Distribution Of Picophytoplankton Research Articles

Distribution of picophytoplankton in the northern slope of the South China Sea under environmental variation induced by a warm eddy

Mesoscale eddies have been reported to have a substantial impact on the distribution of phytoplankton through the regulation of environmental variables in the open ocean. However, the influence of warm eddies on phytoplankton in continental slopes remains largely unknown. To reveal the impact of mesoscale eddies within slope regions, we conducted a field investigation of picophytoplankton on the northern slope of the South China Sea during an anticyclonic warm eddy propagation. We observed different picophytoplankton distribution patterns. Synechococcus dominated the picophytoplankton community in the Kuroshio-affected eddy core rather than the previously reported Prochlorococcus, and Prochlorococcus dominated outside the eddy in the shelf. In addition, through further vertical study of typical layers, we found that the influence of warm eddy varied in different layers. Analysis of the mechanisms indicated that the distributions were attributed to warm eddy-induced nutrients and light variations and the physical processes in it.

Water column stratification governs picophytoplankton community structure in the oligotrophic eastern Indian ocean

Under the background of global warming, the area extent of the oligotrophic tropical oceans has growing due to increased water-column stratification over the past decades. Picophytoplankton is usually the most dominant phytoplankton group in oligotrophic tropical oceans and substantially contribute to carbon biomass and primary production three. Understanding how vertical stratification governs the community structure of picophytoplankton communities in oligotrophic tropical oceans is important for comprehensively understanding the plankton ecology and biogeochemical cycle in these areas. In this study, the distribution of the picophytoplankton communities in the eastern Indian Ocean (EIO) was investigated during a period of thermal stratification in the spring of 2021. Prochlorococcus contributed most (54.9%) to picophytoplankton carbon biomass, followed by picoeukaryotes (38.5%) and Synechococcus (6.6%). Vertically, the three picophytoplankton groups showed quite different distribution pattern: the abundance of Synechococcus was highest in the surface layer, while Prochlorococcus and picoeukaryotes were usually located between 50 m and 100 m. The relationship between the abundance of picophytoplankton and environmental factors was analyzed, and the results revealed that picophytoplankton distribution was strongly correlated with the degree of vertical stratification of the water column. The density of Synechococcus was higher in strongly stratified waters, while Prochlorococcus was more abundant in regions of weaker stratification. This is mainly attributed to variation of physicochemical parameters such as nutrient structures and temperature resulted from water column stratification. Understanding the distribution patterns of these organisms and their relationship with stratification in the oligotrophic EIO is essential for comprehensive understanding on oligotrophic tropical ecosystem with increasing stratification in future.

Vertical distribution of picophytoplankton in the NW shelf and deep-water area of the Black Sea in spring

Structure and functions of picophytoplankton and their links to the water column density stratification and nutrient vertical profiles were studied in the Black Sea open waters along a transect from the Western Gyre to the NW shelf during spring homothermy in April of 2017. Abundances of picocyanobacteria of the genus Synechococcus (0.85 ± 0.96 (SD) × 10 3 cells ml −1 ) and eukaryotic picoalgae (5.74 ± 5.99 × 10 3 cells ml −1 ) and their intracellular pigment (chl a , phycoerythrin) contents were quantified using flow cytometry. The distribution of these variables in the upper 100-m layer was non-uniform. Along the whole transect, Synechococcus and picoeukaryote abundance maxima (up to 4 × 10 3 and 3 × 10 4 cells ml −1 , respectively) were observed at the water temperature of 8–8.5°С in the depth range between 30 and 40 m. Picoeukaryotes dominated the total community. The share of Synecococcus averaged about 22% and increased with depth up to 80%. Picophytoplankton abundance dropped abruptly through the oxycline but the cells were found in the suboxic layer at about 10 3 cells ml −1 and in a sample from the anoxic zone at 10 2 cells ml −1 . Intracellular chl a maxima were revealed in the nitrate peak at sigma- t density of 15.5. In the surface and suboxic layers, non-specific green autofluorescence (GAF) was detected in picophytoplankton cells that might provide evidence of their stress state in adverse environment. Multivariate analysis has revealed tight coupling between abiotic and microbiological variables in three statistically distinct pelagic regions of the transect, corresponding to the abyss, the continental slope and the shelf. • Picoeukaryotes dominated picophytoplankton but the proportion of Synecococcus increased with depth. • Picophytoplankton abundance dropped abruptly through oxycline but still survived in suboxic layer. • Non-specific green autofluorescence (GAF) was detected in picophytoplankton by flow cytometry. • Picophytoplankton GAF maxima were revealed in surface and suboxic layers, indicating stress conditions.

Size-Fractionated Filtration Combined with Molecular Methods Reveals the Size and Diversity of Picophytoplankton.

Simple SummaryIn order to accurately characterize the composition of the picophytoplankton community by size in the marine environment, we used a size-fractionated filtration plus a high-throughput sequencing molecular method. The results showed that this method can detect the composition of picophytoplankton in different particle size ranges in detail, and it is accurate in assessing the vertical distribution patterns and size of phytoplankton. This method can enrich the study of phytoplankton communities with diameters of less than 2 μm.In this study, flow cytometry (FCM) and size-fractionated filtration, together with high-throughput molecular sequencing methods (SM), were used to investigate picophytoplankton. A particle separation filter and a higher-throughput sequencing method were used to evaluate the composition of a euphotic zone of picophytoplankton—especially picoeukaryotic phytoplankton—in the Western Pacific, and the results of flow cytometry, which is a classic way to detect picophytoplankton, were used as a standard to evaluate the reliability of the results of the SMs. Within a water column of 200 m, six water depths (5, 25, 50, 113 (DCM), 150, and 200 m) were established. In order to further study the particle size spectra of the picophytoplankton, size-fractionated filtration was used to separate water samples from each water depth into three particle size ranges: 0.2–0.6, 0.6–1.2, and 1.2–2 μm. A total of 36 (6 × 3 × 2) samples were obtained through PCR amplification of the 18S rRNA V4 hypervariable region and 16S rRNA, which were biased toward phytoplankton plastids, and then high-throughput sequencing was performed. The estimation of the picophytoplankton diameter relied on forward scattering (FSC) through FCM. The estimation of the vertical distribution and diameter of the picophytoplankton using the SM was consistent with the results with FCM; thus, we believe that the estimation of picophytoplankton composition with the SM has value as a reference, although the size-fractionated filtration seemed to cause some deviations. In addition to Prochlorococcus and Synechococcus, the SM was used to evaluate the composition of picoeukaryotic phytoplankton, which mainly included Prymnesiophycea (Haptophyta) (38.15%), Cryptophyceae (Cryptophyta) (22.36%), Dictyochophyceae (Chrysophyta) (12.22%), and Mamiellophyceae (Chlorophyta) (3.31%). In addition, the SM also detected Dinophyceae (Dinoflagellata) (11.69%) sequences and a small number of Bacillariophyceae (Diatom) (1.64%) sequences, which are generally considered to have large particle sizes. The results of the SM also showed that the picoeukaryotic phytoplankton were not evenly distributed in the euphotic layer, and the vertical distributions of the different picoeukaryotic phytoplankton were different. An analysis of correlations with environmental factors showed that temperature was the main environmental factor controlling the vertical distribution of picophytoplankton.

Spatial Distribution of Picophytoplankton in Southeastern Coast of Peninsular Malaysia Using Flow Cytometry

The distribution of picocyanobacteria from two genera, Synechococcus and Prochlorococcus, and picoeukaryotes in surface water (0.5 m) was investigated by flow cytometry in the southeastern coast of Peninsular Malaysia during the Southwest monsoon in August 2014. During the cruise, Synechococcus cells were predominant throughout the study area, contributing as much as 50% to the total picophytoplankton population, whereas picoeukaryotes and Prochlorococcus constituted only 31% and 19% of the population, respectively. Spatially, Synechococcus and picoeukaryotes were more dominant in coastal waters, while Prochlorococcus appeared to be more highly abundant in offshore waters. Furthermore, the percentage contribution of each population to total picophytoplankton also exhibited different spatial distribution patterns along a coastal-offshore gradient. The percentage contribution of Synechococcus was spatially constant throughout the study area, while the fraction contributed by picoeukaryotes showed a reduced contribution from coastal to offshore waters. In contrast, Prochlorococcus exhibited an increased proportion to total picophytoplankton across a coastal-offshore gradient, suggesting the increasing importance of this population in offshore waters of the study area. As revealed by Canonical Correlation Analysis, the abundance of Synechococcus and picoeukaryotes increased significantly with reducing dissolved oxygen levels and pH, and with increasing total chlorophyll. In contrast, temperature was the only factor influencing the abundance of Prochlorococcus significantly increased with decreasing water temperature in the study area. Overall, results of the present study provide valuable information on the role of regional environmental factors in the distribution and dominance of picophytoplankton communities that are not only critical for the ocean productivity but also the impact on the carbon cycle in the study area.

Picophytoplankton distribution along Khatanga Bay-shelf-continental slope environment gradients in the western Laptev Sea

The spatial variations of photosynthetic picoplankton abundance and biomass and the picoplankton's contribution to chlorophyll a concentration along the transect from Khatanga Bay to the continental slope in the western part of the Laptev Sea were studied in September 2017. Picoeukaryotes dominated in the picophytoplankton communities. Picophytoplankton in Khatanga Bay showed more variability than those over the Laptev shelf and continental slope: abundance and biomass were the highest in the southern part of the bay and markedly decreased with increasing salinity in its northern part. Picocyanobacteria were found over the shelf and slope at temperatures of +2.4 to -1.6°С and salinity from 22 to 34. Picophytoplankton contribution to total chlorophyll a on the shelf was higher than in Khatanga Bay. The study of picophytoplankton of Khatanga Bay and in the western Laptev Sea can serve as a baseline for future assessment of the Laptev Sea ecosystem response to interannual and climate changes.

A machine-learning approach to modeling picophytoplankton abundances in the South China Sea

Picophytoplankton, the smallest phytoplankton (<3 µm), contribute significantly to primary production in the oligotrophic South China Sea. To improve our ability to predict picophytoplankton abundances in the South China Sea and infer the underlying mechanisms, we compared four machine learning algorithms to estimate the horizontal and vertical distributions of picophytoplankton abundances. The inputs of the algorithms include spatiotemporal (longitude, latitude, sampling depth and date) and environmental variables (sea surface temperature, chlorophyll, and light). The algorithms were fit to a dataset of 2442 samples collected from 2006 to 2012. We find that the Boosted Regression Trees (BRT) gives the best prediction performance with R2 ranging from 77% to 85% for Chl a concentration and abundances of three picophytoplankton groups. The model outputs confirm that temperature and light play important roles in affecting picophytoplankton distribution. Prochlorococcus, Synechococcus, and picoeukaryotes show decreasing preference to oligotrophy. These insights are reflected in the vertical patterns of Chl a and picoeukaryotes that form subsurface maximal layers in summer and spring, contrasting with those of Prochlorococcus and Synechococcus that are most abundant at surface. Our forecasts suggest that, under the “business-as-usual” scenario, total Chl a will decrease but Prochlorococcus abundances will increase significantly to the end of this century. Synechococcus abundances will also increase, but the trend is only significant in coastal waters. Our study has advanced the ability of predicting picophytoplankton abundances in the South China Sea and suggests that BRT is a useful machine learning technique for modelling plankton distribution.

Picophytoplankton distribution at the Ob section and in western part of the Kara sea

The spatial distribution of picophytoplankton abundance, biomass, chlorophyll a and contribution of picoalgae to total chlorophyll a was studied in the outer Ob estuary with an adjacent shelf and in the western part of the Kara Sea. In August-September picophytoplankton abundance and biomass varied from 0.1 to 17.3106 cell/l and from 0.06 to 9.20 mg С/m3, respectively. Cyanobacteria dominated in plankton picofraction, its contribution to total picophytoplankton biomass did not exceed 11%. The highest contribution of picophytoplankton to the total phytoplankton abundance was observed at a lower (11 mg/m2) chlorophyll a concentration in the euphotic layer. The spatial heterogeneity of picoforms contribution was determined by the silicon concentration.

Picophytoplankton Distribution at the Ob River Section and in the Western Part of the Kara Sea

The spatial distribution of picophytoplankton abundance, biomass, chlorophyll a and the contribution of picoalgae to the total chlorophyll a was studied in the outer Ob River estuary with the adjacent shelf and in the western part of the Kara Sea. In August–September, the picophytoplankton abundance and biomass varied from 0.1 to 17.3 × 106 cell/L and from 0.06 to 9.20 mg С/m3, respectively. Photosynthetic picoeukaryotes dominated in the plankton picofraction; the contribution of cyanobacteria to the total picophytoplankton biomass did not exceed 11%. The highest contribution of picophytoplankton to the total phytoplankton abundance was observed at a lower (<11 mg/m2) euphotic zone integrated chlorophyll a. The spatial heterogeneity of picoforms contribution was determined by the silicon concentration.

Spatial Distribution of Picophytoplankton in the White Sea in the Beginning of Summer

Biomass of photosynthetic picoplankton (Bpic), its contribution to the total phytoplankton biomass (Bpic%), chlorophyll a concentration (Chl), and associated hydrophysical characteristics of the water masses in the White Sea were estimated in June 2015 at 47 stations located in the open parts and in the inlets of the Onega and Kandalaksha Bays and in the western part of the Basin. Spatial variability of mean values of Bpic in the photic layer (0.01–1.91 mg C/m3) was preconditioned by sub- and mesoscale heterogeneity of the hydrological conditions. The values of Bpic were higher near the frontal zones than those in the water masses characterized by quasi-homogeneous distribution of the thermohaline characteristics. The relative contribution of Bpic did not exceed 1% at half of the stations and varied from 1 to 8% for the rest of the studied water area. The value of Bpic% reached 40.5% in the Basin and did not exceed 2% during the phytoplankton bloom in Knyazhaya Inlet (Chl > 3 mg/m3) accompanied by the dominance of Skeletonema costatum sensu lato.

Responses of the picophytoplankton community to temperature fronts in the northeastern Arabian Sea during the northeast monsoon

We investigated the responses of the picophytoplankton (< 3 µm) community to a temperature filament and front through high resolution spatial (~ 1 NM) sampling (November-23 to December-11, 2012) in the northeastern Arabian Sea (69°E, 18.85°N to 20.25°N). Samples were collected at discrete depths within the 100 m water column. Synechococcus dominated the picophytoplankton community numerically and in terms of biomass along the entire transect. To investigate the patterns of variability in picophytoplankton distribution, depending on the water mass characteristics, the entire transect was divided into four zones (1) south of filament (SFIL) with warm oligotrophic waters, (2) filament (FIL) with cooler and low saline waters, (3) north of filament (NFIL) with relatively cooler waters than the SFIL and (4) front (FRO) with relatively cooler and less saline waters than the FIL. Depth-integrated abundance and biomass of Synechococcus were relatively higher within the FIL and FRO whereas Prochlorococcus and picoeukaryotes were abundant in SFIL and NFIL. Redundancy analysis of environmental variables and picophytoplankton abundance showed that lower saline water mass within the mesoscale features harbored relatively higher Synechococcus abundance and biomass. Two Synechococcus ecotypes were distinguished based on the fluorescence intensity of the accessory pigment, phycoerythrin; the one with higher intensity (open ocean ecotype) dominating in the FIL and the other with lower intensity in the FRO (coastal ecotype). The relatively lower saline surface water mass at the FRO, probably a result of coastal advection, could have introduced the latter ecotype. Vertically, a positive correlation of Prochlorococcus with nutrients and Synechococcus with temperature corroborates their higher and lower abundance and biomass, respectively in the deeper waters. The positive correlation of Synechococcus with the total chlorophyll biomass indicates a similar response to environmental variables within the mesoscale features. This study shows that picophytoplankton contribution (16–24%) to the total phytoplankton carbon biomass in tropical mesoscale features is likely to have important consequences on the planktonic food web function.

Picoplankton distribution influenced by thermohaline circulation in the southern Adriatic

In this study, we focus on the interactive dynamics between physico-chemical processes and picoplankton distribution in order to advance our current understanding of the roles of various parameters in regulating picoplankton community structure in highly dynamic marine system such as the South Adriatic Sea. The research was carried out between October 2011 and September 2012 along the transect in the northern part of the South Adriatic Pit. The deep water convection occurred in the southern Adriatic during February 2012, with vertical mixing reaching the depth of 500 m. The picoplankton community was highly affected by this mixing event, whilst its compartments each responded differently. During deep water convection low nucleic acid heterotrophic bacteria (LNA HB) and Synechococcus had their lowest abundances (4 × 105 cell ml−1 and 8 × 102 cell ml−1, respectively), picoeucaryotes had their highest abundances (104 cell ml−1), while Prochlorococcus was absent from the area, most likely due to intense cooling and vertical mixing. In March 2012 Eastern Adriatic Current (EAC) brought warm and saline water with more nutrients, which resulted in the proliferation of high nucleic acid heterotrophic bacteria (HNA HB), having maximal abundance (4 × 105 cell ml−1). The re-establishment of Levantine Intermediate Water (LIW) intrusion after the deep water convection resulted in the re-appearance of Prochlorococcus and maximal abundances of Synechococcus (4 × 104 cell ml−1) in May 2012. The distribution of picoheterotrophs was mainly explained by the season, while the distribution of picophytoplankton was explained by the depth. Aside from nutrients, salinity was an important parameter, affecting particularly Prochlorococcus. The re-appearance of Prochlorococcus in the southern Adriatic during the period of LIW intrusion, together with their correlation with salinity, indicates their potential association with LIW. The relationship between Prochloroccocus distribution and physico-chemical environmental parameters provides an important insight into the ecological roles and niche preferences of this group.

Seasonal variability of picophytoplankton under contrasting environments in northern Tunisian coasts, southwestern Mediterranean Sea

We investigated at the single cell level during 16months (June 2012 to September 2013) the temporal distribution of picophytoplankton (picoeukaryotes, Synechococcus and Prochlorococcus) communities in two contrasted ecosystems: the Bay of Bizerte characterised by an oligotrophic regime typical of the Mediterranean Sea and the Bizerte Lagoon that exhibits a mesotrophic/eutrophic state. We aimed at depicting seasonal variations and quantifying the relationships between the environmental factors and the structure and abundance of picophytoplankton communities. Results showed that picophytoplankton groups were able to grow under a wide range of environmental conditions varying seasonally, although their abundances and contributions to the total chlorophyll biomass significantly varied and showed importance in the Bay of Bizerte. Synechococcus was the most abundant group reaching 225∗103cells·cm−3 in the Bay and 278∗103cells·cm−3 in the lagoon. This group was present all over the year in both ecosystems. Structural equation model results pointed out a different configuration regarding the picophytoplankton environmental drivers. The complexity of the configuration, i.e. number of significant links within the system, decreased under enhanced eutrophication conditions. The less exposure to anthropogenic stress, i.e. in the Bay of Bizerte, highlight a larger role of nutrient and hydrological conditions on the seasonal variations of picophytoplankton, whereas a negative effect of eutrophication on picophytoplankton communities was unveiled in the Bizerte Lagoon. We stress that such influence may be exacerbated under expected scenarios of Mediterranean warming conditions and nutrient release in coastal ecosystems.

Abundance and Biogeography of Picoprasinophyte Ecotypes and Other Phytoplankton in the Eastern North Pacific Ocean.

Eukaryotic algae within the picoplankton size class (≤2 μm in diameter) are important marine primary producers, but their spatial and ecological distributions are not well characterized. Here, we studied three picoeukaryotic prasinophyte genera and their cyanobacterial counterparts, Prochlorococcus and Synechococcus, during two cruises along a North Pacific transect characterized by different ecological regimes. Picoeukaryotes and Synechococcus reached maximum abundances of 1.44 × 10(5) and 3.37 × 10(5) cells · ml(-1), respectively, in mesotrophic waters, while Prochlorococcus reached 1.95 × 10(5) cells · ml(-1) in the oligotrophic ocean. Of the picoeukaryotes, Bathycoccus was present at all stations in both cruises, reaching 21,368 ± 327 18S rRNA gene copies · ml(-1). Micromonas and Ostreococcus clade OI were detected only in mesotrophic and coastal waters and Ostreococcus clade OII only in the oligotrophic ocean. To resolve proposed Bathycoccus ecotypes, we established genetic distances for 1,104 marker genes using targeted metagenomes and the Bathycoccus prasinos genome. The analysis was anchored in comparative genome analysis of three Ostreococcus species for which physiological and environmental data are available to facilitate data interpretation. We established that two Bathycoccus ecotypes exist, named here BI (represented by coastal isolate Bathycoccus prasinos) and BII. These share 82% ± 6% nucleotide identity across homologs, while the Ostreococcus spp. share 75% ± 8%. We developed and applied an analysis of ecomarkers to metatranscriptomes sequenced here and published -omics data from the same region. The results indicated that the Bathycoccus ecotypes cooccur more often than Ostreococcus clades OI and OII do. Exploratory analyses of relative transcript abundances suggest that Bathycoccus NRT2.1 and AMT2.2 are high-affinity NO3 (-) and low-affinity NH4 (+) transporters, respectively, with close homologs in multiple picoprasinophytes. Additionally, in the open ocean, where dissolved iron concentrations were low (0.08 nM), there appeared to be a shift to the use of nickel superoxide dismutases (SODs) from Mn/Fe/Cu SODs closer inshore. Our study documents the distribution of picophytoplankton along a North Pacific ecological gradient and offers new concepts and techniques for investigating their biogeography.

冬季南海南部微微型浮游植物分布及其影响因素

冬季南海南部微微型浮游植物分布及其影响因素

Ecophysiology of picophytoplankton in different water masses of the northern Bering Sea

Picophytoplankton are important primary producers in oligotrophic waters and sensitive to environmental changes. However, little is known about their ecophysiology in the northern Bering Sea with complex water masses. The distribution of picophytoplankton with their optical physiological features and physicochemical characteristics as well as water masses were investigated on the northern Bering Sea Shelf during the summer of 2008. Flow cytometry and statistical analysis including Pearson correlation analysis and cluster analysis were the main methods used. Synechococcus and picoeukaryotes were the primary existing picophytoplankton assemblages, with their respective abundances ranging from 0 to 2.69 × 106 and 0.47 × 106 to 13.20 × 106 cells l−1 and peaking at water depths of 10–30 m with surface light levels of 30–50 %. Larger Synechococcus cells contained larger amounts of chlorophyll a (Chl a) and phycoerythrin. Low temperature, high nutrient concentrations and a high N/P value (>7) might limit cell abundance of picoeukaryotes, as shown by their close relationships. With an increase of temperature and oligotrophic freshwater input, smaller picophytoplankton would thrive and the cellular Chl a (Chl a/cell) increase with higher contribution to total Chl a. Seven water types with different physicochemical and biological characteristics were differentiated using the mini-ecosystem (a descriptor of a composite of parameters defining a composite water type community, including temperature, salinity, macronutrients and community abundance of picophytoplankton) as an indicator. They are Alaska Coastal Water, Bering Shelf Surface Water, 20–40 m of Bering Shelf Water, Bering Shelf Cold Water, Anadyr Water, Anadyr-Bering Shelf Water (Bering Sea Water) and Cold Pool.

Effects of coastal upwelling on picophytoplankton distribution off the coast of Zhanjiang in South China Sea

Abstract Coastal upwelling occurred along the west coast of Guangdong in the northern South China Sea during the summer of 2006. The effects of upwelling on the vertical and horizontal distributions of Prochlorococcus and Synechococcus were investigated. A distinct vertical temperature difference between the surface water and water at a depth of 30 m was observed in the coastal upwelling region. There was a clear spatial variability of temperature, and an increasingly obvious horizontal gradient was created from the coast to offshore waters. Picophytoplankton communities observed from the coast to offshore waters were significantly different. In the coastal upwelling waters, the picophytoplankton community was dominated by Synechococcus within the euphotic zone. Prochlorococcus dominated the picophytoplankton community in the euphotic zone in the non-upwelling region. This difference in the picophytoplankton community structure was due to different hydrodynamics. The results of canonical correspondence analysis demonstrate that temperature, salinity, and phosphate concentration may be important factors affecting the distribution of Prochlorococcus and Synechococcus.

Influence of the physical forcing of different water masses on the spatial and temporal distributions of picophytoplankton in the northern East China Sea

To investigate the temporal–spatial distribution of picophytoplankton in relation to different water masses in the northern East China Sea (ECS), picophytoplankton abundance and biomass were investigated using flow cytometry with environmental factors in May, August, and November 2010 and February 2012. Five picophytoplankton populations, including Prochlorococcus (Pro), low and high orange fluorescence Synechococcus (Syn1 and Syn2), and small and large sized picoeukaryotes (SPEuks and LPEuks) were discriminated, and each group responded differently to the water mass distribution. Syn1 was the predominant group in the picophytoplankton abundance in all seasons, indicating ecological importance as a primary producer in the northern ECS. LPEuks was a minor group in terms of the abundance but they contributed significantly to the total picophytoplankton carbon biomass in spring and winter due to their larger size among picophytoplankton groups. Two geographical groups were distinguished in the northern ECS. One group (including Syn1 and LPEuks) was distributed mainly in the western area affected by the Changjiang discharge and Chinese coastal waters, and the other group (including Pro, Syn2, and SPEuks) dominated picophytoplankton abundance in the eastern area characterized by the Kuroshio intrusion. Pro was detected in the eastern side of the study area during each survey, except in May, indicating the possible effect of the low Kuroshio intrusion on the northern ECS in late spring. This study shows that the distributions of these picophytoplanktons are strongly influenced by the seasonal fluctuations of the Changjiang discharge and Kuroshio intrusion in the northern ECS.

盐湖微微型浮游植物多样性研究进展

PDF HTML阅读 XML下载 导出引用 引用提醒 盐湖微微型浮游植物多样性研究进展 DOI: 10.5846/stxb201303040337 作者: 作者单位: 山东江河湿地研究院,中国水利水电科学研究院 作者简介: 通讯作者: 中图分类号: 基金项目: 流域水循环模拟与调控国家重点实验室自主研究资助项目（2013ZY06）；青海省水利厅前期资助项目；山东省科技厅星火计划资助项目（2012XH11008）；山东省优秀中青年科学家科研奖励基金计划（BS2013NY015） Biodiversity and research progress on picophytoplankton in saline lakes Author: Affiliation: State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research,Beijing,State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research,Beijing Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:盐湖在地球表层分布较广，中国是世界上盐湖分布稠密的国家。尽管盐湖生态环境极端恶劣，但它们依然是陆地特别是高原生态系统中十分重要的组成部分。微微型浮游植物（Picophytoplankton）通常是指粒径在0.2-3 μm之间的光合自养型浮游生物，在这一生态类群中既有原核生物也有真核生物。微微型浮游植物不仅是海洋生态系统中生物量和生产力的最重要贡献者，也是盐湖生态系统最重要的组成部分。最近的调查数据显示，在东非Bogoria 和 Nakuru苏打盐湖中微微型浮游植物的生产力占整个浮游植物生产力的53%-68%。迄今为止，对盐湖微微型浮游植物多样性的研究多集中于盐田（Solar salterns）、盐池（Saline ponds）以及碱湖（Soda lakes）等超盐水体中；超盐盐湖中最常见的微微型浮游植物主要是蓝细菌（Cyanobacteria）类群，包括席蓝细菌属（Phormidium）、节旋藻属（Arthrospira）和隐杆藻属（Aphanothece）。分子生物学的研究显示，低碱浅水盐湖中微微型浮游植物具有丰富的多样性，主要类群是微微型原核浮游植物，还有部分种类与真核藻类质体序列高度相似。盐湖生态系统中微微型浮游植物群落结构演替变化的研究已经逐渐引起更多研究者的关注。已有的研究资料显示，水体矿化度是影响微微型浮游植物平面分布及群落结构组成的重要因子；光照、营养成分和温度等也会影响盐湖水体中微微型浮游植物平面分布及群落结构组成。综述了国内外对不同类型盐湖生态系统中微微型浮游植物多样性研究的概况，探讨了不同地理区域各种盐湖中微微型浮游植物群落结构的演替变化，并就我国未来加强盐湖中微微型浮游植物多样性构成、分布与变动及驱动变化的因子等研究提出了建议。 Abstract:Saline lakes are widely distributed on the surface of the earth, with a relatively high density of salt lakes recorded in China. Saline lakes are often productive and comprise an important part of the highland ecosystem, since they harbor many novel prokaryotic microorganisms under harsh environmental conditions. However, little research has been conducted in these systems, and understanding about the community diversity and dynamics of picophytoplankton assemblages in such environments is limited. Picophytoplankton, defined as phytoplankton with a diameter less than 0.2-3 μm and composed of both prokaryotes and eukaryotes, not only play a crucial role for primary productivity in marine ecosystems, but also in saline lake ecosystems. Recent survey data suggest that picophytoplankton contribute from 53%-68% of the productivity in the total phytoplankton community in Lake Bogoriau and Lake Nakuru in East Africa. Biodiversity research of picophytoplankton has mainly focused on hypersaline lakes, such as solar salterns, saline ponds, and soda lakes. The most dominant taxa included Arthrospira, Phormidium, and Aphanothece, known as cyanobacteria in hypersaline lakes. Molecular analyses revealed significant genetic diversity in hyposaline soda lakes. After cloning and sequencing, the results found that the majority of the retrieved sequences belonged to prokaryotic picophytoplankton, while the others showed high similarity with eukaryotic algal plastids. Research on the picophytoplankton community patterns and seasonal succession in saline lakes has been attracting the attention of more and more scientists in recent years. Total dissolved solids were identified as the predominant factor structuring the spatial distribution of picophytoplankton. Light intensity, nutrient composition, and temperature also affected the spatial distribution and community composition of picophytoplankton. In this paper, the biodiversity patterns, spatial distributions, and community succession of picophytoplankton within different geographical regions were compared and summarized through literature reviews. Our results highlight the importance of more comprehensive investigation about the diversity, distribution, and ecological role of picophytoplankton in saline lakes at the national level in China. 参考文献 相似文献 引证文献

Remote sensing of picophytoplankton distribution in the northern South China Sea

By using a global data set (NOMAD), improved algorithms were developed for deducing from ocean color remote sensing data the concentrations of phytoplankton pigments, total chlorophyll a (TChl_a), zeaxanthin (Zea) and fucoxanthin (Fuco), and the associated primary phytoplankton groups, namely, Prochlorococcus, Synechococcus, haptophytes and diatoms, in the oceans. A modified classification for the waters of the world's ocean based on the dominant phytoplankton group was then devised. By using a local data set from the northern South China Sea (NSCS), algorithms were also developed for assessing the cell abundances of picophytoplankton, Prochlorococcus, Synechococcus and pico-eukaryotes, in this region. These algorithms were then applied to the remotely sensed data from the MODerate-resolution Imaging Spectrometer at Aqua sensor (MODIS-Aqua) to study the abundances and the distributional patterns of picophytoplankton in the entire NSCS. The results agreed well with field observations, which were available only from selected locations in the study area. On a basin scale, the results were consistent with expected variations in phytoplankton pigments, phytoplankton community composition, and picophytoplankton biomass, in response to the major known environmental phenomena in the NSCS, such as the progressive increase in biological productivity towards the coast, the runoff from the Pearl River, higher biological productivity in the wintertime, upwelling around the Taiwan Bank, winter upwelling northwest of the Luzon Island, and the transformation and dissipation of internal waves off the Dongsha Atoll. This work represents the first effort in estimating the cell abundances of the principal picophytoplankton groups in the oceans from space. The general application of this approach to the global ocean needs to be further validated and calibrated with a more extensive data base from field observations in other parts of the oceans.