Southwest monsoon-driven changes in the phytoplankton community structure in the central Arabian Sea (2017–2018): After two decades of JGOFS

Aeolian Dust and Sea Salt in Marine Aerosols over the Arabian Sea during the Southwest Monsoon: Sources and Spatial Variability

“…The chemical reactions of DMS with OH – (hydroxyl radical) and NO 3 – (nitrate radical) lead to the formation of nss-SO 4 2– and methane sulfonic acid (MSA). − SO 4 2– is the second most dominant anion with a contribution of ∼14% (SSD-40) and ∼10% (SSD-55) followed by nitrates having a contribution of ∼5% (SSD-40) and 3% (SSD-55) (Figure ), which are mainly attributed to the multi-phase chemistry from the precursor gases. , In addition, relatively higher nss-SO 4 2– (2.9 ± 1.4 μg m –3 and 3.6 ± 3.2 μg m –3 in SSD-40 and SSD-55, respectively) and NO 3 – (2.8 ± 0.6 μg m –3 and 4.3 ± 5.2 μg m –3 in SSD-40 and SSD-55, respectively) are observed in NCOT as compared to other transects. Chowdhury et al have recently reported a significant north–south gradient in primary productivity with the highest in the northern Arabian Sea (19–21°N). This is mainly related to the enhanced productivity associated with shallower mixed layer depth and positive Ekman pumping .…”

“…Chowdhury et al have recently reported a significant north–south gradient in primary productivity with the highest in the northern Arabian Sea (19–21°N). This is mainly related to the enhanced productivity associated with shallower mixed layer depth and positive Ekman pumping . These different environmental parameters can lead to high nutrient concentrations in the surface waters of the northern Arabian Sea and can significantly lead to higher biogenic emission that can contribute sulfate, nitrate, and ammonium abundances in the aerosols.…”

Biogeographical Classification of the Global Ocean From BGC‐Argo Floats

“…As a result, and in contrast to the EQ biome, nutrient concentration within the mixed layer is the primary driver of biomass accumulation within the AR biome, as reflected by a positive relationship between [Chl a ] pz and N MLD and a negative relationship between [Chl a ] pz and iPAR NO3 (Figure 7a , Table S8 in Supporting Information S1 ). Notably, this is the opposite of the trends observed in the LCB and HCB biomes, highlighting the distinct drivers of bloom dynamics across the three biomes: detrainment and subsequent depletion of nutrients in HCB and LCB, and sustained nutrient delivery via upwelling in AR (Chowdhury et al., 2021 ; Cullen et al., 2002 ). Shoaling of the MLD during the intermonsoon results in a rapid depletion of nitrate near the surface, accompanied by the formation of a DCM, and increases in iPAR NO3 (Mccreary et al., 1996 ; Prasanth et al., 2021 ; Ravichandran et al., 2012 ).…”

A Regional Review of Marine and Coastal Impacts of Climate Change on the ROPME Sea Area

“…There is great natural variability in the composition, distribution and productivity of phytoplankton across seasons and between the subregions of the RSA. Within the I-RSA, there is also a marked gradient in terms of phytoplankton communities from those influenced by the freshwater outflow from the Shatt Al-Arab estuary in the north to those nearer the Strait of Hormuz [13,[77][78][79][80][81]. In the O-RSA, primary productivity is governed mainly by the strength and timing of the upwelling, and some projections of primary productivity show increases at a decadal scale, linked to an enhanced upwelling from stronger wind activity [13,82].…”

“…In the I-RSA, on the other hand, iron fertilization through dust deposition is likely a regulating factor for phytoplankton growth and composition [13,80]. Large-scale, long-term changes in phytoplankton community structure and in primary productivity in the RSA would have cascade effects throughout the entire marine food web, but natural variability and a lack of high-resolution data mean that future projections carry considerable uncertainty, and more research is needed to better understand current and future changes [30,74,78,79,81,83,84].…”