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Al Ashhab, A.

Publications and source records attributed to Al Ashhab, A..

2 recordsLinked to original sources
bioRxiv2021

Seasonal dynamics are the major driver of microbial diversity and composition in intensive freshwater aquaculture

Aquaculture facilities such as fishponds are one of the most anthropogenically impacted freshwater ecosystems. The high fish biomass reared in aquaculture is associated with an intensive input into the water of fish-feed and fish excrements. This nutrients load may affect the microbial community in the water, which in turn can impact the fish health. To determine to what extent aquaculture practices and natural seasonal cycles affect the microbial populations, we characterized the microbiome of an inter-connected aquaculture system at monthly resolution, over three years. The system comprised two fishponds, where fish are grown, and a "control" operational water reservoir in which fish are not actively stocked. Clear natural seasonal cycles of temperature and inorganic nutrients concentration, as well as recurring cyanobacterial blooms during summer, were observed in both the fishponds and the reservoir. The structure of the aquatic bacterial communities in the system, characterized using 16S rRNA sequencing, was explained primarily by the natural seasonality, whereas aquaculture-related parameters had only a minor explanatory power. However, the cyanobacterial blooms were characterized by different cyanobacterial clades dominating at each fishpond, possibly in response to distinct nitrogen and phosphate ratios. In turn, nutrient ratios may have been by the magnitude of fish feed input. Taken together, our results show that, even in strongly anthropogenically impacted aquatic ecosystems, the structure of bacterial communities is mainly driven by the natural seasonality, with more subtle effects if aquaculture-related factors. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=114 SRC="FIGDIR/small/433039v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@154d693org.highwire.dtl.DTLVardef@d35ae9org.highwire.dtl.DTLVardef@1f5a7a2org.highwire.dtl.DTLVardef@d07fbc_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIWe present three years of monthly microbiome data from an aquaculture facility. C_LIO_LIThe microbiome changes seasonally, likely driven by temperature and rainwater runoff. C_LIO_LISummer blooms of toxin-producing cyanobacteria are repeatedly observed. C_LIO_LIFish food may impact microbiome through changes in nutrient ratios. C_LI

ecology↗
bioRxiv2020

Temporal and spatial changes in phyllosphere microbiome of acacia trees growing in super arid environments

Along the arid Arava, southern Israel, acacia trees (Acacia raddiana and Acacia tortilis) are considered keystone species. In this study, we investigated the ecological effects of plant species, microclimate (different areas within the tree canopies) and seasonality on the endophytic and epiphytic microbiome associated with these two tree species. 186 leaf samples were collected along different seasons throughout the year and their microbial communities were studied using the diversity of the 16S rDNA gene sequenced on the 150-PE Illumina sequencing platform. Results show that endophytic, but not epiphytic, microbiome communities were different between the two acacia species. Endophytic, but not epiphytic, microbiome was affected by temporal changes (seasons) in air temperature. Acacia canopy microclimate was also found to have a significant effect on exosphere microbiome, with A. tortilis having a higher microbial diversity than A. raddiana with significantly different community compositions in different seasons. ImportanceThe evolutionary relationships and interactions between plants and their microbiome are of high importance to the survival of plants in extreme conditions. Changes in microbiome of plants can affect plant development, growth and health. In this study, we explored the relationship between keystone desert trees and their microbiome along seasonal variation. These results shed light on the importance and uniqueness of desert phyllosphere microbiome. Although acacia trees are considered keystone species in many arid regions, to the best of our knowledge, this is the first time that microbial descriptors have been applied in these systems. This work constitutes a new approach to the assessment of these important trees and a stepping stone in the application of microbial communities as a putative marker in a changing environment.

ecology↗