Nitrogen uptake by the shoots of smooth cordgrass Spartina alterniflora

Mozdzer, Thomas J.; Kirwan, Matthew L.; McGlathery, K. J.; Zieman, Joseph C.

doi:10.3354/meps09117

Cited by 21 publications

(18 citation statements)

References 37 publications

(50 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We suggest that there is potential for DON uptake by S. alterniflora in high-latitude salt marshes to account for more than the 24% of plant N demand previously reported for mid-latitude salt marshes (Mozdzer et al 2010(Mozdzer et al , 2011. We suggest that there is potential for DON uptake by S. alterniflora in high-latitude salt marshes to account for more than the 24% of plant N demand previously reported for mid-latitude salt marshes (Mozdzer et al 2010(Mozdzer et al , 2011.…”

Section: Discussionmentioning

confidence: 55%

See 1 more Smart Citation

Latitudinal variation in the availability and use of dissolved organic nitrogen in Atlantic coast salt marshes

Mozdzer

McGlathery

Mills

et al. 2014

Ecology

View full text Add to dashboard Cite

North American Atlantic salt marshes are generally considered to be nitrogen (N) limited systems, and plants within these marshes were historically thought to use only inorganic forms of N, such as NH 4 þ . Recent research has suggested that Spartina alterniflora may take up some organic nitrogen compounds directly. To determine the availability of dissolved organic nitrogen (DON) to S. alterniflora in marshes along the North American Atlantic coast, porewater was sampled at eight field sites along the North American Atlantic Coast, ranging from Maine (448 N) to Florida (308 N). To determine if a latitudinal gradient existed in the assimilation of either DON or NH 4 þ , replicated mesocosm experiments were conducted with S. alterniflora plants at three field sites (Massachusetts, Virginia, South Carolina), which represented three distinct ecotypes in the latitudinal range. To determine how microbial activity may influence DON availability, we also assessed rates of microbial activity. We found that porewater DON availability increased linearly with latitude. While S. alterniflora assimilated DON at all sites, plants from the southernmost site had 50% greater NH 4 þ assimilation rates than the other two sites, suggesting that low-latitude S. alterniflora may rely more strongly on NH 4 þ as an N source. In contrast, high-latitude salt marshes contain greater pools of available DON, and high-latitude S. alterniflora plants exhibit similar uptake rates of DON and NH 4 þ , suggesting a greater reliance upon DON as an N source. We also found that microbial activity decreased by an order of magnitude with increasing latitude along our latitudinal gradient. This suggests that DON uptake is more important at highlatitude locations, where temperature constrains microbial mineralization of organic N. Our analysis also suggests that N limitation of S. alterniflora increases with decreasing latitude. We suggest that other detritus-based ecosystems may exhibit similar latitudinal patterns regarding DON availability and use.

show abstract

Section: Discussionmentioning

confidence: 55%

“…We previously demonstrated that S. alterniflora can use DON directly via roots (Mozdzer et al 2010) as well as through foliar uptake (Mozdzer et al 2011), and that DON can provide up to 24% of plant N demand (Mozdzer et al 2010). Direct uptake of DON in salt marsh ecosystems may help explain the high productivity of oligotrophic marshes.…”

Section: Introductionmentioning

confidence: 99%

Latitudinal variation in the availability and use of dissolved organic nitrogen in Atlantic coast salt marshes

Mozdzer

McGlathery

Mills

et al. 2014

Ecology

View full text Add to dashboard Cite

show abstract

“…Based on recent data (2015), nutrient enrichment elevated porewater nitrate threefold in marsh sediments; however, porewater nitrate was still an order of magnitude lower than porewater ammonium, which did not vary significantly between treatments (T. Mozdzer, unpublished data). Second, foliar uptake rates of ammonium are six times higher than nitrate in S. alterniflora even given an order of magnitude difference in N-availability for nitrate in the water column (Mozdzer et al 2011). Third, as an anion, nitrate-N moves freely through our system and is likely exported before it can be used.…”

Section: Discussionmentioning

confidence: 92%

“…Second, foliar uptake rates of ammonium are six times higher than nitrate in S. alterniflora even given an order of magnitude difference in N‐availability for nitrate in the water column (Mozdzer et al. ). Third, as an anion, nitrate‐N moves freely through our system and is likely exported before it can be used.…”

Section: Discussionmentioning

confidence: 99%

Saltmarsh plant responses to eutrophication

Johnson¹,

Warren

Deegan

et al. 2016

Ecological Applications

View full text Add to dashboard Cite

Abstract. In saltmarsh plant communities, bottom-up pressure from nutrient enrichment is predicted to increase productivity, alter community structure, decrease biodiversity, and alter ecosystem functioning. Previous work supporting these predictions has been based largely on short-term, plot-level (e.g., 1-300 m 2 ) studies, which may miss landscape-level phenomena that drive ecosystem-level responses. We implemented an ecosystem-scale, nine-year nutrient experiment to examine how saltmarsh plants respond to simulated conditions of coastal eutrophication. Our study differed from previous saltmarsh enrichment studies in that we applied realistic concentrations of nitrate (70-100 μM NO 3 − ), the most common form of coastal nutrient enrichment, via tidal water at the ecosystem scale (~60,000 m 2 creeksheds). Our enrichments added a total of 1,700 kg N·creek −1 ·yr −1 , which increased N loading 10-fold vs. reference creeks (low-marsh, 171 g N·m −2 ·yr −1 ; high-marsh, 19 g N·m −2 ·yr −1 ). Nutrients increased the shoot mass and height of low marsh, tall Spartina alterniflora; however, declines in stem density resulted in no consistent increase in aboveground biomass. High-marsh plants S. patens and stunted S. alterniflora did not respond consistently to enrichment. Nutrient enrichment did not shift community structure, contrary to the prediction of nutrient-driven dominance of S. alterniflora and Distichlis spicata over S. patens. Our mild responses may differ from the results of previous studies for a number of reasons. First, the limited response of the high marsh may be explained by loading rates orders of magnitude lower than previous work. Low loading rates in the high marsh reflect infrequent inundation, arguing that inundation patterns must be considered when predicting responses to estuarine eutrophication. Additionally, we applied nitrate instead of the typically used ammonium, which is energetically favored over nitrate for plant uptake. Thus, the form of nitrogen enrichment used, not just N-load, may be important in predicting plant responses. Overall, our results suggest that when coastal eutrophication is dominated by nitrate and delivered via flooding tidal water, aboveground saltmarsh plant responses may be limited despite moderate-to-high water-column N concentrations. Furthermore, we argue that the methodological limitations of nutrient studies must be considered when using results to inform management decisions about wetlands.

show abstract

“…SIC may account for more than 60 % of soil total carbon in wetlands of the Yangtze River estuary (Cheng et al 2006). Although S. alterniflora could reduce soil pH through secreting low molecular weight organic acids by roots (Hines et al 1994) and preferential uptake of NH þ 4 -N (Mozdzer et al 2011), mean pH value of the water near the Yangtze River estuary was *8.2 (Patra et al 2007). Thus, periodic tidal inundation can maintain the alkaline environment (pH [ 8.0) of soils, ensuring the stability of the SIC pool in the estuary.…”

Section: Tidal Effects On Soil Propertiesmentioning

confidence: 97%

Effects of semi-lunar tidal cycling on soil CO2 and CH4 emissions: a case study in the Yangtze River estuary, China

Hua

et al. 2015

Wetlands Ecol Manage

View full text Add to dashboard Cite

Coastal wetlands, commonly inundated by periodic tides, have been recognized as important sources of greenhouse gases. However, little is known of tidal effects on in situ soil CO 2 and CH 4 emissions in a semi-lunar tidal cycle consisting of neap and spring tide periods (NTP and STP). A field study was conducted in the Yangtze River estuary to investigate temporal variations of soil CO 2 and CH 4 emissions along with the transition from NTP to STP in a semilunar tidal cycle. Soil moisture, salinity and sulfate were significantly greater in STP than in NTP, whereas soil redox potential had an opposite pattern because of frequent tidal inundation. Soil CO 2 and CH 4 effluxes decreased significantly in STP, being 29-34 and 28-35 %, respectively, compared with those in NTP. The decrease in soil CO 2 effluxes was likely attributable to two causes, an anaerobic environment inhibiting CO 2 production, and tidal inundation impeding CO 2 diffusion from the soil into the atmosphere. The inhibition of methanogenesis by increased soil salinity and sulfate was likely the primary reason of the decrease in CH 4 effluxes during STP. Our results suggest that the effects of semi-lunar tidal cycling significantly reduce soil carbon emissions, which may be one of the potential mechanisms underlying strong carbon accumulation in wetlands of the Yangtze River estuary.

show abstract

Nitrogen uptake by the shoots of smooth cordgrass Spartina alterniflora

Cited by 21 publications

References 37 publications

Latitudinal variation in the availability and use of dissolved organic nitrogen in Atlantic coast salt marshes

Latitudinal variation in the availability and use of dissolved organic nitrogen in Atlantic coast salt marshes

Saltmarsh plant responses to eutrophication

Effects of semi-lunar tidal cycling on soil CO2 and CH4 emissions: a case study in the Yangtze River estuary, China

Contact Info

Product

Resources

About