Spatial and temporal patterns of benthic nutrient cycling define the extensive role of internal loading in an agriculturally influenced oxbow lake

Nifong, Rachel L.; Taylor, Jason M.; DeVilbiss, Stephen

doi:10.1007/s10533-022-00935-7

Cited by 8 publications

(1 citation statement)

References 107 publications

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“…Excess bioavailable N may be removed from streams through complete microbial denitrification, which converts bioavailable nitrate to inert N 2 gas (Mulholland et al, 2008; Schlesinger, 2009). In contrast, nutrient loading to agricultural water bodies in the spring can lead to high algal production and eventual limitation in the summer, potentially stimulating N‐fixation (Marcarelli & Wurtsbaugh, 2009; Nifong et al, 2022). Decomposition of herbicides and pesticides can also be accelerated by bacteria that possess the unique cellular machinery required to metabolize these compounds, helping reduce toxic effects to wildlife and lower concentrations in drinking water (Aislabie & Lloyd‐Jones, 1995).…”

Section: Introductionmentioning

confidence: 99%

Salinization and sedimentation drive contrasting assembly mechanisms of planktonic and sediment‐bound bacterial communities in agricultural streams

DeVilbiss,

Taylor,

Hicks

2023

Global Change Biology

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Agriculture is the most dominant land use globally and is projected to increase in the future to support a growing human population but also threatens ecosystem structure and services. Bacteria mediate numerous biogeochemical pathways within ecosystems. Therefore, identifying linkages between stressors associated with agricultural land use and responses of bacterial diversity is an important step in understanding and improving resource management. Here, we use the Mississippi Alluvial Plain (MAP) ecoregion, a highly modified agroecosystem, as a case study to better understand agriculturally associated drivers of stream bacterial diversity and assembly mechanisms. In the MAP, we found that planktonic bacterial communities were strongly influenced by salinity. Tolerant taxa increased with increasing ion concentrations, likely driving homogenous selection which accounted for ~90% of assembly processes. Sediment bacterial phylogenetic diversity increased with increasing agricultural land use and was influenced by sediment particle size, with assembly mechanisms shifting from homogenous to variable selection as differences in median particle size increased. Within individual streams, sediment heterogeneity was correlated with bacterial diversity and a subsidy‐stress relationship along the particle size gradient was observed. Planktonic and sediment communities within the same stream also diverged as sediment particle size decreased. Nutrients including carbon, nitrogen, and phosphorus, which tend to be elevated in agroecosystems, were also associated with detectable shifts in bacterial community structure. Collectively, our results establish that two understudied variables, salinity and sediment texture, are the primary drivers of bacterial diversity within the studied agroecosystem, whereas nutrients are secondary drivers. Although numerous macrobiological communities respond negatively, we observed increasing bacterial diversity in response to agricultural stressors including salinization and sedimentation. Elevated taxonomic and phylogenetic bacterial diversity likely increases the probability of detecting community responses to stressors. Thus, bacteria community responses may be more reliable for establishing water quality goals within highly modified agroecosystems that have experienced shifting baselines.

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Section: Introductionmentioning

confidence: 99%

Salinization and sedimentation drive contrasting assembly mechanisms of planktonic and sediment‐bound bacterial communities in agricultural streams

DeVilbiss,

Taylor,

Hicks

2023

Global Change Biology

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Evaluating O₂ : Ar, N₂ : Ar, and ^29,30N₂ using membrane inlet mass spectrometry configured to minimize oxygen interference

Boedecker,

Taylor,

Tappenbeck

et al. 2024

Limnology & Ocean Methods

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Membrane inlet mass spectrometry (MIMS) provides detailed measures of dissolved 28,29,30N2, O2, and argon (Ar) for estimating important gas fluxes and concentrations in aquatic ecosystems. Previous studies demonstrated a large O2 scavenging effect while using a MIMS, where varying concentrations of O2 can affect measured N2 : Ar because O2 interacts with N2 in the ion source to produce NO+ (m/z = 30), potentially decreasing the detected current for 28,29N2 and increasing the detected current for 30N2. A common solution is to use a muffle furnace heated to 600°C with a copper reduction column to reduce the concentration of O2 to minimal levels and accurately measure 28,29,30N2. However, this solution eliminates the detection of O2 in environmental samples, which is a major benefit of using a MIMS. We questioned whether the MIMS was sensitive enough to provide accurate O2 estimates when using the furnace and whether the O2 scavenging effect was real and consistent among MIMS. We conducted four separate experiments on three different MIMS to test the O2 scavenging effect and the potential detection of O2 when using a MIMS with furnace. The furnace removed ~ 99% of O2, and O2 scavenging had little to no detectable effect on N2 : Ar and an unclear effect on 29N2 : 28N2, but increased 30N2 : 28N2. In most cases, accurate O2 data could be retrieved despite using the furnace. The need for O2 reduction may be limited to measuring accurate 30N2 : 28N2 in isotope pairing studies, but without substantial loss of MIMS measurements used to describe O2 dynamics.

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In-situ N2:Ar ratios describe the balance between nitrogen fixation and denitrification in shallow eutrophic experimental lakes

et al. 2023

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Spatial and temporal patterns of benthic nutrient cycling define the extensive role of internal loading in an agriculturally influenced oxbow lake

Cited by 8 publications

References 107 publications

Salinization and sedimentation drive contrasting assembly mechanisms of planktonic and sediment‐bound bacterial communities in agricultural streams

Salinization and sedimentation drive contrasting assembly mechanisms of planktonic and sediment‐bound bacterial communities in agricultural streams

Evaluating O₂ : Ar, N₂ : Ar, and ^29,30N₂ using membrane inlet mass spectrometry configured to minimize oxygen interference

In-situ N2:Ar ratios describe the balance between nitrogen fixation and denitrification in shallow eutrophic experimental lakes

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Spatial and temporal patterns of benthic nutrient cycling define the extensive role of internal loading in an agriculturally influenced oxbow lake

Cited by 8 publications

References 107 publications

Salinization and sedimentation drive contrasting assembly mechanisms of planktonic and sediment‐bound bacterial communities in agricultural streams

Salinization and sedimentation drive contrasting assembly mechanisms of planktonic and sediment‐bound bacterial communities in agricultural streams

Evaluating O2 : Ar, N2 : Ar, and 29,30N2 using membrane inlet mass spectrometry configured to minimize oxygen interference

In-situ N2:Ar ratios describe the balance between nitrogen fixation and denitrification in shallow eutrophic experimental lakes

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Evaluating O₂ : Ar, N₂ : Ar, and ^29,30N₂ using membrane inlet mass spectrometry configured to minimize oxygen interference