Community Structure of the Bacteria Associated with Nodularia sp. (Cyanobacteria) Aggregates in the Baltic Sea

Tuomainen, Jaana; Hietanen, Susanna; Kuparinen, Jorma; Martikainen, Pertti J.; Servomaa, Kristina

doi:10.1007/s00248-006-9130-0

Cited by 38 publications

(44 citation statements)

References 54 publications

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“…Further, when we compared members of our library with common surface associated or algal associated organisms-for example, specific members of the Roseobacteria clade (Mayali et al, 2008;Wagner-Döbler et al, 2009) and 9% respectively of OTUs which share 97 PSI or better with their nearest GenBank relatives. These results are similar to those obtained during a study of the bacterial flora associated with another filamentous cyanobacterium, Nodularia, which found that the majority of epibiont clones associated with Nodularia represented novel taxa (Tuomainen et al, 2006). Our data suggest that the phycosphere associated with Trichodesmium and other cyanobacteria is a novel ecological niche host to unexplored genetic diversity.…”

Section: Puff and Tuft-type Trichodesmium Colonies Are A Unique Envirsupporting

confidence: 90%

“…These associations are the subject of numerous studies and in many cases have been found to be quite specific (Paerl & Gallucci, 1985;Fisher et al, 1998;Stevenson & Waterbury, 2006;Tuomainen et al, 2006) and in some cases, symbiotic . Bacteria colonize algae throughout their life-cycle and at all bloom stages and this colonization is not considered to be a sign of senescence or disease Sapp et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…They are capable of fixing at least 80 Gt N y -1 in extremely low-nutrient, oligotrophic marine environments; as such, they are understood to be a major source of fixed carbon and reduced nitrogen to these environments and fuel hotspots of microbial activity in surface waters (Letelier & Karl, 1996;Capone et al, 1997;Carpenter et al, 1997) The heterotrophic epibionts attached to nitrogen-fixing cyanobacteria may well achieve broad ecological impacts insomuch as they may influence the longevity of blooms (Tuomainen et al, 2006) and the efficiency of nitrogen fixation by contributing to the formation of anoxic microzones within cyanobacterial colonies Paerl & Pinckney, 1996). It is extraordinarily difficult to isolate Trichodesmium spp.…”

Section: Introductionmentioning

confidence: 99%

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Microbial interactions associated with biofilms attached to Trichodesmium spp. and detrital particles in the ocean

Hmelo¹

2010

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Quorum sensing (QS) via acylated homoserine lactones (AHLs) was discovered in the ocean, yet little is known about its role in the ocean beyond its involvement in certain symbiotic interactions. The objectives of this thesis were to constrain the chemical stability of AHLs in seawater, explore the production of AHLs in marine particulate environments, and probe selected behaviors which might be controlled by AHL-QS. I established that AHLs are more stable in seawater than previously expected and are likely to accumulate within biofilms. Based on this result, I chose to study AHL-QS in the bacterial communities inhabiting biofilms attached to Trichodesmium spp. and detrital (photosynthetically-derived sinking particulate organic carbon, POC) particles. These hot spots of microbial activity are primary sites of interaction between marine primary producers and heterotrophs and crucial components of the biological pump.Biofilm communities associated with Trichodesmium thiebautii colonies in the Sargasso Sea differed considerably from seawater microbial communities. In addition, there was no overlap between the communities associated with tuft and puff colonies. These results suggest that bacterial communities associated with Trichodesmium are not random; rather, Trichodesmium selects for specific microbial flora. Novel 16S rRNA gene sequences are present both in clone libraries constructed from DNA extracted from colonies of Trichodesmium spp. and in culture collections derived from wild and laboratory cultivated Trichodesmium spp., supporting the idea that the phycosphere of Trichodesmium is a unique microenvironment.Using high performance liquid chromatography-mass spectrometry, I demonstrated that bacteria isolated from Trichodesmium synthesize AHLs. In addition, I detected AHLs in sinking particles collected from a site off of Vancouver Island, Canada. AHLs were subsequently added to laboratory cultures of non-axenic Trichodesmium colonies and sinking POC samples. This is the first time AHLs have been detected in POC and indicates that AHL-QS was occurring in POC. Further, I showed that AHLs enhanced certain organic-matter degrading hydrolytic enzyme activities. My results suggest that AHL-QS is a factor regulating biogeochemically relevant enzyme activities on sinking POC and within the biofilms attached to Trichodesmium colonies and thereby may impact the timing and magnitude of biogeochemical fluxes in the ocean.

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Section: Puff and Tuft-type Trichodesmium Colonies Are A Unique Envirsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Microbial interactions associated with biofilms attached to Trichodesmium spp. and detrital particles in the ocean

Hmelo¹

2010

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“…The lowest NH 4 þ release was measured in colonies with the highest respiration relative to gross photosynthesis (Table 3). N. spumigena is usually colonized by a diverse community of bacteria exhibiting high ecto-enzymatic activities (Hoppe, 1981;Stoecker et al, 2005;Tuomainen et al, 2006), and a significant fraction of the primary production, measured by use of H 14 CO 3 in N. spumigena colonies from the Baltic Sea, was incorporated into the associated bacteria (Hoppe, 1981). Many pelagic bacteria are motile, show chemotaxis and their colonization rates of particles are in the order of minutes (Kiørboe et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

Carbon, nitrogen and O2 fluxes associated with the cyanobacterium Nodularia spumigena in the Baltic Sea

et al. 2011

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Photosynthesis, respiration, N 2 fixation and ammonium release were studied directly in Nodularia spumigena during a bloom in the Baltic Sea using a combination of microsensors, stable isotope tracer experiments combined with nanoscale secondary ion mass spectrometry (nanoSIMS) and fluorometry. Cell-specific net C-and N 2 -fixation rates by N. spumigena were 81.6±6.7 and 11.4 ± 0.9 fmol N per cell per h, respectively. During light, the net C:N fixation ratio was 8.0 ± 0.8. During darkness, carbon fixation was not detectable, but N 2 fixation was 5.4 ± 0.4 fmol N per cell per h. Net photosynthesis varied between 0.34 and 250 nmol O 2 h À1 in colonies with diameters ranging between 0.13 and 5.0 mm, and it reached the theoretical upper limit set by diffusion of dissolved inorganic carbon to colonies (41 mm). Dark respiration of the same colonies varied between 0.038 and 87 nmol O 2 h À1 , and it reached the limit set by O 2 diffusion from the surrounding water to colonies (41 mm). N 2 fixation associated with N. spumigena colonies (41 mm) comprised on average 18% of the total N 2 fixation in the bulk water. Net NH 4 þ release in colonies equaled 8-33% of the estimated gross N 2 fixation during photosynthesis. NH 4 þ concentrations within light-exposed colonies, modeled from measured net NH 4 þ release rates, were 60-fold higher than that of the bulk. Hence, N. spumigena colonies comprise highly productive microenvironments and an attractive NH 4 þ microenvironment to be utilized by other (micro)organisms in the Baltic Sea where dissolved inorganic nitrogen is limiting growth.

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“…For instance, in the Baltic Sea, Grossart et al (2003) found 100 to 360 times higher cell-specific protease and β-glucosidase activities, respectively, in aggregates compared to water surrounding the aggregates. As aggregates often harbor diverse communities of microorganisms that differ from their free living counterparts (DeLong et al, 1993;Bidle and Fletcher, 1995;Tuomainen et al, 2006), differences in microbial community structure may explain variations in the level of cell-specific activity.…”

Section: Introductionmentioning

confidence: 99%

Changes in the spectrum and rates of extracellular enzyme activities in seawater following aggregate formation

2010

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Abstract. Marine snow aggregates are heavily colonized by heterotrophic microorganisms that express high levels of hydrolytic activities, making aggregates hotspots for carbon remineralization in the ocean. To assess how aggregate formation influences the ability of seawater microbial communities to access organic carbon, we compared hydrolysis rates of six polysaccharides in coastal seawater after aggregates had been formed (via incubation on a roller table) with hydrolysis rates in seawater from the same site that had not incubated on a roller table (referred to as whole seawater). Hydrolysis rates in the aggregates themselves were up to three orders of magnitude higher on a volume basis than in whole seawater. The enhancement of enzyme activity in aggregates relative to whole seawater differed by substrate, suggesting that the enhancement was under cellular control, rather than due to factors such as lysis or grazing. A comparison of hydrolysis rates in whole seawater with those in aggregatefree seawater, i.e. the fraction of water from the roller bottles that did not contain aggregates, demonstrated a nuanced microbial response to aggregate formation. Activities of laminarinase and xylanase enzymes in aggregate-free seawater were higher than in whole seawater, while activities of chondroitin, fucoidan, and arabinogalactan hydrolyzing enzymes were lower than in whole seawater. These data suggest that aggregate formation enhanced production of laminarinase and xylanase enzymes, and the enhancement also affected the surrounding seawater. Decreased activities of chondroitin, fucoidan, and arabinoglactan-hydrolyzing enzymes in aggregate-free seawaters relative to whole seawater are likely due to shifts in enzyme production by the aggregateCorrespondence to: K. Ziervogel (ziervoge@email.unc.edu) associated community, coupled with the effects of enzyme degradation. Enhanced activities of laminarin-and xylanhydrolyzing enzymes in aggregate-free seawater were due at least in part to cell-free enzymes. Measurements of enzyme lifetime using commercial enzymes suggest that hydrolytic cell-free enzymes may be active over timescales of days to weeks. Considering water residence times of up to 10 days in the investigation area (Apalachicola Bay), enzymes released from aggregates may be active over timescales long enough to affect carbon cycling in the Bay as well as in the adjacent Gulf of Mexico. Aggregate formation may thus be an important mechanism shaping the spectrum of enzymes active in the ocean, stimulating production of cell-free enzymes and leading to spatial and temporal decoupling of enzyme activity from the microorganisms that produced them.

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Community Structure of the Bacteria Associated with Nodularia sp. (Cyanobacteria) Aggregates in the Baltic Sea

Cited by 38 publications

References 54 publications

Microbial interactions associated with biofilms attached to Trichodesmium spp. and detrital particles in the ocean

Microbial interactions associated with biofilms attached to Trichodesmium spp. and detrital particles in the ocean

Carbon, nitrogen and O2 fluxes associated with the cyanobacterium Nodularia spumigena in the Baltic Sea

Changes in the spectrum and rates of extracellular enzyme activities in seawater following aggregate formation

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