Transport and Retention of Nitrogen, Phosphorus and Carbon in North America’s Largest River Swamp Basin, the Atchafalaya River Basin

Abstract

Abstract:Floodplains and river corridor wetlands may be effectively managed for reducing nutrients and carbon. However, our understanding is limited to the reduction potential of these natural riverine systems. This study utilized the long-term river discharge and water quality records from an upriver and a downriver location of the Atchafalaya River to quantify the inflow, outflow, and inflow-outflow mass balance of total Kjeldahl nitrogen (TKN = organic nitrogen + ammonia nitrogen), nitrate + nitrite nitrogen (NO 3 + NO 2 ), total phosphorous (TP), and total organic carbon (TOC) through the largest river swamp basin in North America. The study found that, over the past 27 years, the Atchafalaya River Basin (ARB) acted as a significant sink for TKN (annual retention: 24%), TP (41%), and TOC (12%), but a source for NO 3 + NO 2 nitrogen (6%). On an annual basis, ARB retained 48,500 t TKN, 16,900 t TP, and 167,100 t TOC from the river water. The retention rates were closely and positively related to the river discharge with highs during the winter and spring and lows in the late summer. The higher NO 3 + NO 2 mass outflow occurred throughout spring and summer, indicating an active role of biological processes on nitrogen as water and air temperatures in the basin rise.

Phosphorus Fluxes from Three Coastal Watersheds under Varied Agriculture Intensities to the Northern Gulf of Mexico

“…Fluxes of TP and DIP are the product of the river's discharge and concentrations of TP and DIP; therefore, there often exists a close relationship between nutrient fluxes and discharge. In this study, we estimated freshwater daily nutrient fluxes of the three rivers using a rating curve that can be described as the following log-linear regression model [15]:…”

Similaridade De Eutrofização Das Águas Superficiais Da Bacia Do Alto Jaguaribe, Ceará

“…Tal concentração o classifica como hipereutrófico. Como o valor da razão N:P foi inferior a 16 há uma propensão que nesse reservatório ocorra um aumento da quantidade de cianobactérias e macrófitas (SMITH et al, 1995;XU et al, 2013), corroborando com o elevado teor de Cl 'a' encontrado.…”

“…Além dessas consequências, traz consigo diversos problemas indesejáveis, tais como contaminação da água destinada ao abastecimento público, diminuição do oxigênio dissolvido, maus odores e crescimento de macrófitas (SCHINDLER, 2012;BARBOSA et al, 2012). A adição do nitrogênio (N) e fósforo (P) em ecossistemas aquáticos, além de causarem o aumento da produção primária e floração de algas e cianobactérias tóxicas, promovem também a elevação da turbidez, a mortandade dos peixes, perca do habitat natural e riscos à saúde humana (XU, 2013).…”

Rethinking the Mississippi River diversion for effective capture of riverine sediments

“…In contrast, because of its use as a floodway for the Mississippi River, the 200-km long Atchafalaya River is allowed to flow through wider flood plains surrounded by levees on the east and west for about 10-35 km. The levee-confined area, also known as the Atchafalaya River Floodway Basin, encompasses a total area of 3923 km 2 (Xu, 2013) with heavily braided river channels, open water areas, wooded lowlands, cypress-tupelo surface flow swamps, and some freshwater marshes in the lower basin area. The Atchafalaya River enters the Gulf of Mexico through two outlets: the Morgan City Outlet and the Wax Lake Outlet, and they have a discharge ratios of approximately 60% and 40%, respectively.…”