Diagenesis of Organic Matter in a Wetland Receiving Hypereutrophic Lake Water: I. Distribution of Dissolved Nutrients in the Soil and Water Column

Abstract

A recently constructed marsh from previously drained agricultural land currently receives nutrient-laden water from adjacent hypereutrophic Lake Apopka, located in central Florida. Lake water is allowed to cycle through the marsh, allowing settlement of participate organic matter, which forms a floe sediment layer on the native peat soil surface. The water leaving the marsh is returned to the lake after a retention time of 3 to 12 d. This study determined changes in temporal and spatial distribution of selected nutrients in the soil-water column of the marsh during the first 13 mo of operation. In situ distribution of selected chemical species (H+, NH/, soluble P, SO3~, dissolved organic C, dissolved inorganic C, CJL,, Ca, Mg, Fe, Mn, AT) were measured using soil pore water equilibrators at 3, 8, and 13 mo after marsh creation. Initial flooding of the agricultural soils resulted in high concentrations of NW (11 mg N L~') and soluble P (31 mg P L "') as a result of solubilization and anaerobic decomposition. Initially rapid soluble P flux (mean = 2.4 mg P m" 2 d" 1 ) occurred from soil to the water column, although lower flux (mean = 0.8 mg Pm" 2 d~') occurred after 10 additional months of operation. In contrast, initial flux of NHJ" into the water column was generally lower (mean = 3.4 mg N m~2 d' 1 ) than observed after 10 additional months (mean = 8.2 mg N m~' d" 1 ). Microbial degradation and nutrient regeneration from settled labile organic matter appeared to support nutrient flux to the water column. After 13 mo of flooding, 75% of the variability of NHtf-N and 65% of the variability of soluble P contained in the water and floe sediment was explained by (DIG + CHO-C mineralized from settled organic matter. Anaerobic conditions in both the floe sediment and peat soil layers (indicated by increased amounts of dissolved CHU and Fe, and by SOI' reduction) had significant effects on nutrient retention and release in the soil-water column.

Use of wetland buffer areas to reduce nitrogen transport from forested catchments: Retention capacity, emissions of N2O and CH4 and vegetation composition dynamics

“…The capacity of the soil to retain nutrients varies depending on the physical and chemical soil characteristics, such as the cation exchange capacity (Lance 1972), the soil sorption properties (D´Angelo and Reddy 1994), and the form of nutrient in the throughflowing water (Lance 1972). Ammonium (NH 4 + ) can be retained into cation exchange sites of the soil (Lance 1972, Heikkinen et al 1994, while nitrate (NO 3 -) generally remains in soluble form, unless assimilated by vegetation or microbial communities.…”

“…Peat soils usually have high cation exchange capacity (CEC), which enables a considerable potential to the retention of NH 4 + (Heikkinen et al 1994). The effective cation exchange capacity is generally highest in the peat surface layer (Ronkanen and Kløve 2009), however, water table level fluctuations may affect the CEC (Lance 1972, D´Angelo andReddy 1994). Flooding of aerobic peat soil may result in NH 4 + release, because anaerobic bacteria has lower requirements for N, leaving more NH 4 + available for transport from the soil to the water column (D´Angelo and Reddy 1994).…”

“…The effective cation exchange capacity is generally highest in the peat surface layer (Ronkanen and Kløve 2009), however, water table level fluctuations may affect the CEC (Lance 1972, D´Angelo andReddy 1994). Flooding of aerobic peat soil may result in NH 4 + release, because anaerobic bacteria has lower requirements for N, leaving more NH 4 + available for transport from the soil to the water column (D´Angelo and Reddy 1994). Also, when previously anaerobic soil layers become aerobic, the adsorbed NH 4 + can be oxidized to NO 3 -, which is then easily leached during next inundation (Lance 1972).…”

Spatial Variation, Pollution Assessment and Source Identification of Major Nutrients in Surface Sediments of Nansi Lake, China

“…They were air-dried at room temperature (25)(26)(27)(28) • C) and then passed through 10-mesh polyethylene sieve to remove stones and other debris. A portion (about 50 g) was ground in an agate grinder and sieved through 100-mesh polyethylene sieve before chemical analysis.…”

Effects of Nonaerated Circulation Water Velocity on Nutrient Release from Aquaculture Pond Sediments

“…Water temperature is known to indirectly influence P release in sediments [26], with a high temperature boosting the activity of some substances and accelerating physical, chemical, and biological reactions such as the diffusion and degradation of organic matter. Microorganisms can also decompose organic P in sediments into inorganic P and convert insoluble phosphorus compounds into soluble ones and higher metabolic rates can accelerate the degradation of organic matter [27], thus promoting P release from sediments. For N release, Liu et al [28] reported that water temperature can influence degradation speed, when temperatures drop too low, the degradation of N in deeper-sediments can cease altogether.…”