Distribution of phosphatase activity in marsh sediments along an estuarine salinity gradient

Huang, Xiaoqing; Morris, James T.

doi:10.3354/meps292075

Cited by 28 publications

(14 citation statements)

References 20 publications

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“…Some data on the below-and aboveground biomass from plots treated with 12 different combinations of N (ammonium sulfate), P (superphoshate) and Fe (Ironite) (n = 3 plots per treatment) additions to an LA-C salt marsh are described by Darby & Turner (2008b), and included here. The nutrient loading rates applied in this analysis are within the range of N and P loadings to GOM estuaries (Turner & Rabalais 1999) and are comparable to those of others (Valiela et al 1976, Mendelssohn 1979, Morris & Bradley 1999, Huang & Morris 2005.Spartina alterniflora was harvested by clipping vegetation at the sediment surface. All standing live and dead culms and litter were removed from the control and fertilized plots and placed into pre-labeled plastic bags and transported to the Louisiana State University 64 Darby & Turner: Salt marsh belowground biomass and eutrophication (LSU) processing laboratory.…”

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confidence: 70%

Effects of eutrophication on salt marsh root and rhizome biomass accumulation

Darby¹,

Turner²

2008

Mar. Ecol. Prog. Ser.

142

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The root:shoot ratio of grassland plants may be lower in high fertility sites than in low fertility sites as plants modify their root, rhizome and shoot morphologies (and masses) to suit prevailing nutrient availability. We conducted geographically diverse and regionally specific field sampling and measured above-and belowground plant biomasses in western Atlantic and Gulf of Mexico salt marshes to determine whether there is a similar morphological response in Spartina alterniflora, the dominant salt marsh plant. Coastal nutrient addition/enrichment, which is widespread and ongoing, may lower root and rhizome biomass, belowground production and organic accumulation in this species. Higher soil respiration and a lower Eh (redox potential) are expected additional soil property changes. The addition of P, more than of N, seems to reduce root and rhizome biomass accumulation. The cumulative effects of increased nutrient loadings on salt marshes may be to decrease soil elevation and accelerate the conversion of emergent plant habitat to open water, particularly on the lower marsh. The recommendations for management practices intended to conserve coastal marshes include reducing nutrient loading to coastal zones, solving water quality problems with a multiple nutrient approach, and choosing monitoring metrics that are based on both above-and belowground plant biomass.KEY WORDS: Salt marsh · Nutrients · Spartina alterniflora · Belowground biomass · Die-back Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 363: [63][64][65][66][67][68][69][70] 2008 accretion is too low or too high, respectively. An aggressive new form of Phragmites australis apparently out-competes Spartina alterniflora on the landward side of cordgrass distribution; in part, the dominance of P. australis results from its greater belowground biomass production, with a consequent rise in soil elevation that has negative effects on S. alterniflora (Rooth & Stevenson 2000, Bertness et al. 2002. Soil elevation may be lowered to the detriment of cordgrass survival if either root production is decreased or the decomposition of accumulated organic matter is accelerated sufficiently that net organic accumulation is less than relative sea level rise. Additional evidence for the influence of belowground biomass on marsh vigor is that the amount of live root + rhizome (R+R) biomass is a diagnostic of plant health in Louisiana salt marshes (Turner et al. 2004). The R+R biomass there was 7 times higher in marshes categorized as 'healthy' than in deteriorating 'unhealthy' marshes.An implication of these observations is that the increases in nutrient loading to coastal systems, which are widespread (National Research Council 2000, Cloern 2001, Rabalais 2002, Howarth & Marino 2006, may alter marsh ecosystem functions and perhaps compromise the long-term stability of salt marshes by reducing root production and causing a consequential decline in soil organic accumulation. Morris & Bradley (1999), for example, f...

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confidence: 70%

Effects of eutrophication on salt marsh root and rhizome biomass accumulation

Darby¹,

Turner²

2008

Mar. Ecol. Prog. Ser.

142

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“…6,7,10À13 M1 featured unrestricted opportunities for Fe(II)/Fe(III) cycling; i.e., no precipitating agents were deliberately added. Design M2 incorporated a precipitating agent (PO 4 3-, representing total phosphate species for the discussion) to restrict cycling by encouraging Fe(III) precipitation, as well as pH, Cl À , Br À , Fe(II), CO 3 2-, and SRNOM. M1 and M2 were five-and sixfactor BoxÀWilson designs, respectively, with each factor except pH varied across five concentration levels across a range that corresponded to fresh water to approximately 40 parts per thousand salinity.…”

Section: ' Introductionmentioning

confidence: 99%

“…M1 was a five-factor central composite design that included Cl À , Br À , Fe(II), CO 3 2-, and SRNOM; and was repeated in its entirety at pH 6.5, 7.0, 7.5, 8.0, and 8.5. M2 was a six-factor central composite design representing conditions that forced precipitation by the addition of PO 4 3-as the sixth variable. This was also repeated at pH 6.5, 7.0, 7.5, 8.0, and 8.5.…”

Section: ' Introductionmentioning

confidence: 99%

Combinatorial Parameter Space As an Empirical Tool for Predicting Water Chemistry: Fe(II) Oxidation Across a Watershed

Burns

Craig

Shaw

et al. 2011

Environ. Sci. Technol.

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Fe(II) oxidation kinetics in surface waters are a complex function of the concentration of several dissolved species that vary geographically and temporally across watersheds. This work reports an empirical, combinatorial investigation of Fe(II) oxidation that simultaneously evaluated these variations across the pH, Fe(II), PO₄³⁻, Cl⁻, Br(-), CO₃²⁻, and natural organic matter (NOM) axes. The work assayed the effects of independent and dependent variables through application of a novel experimental design that varied Fe(II), PO₄³⁻, Cl⁻, Br⁻, and CO₃²⁻ along the pH axis. Each factor was varied across concentration ranges corresponding to the natural variation between typical fresh and salt water. The system was designed to describe the oxidation of Fe(II) that occurs when Fe(II)-rich groundwaters are mixed rapidly with oxic overlaying waters as a result of tidal movement, bioturbation, dredging, and other mixing/resuspension events. Factors and interfactor interactions were statistically evaluated to determine their importance to Fe(II) oxidation at the 95% level of confidence. Significant factors were retained and used to construct predictive numerical models of Fe(II) oxidation rates. Two models (M1 and M2) were constructed to represent the conditional endmembers of unrestricted Fe cycling (M1) and restricted Fe cycling (due to forced precipitation of Fe(III), M2). The models were challenged to predict net Fe(II) oxidation rates across a watershed (the Congaree/Santee rivers, sampled at ten different locations in South Carolina). The models were generally capable of predicting Fe(II) oxidation rates to within the 95% confidence interval, although M2 consistently overpredicted the rate relative to M1. The minimum initial Fe(II) concentration needed to observe Fe cycling is estimated based on the model output.

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“…The root and rhizome (R&R) biomass resists erosion, contributes to the accumulation of organic matter as sea level rises and the marsh soils compact, and is the organic benthic matrix important to various feeding guilds, including those supporting commercially valuable fisheries. S. alterniflora R&R production, however, may not be limited by nitrogen availability because these structures are foraging for nutrients in a P-limited soil microbial community (Sundareshwar et al 2003;Huang and Morris 2005). In other words, the belowground production may be limited by phosphorous and nitrogen.…”

Section: Introductionmentioning

confidence: 99%

Below- and Aboveground Biomass of Spartina alterniflora: Response to Nutrient Addition in a Louisiana Salt Marsh

Darby

Turner

2008

Estuaries and Coasts: J CERF

178

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The responses of Spartina alterniflora aboveand belowground biomass to various combinations of N, P, and Fe were documented in a 1-year field experiment in a Louisiana salt marsh. Five levels of N additions to 0.25 m 2 plots resulted in 18% to 138% more live aboveground biomass compared to the control plots and higher stem densities, but had no effect on the amount of live belowground biomass (roots and rhizomes; R&R). There was no change in the aboveground biomass when P or Fe was added as part of a factorial experiment of +P, +N, and +Fe additions, but there was a 40% to 60% decrease in the live belowground biomass, which reduced the average R&R:S ratio by 50%. The addition of various combinations of nutrients had a significant affect on the belowground biomass indicating that the addition of P, not N, eased the need for root foraging activity. The end-of-the-growingseason N:P molar ratios in the live above-and belowground tissues of the control plot was 16.4 and 32.7, respectively. The relative size of the belowground standing stocks of N and P was higher than in the aboveground live tissues, but shifted downwards to about half that in fertilized plots. We conclude that the aboveground biomass was directly related to N availability, but not P, and that the accumulation of belowground biomass was not limited by N. We suggest that the reduction in belowground biomass with increased P availability, and the lower absolute and relative belowground standing stocks of P as plant tissue N:P ratios increased, is related to competition with soil microbes for P. One implication for wetland management and restoration is that eutrophication may be detrimental to long-term salt marsh maintenance and development, especially in organicrich wetland soils.

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Distribution of phosphatase activity in marsh sediments along an estuarine salinity gradient

Cited by 28 publications

References 20 publications

Effects of eutrophication on salt marsh root and rhizome biomass accumulation

Effects of eutrophication on salt marsh root and rhizome biomass accumulation

Combinatorial Parameter Space As an Empirical Tool for Predicting Water Chemistry: Fe(II) Oxidation Across a Watershed

Below- and Aboveground Biomass of Spartina alterniflora: Response to Nutrient Addition in a Louisiana Salt Marsh

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