Skip to main content
ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Commodity Utilization Research » Research » Publications at this Location » Publication #305008

Title: Influence of natural organic matter on the bioavailability and preservation of organic phosphorus in lake sediments

Author
item ZHU, YUANRONG - Chinese Research Academy Of Environmental Sciences
item WU, FENGCHANG - Chinese Research Academy Of Environmental Sciences
item He, Zhongqi
item GIESY, JOHN - University Of Saskatchewan
item FENG, WEIYING - Chinese Research Academy Of Environmental Sciences
item MU, YUNSONG - Chinese Research Academy Of Environmental Sciences
item FENG, CHENGLIAN - Chinese Research Academy Of Environmental Sciences
item ZHAO, XIAOLI - Chinese Research Academy Of Environmental Sciences
item LIAO, HAIQING - Chinese Research Academy Of Environmental Sciences
item TANG, ZHI - Chinese Research Academy Of Environmental Sciences

Submitted to: Chemical Geology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/2015
Publication Date: 3/21/2015
Citation: Zhu, Y., Wu, F., He, Z., Giesy, J.P., Feng, W., Mu, Y., Feng, C., Zhao, X., Liao, H., Tang, Z. 2015. Influence of natural organic matter on the bioavailability and preservation of organic phosphorus in lake sediments. Chemical Geology. 397:51-60.

Interpretive Summary: Eutrophication is the primary water quality issue for most lakes in China, and severely impedes the beneficial uses of the lake resource and sustainable economic development. Phosphorus (P) is the primary controllable limiting nutrient in most lake ecosystems. As external inputs of P have been gradually reduced over the last decades, the biogeochemical cycle of internal P accumulated in the sediments has become the key factor to maintain the eutrophication of lakes. In this study, enzymatic hydrolysis and 31P-NMR were used in characterization of P in the sediments from algae-dominated and macrophyte-dominated regions of Lake Taihu, a large shallow eutrophic lake in China. The influence of organic matter on the enzymatic hydrolysis of organic P was analyzed. Observations suggested that the bioavailability of Po in the sediments would be reduced by forming organic P-metal-organic matter complexes. Thus, we concluded that the widely distributed organic matter in the sediments would be an important factor for organic P bioavailability and preservation, thus biogeochemical cycle of organic P in the lakes.

Technical Abstract: Organic P (Po) was sequentially extracted by H2O and NaOH-EDTA in the sediments from algae- and macrophyte-dominated regions of Lake Taihu, China and then analyzed by enzymatic hydrolysis and solution 31P-NMR spectroscopy. The amount of H2O-Po was 0.8-2.0 mg kg-1, 45.5% to 89.4% of which could be hydrolyzed by phosphatases including alkaline phosphatase, phosphodiesterase and phytase. Compared with algae-dominated regions, phytate-like P was the main composition of bioavailable H2O-Po in the macrophyte-dominated regions. For NaOH-EDTA Po, large proportion of phytate-like P was likely incorporated to high molecular weight organic matter to form a complex “unknown Po”, and then resistant to enzymatic hydrolysis. Enzymatic hydrolysis showed that NaOH-EDTA Po characterized by 31P-NMR couldn’t be completely hydrolyzed , especially in the macrophyte-dominated regions, which implied some Po associated with organic matter and/or metals in the sediments. Condensed P (e.g., pyrophosphate) and phytate-like P (e.g., inositol phosphates) were strong resisted to enzymatic hydrolysis in the presence of HA and/or metal ions. These observations suggested that the bioavailability of Po in the sediments would be reduced by forming Po-metal ions (Mn+)-HA or Po-Mn+ complexes. Thus, we concluded that the widely distributed organic matter in the sediments would be an important factor for Po bioavailability and preservation, thus biogeochemical cycle of Po in the lakes.