Impact of Suspended Inorganic Particles on Phosphorus Cycling in the Yellow River (China)

Abstract

Phosphorus (P) in water and sediment in the Yellow River was measured for 21 stations from the source to the Bohai Sea in 2006−2007. The average total particulate matter (TPM) increased from 40 mg/L (upper reaches) to 520 mg/L (middle reaches) and 950 mg/L in the lower reaches of the river. The average dissolved PO 4 concentration (0.43 μmol/L) was significantly higher than that in 1980's but lower than the world average level despite high nutrient input to the system. Much of the P input was removed by adsorption, which was due to the high TPM rather than the surface activity of the particles since they had low labile Fe and low affinity for P. The sediment was a sink for P in the middle to lower reaches but not in the upper to middle reaches. TPM has been reduced by more than an order of magnitude due to artificial dams operating over recent decades. Modeling revealed that TPM of 0.2−1 g/L was a critical threshold for the Yellow River, below which most of the phosphate input cannot be removed by the particles and may cause eutrophication. These findings are important for river management and land−ocean modeling of global biogeochemical P cycling.

Phosphorus release from coastal sediments: Impacts of the oxidation-reduction potential and sulfide

“…The total input of P into aquatic systems is determined by both external inputs as well as internal recycling from the benthic sediments to the water column (Pan et al, 2013;Kraal et al, 2015). Excessive input of P can lead to eutrophication, which adversely affects coastal zone ecosystems in many areas around the world (Yang et al, 2015).…”

“…P exchange processes between the sediment and overlying water are known to be affected by physico-chemical conditions and biological processes, which can also influence the existing forms of P (Qian et al, 2011;Pan et al, 2013). Anoxic marine sediments are generally thought to have diminished sedimentary P retention capacity (Ingall et al, 1993).…”

Characterization of biogenic phosphorus in sediments from the multi-polluted Haihe River, China, using phosphorus fractionation and 31 P-NMR

“…The average sediment TP concentration was 2448 mg kg −1 and TP concentrations exceeded 1000 mg kg −1 at 55.6% of sampling sites. Because of the excessive P inputs, significant amounts of P have accumulated in the river sediments, and exceed what has been reported for Bronx River (Wang and Pant, 2010), Yellow River (Pan et al, 2013), Illinois River (Haggard and Soerens, 2006) and Amazon River (Berner and Rao, 1994).…”

Phosphorus distribution and sorption-release characteristics of the soil from newly submerged areas in the Danjiangkou reservoir, China

“…The centrifuge tubes were capped and incubated at 25 ± 1 • C in an orbital shaker at 200 rpm for different time intervals, varying within 64 h (0, 0.25, 0.5, 1, 2, 3, 5, 7, 9, 18, 27, 36, 48, and 64 h). The samples were immediately centrifuged at 4390 × g for 15 min, and filtered through 0.45 m GF/C filter membrane, the results described in following sections are mean of three analyzing parallel samples (Pan et al, 2013).…”

“…It was implied that only some of the P fractions could be released from soils into the overlying water. The NaOH-P could easily be released from soils and was identified as the major fraction of soils influencing the P distribution in the overlying water (Pan et al, 2013). In many eutrophic reservoirs, oxygen penetration into the sediments is limited within a confined layer and the release of P was attributed to reduction of iron hydroxides and iron phosphate under anoxic conditions (Ahlgren et al, 2005).…”