scholarly journals Coupling of heterotrophic bacteria to phytoplankton bloom development at different pCO<sub>2</sub> levels: a mesocosm study

2008 ◽  
Vol 5 (1) ◽  
pp. 317-359 ◽  
Author(s):  
M. Allgaier ◽  
U. Riebesell ◽  
M. Vogt ◽  
R. Thyrhaug ◽  
H.-P. Grossart
Keyword(s):  
Community Structure ◽  
Heterotrophic Bacteria ◽  
Phytoplankton Bloom ◽  
C:N Ratio ◽  
Life Forms ◽  
Bacterial Activity ◽  
Free Living ◽  
Seawater Chemistry ◽  
Attached Bacteria ◽  
Living Bacteria

Abstract. The predicted rise in anthropogenic CO2 emissions will increase CO2 concentrations and decrease seawater pH in the upper ocean. Recent studies have revealed effects of pCO2 induced changes in seawater chemistry on a variety of marine life forms, in particular calcifying organisms. To test whether the predicted increase in pCO2 will directly or indirectly (via changes in phytoplankton dynamics) affect abundance, activities, and community composition of heterotrophic bacteria during phytoplankton bloom development, we have aerated mesocosms with CO2 to obtain triplicates with three different partial pressures of CO2 (pCO2): 350 µatm (1×CO2), 700 µatm (2×CO2) and 1050 µatm (3×CO2). The development of a phytoplankton bloom was initiated by the addition of nitrate and phosphate. In accordance to an elevated carbon to nitrogen drawdown at increasing pCO2, bacterial production (BPP) of free-living and attached bacteria as well as cell-specific BPP (csBPP) of attached bacteria were related to the C:N ratio of suspended matter. These relationships significantly differed among treatments. However, bacterial abundance and activities were not statistically different among treatments. Solely community structure of free-living bacteria changed with pCO2 whereas that of attached bacteria seemed to be independent of pCO2 but tightly coupled to phytoplankton bloom development. Our findings imply that changes in pCO2, although reflected by changes in community structure of free-living bacteria, do not directly affect bacterial activity. Furthermore, bacterial activity and dynamics of heterotrophic bacteria, especially of attached bacteria, were tightly linked to phytoplankton development and, hence, may also potentially depend on changes in pCO2.

scholarly journals Coupling of heterotrophic bacteria to phytoplankton bloom development at different <i>p</i>CO<sub>2</sub> levels: a mesocosm study

2008 ◽  
Vol 5 (4) ◽  
pp. 1007-1022 ◽  
Author(s):  
M. Allgaier ◽  
U. Riebesell ◽  
M. Vogt ◽  
R. Thyrhaug ◽  
H.-P. Grossart
Keyword(s):  
Community Structure ◽  
Heterotrophic Bacteria ◽  
Phytoplankton Bloom ◽  
C:N Ratio ◽  
Life Forms ◽  
Bacterial Activity ◽  
Free Living ◽  
Seawater Chemistry ◽  
Attached Bacteria ◽  
Living Bacteria

Abstract. The predicted rise in anthropogenic CO2 emissions will increase CO2 concentrations and decrease seawater pH in the upper ocean. Recent studies have revealed effects of pCO2 induced changes in seawater chemistry on a variety of marine life forms, in particular calcifying organisms. To test whether the predicted increase in pCO2 will directly or indirectly (via changes in phytoplankton dynamics) affect abundance, activities, and community composition of heterotrophic bacteria during phytoplankton bloom development, we have aerated mesocosms with CO2 to obtain triplicates with three different partial pressures of CO2 (pCO2): 350 μatm (1×CO2), 700 μatm (2×CO2) and 1050 μatm (3×CO2). The development of a phytoplankton bloom was initiated by the addition of nitrate and phosphate. In accordance to an elevated carbon to nitrogen drawdown at increasing pCO2, bacterial production (BPP) of free-living and attached bacteria as well as cell-specific BPP (csBPP) of attached bacteria were related to the C:N ratio of suspended matter. These relationships significantly differed among treatments. However, bacterial abundance and activities were not statistically different among treatments. Solely community structure of free-living bacteria changed with pCO2 whereas that of attached bacteria seemed to be independent of pCO2 but tightly coupled to phytoplankton bloom development. Our findings imply that changes in pCO2, although reflected by changes in community structure of free-living bacteria, do not directly affect bacterial activity. Furthermore, bacterial activity and dynamics of heterotrophic bacteria, especially of attached bacteria, were tightly correlated to phytoplankton development and, hence, may also potentially depend on changes in pCO2.

Distribution of heterotrophic bacteria in relation to the concentration of particulate organic matter in seawater

1983 ◽  
Vol 29 (5) ◽  
pp. 570-575 ◽  
Author(s):  
Kimio Fukami ◽  
Usio Simidu ◽  
Nobuo Taga
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
Heterotrophic Bacteria ◽  
Viable Count ◽  
Plate Count ◽  
Free Living ◽  
Count Method ◽  
Attached Bacteria ◽  
Geographical Scale ◽  
Living Bacteria

The relationship between the number of bacteria and the concentration of particulate organic carbon (POC) in seawater was investigated. In coastal seawater in summer, the POC concentration showed better correlation to the density of bacteria obtained by the viable plate count method (viable count, V.C.) than by the total direct count method (total count, T.C.). The number of attached bacteria (A) showed significant fluctuation, both laterally on a geographical scale and vertically in the water column; on the other hand, the number of free-living bacteria (F) was relatively constant. The POC concentration had a much higher correlation with A (r = 0.8795) than with T.C. (r = 0.7339), and had a low correlation with F (r = 0.6935). Moreover, a very good correlation was observed between the density of bacteria obtained by V.C. and A (r = 0.9153). These results indicate that when the concentration of particulate organic matter (POM) increases, some free-living bacteria become attached to POM, and grow on the surface of POM. These communities of attached bacteria have the ability to make colonies on plate media and can be counted as the "viable plate count."

Bacterial community structure in cooling water and biofilm in an industrial recirculating cooling water system

2013 ◽  
Vol 68 (4) ◽  
pp. 940-947 ◽  
Author(s):  
Jinmei Wang ◽  
Min Liu ◽  
Huijie Xiao ◽  
Wei Wu ◽  
Meijuan Xie ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Water System ◽  
Cooling Water ◽  
Water Systems ◽  
Rrna Gene ◽  
Free Living ◽  
Cooling Water System ◽  
Attached Bacteria ◽  
Living Bacteria

Microbial fouling is a serious problem in open recirculating cooling water systems. The bacterial communities that cause it have not been fully understood. In this study, we analyzed the community structure of free-living bacteria and particle-attached bacteria in cooling water, and bacteria in biofilm collected from the wall of the water reservoir in an industrial recirculating cooling water system by construction of a 16S rRNA gene clone library. Based on amplified ribosomal DNA restriction analysis, clones of all three libraries were clustered into 45 operational taxonomic units (OTUs). Thirteen OTUs displaying 91–96% sequence similarity to a type strain might be novel bacterial species. Noted differences in community structure were observed among the three libraries. The relative species richness of the free-living bacteria in cooling water was much lower than that of particle-attached bacteria and bacteria in biofilm. The majority of the free-living bacterial community (99.0%) was Betaproteobacteria. The predominant bacteria in the particle-attached bacterial community were Alphaproteobacteria (20.5%), Betaproteobacteria (27.8%) and Planctomycetes (42.0%), while those in the biofilm bacterial community were Alphaproteobacteria (47.9%), Betaproteobacteria (11.7%), Acidobacteria (13.1%) and Gemmatimonadetes (11.3%). To control microbial fouling in industrial recirculating cooling water systems, additional physiological and ecological studies of these species will be essential.

scholarly journals Dynamics of Free-Living and Attached Bacterial Assemblages in Skeletonema sp. Diatom Cultures at Elevated Temperatures

2021 ◽  
Vol 8 ◽  
Author(s):  
Zichao Deng ◽  
Shouchang Chen ◽  
Ping Zhang ◽  
Xu Zhang ◽  
Jonathan M. Adams ◽  
...  
Keyword(s):  
Community Structure ◽  
Elevated Temperature ◽  
Bacterial Communities ◽  
Elevated Temperatures ◽  
Bacterial Species ◽  
Positive Interactions ◽  
Growth Stages ◽  
Free Living ◽  
Attached Bacteria ◽  
Living Bacteria

In the context of global warming, changes in phytoplankton-associated bacterial communities have the potential to change biogeochemical cycling and food webs in marine ecosystems. Skeletonema is a cosmopolitan diatom genus in coastal waters worldwide. Here, we grew a Skeletonema strain with its native bacterial assemblage at different temperatures and examined cell concentrations of Skeletonema sp. and free-living bacteria, dissolved organic carbon (DOC) concentrations of cultures, and the community structure of both free-living and attached bacteria at different culture stages. The results showed that elevated temperature increased the specific growth rates of both Skeletonema and free-living bacteria. Different growth stages had a more pronounced effect on community structure compared with temperatures and different physical states of bacteria. The effects of temperature on the structure of the free-living bacterial community were more pronounced compared with diatom-attached bacteria. Carbon metabolism genes and those for some specific amino acid pathways were found to be positively correlated with elevated temperature, which may have profound implications on the oceanic carbon cycle and the marine microbial loop. Network analysis revealed evidence of enhanced cooperation with an increase in positive interactions among different bacteria at elevated temperature. This may help the whole community to overcome the stress of elevated temperature. We speculate that different bacterial species may build more integrated networks with a modified functional profile of the whole community to cope with elevated temperature. This study contributes to an improved understanding of the response of diatom-associated bacterial communities to elevated temperature.

Biodegradation of Organic Substances by Biological Activated Carbon – Simulation of Bacterial Activity on Granular Activated Carbon

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2031-2034 ◽  
Author(s):  
W. Nishijima ◽  
M. Tojo ◽  
M. Okada ◽  
A. Murakami
Keyword(s):  
Activated Carbon ◽  
Community Structure ◽  
Granular Activated Carbon ◽  
Bacterial Activity ◽  
Organic Substances ◽  
Aminobenzoic Acid ◽  
Biological Activated Carbon ◽  
Support Medium ◽  
Attached Bacteria ◽  
The Difference

Biodegradation of organic substances by attached bacteria on biological activated carbon (BAC) was studied to clarify the advantages of granular activated carbon (GAC) as support media over conventional media without adsorption capacity with regard to biodegradation activity and community structure of attached bacteria. Anthracite (AN) was used as reference support medium without adsorbability. Low molecular organic substances with different biodegradability and adsorbability (phenol, glucose, benzoic acid and m-aminobenzoic acid) were fed into completely mixed BAC and AN reactors. The rate of biodegradation by BAC reactors fed with biodegradable organic substances was approximately 3 times as high as that by AN reactors. The difference in adsorbability of organic substances onto GAC had little effects on the rate of biodegradation. The structure of GAC with micro and macro pores did not provide better habitat for attached bacteria with regard to the size of population in comparison with anthracite without pores. The rates of biodegradation per attached bacteria for biodegradable organic substances in the BAC reactors were from 1.7 to 4.9 times higher than those in the AN reactors. GAC, as a bacterial support media, stimulated the biodegradation activity of each bacteria without increase in their population and probably with little change in their species composition. Although the number of attached bacteria on BAC was not different significantly from that on anthracite, m-aminobenzoic acid with low biodegradability was degraded only by the GAC reactor.

scholarly journals Diel Protein Regulation of Marine Picoplanktonic Communities Assessed by Metaproteomics

2021 ◽  
Vol 9 (12) ◽  
pp. 2621
Author(s):  
Augustin Géron ◽  
Johannes Werner ◽  
Philippe Lebaron ◽  
Ruddy Wattiez ◽  
Sabine Matallana-Surget
Keyword(s):  
Heterotrophic Bacteria ◽  
Temporal Structure ◽  
Sea Surface ◽  
Diel Cycle ◽  
Diel Variation ◽  
Protein Regulation ◽  
Free Living ◽  
Bacterial Populations ◽  
Form Complex ◽  
Attached Bacteria

The diel cycle is of enormous biological importance in that it imposes temporal structure on ecosystem productivity. In the world’s oceans, microorganisms form complex communities that carry out about half of photosynthesis and the bulk of life-sustaining nutrient cycling. How the functioning of microbial communities is impacted by day and night periods in surface seawater remains to be elucidated. In this study, we compared the day and night metaproteomes of the free-living and the particle-attached bacterial fractions from picoplanktonic communities sampled from the northwest Mediterranean Sea surface. Our results showed similar taxonomic distribution of free-living and particle-attached bacterial populations, with Alphaproteobacteria, Gammaproteobacteria and Cyanobacteria being the most active members. Comparison of the day and night metaproteomes revealed that free-living and particle-attached bacteria were more active during the day and the night, respectively. Interestingly, protein diel variations were observed in the photoautotroph Synechococcales and in (photo)-heterotrophic bacteria such as Flavobacteriales, Pelagibacterales and Rhodobacterales. Moreover, our data demonstrated that diel cycle impacts light-dependent processes such as photosynthesis and UV-stress response in Synechococcales and Rhodobacterales, respectively, while the protein regulation from the ubiquitous Pelagibacterales remained stable over time. This study unravels, for the first time, the diel variation in the protein expression of major free-living and particle-attached microbial players at the sea surface, totaling an analysis of eight metaproteomes.

The Potential of Free-Living Ground Water Bacteria to Degrade Aromatic Hydrocarbons and Heterocyclic Compounds

1988 ◽  
Vol 20 (3) ◽  
pp. 109-118 ◽  
Author(s):  
E. Arvin ◽  
B. Jensen ◽  
J. Aamand ◽  
C. Jørgensen
Keyword(s):  
Ground Water ◽  
Aromatic Hydrocarbons ◽  
Biomass Concentration ◽  
Nitrogen And Phosphorus ◽  
Free Living ◽  
Soil Fractions ◽  
Fine Soil ◽  
Attached Bacteria ◽  
Considerable Degradation ◽  
Living Bacteria

This study has documented that a considerable degradation potential related to aromatic hydrocarbons and aromatic nitrogen-, sulphur- and oxygen- containing compounds is associated with the free-living ground water bacteria. All studies were performed under aerobic conditions and with surplus of nitrogen and phosphorus. After a lag period, which differs considerably between locations upstream and downstream of hydrocarbon spills, the free-living bacteria are able to degrade the hydrocarbons to concentrations less than 1 µg/l. The bacteria from one site were able to degrade naphthalene according to a zero order reaction even at 1 µg/l. Preliminary experiments indicate that the free-living bacteria may have a relatively high activity compared to the attached bacteria when compared on the basis of the same total bacteria numbers. The hypothesis is put forward that, although the attached biomass concentration in the aquifer may be much higher than the free-living biomass, the latter is still very important for the degradation capability if the attached bacteria are fixed in the fine soil fractions (silt, etc), the reason being that the flow of water, and with this the flux of substrate, is relatively small to the attached bacteria due to low hydraulic conductivity in the fine soil fractions.

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