The variations in nutrient utilization in the euphotic layer was studied using geochemical tracers N* (NO₃^- −16PO₄³⁻) and Si* (Si(OH)₄ – NO₃^-) along two transect 57°30′E (T1) and 47°E (T2) during austral summer 2011 in the Indian Ocean sector of the Southern Ocean. Seawater samples collected from 8 depths within the euphotic zone (upper 200 m) along two meridional transects were analysed for nitrate, nitrite, silicate, phosphate and chlorophyll a (chl a). Clear meridional differences in nutrient limitation were observed along the two transects. Depletion of silicate at Antarctic Zone (AZ) stations was 1.6 times higher in T1 than in T2. Significant inverse correlations were observed for N* (p < 0.0001) and Si* (p < 0.001) values with temperature and salinity implying that redistribution of preformed nutrients was influenced by hydrography. However, significant variances in Si* (p < 0.001 at SSTF and p < 0.01 at PF-2) along the two transects could be attributed to differential uptake of silica by phytoplankton. Low Si* values were obtained at Polar Front 1 (PF1) and South Subtropical Front (SSTF) along T1 and from Sub Antarctic Front (SAF) to Polar Frontal Zone (PFZ) along T2. Although hydrography did have inverse correlation with tracers, the observed values indicate high consumption of silicate. Relatively higher Si* values in the north of SSTF coincided with lower abundance of diatoms in these waters. Conversely, high Si* values and abundance of diatoms at Antarctic Zone (AZ) indicate less consumption of Si. The biological consumption of nitrate was more clearly discerned in the northern region where nitrogen strongly limits the productivity both along T1 (39°S and the Agulhas Retroflection Front (ARF)) and T2 (40°S). Our observations suggest that much of the tracer distribution in these waters can be explained by the dominant phytoplankton groups, but influence of other biotic components on nutrient tracer distribution cannot be ruled out.

使用地球化学示踪剂在透光层中的营养物利用的变化进行了研究N *（NO ₃ ^- -16PO ₄ ^3-）和硅*硅烷（Si（OH）₄ - NO ₃ ^- ）沿着两个断面57°30'E（T1 ）和南极印度洋地区2011年夏季夏季的47°E（T2）。分析了沿两个子午线样线在富营养区（200 m以上）的8个深度收集的海水样品中的硝酸盐，亚硝酸盐，硅酸盐，磷酸盐和叶绿素a（chl a）。）。沿两个样带观察到营养限制的明显子午线差异。在T1中，南极区（AZ）站的硅酸盐耗竭比T2高1.6倍。观察到N *（p <0.0001）和Si *（p <0.001）值与温度和盐度呈显着负相关，这暗示着预先形成的养分的重新分布受到水文学的影响。然而， 沿着两个样线的Si *（ 在SSTF处p <0.001，在PF-2处p <0.01）的显着变化可归因于浮游植物对二氧化硅的不同吸收。低硅*沿T1的极地锋1（PF1）和南亚热带锋面（SSTF）以及沿着T2的亚南极锋（SAF）到极地带（PFZ）获得了这些值。尽管水文学确实与示踪剂成反比，但观测值表明硅酸盐的消耗量很大。在这些水域中，SSTF北部相对较高的Si *值与较低的硅藻含量相吻合。相反，高Si *南极区（AZ）硅藻的含量和丰度表明硅的消耗较少。在北部地区，氮在T1（39°S和Agulhas Retroflection Front（ARF）和T2（40°S）上都强烈限制了生产力）的北部地区，硝酸盐的生物消耗更加明显。我们的观察结果表明，这些水域中的示踪剂分布大部分可以由浮游植物的优势种群解释，但不能排除其他生物成分对营养物示踪剂分布的影响。