Picoeukaryote distribution in relation to nitrate uptake in the oceanic nitracline

Painter, Stuart C.; Patey, Matthew D.; Tarran, Glen A.; Torres-Valdés, Sinhue

doi:10.3354/ame01695

Cited by 25 publications

(21 citation statements)

References 105 publications

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“…Differences in relative abundances of phytoplankton groups between Z u and Z l showed a clear two-tiered vertical niche partition, with Prochlorococcus and Synechococcus reaching maximum abundances in the Z u and PPE achieving maximum abundances in the Z l . This vertical distribution has been well documented in other regions, and is thought to be characteristic of highly stratified oligotrophic systems (Dore et al, 2008;Painter et al, 2014;Partensky et al, 1996). Based on estimates from HPLC data, larger organisms such as diatoms and dinoflagellates were present in very low abundance along the transect, in comparison to small-sized phytoplankton.…”

Section: Distribution Of Pigments and Photo Acclimation In Different mentioning

confidence: 52%

Microbial community structure in the western tropical South Pacific

2018

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Abstract. Oligotrophic regions play a central role in global biogeochemical cycles, with microbial communities in these areas representing an important term in global carbon budgets. While the general structure of microbial communities has been well documented in the global ocean, some remote regions such as the western tropical South Pacific (WTSP) remain fundamentally unexplored. Moreover, the biotic and abiotic factors constraining microbial abundances and distribution remain not well resolved. In this study, we quantified the spatial (vertical and horizontal) distribution of major microbial plankton groups along a transect through the WTSP during the austral summer of 2015, capturing important autotrophic and heterotrophic assemblages including cytometrically determined abundances of non-pigmented protists (also called flagellates). Using environmental parameters (e.g., nutrients and light availability) as well as statistical analyses, we estimated the role of bottom-up and top-down controls in constraining the structure of the WTSP microbial communities in biogeochemically distinct regions. At the most general level, we found a "typical tropical structure", characterized by a shallow mixed layer, a clear deep chlorophyll maximum at all sampling sites, and a deep nitracline. Prochlorococcus was especially abundant along the transect, accounting for 68 ± 10.6 % of depth-integrated phytoplankton biomass. Despite their relatively low abundances, picophytoeukaryotes (PPE) accounted for up to 26 ± 11.6 % of depth-integrated phytoplankton biomass, while Synechococcus accounted for only 6 ± 6.9 %. Our results show that the microbial community structure of the WTSP is typical of highly stratified regions, and underline the significant contribution to total biomass by PPE populations. Strong relationships between N 2 fixation rates and plankton abundances demonstrate the central role of N 2 fixation in regulating ecosystem processes in the WTSP, while comparative analyses of abundance data suggest microbial community structure to be increasingly regulated by bottom-up processes under nutrient limitation, possibly in response to shifts in abundances of high nucleic acid bacteria (HNA).

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Section: Distribution Of Pigments and Photo Acclimation In Different mentioning

confidence: 52%

Microbial community structure in the western tropical South Pacific

2018

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“…The close relationship between DCM layers and picoeukaryote abundance reported here has been previously described at the western boundary of the southern Atlantic Gyre (Zubkov et al, 2000) and close to its center (Tarran, Heywood & and, 2006). Painter et al (2014) observed maximum picoeukaryote abundance coinciding with maximum NO 3 uptake rates, near the nitracline, which indicate that these populations may be major players for production in the deeper layers of the euphotic zone, fueling the downward flux of carbon to the ocean interior through the formation of aggregates (Lomas & Moran, 2011). This dominance at the DCM could be linked to their better adaptation to low light levels compared to larger phytoplankton and Synechococcus (Worden & Not, 2008).…”

Section: Discussionmentioning

confidence: 92%

Pico and nanoplankton abundance and carbon stocks along the Brazilian Bight

Ribeiro

Santos

Marie

et al. 2016

PeerJ

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Pico and nanoplankton communities from the Southwest Atlantic Ocean along the Brazilian Bight are poorly described. The hydrography in this region is dominated by a complex system of layered water masses, which includes the warm and oligotrophic Tropical Water (TW), the cold and nutrient rich South Atlantic Central Water (SACW) and the Coastal Water (CW), which have highly variable properties. In order to assess how pico- and nanoplankton communities are distributed in these different water masses, we determined by flow cytometry the abundance of heterotrophic bacteria, Prochlorococcus, Synechococcus and autotrophic pico and nanoeukaryotes along three transects, extending from 23°S to 31°S and 39°W to 49°W. Heterotrophic bacteria (including archaea, maximum of 1.5 × 106 cells mL−1) were most abundant in Coastal and Tropical Water whereas Prochlorococcus was most abundant in open-ocean oligotrophic waters (maximum of 300 × 103 cells mL−1). Synechococcus(up to 81 × 103 cells mL−1), as well as autotrophic pico and nanoeukaryotes seemed to benefit from the influx of nutrient-rich waters near the continental slope. Autotrophic pico and nanoeukaryotes were also abundant in deep chlorophyll maximum (DCM) layers from offshore waters, and their highest abundances were 20 × 103 cells mL−1 and 5 × 103 cells mL−1, respectively. These data are consistent with previous observations in other marine areas where Synechococcus and autotrophic eukaryotes dominate mesotrophic waters, whereas Prochlorococcus dominate in more oligotrophic areas. Regardless of the microbial community structure near the surface, the carbon stock dominance by autotrophic picoeukaryotes near the DCM is possibly linked to vertical mixing of oligotrophic surface waters with the nutrient-rich SACW and their tolerance to lower light levels.

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“…The works by Fawcett et al (2011Fawcett et al ( , 2014 and Painter et al (2014), all conducted in the subtropical North Atlantic, provide evidence that PPE derive a significant fraction of their cellular nitrogen demand via assimilation of nitrate. However, it is not clear how applicable these results are to plankton nutritional dynamics at Station ALOHA in the subtropical North Pacific.…”

Section: Discussionmentioning

confidence: 99%