A5010138029- Microbial Community Ecology and Physiology
- Marine and coastal ecosystems
- Protist diversity and phylogeny
- Genomics and Phylogenetic Studies
- Marine Biology and Ecology Research
- Bacteriophages and microbial interactions
- Wastewater Treatment and Nitrogen Removal
- Vibrio bacteria research studies
- Environmental DNA in Biodiversity Studies
- Marine and environmental studies
- Marine Bivalve and Aquaculture Studies
- Isotope Analysis in Ecology
- Aquaculture disease management and microbiota
- Identification and Quantification in Food
- Water Quality Monitoring Technologies
- Fish Ecology and Management Studies
- Aquatic Ecosystems and Phytoplankton Dynamics
- Methane Hydrates and Related Phenomena
- Aquatic and Environmental Studies
- Water Quality Monitoring and Analysis
- Evolution and Genetic Dynamics
- Global Energy and Sustainability Research
- Fish Biology and Ecology Studies
- Indoor Air Quality and Microbial Exposure
- Oil Spill Detection and Mitigation
Linnaeus University
2010-2021
Lund University
2009-2017
Swedish Institute
2010-2014
University of Gothenburg
2014
Länssjukhuset i Kalmar
2002-2009
Cargotec (Poland)
1999
Umeå University
1984-1997
State University of New York
1985-1988
Scripps Institution of Oceanography
1984-1985
University of California, San Diego
1984-1985
ABSTRACT Total bacterial abundances estimated with different epifluorescence microscopy methods (4′,6-diamidino-2-phenylindole [DAPI], SYBR Green, and Live/Dead) flow cytometry (Syto13) showed good correspondence throughout two microcosm experiments coastal Mediterranean water. In the Syto13-stained samples we could differentiate bacteria apparent high DNA (HDNA) content low (LDNA) content. HDNA bacteria, “live” (determined as such Molecular Probes Live/Dead Bac Light viability kit),...
Abstract Because of their small size, great abundance and easy dispersal, it is often assumed that marine planktonic microorganisms have a ubiquitous distribution prevents any structured assembly into local communities. To challenge this view, bacterioplankton communities from coastal waters at nine locations distributed world‐wide were examined through the use comprehensive clone libraries 16S ribosomal RNA genes, used as operational taxonomic units (OTU). Our survey analyses show there...
Frequency of dividing cells is suggested to be an indirect measure the mean growth rate aquatic bacterial community. Seasonal changes in frequency were found which covariated with uptake 14 C-labeled phytoplankton exudates. Batch and continuous culture experiments, using brackish water bacteria pure mixed enrichment cultures, performed establish a relationship between rate. An improved technique for direct counts, fluorescent staining epifluorescence microscopy, presented. Based on 6-month...
Bacterial community composition and functional potential change subtly across gradients in the surface ocean. In contrast, while there are significant phylogenetic divergences between communities from freshwater marine habitats, underlying mechanisms to this structuring yet remain unknown. We hypothesized that of natural bacterial is linked striking divide microbiomes. To test hypothesis, metagenomic sequencing microbial along a 1,800 km transect Baltic Sea area, encompassing continuous...
Recent literature indicates that dissolved organic carbon (DOC) may accumulate in productive surface waters. Such accumulation will allow export of DOC to the aphotic zone by diffusion and downwelling. As an alternative models based on low degradability, we here propose a mechanism where bacterial consumption is restricted due food web mechanisms controlling both growth biomass bacteria: rate kept bacteria‐phytoplankton competition for mineral nutrients, predators. With such mechanism,...
Counts of heterotrophic bacteria in marine waters are usually the order 5 x 10(sup5) to 3 10(sup6) ml(sup-1). These numbers derived from unspecific fluorescent staining techniques (J. E. Hobbie, R. J. Daley, and S. Jasper, Appl. Environ. Microbiol. 33:1225-1228, 1977; K. G. Porter Y. Feig, Limnol. Oceanogr. 25:943-948, 1980) subsequently defined as total counts bacteria. In samples Baltic Sea, North Sea (Skagerrak), northeastern Mediterranean we found that only a minor fraction (2 32%) can...
Seawater cultures were used to study seasonal and diel variations in bacterial growth nutrient availability.In both the Baltic Sea Northeast Mediterranean, least available component for was phosphorus.In Sea, carbon excess on all sampling occasions.Compared controls, additions of nonlimiting concentrations inorganic nitrogen phosphorus increased yield bacteria compared control with 156% degradation dissolved organic (DOC) by 64 % (as determined high temperature catalytic...
We developed a simple technique for the high-yield extraction of purified DNA from mixed populations natural planktonic marine microbes (primarily bacteria). This is necessary step several molecular biological approaches to study microbial communities in nature. The microorganisms near-shore and brackish water samples, ranging volume 8 40 liters, were collected on 0.22-μm-pore-size fluorocarbon-based filters, after prefiltration through glass fiber remove most eucaryotes. was extracted...
The coupling between the presence of predominant bacterial species and particular biogeochemical processes is primary interest in current microbial ecology. Molecular methods such as microarrays real‐time polymerase chain reaction (PCR) may be used to estimate or expression different genes (e.g., 16S rDNA nifH ) environmental samples; however, quantitative, these require a reproducible efficient DNA extraction protocol. Using picogreen quantification, PCR, an internal standard, we step‐wise...
AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsSpecials 17:13-26 (1999) - doi:10.3354/ame017013 Coupling between bacterioplankton species composition, population dynamics, and organic matter degradation Jarone Pinhassi1, Farooq Azam2, Johanna Hemphälä3, Richard A. Long2, Josefina Martinez2, Ulla Li Zweifel3, Åke Hagström3,* 1Department of Microbiology, Umeå University,...
In an attempt to quantify the organic fluxes within microbial loop of oligotrophic Mediterranean water, pools and production rates were monitored.The cyanobacteria its dynamics dominated overall productivity in system.The largest standing stock was that bacterioplankton growth consumed 8.3 pg C 1-' d-', hence about 60 % primary required for bacterial growth.Using MiniCap technique, we measured a predation on bacteria 2 6 X 104 ml-' h-'.This good agreement with rate 2.3 cells rnl-' h-' Thus,...
Cyanobacteria are thought to be the main N(2)-fixing organisms (diazotrophs) in marine pelagic waters, but recent molecular analyses indicate that non-cyanobacterial diazotrophs also present and active. Existing data are, however, restricted geographically by limited sequencing depths. Our analysis of 79,090 nitrogenase (nifH) PCR amplicons encoding 7,468 unique proteins from surface samples (ten DNA two RNA samples) collected at ten locations world-wide provides first in-depth survey a...
ABSTUCT:The major objective of this study was to examine the ability marine bacteria grow in paricle-free unenriched seawater and characterize growth.A natural assemblage inoculated into particle-free (0.22 pm filtered) seawater.The inoculum, mainly free-living bacteria, prepared by filtering through a 0.6 Nuclepore filter.Growth on dissolved organic matter unambiguously demonstrated parallel increases cell number, ATP, biovolume.Doubling times these 'seawater cultures' were 9 18 h,...
The density of specific aquatic bacteria was determined by use whole-genome DNA hybridization towards community DNA. From a coastal marine environment (northern Baltic Sea), 48 were isolated on solid media over 1-year period. Based the presented protocol, total isolates ranged between 7 and 69% acridine orange direct counts. When compared to number nucleoid-containing cells, range increased 29 111%. Thus, our results showed that able form colonies accounted for large fraction...
ABSTRACT All of the marine bacterioplankton-derived 16S ribosomal DNA sequences previously deposited in GenBank were reanalyzed to determine number bacterial species oceanic surface waters. These have been entered into database since 1990. The rate new additions reached a peak 1999 and subsequently leveled off, suggesting that much microbial richness has sampled. When dereplicated by using 97% similarity as cutoff, 1,117 unique ribotypes found. Of sequences, 609 came from uncultured...
The effect of rnicroflagellate grazing on the size distribution bacterial cells was studied using a heterotrophic microflagellate, Ochromonas sp., and mixed seawater bacteria in 2-stage continuous culture.The flagellate grazed selectively, preferring larger than 0.2 pm3.Median cell volume reduced by 47 %, median length 36 O/ O width 8 % compared to ungrazed control bacteria.An unexpected result drastic increase numbers bactena 3 smallest classes chemostat with flagellates.The natural pelagic...
The presence of bacteria in aerosols has been known for centuries, but information on their identity and role dispersing microbial traits is still limited. This study monitored the airborne bacterial community during an annual survey using samples collected from a 25-m tower near Baltic Sea coast. number CFU was estimated agar plates while most probable (MPN) viable dilution-to-extinction culturing assays (DCAs). MPN values produced quantitatively similar results, displaying pronounced...
A bacterial community may be resistant to environmental disturbances if some of its species show metabolic flexibility and physiological tolerance the changing conditions. Alternatively, can change composition thereby potentially affect ecosystem processes. The impact disturbance on bacterioplankton communities was examined in continuous seawater cultures. Bacterial assemblages from geographically closely connected areas, Baltic Sea (salinity 7 high dissolved organic carbon [DOC]) Skagerrak...
AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsSpecials 21:245-256 (2000) - doi:10.3354/ame021245 Seasonal succession in marine bacterioplankton Jarone Pinhassi1,*, Åke Hagström2 1Department of Microbiology, Umeå University, 90187 Umeå, Sweden 2Marine Science, Kalmar Box 905, 39129 Kalmar, *E-mail: jarone@micro.umu.se ABSTRACT: Here we examine seasonal distribution species...
AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsSpecials 21:231-244 (2000) - doi:10.3354/ame021231 Biogeographical diversity among marine bacterioplankton Åke Hagström1,*, Jarone Pinhassi2, Ulla Li Zweifel1 1Marine Science, Kalmar University, Box 905, 39129 Kalmar, Sweden 2Department of Microbiology, Umeå 90187 Umeå, *E-mail: ake.hagstrom@ng.hik.se ABSTRACT: The phylogenetic...
In the Bothnian Sea, there was a marked seasonal variation of dissolved organic C (DOC) in 1990–1992, with large increase DOC concentrations summer at two stations. The accumulation coastal station persisted for 5 months, reaching peak values 24–31% above mean winter value (288 µ M). At offshore were elevated throughout water column July, 14% (291 concentration significantly correlated to flow an adjacent river, suggesting that source largely explained by riverine input. Bioassays indicated...
The Baltic Sea is one of the largest brackish environments on Earth. Despite extensive knowledge about food web interactions and pelagic ecosystem functioning, information bacterial community composition in scarce. We hypothesized that due to eutrophic low-salinity environment long water residence time (>5 years), bacterioplankton from proper shows a native "brackish" influenced by both freshwater marine phylotypes. surface (3-m depth) was examined at single station throughout full year....