and research on the application of generalized additive mixture model(GAMMS)in the response relationship between the photosynthetic pigments of the characterized ultraphytoplankton and the environmental parameters.The result showed as follows:?.Nitrate was negatively correlated with fucoxanthin and chlorophyll b,phosphate had a strong non-linear relationship with neoxanthin,ammonium and alloxanthin were almost positively correlated with a linear relationship.Fucoxanthin,neoxanthin,alloxanthin,chlorophyll b were positively correlated with total nitrogen.Fucoxanthin and alloxanthin were negatively correlated with water temperature,and neoxanthin and chlorophyll b were positively correlated with water temperature.dissolved oxygen(DO),p H had a strong nonlinear relationship with fucoxanthin,chlorophyll b,alloxanthin,and neoxanthin.?.The interaction between nutrients and transparency was a good indicator for the distribution of characteristic photosynthetic pigments with strong specificity.Both fucoxanthin and chlorophyll b were stably distributed in water with high phosphate and low transparency.Neoxanthin and alloxanthin were mainly distributed in water with low nitrate and high transparency.?.Compared with the pigment model,the predictive ability of neoxanthin and chlorophyll b models was relatively good.The deviation of the model mainly appeared in 2013,2014 and April 2015.?.Cryptophytes decreased gradually from spring to summer,which showed a low peak in summer and increased gradually from summer to winter.Cryptophytes had a strong nonlinear relationship with total nitrogen(effective degree of freedom was 2.49).The interaction between ammonium and transparency had a significant effect on Cryptophytes.Cryptophytes was mainly distributed in the water body with high ammonium and high transparency.The research results could provide data basis and method support for biodiversity research,ecological environment monitoring and management of the Three Gorges Reservoir,and could also provide model support for using photosynthetic pigments as environmental parameters to predict the evolutionary changes of ultraphytoplankton community in the Three Gorges reservoir.