Short‐ and long‐term effects of nutrient enrichment on salt marsh plant production and microbial community structure

Abstract

1. Nutrient enrichment impacts ecosystems globally. Population history, especially past resource environments, of numerically dominant plant species may affect their responses to subsequent changes in nutrient availability. Eutrophication can also alter plant-microbe interactions via direct effects on associated microbial communities or indirect effects on dominant species' biomass production/allocation as a result of modified plant-soil interactions.2. We combined a greenhouse common garden and a field reciprocal transplant of a salt marsh foundation species (Spartina alterniflora) within a long-term, wholeecosystem, nutrient-enrichment study to determine whether enrichment affects plant production and microbial community structure differently depending on plant population history. For the greenhouse portion, we collected 20 S. alterniflora genotypes-10 from an enriched creek that had received elevated nutrient inputs for 10 years and 10 from an unenriched reference creek-and reared them in a common garden for 1 year. For the field portion, we conducted a 2-year, fully crossed reciprocal transplant experiment with two gardens each at the enriched and unenriched sites; we examined the effects of source site (i.e. population history), garden site and plant genotype.3. After 2 years, plants in enriched gardens had higher above-ground biomass and altered below-ground allocation compared to plants in unenriched gardens.However, performance also depended on plant population history: plants from the enriched site had decreased above-ground and rhizome production compared to plants from the unenriched site, most notably in unenriched gardens. In addition, almost all above-and below-ground traits varied depending on plant genotypic identity.4. Effects of nutrient enrichment on the associated microbial community were also pronounced. Following 1 year in common garden, microbial community structure varied by plant population history and S. alterniflora genotypic identity. However, at the end of the reciprocal transplant, microbial communities differed primarily between enriched and unenriched gardens. 5. Synthesis. Nutrient enrichment can impact plant foundation species and associated soil microbes in the short term. Most importantly, nutrient enrichment can

Spatial and temporal variations in salt marsh microorganisms of the Wadden Sea

“…Recent studies indicated the use of these marine resources by soil mesofauna of the salt marsh (Haynert et al, 2017 ; Winter et al, 2018 ). The activity of microbes breaking down plant material is influenced by abiotic factors such as soil temperature, water concentration, nutrient addition, and soil anoxia (Hanley et al, 2021 ; Hemminga & Buth, 1991 ). Therefore, changes in abiotic pressures across marsh zones may influence microbial processes via changes in microbial community composition and thereby their functioning as blue carbon system.…”

“…Therefore, changes in abiotic pressures across marsh zones may influence microbial processes via changes in microbial community composition and thereby their functioning as blue carbon system. However, most studies focusing on the breakdown of detrital material and microbial activity, investigated North American salt marshes (Gandy & Yoch, 1988 ; Hanley et al, 2021 ; Newell et al, 1989 ; Sherr & Payne, 1978 ), differing from Wadden Sea marshes in their microtidal range (<2 m) and their organogenic nature resulting in the accretion of organic material, rather than sediment (Allen, 2000 ; Kearney & Turner, 2016 ). Studies on European marshes focused on the rate of decomposition, the contribution of fungi or bacteria, and the fate of detrital material of salt marsh plants (Benner et al, 1984 ; Bouchard et al, 1998 ; Bouchard & Lefeuvre, 2000 ).…”

Mitigation of nitrogen inputs causes native Phragmites australis recovery following Spartina alterniflora invasion

“…3). Although exotic plants can invade low-resource ecosystems by optimizing their strategies (e.g., increasing root biomass allocation) to acquire and use resources 25,42 , the long-lasting effects of nutrient enrichment on plants (e.g., decreasing their nutrient acquisition e ciency) may compromise their ability to absorb nutrients [42][43][44] . Moreover, invasive plants can increase soil N by stimulating the decomposition of their nutrient-rich litter in fertile soils of terrestrial ecosystems 45,46 , but these oxic decomposition processes are largely limited in the water-saturated, anoxic sediments of wetlands 47,48 .…”

The structure of coastal invertebrate communities and their temporal and spatial dynamics

“…Recent studies indicated the use of these marine resources by soil mesofauna of the salt marsh . The activity of microbes breaking down plant material is influenced by abiotic factors such as soil temperature, water concentration, nutrient addition, and soil anoxia (Hanley et al, 2021;Hemminga & Buth, 1991). Therefore, changes in abiotic pressures across marsh zones may influence microbial processes via changes in microbial community composition and thereby their functioning as blue carbon system.…”

“…Therefore, changes in abiotic pressures across marsh zones may influence microbial processes via changes in microbial community composition and thereby their functioning as blue carbon system. However, most studies focusing on the breakdown of detrital material and microbial activity, investigated North American salt marshes (Gandy & Yoch, 1988;Hanley et al, 2021;Newell et al, 1989;Sherr & Payne, 1978), differing from Wadden Sea marshes in their microtidal range (<2 m) and their organogenic nature resulting in the accretion of organic material, rather than sediment . Studies on European marshes focused on the rate of decomposition, the contribution of fungi or bacteria, and the fate of detrital material of salt marsh plants .…”