Long-term phenomenological model of phosphorus and oxygen for stratified lakes

Abstract

Abstraet-A budget model is developed to predict the long-term response of a lake to changes in its phosphorus loading. This model computes total phosphorus and hypolimnetic oxygen concentrations, taking sediment-water interactions into account. The lake is treated as two segments: the water and a surface sediment layer. A total phosphorus budget for the water accounts for inputs due to external loading and recycle from the sediments. It reflects losses due to flushing and settling. The sediment layer gains total phosphorus by settling and loses total phosphorus by recycle and burial. The recycle from the sediments to the water is dependent on the levels of sediment total phosphorus and hypolimnetic oxygen. Hypolimnetic oxygen concentration is estimated with a semi-empirical model. The model is applied to Shagawa Lake. An analysis is performed to demonstrate how its predictions replicate in-lake changes not possible with simpler phosphorus budget models.

Long‐term changes in the areal hypolimnetic oxygen deficit (AHOD) of Onondaga Lake: Evidence of sediment feedback

“…There are two contributing features. First, v t values are generally systematically higher early in the stratification interval, associated with weak water column stability (Wodka et al 1983;Chapra 1997). Thus, hypolimnia of productive lakes that experience DO depletion before the onset of strong thermal stratification will also likely receive substantial DO inputs as a result of intense vertical mixing during this period of weak stability (Fig.…”

“…Burns (1995) expanded this listing of factors that can affect VHOD (or AHOD) to nine and included the delayed decomposition of organic material in sediments. Despite these issues, AHOD has been found to be correlated with primary production and its surrogates, total phosphorus concentration (TP; Rast and Lee 1978;Chapra and Canale 1991), chlorophyll a (Chl a) concentration (Vollenweider and Janus 1981), and Secchi disc transparency (Lasenby 1975). Some of the problems inherent in cross-sectional studies with AHOD are eliminated or ameliorated in the application of this metric to long-term data from a single lake.…”

“…AHOD obs was adjusted for two factors: (1) vertical mixing inputs of DO from overlying layers into the hypolimnion and (2) temperature of the hypolimnion. Depletion rates for 1978-1981 were presented previously by Effler et al (1986) Values of v t were estimated according to Chapra (1997),…”

“…Values of AHOD vm were normalized to 10ЊC (average T h during the intervals of AHOD calculations was 9.4ЊC), to accommodate the effects of interannual differences in T h on hypolimnetic metabolism, with the use of a modified Arrhenius expression (Chapra 1997).…”

Empirical estimation of total phosphorus concentration in the mainstream of the Qiantang River in China using Landsat TM data

“…Theoretical phosphorus models based on mass balance have been developed (e.g. Vollenweider 1976, Imboden and Gä chter 1978, Jorgensen et al 1986, Chapra and Canale 1991 to predict phosphorus concentration of rivers and lakes, although each of them has some degree of limitation (Malmaeus and Hakanson 2004). The Vollenweider approach to predicting phosphorus concentration using basic mass-balance modelling and regression analysis has been tested by many others (e.g.…”