In order to examine the spatial variability and controlling factors of primary production in the Indian Ocean, deck-incubation primary production (¹³C method) and hydrographic properties were measured at 25 locations during inter-monsoon period (April–May 2014). Low concentration of nutrients were observed in the upper 30 m due to stratification of water column. Chlorophyll-a (Chl-a) in the mixed layer was, however, relatively higher in the Bay of Bengal (BoB) than in the Arabian Sea (AS) due to influence of river discharge and eddies. A prominent deep Chl-a maximum (DCM) was observed in the entire study region centred around 75 m of depth. The mixed layer integrated primary production displayed linear relation with nitrate and phosphate indicating that nutrients enriched through mixing enhanced primary production in the upper ocean. The photic zone integrated production was higher in the AS (1483 ± 202 mg C m⁻² d⁻¹) followed by Equatorial Indian Ocean (EIO; 1182 ± 360 mg C m⁻² d⁻¹), BoB (878 ± 390 mg C m⁻² d⁻¹), and South Indian Ocean (SIO; 740 ± 281 mg C m⁻² d⁻¹) in the Indian Ocean. Eddies were found to modify primary production in the Indian Ocean as production observed was lower in the anticyclonic eddies (ACE) by ~43% while higher by ~52% in the cyclonic eddy (CE) than no-eddy (NE) region. The primary production in the AS was only 70% higher than in the BoB compared to the hitherto estimated as 150%. We believe our estimate as more accurate because it takes into account the high spatial variability caused by eddies and sampling representation during different phases of the Indian Ocean Dipole (IOD). Vertically Generalized Primary Production model (VGPM) underestimated photic zone primary production by 40–70% whereas carbon-based primary production model (CbPM) estimated close to that of measured primary production in the BoB, EIO and SIO whereas underestimated by ~30% in the AS.. There is need for generating more data in order to test the performance of remote sensing models in the Indian Ocean.

为了研究印度洋初级生产的空间变异性和控制因素，甲板孵化初级生产（¹³季风期间（2014年4月至5月）在25个地点测量了C法）和水文特性。由于水柱分层，在上层30 m处观察到了低浓度的养分。但是，由于河水排放和涡流的影响，混合湾中的叶绿素-a（Chl-a）在孟加拉湾（BoB）中比在阿拉伯海（AS）中相对较高。在大约75 m深度的整个研究区域中观察到了明显的深Chl-a最大值（DCM）。混合层综合初级生产与硝酸盐和磷酸盐显示线性关系，表明通过混合富集的养分提高了上层海洋的初级生产。在AS中，光区的综合产量较高（1483±202 mg C m ^-2 d ^-1），然后是赤道印度洋（EIO; 1182±360 mg C m ^-2 d ^-1），BoB（878±390 mg C m ^-2 d ^-1）和南印度洋（SIO; 740±281 mg C m ⁻² d ⁻¹）在印度洋。发现涡旋改变了印度洋的初级生产，因为在反气旋涡旋（ACE）中观察到的产量比无涡旋（NE）区域低约43％，而在旋风涡旋（CE）中则高出〜52％。AS的主要生产量仅比BoB高70％，而迄今为止估计为150％。我们认为我们的估算更为准确，因为它考虑了印度洋偶极子（IOD）不同阶段中由涡流和采样表示引起的高空间变异性。垂直广义初级生产模型（VGPM）低估了光合作用区的初级生产40-70％，而碳基初级生产模型（CbPM）估计接近BoB，EIO和SIO中测得的初级生产，而低估了约30％。 AS ..