scholarly journals Microbial and nutrient dynamics in mangrove, reef, and seagrass waters over tidal and diurnal time scales

2020 ◽  
Vol 85 ◽  
pp. 101-119
Author(s):  
CC Becker ◽  
L Weber ◽  
JJ Suca ◽  
JK Llopiz ◽  
TA Mooney ◽  
...  

In coral reefs and adjacent seagrass meadow and mangrove environments, short temporal scales (i.e. tidal, diurnal) may have important influences on ecosystem processes and community structure, but these scales are rarely investigated. This study examines how tidal and diurnal forcings influence pelagic microorganisms and nutrient dynamics in 3 important and adjacent coastal biomes: mangroves, coral reefs, and seagrass meadows. We sampled for microbial (Bacteria and Archaea) community composition, cell abundances and environmental parameters at 9 coastal sites on St. John, US Virgin Islands that spanned 4 km in distance (4 coral reefs, 2 seagrass meadows and 3 mangrove locations within 2 larger bays). Eight samplings occurred over a 48 h period, capturing day and night microbial dynamics over 2 tidal cycles. The seagrass and reef biomes exhibited relatively consistent environmental conditions and microbial community structure but were dominated by shifts in picocyanobacterial abundances that were most likely attributed to diel dynamics. In contrast, mangrove ecosystems exhibited substantial daily shifts in environmental parameters, heterotrophic cell abundances and microbial community structure that were consistent with the tidal cycle. Differential abundance analysis of mangrove-associated microorganisms revealed enrichment of pelagic oligotrophic taxa during high tide and enrichment of putative sediment-associated microbes during low tide. Our study underpins the importance of tidal and diurnal time scales in structuring coastal microbial and nutrient dynamics, with diel and tidal cycles contributing to a highly dynamic microbial environment in mangroves, and time of day likely contributing to microbial dynamics in seagrass and reef biomes.

2013 ◽  
Vol 864-867 ◽  
pp. 339-342
Author(s):  
Ji Hua Wang ◽  
Jan Fei Guan ◽  
Di Cui ◽  
Ang Li ◽  
Xiang Liu ◽  
...  

In urban river ecosystem, microorganism plays a vital role in maintaining ecological balance. Microbial community structure changes triggered with the river remediation progress. However, the change process in different sites from ecological remediation river has not been explored deeply before. We used polymerase chain reaction-denaturing gradient gelelectrophoresis (PCR-DGGE) to examine bacterial diversity of ecological remediated river in Changzhou City, China, and with rarely and severely contaminated rivers which from the same regions as reference. Molecular data were related to environmental parameters through multivariate analysis to investigate the relationship between potential impact of water quality and microbial community structure. As the ecological remediated river, NH3-N and TP were the important environmental variables influencing microbial community composition. After remediation, the microbial community structure showed a good consistency in each site, the microbial diversity and function were greatly improved, too.


2016 ◽  
Author(s):  
Manuel Aira ◽  
Andrea Tato ◽  
Jorge Domínguez

Bracken fern (Pteridium aquilinum) is one of the most successful plant colonizers of soils in temperate regions; however, its effects on microbial community structure and activity and nutrient dynamics remain poorly understood. We studied whether colonization of forest soil by bracken fern modifies the structure and function of the soil microbial communities and considered the implications for ecosystem functioning. For this purpose, we analyzed microbial community structure (PLFAs) and activity (basal respiration, metabolic quotient), litter decomposition and nutrient dynamics (C, N and P) in monospecific oak (Quercus robur L.), eucalyptus (Eucalyptus globulus Labill.) and maritime pine forests (Pinus pinaster Aiton) colonized by bracken fern. Colonization of forest soil by bracken fern led to a reduction in differences in microbial community structure, as revealed by principal component and cluster analysis, although samples from oak forests were grouped separately. According to this, bracken litter decomposed to a greater extent than native tree litter in pine forest soils, whereas the opposite was found in oak forest soils. Such differences were not observed in eucalyptus forest soils. Colonization by bracken fern affected C mineralization, with no difference between the different types of forest; however, both N and P mineralization were higher in oak than in the other types of forest. In conclusion, colonization by bracken fern homogenizes soil microbial community structure. Differences in the decomposability of bracken litter in the different forest systems suggest a high degree of metabolic specialization of soil microorganisms. Thus, the soil microorganisms associated with bracken are continuously driven to decompose the bracken litter. In the long-term this will alter nutrient cycling, slowing decomposition and enhancing sequestering of nutrients by bracken ferns.


2016 ◽  
Author(s):  
Christian Wurzbacher ◽  
Andrea Fuchs ◽  
Katrin Attermeyer ◽  
Katharina Frindte ◽  
Hans-Peter Grossart ◽  
...  

AbstractSediments are depositional areas where particles sink from water columns, but they are also microbial hotspots that play an important role in biogeochemical cycles. Unfortunately, the importance of both processes in structuring microbial community composition has not been assessed. We surveyed all organismic signals of the last ca. 170 years of sediment by metabarcoding, identifying global trends for eukaryotes, bacteria, archaea, and monitored 40 sediment parameters. We linked the microbial community structure to ongoing and historical environmental parameters and defined three distinct sediment horizons. This not only expands our knowledge of freshwater sediments, but also has profound implications for understanding the microbial community structure and function of sediment communities in relation to future, present, and past environmental changes.


2016 ◽  
Author(s):  
Manuel Aira ◽  
Andrea Tato ◽  
Jorge Domínguez

Bracken fern (Pteridium aquilinum) is one of the most successful plant colonizers of soils in temperate regions; however, its effects on microbial community structure and activity and nutrient dynamics remain poorly understood. We studied whether colonization of forest soil by bracken fern modifies the structure and function of the soil microbial communities and considered the implications for ecosystem functioning. For this purpose, we analyzed microbial community structure (PLFAs) and activity (basal respiration, metabolic quotient), litter decomposition and nutrient dynamics (C, N and P) in monospecific oak (Quercus robur L.), eucalyptus (Eucalyptus globulus Labill.) and maritime pine forests (Pinus pinaster Aiton) colonized by bracken fern. Colonization of forest soil by bracken fern led to a reduction in differences in microbial community structure, as revealed by principal component and cluster analysis, although samples from oak forests were grouped separately. According to this, bracken litter decomposed to a greater extent than native tree litter in pine forest soils, whereas the opposite was found in oak forest soils. Such differences were not observed in eucalyptus forest soils. Colonization by bracken fern affected C mineralization, with no difference between the different types of forest; however, both N and P mineralization were higher in oak than in the other types of forest. In conclusion, colonization by bracken fern homogenizes soil microbial community structure. Differences in the decomposability of bracken litter in the different forest systems suggest a high degree of metabolic specialization of soil microorganisms. Thus, the soil microorganisms associated with bracken are continuously driven to decompose the bracken litter. In the long-term this will alter nutrient cycling, slowing decomposition and enhancing sequestering of nutrients by bracken ferns.


2009 ◽  
Vol 27 (4) ◽  
pp. 385-387
Author(s):  
W. D. Eaton ◽  
B. Wilmot ◽  
E. Epler ◽  
S. Mangiamelli ◽  
D. Barry

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