Contribution of bacteria in the mucilage of Microcystis spp. (Cyanobacteria) to benthic and pelagic bacterial production in a hypereutrophic lake

Abstract

The mucilage of cyanobacteria represents a unique habitat for both water column and sediment bacteria. In Lake Vallentunasjön, Sweden, the pelagic Microcystis‐associated bacteria constituted 19–40% of the total bacterial abundance, and their contribution to the total bacterial production was 7–30%. In the sediment, the mucilage bacteria constituted only 1–5% of the total bacterial abundance, but contributed with 8–13% to the total bacterial production during the summer. Microcystis‐associated bacteria thus were less active (bacterial production/cell) than ambient water column bacteria, while in the sediments the Microcystis colonies were ‘hot spots’ with enhanced bacterial activity as compared to other sediment bacteria.

Quantitative studies on phosphorus transference occuring between Microcystis aeruginosa and its attached bacterium (Pseudomonas sp.)

“…When the intracellular phosphorus content of M. aeruginosa was luxury, it grew by utilization of the intracellular phosphorus in its lag and exponential phases (Okada & Sudo, 1982), thus, only 20% of intracellular phosphorus was released form M. aeruginosa to aqueous solution and to Pseudomonas. However, M. aeruginosa released a lot of phosphorus in its stationary and decline phases while it could simultaneously provide Pseudomonas with organic carbon and trace elements (Sommaruga & Robarts, 1997;Worm, 1998;Brunberg, 1999). Thus, the growth of Pseudomonas was better and the assimilated phosphorus was more when M. aeruginosa was in decline phase than that in stationary phase.…”

Morphological Response of Microcystis aeruginosa to Grazing by Different Sorts of Zooplankton

“…The weaker colonyinducing effect may be due to axenic culture of M. aeruginosa used in the experiment. It is well known that the mucilage keeps the typical shape of a Microcystis colony and colonies of Microcystis in eutrophic lakes are commonly found with numerous bacteria embedded in the mucilage (Bostro¨m et al, 1989;Brunberg, 1999). It is likely that the colony formation of this species in natural water is also associated with other factors such as bacteria may give an advantage to M. aeruginosa to maintain colony mucilage (Brunberg, 1999).…”

“…It is well known that the mucilage keeps the typical shape of a Microcystis colony and colonies of Microcystis in eutrophic lakes are commonly found with numerous bacteria embedded in the mucilage (Bostro¨m et al, 1989;Brunberg, 1999). It is likely that the colony formation of this species in natural water is also associated with other factors such as bacteria may give an advantage to M. aeruginosa to maintain colony mucilage (Brunberg, 1999). In addition, various abiotic factors of the field environment, such as temperature, light, nutrients, and windinduced turbulence, may also play an important role on colony formation in M. aeruginosa.…”

Metatranscriptomic Evidence for Co-Occurring Top-Down and Bottom-Up Controls on Toxic Cyanobacterial Communities

“…To date, research efforts have broadly identified nutrient inputs and temperature as contributing factors in the development of such blooms, but little focus, due primarily to methodological limitations, has been allocated to the study of the cellular physiology and metabolism of the entire bloom community. Not only do bloom-forming organisms such as Microcystis aeruginosa live in competition with other phytoplankton species, they also live in concert with heterotrophic bacteria, which can attach to the mucilaginous matrix produced by M. aeruginosa colonies (15,16). There is a dearth of information concerning the functional role that co-occurring bacteria may play in bloom dynamics, although recent studies suggest that heterotrophs may play an important role in the metabolism of some nutrients (17,18).…”