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  • 1
    Electronic Resource
    Electronic Resource
    The microbial food web along salinity gradients (2000)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology ecology 32 (2000), S. 0 
    Details
    ISSN: 1574-6941
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The microbial food web was studied along a gradient of salinity in two solar salterns used for the commercial production of salt. The different ponds in the salterns provide a wide range of ecosystems with food webs of different complexities. Abundance of prokaryotes, cell volume, prokaryotic heterotrophic production, chlorophyll a, abundance of heterotrophic flagellates, ciliates and phytoplankton were determined in several ponds in each saltern. Increases in salinity resulted in a progressive reduction in the abundance and number of different groups of eukaryotic microorganisms present, but an increase in biomass of prokaryotes. Maximal activity of both phyto- and bacterioplankton was found at a salinity of around 100‰, where there was also a maximum in chlorophyll a concentration. Growth rates of heterotrophic prokaryotes decreased with increasing salinity. Bacterivory disappeared above 250‰ salinity, whereas other loss factors such as viral lysis appeared to be of minor importance throughout the gradient [Guixa-Boixereu et al. (1996) Aquat. Microb. Ecol. 11, 215–227].
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6941.2000.tb00708.x
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Light-dependent phagotrophy in the freshwater mixotrophic chrysophyte Dinobryon cylindricum (1993)
    Springer
    Microbial ecology 25 (1993), S. 93-111 
    Details
    ISSN: 1432-184X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mixotrophic (bacterivorous), freshwater chrysophyte Dinobryon cylindricum was cultured under a variety of light regimes and in bacterized and axenic cultures to investigate the role of phototrophy and phagotrophy for the growth of this alga. D. cylindricum was found to be an obligate phototroph. The alga was unable to survive in continuous darkness even when cultures were supplemented with high concentrations of bacteria, and bacterivory ceased in cultures placed in the dark for a period longer than one day. Axenic growth of the alga was poor even in an optimal light regime. Live bacteria were required for sustained, vigorous growth of the alga in the light. Carbon (C), nitrogen (N), and phosphorus (P) budgets determined for the alga during growth in bacterized cultures indicated that bacterial biomass ingested by the alga may have contributed up to 25% of the organic carbon budget of the alga. Photosynthesis was the source of most (⩾75%) of the organic carbon of the alga. D. cylindricum populations survived but did not grow when cultured in a continuous low light intensity (30 μE m−2 sec−1), or in a light intensity of 150 μE m−2 sec−1 for only two hours each day. Net efficiency of incorporation of bacterial C, N, and P into algal biomass under these two conditions was zero (i.e., no net algal population growth). We conclude that the primary function of bacterivorous behavior in D. cylindricum may be to provide essential growth factor(s) or major nutrients for photosynthetic growth, or to allow for the survival of individuals during periods of very low light intensity or short photoperiod.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00182132
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    Paper (German National Licenses)
    Fulltext
  • 3
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    Unknown
    Uncoupled seasonal variability of transparent exopolymer and Coomassie stainable particles in coastal Mediterranean waters (2021)
    University of California Press
    Details
    Publication Date: 2024-02-07
    Description: Transparent exopolymer particles (TEP) and Coomassie stainable particles (CSP) are gel-like particles, ubiquitous in the ocean, that affect important biogeochemical processes including organic carbon cycling by planktonic food webs. Despite much research on both groups of particles (especially TEP) over many years, whether they exist as distinctly stainable fractions of the same particles or as independent particles, each with different driving factors, remains unclear. To address this question, we examined the temporal dynamics of TEP and CSP over 2 complete seasonal cycles at 2 coastal sites in the Northwestern Mediterranean Sea, the Blanes Bay Microbial Observatory (BBMO) and the L’Estartit Oceanographic Station (EOS), as well as their spatial distribution along a coast-to-offshore transect. Biological, chemical, and physical variables were measured in parallel. Surface concentrations (mean ± standard deviation [SD]) of TEP were 36.7 ± 21.5 µg Xanthan Gum (XG) eq L–1 at BBMO and 36.6 ± 28.3 µg XG eq L–1 at EOS; for CSP, they were 11.9 ± 6.1 µg BSA eq L–1 at BBMO and 13.0 ± 5.9 µg BSA eq L–1 at EOS. Seasonal variability was more evident at EOS, where surface TEP and CSP concentrations peaked in summer and spring, respectively, and less predictable at the shore-most station, BBMO. Vertical distributions between surface and 80 m, monitored at EOS, showed highest TEP concentrations within the surface mixed layer during the stratification period, whereas CSP concentrations were highest before the onset of summer stratification. Phytoplankton were the main drivers of TEP and CSP distributions, although nutrient limitation and saturating irradiance also appeared to play important roles. The dynamics and distribution of TEP and CSP were uncoupled both in the coastal sites and along the transect, suggesting that they are different types of particles produced and consumed differently in response to environmental variability.
    Type: Article , PeerReviewed
    Format: text
    Format: text
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 4
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    Seawater carbonate chemistry and microbial abundances, bacterial activity and extracellular enzyme activities (2016)
    PANGAEA
    Details
    Publication Date: 2024-03-18
    Description: We investigated the effects of an increase in dissolved CO2 on the microbial communities of the Mediterranean Sea during two mesocosm experiments in two contrasting seasons: winter, at the peak of the annual phytoplankton bloom, and summer, under low nutrient conditions. The experiments included treatments with acidification and nutrient addition, and combinations of the two. We followed the effects of ocean acidification (OA) on the abundance of the main groups of microorganisms (diatoms, dinoflagellates, nanoeukaryotes, picoeukaryotes, cyanobacteria, and heterotrophic bacteria) and on bacterial activity, leucine incorporation, and extracellular enzyme activity. Our results showed a clear stimulation effect of OA on the abundance of small phytoplankton (pico- and nanoeukaryotes), independently of the season and nutrient availability. A large number of the measured variables showed significant positive effects of acidification in summer compared with winter, when the effects were sometimes negative. Effects of OA were more conspicuous when nutrient concentrations were low. Our results therefore suggest that microbial communities in oligotrophic waters are considerably affected by OA, whereas microbes in more productive waters are less affected. The overall enhancing effect of acidification on eukaryotic pico- and nanophytoplankton, in comparison with the non-significant or even negative response to nutrient-rich conditions of larger groups and autotrophic prokaryotes, suggests a shift towards medium-sized producers in a future acidified ocean.
    Keywords: Abundance per volume; Alkalinity, total; alpha-glucosidase activity; Aragonite saturation state; beta-glucosidase activity; Bicarbonate ion; Biomass/Abundance/Elemental composition; Blanes_Bay_Microbial_Observatory; Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Chitobiase activity; Chlorophyll a; Coast and continental shelf; Community composition and diversity; Containers and aquaria (20-1000 L or 〈 1 m**2); Entire community; EXP; Experiment; Experiment day; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Laboratory experiment; Leucine aminopeptidase activity; Leucine incorporation rate; Macro-nutrients; Mediterranean Sea; OA-ICC; Ocean Acidification International Coordination Centre; Other metabolic rates; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; pH; Potentiometric titration; Replicate; Salinity; Spectrophotometric; Temperate; Temperature; Temperature, water; Treatment; Type
    Type: Dataset
    Format: text/tab-separated-values, 3914 data points
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    DATA PANGAEA
  • 5
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    A global database of dissolved organic matter (DOM) concentration measurements in coastal waters (CoastDOM v.1) (2023)
    PANGAEA
    Details
    Publication Date: 2024-05-08
    Description: This global database (CoastDOM v.1) contains both previously published and unpublished measurements of Dissolved organic carbon (DOC), nitrogen (DON) and phosphorus (DOP) in coastal waters. The dataset also contains hydrographic data such as temperature and salinity and, to the extent possible, other biogeochemical variables (e.g., Chlorophyll-a, inorganic nutrients) and the inorganic carbon system (e.g., dissolved inorganic carbon and total alkalinity). The data included were collected from 1978 to 2022 and consist of 62339 data points for DOC, 20360 for DON and 13440 for DOP.
    Keywords: Alkalinity, total; Ammonium; Analytical method; Carbon, inorganic, dissolved; Carbon, organic, dissolved; Carbon, organic, particulate; Chlorophyll a; Coastal waters; Comment; DATE/TIME; DEPTH, water; Dissolved Organic Carbon; Dissolved Organic Matter; dissolved organic nitrogen; dissolved organic phosphorus; ELEVATION; global database;; Hydrogen phosphate; Institution; LATITUDE; Location; LONGITUDE; Nitrate and Nitrite; Nitrogen, organic, dissolved; Nitrogen, particulate; Nitrogen, total dissolved; Phosphorus, organic, dissolved; Phosphorus, particulate; Phosphorus, total dissolved; Principal investigator; Quality flag, alkalinity, total; Quality flag, ammonium; Quality flag, carbon, inorganic, dissolved; Quality flag, carbon, organic, dissolved; Quality flag, carbon, organic, particulate; Quality flag, chlorophyll a; Quality flag, hydrogen phosphate; Quality flag, nitrate and nitrite; Quality flag, nitrogen, particulate; Quality flag, nitrogen, total dissolved; Quality flag, phosphorus, particulate; Quality flag, phosphorus, total dissolved; Reference/source; Salinity; Sample ID; Suspended solids, total; Temperature, water; World Oceans Circulation Experiment (WOCE) quality flags according to Jiang et al. (2022)
    Type: Dataset
    Format: text/tab-separated-values, 1286555 data points
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    DATA PANGAEA
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