Transportation Of Major Constituents And Organic Carbon In The Estuary Of Yellow River

Major constituents and organic carbon have been investigated in the Estuary of Yellow River, base on the project of coastline delimitation in the Estuary of Yellow River, which is financially supported by the special fund from the State Oceanic Administration. Samples were collected and analyzed in the Estuary of Yellow River, covering the salinity from 0.5 to 28 in November 2004 (11-04), May (05-05) and September (09-05) 2005. Through the investigation on the temporal and spacial distributions of major constituents, the transportation pattern and influence factors have been studied. Via the study on the total organic carbon (OC) and compound specific composition of fatty acids in suspended particulate matters and surface sediments, we have explored the sources and transportation pattern of organic carbon. The conclusions are demonstrated as followed:1 Major constituentsWith seasonal and compound specific differences, the results show that concentrations of major constituents relate with salinity (S) during the estuarine process, while HCO3- do not change with S. The relative contributions of major constituents in three cruises agree with each other if S>5, which is in turn Cl-> Na+> SO42- > Mg2+> Ca2+> K+ > HCO3- >NO3-, but the relative contributions of major constituents in 09-05 differed from those in 11-04 and 05-05 if S<5, which are in turn (1) 11-04 and 05-05, SO42-> HCO3- > Cl-> Na+> Ca2+> Mg2+> K+ >NO3-, and (2) 09-05, SO42-> HCO3- > Na+> Cl-> Ca2+> Mg2+> K+ >NO3-, respectively. Via a dilution pattern, the major constituents behave conservatively in river and sea areas, but non-conservatively in mixing area. Comparatively, the anions and cations are basically balanced in the Estuary of Yellow River. In conclusion, the concentrations of constant ions are primarily controlled by the physical mixing dilution of freshwater to seawater, and partially effected by biological and chemical factors.2 Organic carbon in suspended particulate mattersThe contents of OC in 05-05 range at 1.12-5.14 mg/L, while those in 09-05 at 0.83-4.32 mg/L, the OC contents decrease from the freshwater to the seawater. More than thirty species of fatty acids have been detected and identified. The fatty acids are dominated by saturated ones for about 63.19 % in 05-05 and 58.57 % in 09-05, in which the short-chain saturated ones (< C20) are predominant, Long-chain fatty acids (> C20) are detectable but in low fractions. Unsaturated, iso- and anteiso-fatty acids are also important fractions, the contents of them are 54.23 % in 05-05 and 55.65 % in 09-05. Composition of compound specific fatty acids suggest that, algal source of fatty acids hold an important position to the total fatty acids, which are 34.51 % in 05-05 and 38.85 % in 09-05. The contributions of different sources follows the order in that, (1) 05-05: multiple >algal > bacteria > terrestrial, and (2)09-05: algal > multiple > bacteria > terrestrial.3 Organic carbon in sedimentsThe contents of OC in 05-05 range at 0.11-0.32 %, while those in 09-05 at 0.09-0.15 %, the OC contents increase from the freshwater to the seawater. The fatty acids are dominated by saturated ones for about 65.77 % in 05-05 and 61.34 % in 09-05, in which the short-chain saturated ones (< C20) are predominant. Long-chain fatty acids (> C20) are detectable but in low fractions. Unsaturated, iso- and anteiso-fatty acids are also important fractions, the contents of them are 45.33 % in 05-05 and 53.37 % in 09-05. Composition of compound specific fatty acids suggest that, algal and multiple sources of fatty acids hold important positions to the total fatty acids. The contributions of different sources follow the order in that, (1) 05-05: multiple >algal > bacteria > terrestrial, and (2) 09-05: algal > multiple > bacteria > terrestrial. By the analysis of fatty acids in surface sediment in Bohai Sea, we find the relative contribution of terrestrial matters from Yellow River to sediment in Bohai Sea decrease with the distances away from the Estuary of Yellow River.