Responses of wetland plants to ammonia and water level

Clarke, Ernest; Baldwin, Andrew H.

doi:10.1016/s0925-8574(01)00080-5

Cited by 132 publications

(54 citation statements)

References 15 publications

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“…Portnoy and Giblin (1997a) report that an abundance of inorganic N, such as increased NH 4 þ , in salinizing sites could also help overcome H 2 S inhibition. However, at high concentrations, NH 4 þ can become toxic to macrophytes (Clarke and Baldwin 2002). Clearly, the interaction between H 2 S toxicity and inorganic N is complex and warrants further investigation, especially as eutrophication is a growing concern for wetland systems (Larsen et al 2010).…”

Section: àmentioning

confidence: 99%

A global perspective on wetland salinization: ecological consequences of a growing threat to freshwater wetlands

et al. 2015

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Abstract. Salinization, a widespread threat to the structure and ecological functioning of inland and coastal wetlands, is currently occurring at an unprecedented rate and geographic scale. The causes of salinization are diverse and include alterations to freshwater flows, land-clearance, irrigation, disposal of wastewater effluent, sea level rise, storm surges, and applications of de-icing salts. Climate change and anthropogenic modifications to the hydrologic cycle are expected to further increase the extent and severity of wetland salinization. Salinization alters the fundamental physicochemical nature of the soil-water environment, increasing ionic concentrations and altering chemical equilibria and mineral solubility. Increased concentrations of solutes, especially sulfate, alter the biogeochemical cycling of major elements including carbon, nitrogen, phosphorus, sulfur, iron, and silica. The effects of salinization on wetland biogeochemistry typically include decreased inorganic nitrogen removal (with implications for water quality and climate regulation), decreased carbon storage (with implications for climate regulation and wetland accretion), and increased generation of toxic sulfides (with implications for nutrient cycling and the health/functioning of wetland biota). Indeed, increased salt and sulfide concentrations induce physiological stress in wetland biota and ultimately can result in large shifts in wetland communities and their associated ecosystem functions. The productivity and composition of freshwater species assemblages will be highly altered, and there is a high potential for the disruption of existing interspecific interactions. Although there is a wealth of information on how salinization impacts individual ecosystem components, relatively few studies have addressed the complex and often non-linear feedbacks that determine ecosystem-scale responses or considered how wetland salinization will affect landscape-level processes. Although the salinization of wetlands may be unavoidable in many cases, these systems may also prove to be a fertile testing ground for broader ecological theories including (but not limited to): investigations into alternative stable states and tipping points, trophic cascades, disturbance-recovery processes, and the role of historical events and landscape context in driving community response to disturbance.

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Section: àmentioning

confidence: 99%

A global perspective on wetland salinization: ecological consequences of a growing threat to freshwater wetlands

et al. 2015

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“…is an amphibious plant that is common in China and adapted to periods of flooding and the consequent hypoxic conditions as a part of its natural life cycle. The use of this species in constructed wetlands for wastewater treatment (Caicedo et al 2000;Clarke & Baldwin 2002) in China is another reason to study its growth. Some previous studies have investigated growth responses and morphological adaptations of A. calamus to average water depth.…”

Section: Introductionmentioning

confidence: 99%

Growth responses and adaptations of the emergent macrophyteAcorus calamusLinn. to different water-level fluctuations

Hua

Cheng

et al. 2013

Journal of Freshwater Ecology

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Acorus calamus Linn. was grown under four water-level fluctuation (WLF) treatments to study the influence of WLF on the growth of the species. The four WLF treatments (designated as 0 cm, 60 cm, 60 AE 30 cm, and 60 AE 60 cm) were initiated with the minimum water levels (0, 60, 30, and 0 cm, respectively) for a week and then switched to the maximal water levels (0, 60, 90, and 120 cm, respectively) one week later. This cycle was repeated six times during 12 weeks. Relative growth rate (RGR), biomass allocation, shoot and below-ground morphology, chlorophyll content, and concentrations of proline, malondialdehyde (MDA), and soluble sugar (SS) of A. calamus were measured. After the 12 weeks' WLF treatment, growth rate differed among the treatments. RGR was negative in the 60 cm treatment. A. calamus showed significant morphological adaptations to WLFs, including different patterns in length, blade length, width and numbers of shoots. The root:shoot ratio was significantly greater in the 0 cm treatment with no significant differences among the other three WLF treatments. SS concentrations in the rhizome and root were higher in the 60 AE 60 cm treatment than in either the 60 cm treatment or 60 AE 30 cm treatment. No clear relationship was found among the treatments for chlorophyll concentrations, proline, or MDA concentrations in the shoots but fluctuating water levels significantly stimulated proline and MDA accumulation. The differences in biomass and morphological variables among treatments suggested that WLF is an important regulator of the growth of A. calamus and that the species is better adapted to cyclic WLFs than to constant deep water.

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“…The high and highly variable nutrient levels in sludge means that any plant used in a drying bed must be able to tolerate a wide range of growing conditions and must be able to withstand the shocks associated with sludge loading and drying. Sludge from public toilets, for example, is high in salts (conductivity up to 15 mS/cm) and ammonia (2 to 5,000 mg/L), which are toxic to most plants (Clarke and Baldwin, 2002). To offset these potentially lethal conditions, public toilet sludge must be diluted with sludge that has lower concentrations of salt and ammonia (e.g.…”

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confidence: 99%