The Pattern of Change in the Abundances of Specific Bacterioplankton Groups Is Consistent across Different Nutrient-Enriched Habitats in Crete

Abstract

A common source of disturbance for coastal aquatic habitats is nutrient enrichment through anthropogenic activities. Although the water column bacterioplankton communities in these environments have been characterized in some cases, changes in ␣-diversity and/or the abundances of specific taxonomic groups across enriched habitats remain unclear. Here, we investigated the bacterial community changes at three different nutrient-enriched and adjacent undisturbed habitats along the north coast of Crete, Greece: a fish farm, a closed bay within a town with low water renewal rates, and a city port where the level of nutrient enrichment and the trophic status of the habitat were different. Even though changes in ␣-diversity were different at each site, we observed across the sites a common change pattern accounting for most of the community variation for five of the most abundant bacterial groups: a decrease in the abundance of the Pelagibacteraceae and SAR86 and an increase in the abundance of the Alteromonadaceae, Rhodobacteraceae, and Cryomorphaceae in the impacted sites. The abundances of the groups that increased and decreased in the impacted sites were significantly correlated (positively and negatively, respectively) with the total heterotrophic bacterial counts and the concentrations of dissolved organic carbon and/or dissolved nitrogen and chlorophyll ␣, indicating that the common change pattern was associated with nutrient enrichment. Our results provide an in situ indication concerning the association of specific bacterioplankton groups with nutrient enrichment. These groups could potentially be used as indicators for nutrient enrichment if the pattern is confirmed over a broader spatial and temporal scale by future studies.

Spatially uniform but temporally variable bacterioplankton in a semi-enclosed coastal area

“…cluster, correlation, and taxonomic analysis) at the class, order, and OTU levels. Group P1 was mainly characterized by the dominance of SAR11 representatives, as shown in previous studies [3,14,15,38]. However, to the best of our knowledge, SAR11 surface community dynamics have only been examined in a seasonal study once before using pyrosequencing [15].…”

“…According to Gilbert et al [15], SAR11 follows nutrient enrichment and dominates in winter, while it seems to decrease in high chlorophyll a and DOC concentrations [15]. In another study across different nutrient-enriched habitats on the north coast of Crete (GR), pyrosequencing highlighted an increase of SAR11 with decreasing DOC concentration and chlorophyll a fluorescence [14]. However, Eiler et al [13] and Tada et al [47] have observed an increase in SAR11 during diatom blooms and in high chlorophyll a concentrations.…”

“…To date, most studies using NGS techniques have focused on the changes in bacterial diversity related to depth [9,19,34], time [5,15,28,49], or space [19,32,35,53] in oceanic and offshore waters. Similar studies of coastal environments close to and directly impacted by land masses are limited [14], while those investigating the temporal shifts of bacterioplankton in these dynamic ecosystems are even less common [52]. Consequently, this study was designed in order to investigate whether location (space) or time (season) were more important in shaping bacterial diversity in a coastal ecosystem under high anthropogenic pressure.…”

Declining diversity of egg-associated bacteria during development of naturally spawned whitefish embryos (Coregonus spp.)

“…They can be used as an indicator of nitrogen or phosphorus deficiency. Alteromonadaceae is a bacterial family that contains many genera that belong to bacterioplankton (Fodelianakis et al 2014) and can resist low temperatures (Ivanova et al 2004). Citrobacter, the last group that was characterized for this group of whitefish eggs, are ubiquitous bacteria that contain many species that may use citrate as a sole carbon source (Madigan et al 2010).…”

Effects of organic pollution on biological communities of marine biofilm on hard substrata

“…DNA extraction was performed according to Massana et al (1997) with some modifications, as described in Fodelianakis et al (2014b). DNA yield was quantified by the use of a spectrophotometer (NanoDrop Technologies, Wilmington, USA).…”