Seasonal evolution of hydrographic properties in the Ross Sea, Antarctica, 1996-1997
Seasonal evolution of hydrographic properties in the Ross Sea, Antarctica, 1996-1997
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DOI：
10.1016/s0967-0645(00)00060-6
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发表时间：
2000-01-01
影响因子：
3
通讯作者：
Sweeney, C
中科院分区：
文献类型：
--
作者：
Gordon, LI;Codispoti, LA;Sweeney, C
本文简要介绍了全球海洋通量联合研究（JGOFS）南极环境和南大洋过程联合研究（AESOPS）在罗斯海进行的四次季节性过程考察的水文和化学结果。数据包括温度、盐度、氧、营养物（NO3-、NO2-、NH 4+、PO 4 -3、Si（OH）（4））、滴定碱度（TA）和总无机CO2（TCO 2）。在早春（1996年10月中旬至11月初），冰层覆盖率接近100%。水柱表现出只有小范围的潜在温度，盐度，营养盐，TA和TCO 2。在这次航行中观察到的这些几乎一致的条件被用作评估地球化学性质季节性变化的初始条件。在次年（1997年）的春季（11月/12月）晚些时候，出现了一个扩大的冰间湖。1997年夏季（1月），海冰覆盖范围极小。融水稀释和暴露的地表沃茨变暖达到最大值。最后，在初秋（1997年4月）快速冷却和冻结的表面沃茨和加强垂直混合的水柱导致返回冬季条件，但与营养物质的显着枯竭仍然明显的表面沃茨。在类似于175 ° E的温度下观察到了改良的环极深水（MCDW），位置随时间呈带状变化。在MCDW之下，在接近180度的部分的东端附近，冰架水（ISW）的向北入侵是持续的，虽然变量。沿着剖面观测到的地球化学变化包括：（1）在100 m左右显著的铵增加;（2）在20-40 m水柱的上部，硝酸盐明显下降;（3）夏季表层沃茨中的硝酸盐减少，在研究区的西端最大;（4）TA的增加主要是由于NO3-的损失;和（5）TCO 2的减少接近“Redfield”比例中碳和氮消耗的预期值。与以前的观测结果一致，在任何一次航行中，氮、磷和硅从未接近极限浓度。(C)2000年由Elsevier Science Ltd.出版
This paper briefly describes hydrographic and chemical results from four seasonal process cruises in the Joint Global Ocean Flux Study (JGOFS) Antarctic Environment and Southern Ocean Process Study (AESOPS) in the Ross Sea. The data include temperature, salinity, oxygen, nutrients (NO3-, NO2-, NH4+, PO4-3, Si(OH)(4)), titration alkalinity (TA), and total inorganic CO2 (TCO2). In early spring (mid-October to early November 1996) ice cover was near 100%. The water column exhibited only small ranges of potential temperature, salinity, nutrients, TA and TCO2. These nearly uniform conditions observed during this cruise were used as initial conditions from which to evaluate seasonal changes in biogeochemical properties. Later in the spring (November/December) of the following year (1997), an expanded polynya was present. In the summer (January) 1997, the sea-ice cover was minimal. Meltwater dilution and warming of exposed surface waters were at their maximum. Finally, in early austral autumn (April 1997) rapid cooling and freezing of surface waters and intensified vertical mixing of the water column resulted in a return toward winter conditions, but with significant depletion of nutrients still evident in surface waters. Modified circumpolar deep water (MCDW) was observed at similar to 175 degreesE., varying in location zonally with time. Beneath the MCDW, near the eastern end of the section at similar to 180 degrees, northward intrusion of ice shelf water (ISW) was persistent though variable. Among the biogeochemical changes observed along this section were: (1) Significant ammonium accretion at about 100 m; (2) appreciable nitrate drawdowns throughout the upper 20-40 m of the water column; (3) silicic acid depletions during the summer in the surface waters, which were largest at the western end of the study area; (4) an increase in TA largely due to the loss of NO3-; and (5) decreases in TCO2 close to expected values for consumption of carbon and nitrogen in "Redfield" proportions. Consistent with previous observations, N, P and Si never approached limiting concentrations during any of the cruises. (C) 2000 Published by Elsevier Science Ltd.