Characteristics of inorganic and organic phosphorus in Lake Sha sediments from a semiarid region, Northwest China: Sources and bioavailability

Authors: MA, HUIHUI - Northwest Normal University; ZHU, YUANRONG - Chinese Research Academy Of Environmental Sciences; JIANG, JUAN - Chinese Research Academy Of Environmental Sciences; BING, XIAOJIE - Chinese Research Academy Of Environmental Sciences; XU, WEINING - Chinese Research Academy Of Environmental Sciences; HU, XIAOYAN - Chinese Research Academy Of Environmental Sciences; ZHANG, SONGLIN - Northwest Normal University; SHEN, YAQIN - Chinese Research Academy Of Environmental Sciences; He, Zhongqi

Submitted to: Applied Geochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/2022
Publication Date: 2/1/2022
Citation: Ma, H., Zhu, Y., Jiang, J., Bing, X., Xu, W., Hu, X., Zhang, S., Shen, Y., He, Z. 2022. Characteristics of inorganic and organic phosphorus in Lake Sha sediments from a semiarid region, Northwest China: Sources and bioavailability. Applied Geochemistry. 137. Article 105209. https://doi.org/10.1016/j.apgeochem.2022.105209.
DOI: https://doi.org/10.1016/j.apgeochem.2022.105209

Interpretive Summary: Phosphorus (P) is a nutrient essential for life and a major contributor to nonpoint-source water eutrophication. Lake Sha is a typical closed plateau lake located in the semiarid region of Northwest China, with high amounts of evaporation, less precipitation, high salinity and fragile ecosystems. This work showed that the rapid degradation of bioavailable diester P would be one of the important sources for the replenishment of bioavailable P for the overlying water in Lake Sha. Additionally, labile monoester P and phytate in sediment were also potential sources of bioavailable P in overlying water. The input of particulate matter with recharge water from the Yellow River was one of the important sources of bioavailable P in Lake Sha. Therefore, it is suggested that particulate nutrients in Lake Sha in recharge water from the Yellow River should be evaluated or treated, such as by flocculent settling. Generally, the source and bioavailability of P in lake sediments could be clarified to a large extent by the characterization of Pi and Po forms together.

Technical Abstract: Phosphorus (P) is a key limiting nutrient in many lake. Sources of organic matter, forms of inorganic P (Pi) and organic P (Po) and their bioavailability in the sediments of Lake Sha in the semiarid region of Northern China were investigated. The results showed that the organic matter in Lake Sha sediments mainly resulted from mixed inputs of aquatic plants, internal bacteria and algae, and some terrestrial C3 plants. The contents and relative proportion of P forms in Lake Sha sediments decreased in the order Ca-P > Res-P > Al-P ˜ Fe-P > NH4Cl-P. Although the contents and relative proportion of Ca-P (calcium-bonded phosphorus) were the greatest, Ca-P was likely preserved in Lake Sha sediments. A large proportion of residual phosphorus (Res-P) in sediment was Po, whose chemical composition, bioavailability and sources were further analyzed by 31P-nuclear magnetic resonance analysis. Aggregative results further showed that the rapid degradation of bioavailable diester P would be one of the important sources for the replenishment of bioavailable P for the overlying water in Lake Sha. Additionally, labile monoester P and phytate in sediment were also potential sources of bioavailable P in overlying water. The input of particulate matter with recharge water from the Yellow River was one of the important sources of bioavailable P in Lake Sha. Therefore, it is suggested that particulate nutrients in Lake Sha in recharge water from the Yellow River should be evaluated or treated, such as by flocculent settling.