Fluorescent Dissolved Organic Matter And Its Relationship With Environmental Factors In Jiaozhou Bay

In this thesis, the fluorescent dissolved organic matter (FDOM) of Jizozhou Bay was studied. To begin with, some parameters of measurement with HITACHI F-4500 fluorescence spectrophotometer and preserving methods of samples were selected through experiments. By measuring and analyzing the fluorescence excitation-emission matrix spectra (EEMS) of dissolved organic matter and relative environmental factors in four typical environments, fluorescence characteristics of dissolved organic matter and their relationship with phytoplankton multiplication, river input and other environmental factors were researched. In addition, it was probed into preliminarily that fluorescence was used to evaluate cross-flow filtration. The main results are as fellows. There are strong protein-like fluorescence in Jiaozhou Bay and strong humic-like fluorescence in the river near Jiaozhou Bay to the contrary. Generally speaking, high-excitation protein-like and humic-like fluorescence is stronger than low-excitation. In addition, marine humic-like fluorescence is very weak. The distributions of fluorescent dissolved organic matter reflect the distributions of dissolved organic matter to some extents. Protein-like fluorescent dissolved organic matter of Jiaozhou Bay is mainly produced in situ. River input is an important origin of humic-like fluorescent dissolved organic matter in Jiaozhou Bay. Effects of river input are evident during low phytoplankton biomass and weak during algae bloom. Phytoplankton is an important origin of protein-like fluorescent dissolved organic matter, while high protein-like fluorescence intensities don't correspond to high phytoplankton biomass. The increment of protein-like fluorescence doesn't consist with phytoplankton multiplication. Protein-like fluorescence is low in lag phase with low biomass and it keeps low in the logarithmic prophase. In logarithmic anaphase protein-like fluorescence increases and it keeps high until the end of decline phase. Organic matter released from phytoplankton is an origin of humic-like fluorescent dissolved organic matter, but humic-like fluorescence doesn't increase with phytoplankton multiplication too. Humic-like fluorescence increases in logarithmic anaphase and reaches maximum and keep stable in decline phase. Fore and aft cross-flow filtration experiments, the positions of protein-like and humic-like fluorescence peaks have little alteration, the balance of fluorescence intensity is not so good as organic carbon mass balance as a whole. Fluorescence balance is suggested only as a supplementary technique for evaluating contaminations or loss by organic carbon mass balance.