从悬浮质和沉降质的观点描述中国云南湖泊的化学动态变化

在对云南抚仙湖、星云湖和洱海3个高原湖怕进行地球化学和湖沼学调查，确定湖水中微粒的溶解浓度和化学成分，对沉降质和沉积物进行分析的基础上，对这些湖泊的化学动态变化进行了讨论。     

Accumulation and Export of Dissolved Organic Carbon in Surface Waters of Subtropical and Tropical Pacific Ocean

Dissolved organic carbon (DOC) concentrations in surface waters of the Pacific Ocean during October–November, 1995, were determined using a high-temperature combustion method. The DOC in the surface mixed-layer was approximately homogeneous with a concentration between 55 and 89 μmol C l⁻¹. This homogeneity indicates that there is a strong control of the vertical distribution of DOC by mixing processes. The DOC concentrations in the mixed-layer in the subtropical region were up to 27 μmol C l⁻¹ higher than in the tropical region. This difference reflects the subtropical accumulation and the tropical export of DOC. There is a significant positive correlation between DOC and chlorophyll a concentrations in the mixed-layer of the North Pacific subtropical region, suggesting that phytoplankton is the primary source of DOC accumulated in this region. Calculations using simple box models suggest that DOC export in the tropical region (0–50 m depth, 10°N-10°S, along 160°W) occurs primarily by poleward advection at a rate of 0.5–3 mmol C m⁻²day⁻¹. A comparison with estimates of the export rate of particulate organic carbon published in previous studies leads us to conclude that DOC export may contribute less to the carbon budget in the tropical region than has recently been supposed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Fluctuation in volume transport distribution accompanied by the Kuroshio front migration in the Tokara Strait

A relation between migration of the Kuroshio front and fluctuation of distribution of volume transport in the Tokara Strait was described, using sea level records at five tide gauge stations around the strait and data which were composed of sea surface temperature, XBT casts, sea surface salinity and velocities at 20 m, 75 m and 150 m depths taken en route a ferryboat. The Kuroshio front extends to about 150 m depth. The sea surface salinity and the horizontal velocities abruptly change at the front. There is a good correlation in a period range from half a month to two months between the migration of the front, which is not only at the surface but also in the subsurface, and the sea level fluctuation at Nakano-shima. A northward migration of the front with a period range from 17 to 50 days decreases the transport in the southern strait between Naze and Nakano-shima but increases in the northern strait between Nakano-shima and Sata-misaki. The northward migration intensifies inflow into Kagoshima Bay and the Ohsumi Branch Current. Correlation between the transport in the northern strait and the Ohsumi Branch Current is significant in the period range from 30 to 50 days. In this significant period range, the former leads the latter by about 3 days.     

Ba, Si, U, Al, Sc, La, Th, C and C/C in a sediment core in the western subarctic Pacific as proxies of past biological production

A sediment core covering the last 145 kyrs was collected in the western subarctic Pacific (WSAP), and analyzed for Ba, U, Al, Sc, La, Yb, Th, biogenic opal (Opal) and organic carbon (C_org) as well as its isotopic ratio (δ¹³C). This study examined the change of past biological production in WSAP with multiple proxies, together with understanding the relation between Loess from the Asian continent and the biological production. The Loess content was estimated from the metal components, Al, Sc, La, Yb and Th. In this high latitude core (50°N), the Loess content was generally high during the glacial periods, but it was also high even in some interglacial periods. The excess amount of Ba relative to the detrital material composition, Ba_ex, showed the best correlation with the Vostok δD (r = 0.72, p < 0.001), indicating that the biological production was lower in the glacial periods than in the interglacials. This corroborates the pervasive correlation between Ba_ex in the polar region, WSAP and the Antarctic Sea, and Antarctic temperature, combined with previous research. This correlation might be explained by the stratification caused by cooling. In addition, the time variations of Ba_ex in WSAP were similar to those of Ba_ex in the Okhotsk Sea and of other proxies (C_org and Opal) in both the Okhotsk and the Bering Sea, indicating the spatial homogeneity of Ba_ex in WSAP including proximal marginal seas. The Opal content was more weakly correlated with the Vostok δD (r = 0.46, p < 0.001) than Ba_ex, reflecting that Opal in WSAP including proximal marginal seas was spatially heterogeneous compared to Ba_ex. While both the C_org content and U_ex, the excess amount of U relative to the detritus composition, were not positively correlated with the Vostok δD, they behaved similarly in the sediments. The positive correlation between δ¹³C and the Vostok δD (r = 0.42, p < 0.001), between δ¹³C and Ba_ex (r = 0.60, p < 0.001) and between δ¹³C and Opal (r = 0.36, p < 0.01) indicates that δ¹³C in WSAP may give some information on the phytoplankton growth rate. There was not a significant correlation between the spatially homogeneous Ba_ex in WSAP and Loess (r = − 0.16, p > 0.01), suggesting that the increase of biological production with the increase of Loess supply during the glacial periods did not occur.