Phytoplankton community structure is governed by salinity gradient and nutrient composition in the tropical estuarine system

Bharathi, M.D.; Venkataramana, V.; Sarma, V. V. S. S.

doi:10.1016/j.csr.2021.104643

Cited by 27 publications

(13 citation statements)

References 53 publications

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“…Groups other than diatoms and cyanobacteria mainly consisted of freshwater species that may have been osmotically stressed due to increasing salinity. Similar results have been found in other TFZs, such as the Youngsan estuary (Sin et al, 2015), Neva estuary (Golubkov et al, 2021), Pen Lann estuary (Bormans et al, 2020), and Indian tropical estuaries (Bharathi et al, 2022). Diatoms and cyanobacteria showed greater salt tolerance and wider salinity ranges than other groups (Cloern & Dufford, 2005;Lemley et al, 2019) because of their strong physiological modulation response to osmotic stress (Helliwell et al, 2021;Singh et al, 2022).…”

Section: Environmental Drivers Of Phytoplankton Variationsupporting

confidence: 84%

“…The phytoplankton community in TFZ is regulated by strong and highly variable gradients in physical properties. These include riverine inflow, consisting of runoff and sediment inputs (Sin & Lee, 2020; Valdes‐Weaver et al., 2006); upstream and downstream advection of algae (Bormans et al., 2019; Muylaert & Sabbe, 1999; Qin & Shen, 2017); salinity and residence time, regulated by freshwater flow and tide (Bukaveckas et al., 2018; Muylaert et al., 2000; Stumpner et al., 2020); and turbulence and sedimentation, including suspended particulate matter (SPM) and Secchi depth (SD) (transparency) associated with light availability (Bharathi et al., 2022; Cloern, 1987; Cole et al., 1992). These properties all vary according to estuarine geography.…”

Section: Introductionmentioning

confidence: 99%

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Physical Drivers of Monthly Variation in Phytoplankton Community in the Tidal Freshwater Zone of the Macrotidal Qiantang River Estuary, Eastern China: Implications for Reducing the Risk of Harmful Cyanobacterial Blooms

Jiang

Zhu

et al. 2023

JGR Oceans

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The Qiantang river estuary flows into Hangzhou Bay, on the East China Sea, and has one of the largest tidal bores worldwide. The tidal freshwater zone (TFZ) in this shallow macrotidal estuary is subjected to strong riverine and marine forcings. We investigated monthly variation of phytoplankton and environmental drivers in the upper and lower sections of TFZ during 2016. Large numbers of phytoplankton taxa (422) and genera (161) were identified. Diatoms were dominant in most months, but cyanobacteria abundance reached its greatest in warm months when runoff was low. Surprisingly, relatively high dominances of marine diatom species (e.g., Cyclotella stylorum, Skeletonema, and Thalassiosira) were observed in the TFZ with salinities usually <1 PSU. Microcystis contributed up to 50% to phytoplankton abundance in the upper TFZ in September, consistent with upstream bloom events. Abundances of phytoplankton and cyanobacteria were significantly negatively correlated with monthly runoff and sediment fluxes. Generalized additive models suggested that variation in phytoplankton abundance was largely explained by river flow, temperature and nutrients. Phytoplankton community composition varied significantly across different months and sections. Redundancy analysis indicated that temperature and flow rate explained more variation in phytoplankton community than other variables, but nutrients, Secchi depth and salinity also contributed significantly to the explained variation. Variance partitioning analysis confirmed that phytoplankton variation was largely regulated by physical variables rather than nutrients. These findings highlight the unexpectedly great phytoplankton species richness, dominance of marine diatoms, and physical drivers in the eutrophic macrotidal TFZ under strong tidal forcing.

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Section: Environmental Drivers Of Phytoplankton Variationsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Physical Drivers of Monthly Variation in Phytoplankton Community in the Tidal Freshwater Zone of the Macrotidal Qiantang River Estuary, Eastern China: Implications for Reducing the Risk of Harmful Cyanobacterial Blooms

Jiang

Zhu

et al. 2023

JGR Oceans

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“…The S of seawater, like temperature and pressure, is a basic parameter for studying the physical and chemical processes of seawater and has an impact on the changes in its biogeochemical properties, such as nutrient distribution and primary production (Bharathi et al, 2022;Howarth et al, 2011). The variations of TN and TP concentrations significantly decreased with increasing S in the PRE (Figure 7).…”

Section: Mixed Behaviours Of Tn and Tp Concentrations In The Prementioning

confidence: 99%

Effects of river input flux on spatiotemporal patterns of total nitrogen and phosphorus in the Pearl River Estuary, China

et al. 2023

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The increasing riverine nutrient sources have significantly affected the ecological environment of estuaries and coastal waters, resulting in deteriorating land-sea water quality and intensified eutrophication. However, the effects of river input flux on spatiotemporal patterns of total nitrogen (TN) and total phosphorus (TP) were poorly understood in the Pearl River Estuary (PRE). In this study, the spatiotemporal patterns of TN and TP concentrations and river input flux of PRE were studied based on the seasonal nutrients monitoring data obtained for the rivers and estuary in 2019. The results showed the spatiotemporal patterns of the TN and TP concentrations in the eight rivers of the PRE were different, and the annual average concentrations of TN and TP in the rivers entering the PRE were 207.18 ± 105.13 and 3.51 ± 1.70 μmol/L, respectively. The annual river TN and TP fluxes discharged into the PRE were 8.61 × 1010 and 1.55 × 109 mol/year, respectively. In addition, the significantly decreasing trends in of TN and TP concentrations from upper estuary to offshore seawater were observed in the PRE, which implied TN and TP showed conservative behaviour in all season and only the dry season, respectively. Moreover, the annual average concentrations of TN and TP in the estuary were 70.64 ± 10.10 and 1.67 ± 0.78 μmol/L, respectively. The annual average ratios of TN/TP for rivers, freshwater, mixed and seawater were 59.31 ± 5.98, 59.45 ± 3.75, 45.73 ± 21.27 and 330.94 ± 434.71 respectively, which were higher than the Redfield ratios. These results indicated that the water quality in most areas of the PRE is significantly polluted and that the TN and TP in seawater were significantly influenced by river inputs. Therefore, monitoring and management of unified TN and TP nutrient indicators discharge from rivers entering the sea can be strengthened in the PRE, and eutrophication mitigation strategy should be established and implemented across river-estuary-coast continuum systems in the Great Bay Area.

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“…Without considering the impact of noise, model (1) degenerates into a deterministic one. Then the equilibria for the deterministic model is E 0 (0, 0), E 1 (P 1 , 0), E * (P * , Z * ), where…”

Section: Stochastic Analysis Of the Modelmentioning

confidence: 99%

“…Phytoplankton are tiny floating plants, usually single-celled algae, which sit at the bottom of the food chain and thus support secondary and tertiary productivity in the ocean [1][2][3]. As the major primary producers in the marine ecosystem, phytoplankton are not only a basic food source for zooplankton, but also provide large amounts of oxygen for humans and other animals after absorbing nearly half of the universal carbon dioxide through photosynthesis [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Stationary Probability Density Analysis for the Randomly Forced Phytoplankton–Zooplankton Model with Correlated Colored Noises

2022

Mathematics

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In this paper, we propose a stochastic phytoplankton–zooplankton model driven by correlated colored noises, which contains both anthropogenic and natural toxins. Using Khasminskii transformation and the stochastic averaging method, we first transform the original system into an Itô diffusion system. Afterwards, we derive the stationary probability density of the averaging amplitude equation by utilizing the corresponding Fokker–Planck–Kolmogorov equation. Then, the stability of the averaging amplitude is studied and the joint probability density of the original two-dimensional system is given. Finally, the theoretical results are verified by numerical simulations, and the effects of noise characteristics and toxins on system dynamics are further illustrated.

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Phytoplankton community structure is governed by salinity gradient and nutrient composition in the tropical estuarine system

Cited by 27 publications

References 53 publications

Physical Drivers of Monthly Variation in Phytoplankton Community in the Tidal Freshwater Zone of the Macrotidal Qiantang River Estuary, Eastern China: Implications for Reducing the Risk of Harmful Cyanobacterial Blooms

Physical Drivers of Monthly Variation in Phytoplankton Community in the Tidal Freshwater Zone of the Macrotidal Qiantang River Estuary, Eastern China: Implications for Reducing the Risk of Harmful Cyanobacterial Blooms

Effects of river input flux on spatiotemporal patterns of total nitrogen and phosphorus in the Pearl River Estuary, China

Stationary Probability Density Analysis for the Randomly Forced Phytoplankton–Zooplankton Model with Correlated Colored Noises

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