Tight Coupling of Glaciecola spp. and Diatoms during Cold-Water Phytoplankton Spring Blooms

Abstract

Early spring phytoplankton blooms can occur at very low water temperatures but they are often decoupled from bacterial growth, which is assumed to be often temperature controlled. In a previous mesocosm study with Baltic Sea plankton communities, an early diatom bloom was associated with a high relative abundance of Glaciecola sequences (Gammaproteobacteria), at both low (2°C) and elevated (8°C) temperatures, suggesting an important role for this genus in phytoplankton-bacteria coupling. In this study, the temperature-dependent dynamics of free-living Glaciecola spp. during the bloom were analyzed by catalyzed reporter deposition fluorescence in situ hybridization using a newly developed probe. The analysis revealed the appearance of Glaciecola spp. in this and in previous spring mesocosm experiments as the dominating bacterial clade during diatom blooms, with a close coupling between the population dynamics of Glaciecola and phytoplankton development. Although elevated temperature resulted in a higher abundance and a higher net growth rate of Glaciecola spp. (Q10 ∼ 2.2), their growth was, in contrast to that of the bulk bacterial assemblages, not suppressed at 2°C and showed a similar pattern at 8°C. Independent of temperature, the highest abundance of Glaciecola spp. (24.0 ± 10.0% of total cell number) occurred during the peak of the phytoplankton bloom. Together with the slightly larger cell size of Glaciecola, this resulted in a ∼30% contribution of Glaciecola to total bacterial biomass. Overall, the results of this and previous studies suggest that Glaciecola has an ecological niche during early diatom blooms at low temperatures, when it becomes a dominant consumer of phytoplankton-derived dissolved organic matter.

Sensitivity of Bacterioplankton to Environmental Disturbance: A Review of Baltic Sea Field Studies and Experiments

“…Typically, OTUs affiliated with Gammaproteobacteria such as Glaciecola spp. proliferate at higher temperatures (von Scheibner et al, 2017). Gammaproteobacteria also increased in relative abundance in warming experiments of bacterioplankton amended with dissolved organic nitrogen sources and incubated in higher temperatures (Vaquer-Sunyer et al, 2015).…”

“…Glaciecola spp. and also measured metabolic activity of these populations (Brettar et al, 2006;Glaubitz et al, 2014;von Scheibner et al, 2017). Importantly, shifts in abundance of these particular populations were typically coupled to pronounced changes in metabolic activity when exposed to environmental disturbance.…”

Bacterial Response to Permafrost Derived Organic Matter Input in an Arctic Fjord

“…These studies demonstrated selective grazing on large metabolically active bacteria by heterotrophic flagellate grazers. Size-selective predator-prey interactions have also been shown for Glaciecola, that first became abundant upon rapid utilization of phytoplankton derived DOM and subsequently declined in their abundance due to grazing (von Scheibner et al, 2017). It was suggested that once abundant, Glaciecola became a target for size selective predation by protists, including heterotrophic nanoflagellates (HNF) due to their above-average cell size.…”

“…Several studies have examined the ability of bacteria to degrade the seasonally available phytoplankton derived DOM and found that an increase of such carbon sources influences both the structure and the activity of the bacterial community (Pinhassi et al, 2004;Sapp et al, 2007;Teeling et al, 2012). Especially a versatile group of Gammaproteobacteria, belonging to the order Alteromonadales, responds immediately both in abundance and activity, when phytoplankton derived DOM becomes available (Eilers et al, 2000;McCarren et al, 2010;Pedler et al, 2014;Beier et al, 2015;von Scheibner et al, 2017). Only few studies have investigated the effects of terrestrial derived DOM on marine microbial community structure and activity (Herlemann et al, 2014(Herlemann et al, , 2017Blanchet et al, 2017;Traving et al, 2017), of which even less have been conducted in the coastal Arctic (Sipler et al, 2017a).…”

Discovery of functional gene markers of bacteria for monitoring hydrocarbon pollution in the marine environment - a metatranscriptomics approach

“…On the one hand, the genus Glaciecola has been suggested as an early marker (responder) of oil pollution and an oil degrading Glaciecola strain has previously been isolated (Chronopoulou, Sanni et al 2015, Krolicka, Boccadoro et al 2017). On the other hand, this genus has also been suggested to be one of the dominant consumers of phytoplankton-derived organic matter during a cold-water spring bloom (von Scheibner, Sommer et al 2017).…”