Influence of local and regional drivers on spatial and temporal variation of ammonia‐oxidizing communities in Gulf of Mexico salt marshes

Abstract

We characterized ammonia-oxidizing archaea (AOA) and bacteria (AOB) from salt marsh sediments in the Gulf of Mexico over 5 years to identify environmental drivers of nitrifying community patterns following the Deepwater Horizon oil spill. Samples were collected from oiled and unoiled sites in July of 2012-2016 from 12 marshes spanning three regions on the Louisiana coast. No consistent oil effect was detected for either AOA or AOB abundance or community composition. At the local scale, abundance was correlated with changes in marsh elevation, suggesting that oxygen may be an important driver. Regional differences in abundance were best explained by salinity and soil moisture, while interannual variation may be more linked to changes in climate and Mississippi River discharge. Variation of AOA communities was correlated with organic sediment nutrients, while AOB communities were correlated with soil extractable nutrients. AOA and AOB diversity and AOB abundance decreased in 2014 in all regions, suggesting that broad-scale drivers, such as climate, may explain synchronous shifts throughout the coastal area. Our results provide insights about large-scale disturbances on nitrifying microbes in the Gulf of Mexico, and suggest that nitrogen cycling may be controlled primarily by local factors, but large-scale drivers might override these localized differences at times.

Distribution and Diversity of Comammox Nitrospira in Coastal Wetlands of China

“…It showed high homology with Nitrosomonas sp. Nm143 isolated from saltmarsh sediment ( Purkhold et al, 2003 ; Bernhard et al, 2019 ), explaining its wide distribution of higher salinity estuaries in the north and south. Among Nitrosospira species, we found that a Nitrosospira -like branch occupies a dominant position with 89% similarity to the other four pure culture clusters, clustered with some sediment samples in the estuary environment ( Jin et al, 2011 ); further analysis of this strain branch is required.…”

Stochastic factors drive dynamics of ammonia-oxidizing archaeal and bacterial communities in aquaculture pond sediment

“…Although AOA and AOB are reported as being globally distributed ( Martiny et al, 2011 ; Cao et al, 2013 ), significant differences in their regional patterns have been detected. For example, significant regional differences in AOA and AOB community composition have been observed in salt marsh sediments ( Martiny et al, 2011 ; Bernhard et al, 2019 ), sea water ( Sintes et al, 2015 ), forest soil ( Chen et al, 2015 ), and other environments, indicating apparent effects of regional conditions on ammonia-oxidizing communities. Our results provide further evidence for the effect of spatial variables on AOA/AOB communities.…”

“…In addition, research on agricultural cropland has indicated a significant influence of stochastic processes besides deterministic processes on bacterial community assembly ( Barnett et al, 2020 ). A recent study on large-scale disturbances on nitrifying microbes also found region-specific patterns of AOA and AOB, and indicated significant role of regional drivers ( Bernhard et al, 2019 ). These findings suggest that a combination of stochastic and deterministic processes might drive microbial community dynamics in environment under disturbance.…”

“…Indeed, there are still many uncertainties concerning AOA and AOB communities in these environments, as they are not necessarily correlated to specific environmental factors ( Wang et al, 2019 ). Factors that control nitrifying communities are found to vary spatiotemporally ( Bernhard et al, 2019 ). Understanding how ammonia-oxidizing communities in agricultural environments, especially under major disturbance, would be affected by changes of spatial and temporal factors would thus be important for understanding their behavior, and might also help improve, for example, the selection of optimal microbiomes for microbial communities that perform better in a desired process ( Wright et al, 2019 ).…”

Hurricane Disturbance Stimulated Nitrification and Altered Ammonia Oxidizer Community Structure in Lake Okeechobee and St. Lucie Estuary (Florida)

“…Few studies have documented changes in ammonia oxidizer community structure following disturbances in aquatic systems. Responses of ammonia oxidizers to various perturbations differ and include increased AOB diversity or abundance (wastewater, Aalto et al, 2018 ; flow restriction, Bernhard et al, 2015 ; flooding, Bouskill et al, 2011 ; storms, Kan, 2018 ), decreased AOA diversity or abundance (storms, Happel et al, 2018 ; hurricanes, Newell et al, 2014 ), or little to no effect (oil spill, Bernhard et al, 2019 ; oil spill, Marton et al, 2015 ). Here, we observed substantial hurricane impacts on the abundance, community composition, and diversity of ammonia oxidizers.…”