Phytoplankton communities determine the spatio-temporal heterogeneity of alkaline phosphatase activity: evidence from a tributary of the Three Gorges Reservoir

Abstract

In order to reveal the role of phytoplankton in the spatio-temporal distribution of alkaline phosphatase activity (APA), monthly investigations were conducted in the Xiaojiang River, a tributary of the Three Gorges Reservoir in China. Different APA fractions, environmental parameters, and phytoplankton communities were followed. High spatio-temporal variations of APA were observed, with the highest value in summer and the lowest in winter. The annual average APAT (total alkaline phosphatase activity) ranged from 7.78–14.03 nmol∙L−1∙min−1 with the highest in the midstream and the lowest in the estuary. The dominant phytoplankton phyla in summer and winter were Cyanophyta and Bacillariophyta, respectively. The mean cell density in the midstream and in the estuary was 5.2 × 107 cell∙L−1 and 1.4 × 107 cell∙L−1, respectively. That APA>3.0 μm was significantly higher than APA0.45-3 μm indicating phytoplankton was the main contributor to alkaline phosphatase. Correlation analysis indicated the dominant species and cell density could determine the distribution pattern of APA. Turbidity, total phosphorus, chemical oxygen demand, water temperature (WT), pH and chlorophyll a were proved to be positively correlated with APA; soluble reactive phosphorus, conductivity, transparency and water level(WL) were negatively correlated with APA. It was concluded that spatio-temporal heterogeneity of APA determined by phytoplankton communities was related to WT and WL.

Human activities' fingerprint on multitrophic biodiversity and ecosystem functions across a major river catchment in China

“…This unique property is associated with changes in water quality. For example, alkaline phosphatase positively correlated with turbidity, chemical oxygen demand, and chlorophyll a (Yuan et al, 2017), meaning that regions with high disturbance may have higher phosphatase activity. Our data confirm this hypothesis, and show that phosphatase activity was highest in High Agriculture/Industry region (see Table S12).…”

Coupling high frequency monitoring and bioassay experiments to investigate a harmful algal bloom in the Bay of Seine (French-English Channel)

“…Previous studies showed that other limitations, like N (Kuenzler and Perras, 1965) or Si (Fuentes et al, 2014), can lead to an increase in APA. Changes in the community structure may also influence APA (Lin et al, 2015;Yuan et al, 2017). The observed differences in the picoeukaryote community under P replete conditions could alter nutrient uptake behaviour because picoeukaryotes are known to be very efficient in assimilating phosphorus.…”

Biochemical Responses and DNA Damage of Chlorella pyrenoidosa H. Chick upon Exposure to Combined Cu and Cd at Environmentally Realistic Levels

“…An aliquot of 2 mL culture in a 15-mL PP tube was mixed with 1 mL 0.5 M Tris-HCl buffer pH 8 and 2 mL 0.3 mM p-nitrophenyl phosphate, incubated for 4 h at 37 o C and then mixed with 0.1 mL 0.1 M NaOH. Subsequently, the sample was filtered with Whatman paper number 42 (Whatman, Jakarta, Indonesia) of known weight and used for alkaline phosphatase activity analysis following the modified method of Ihlenfeldt and Gibson (1975) and Yuan et al (2017), with a 4-nitrophenol standard curve. Activity was expressed as nmol/min/g ww.…”