Carbon and nutrient release from experimental inundation of agricultural and forested floodplain soil and vegetation: influence of floodplain land use on the development of hypoxic blackwater during floods

Abstract

Overbank floods in modified lowland rivers often inundate a mosaic of different land uses (e.g. forests, crops and pastures) on the floodplain. We used a glasshouse experiment to investigate dissolved organic carbon (DOC) and nutrient (TP, NH4+, NOx) releases, chemical oxygen demand (COD) and dissolved oxygen (DO) depletion in water following inundation of soil and vegetation from a lowland river floodplain in southern Australia. Six replicate samples of six intact soil and groundcover treatments were collected during summer; three from a forest (bare soil, wallaby grass and leaf litter) and three from an adjacent paddock (bare soil, wheat and ryegrass). Samples were placed in pots, inundated with river water over 16 days, and their leachates were compared with a river-water control. All vegetated groundcover treatments had significantly higher DOC and COD and significantly less DO at both Day 1 and Day 16 than did the soil-only treatments or the control. Leachates from paddock treatments were less coloured than those from forest treatments, despite having similar concentrations of DOC. Our findings imply that the inundation of any vegetation during summer floods can be a major source of DOC and a major contributor to DO depletion.

Hypoxic conditions interrupt flood‐response movements of three lowland river fish species: Implications for flow restoration in modified landscapes

“…The frequency of small to medium floods is now reduced, and flow patterns exhibit seasonal reversal (Thoms & Sheldon, 2000;Walker, 1985;Walker & Thoms, 1993). Furthermore, when large floods do occur, especially in the southern Murray-Darling Basin, they are increasingly associated with hypoxic conditions due to long periods of floodplain disconnection prior to flooding followed by inundation of a mosaic of floodplain land uses during flooding (Hladyz, Watkins, Whitworth, & Baldwin, 2011;Liu, Watts, Howitt, & McCasker, 2019;Whitworth, Baldwin, & Kerr, 2012).…”

Experimental Study on Creep Properties Prediction of Reed Bales Based on SVR and MLP

“…is used to represent the strain of the reeds in the vertical direction and can be calculated using Equation (2).…”

“…In recent years, over-cultivation of forests and pastures has led to enormous environmental problems [1,2] . Due to their high lignin content, wide distribution, and low cost, reeds are an excellent candidate for a raw material to replace timber in the papermaking industry [3,4] .…”

Influencia de los suelos en la dinámica de transferencia de nutrientes en la interfase suelo-agua en un embalse tropical

“…Este es un proceso altamente complejo que depende no solo de los factores ambientales del agua como son el pH, potencial redox, oxígeno disuelto y temperatura, sino también de la actividad microbiana y de las características del suelo [13]- [15]. Dado que el ingreso de nutrientes a los embalses no solo se da a través del suelo, sino también por medio de sus afluentes, las dos vías en conjunto pueden conducir los embalses a un estado de eutrofización, es decir, a un enriquecimiento de nutrientes que estimula el crecimiento excesivo de plantas y algas acuáticas [16], situación que es particularmente grave en el trópico por la alta disponibilidad de luz y las cálidas temperaturas durante todo el año [8]. Lo anterior da lugar a que la transferencia de nutrientes sea un proceso que afecta la calidad del agua de los embalses, motivo por el cual es fundamental caracterizar los aportes de nutrientes que se dan desde el suelo, al ser una vía para la movilización de estos [14], [17].…”