Papers by Jorma Kuparinen
Aquatic Microbial Ecology, 2002
Deep Sea Research Part II: Topical Studies in Oceanography, 2011
The SOLAS air-sea gas exchange experiment (SAGE) was a multiple-objective study investigating 2 g... more The SOLAS air-sea gas exchange experiment (SAGE) was a multiple-objective study investigating 2 gas-transfer processes and the influence of iron fertilisation on biologically driven gas exchange in
Applied and Environmental Microbiology, Dec 1, 1984
The spring development of both phytoplankton and bacterioplankton was investigated between 18 Apr... more The spring development of both phytoplankton and bacterioplankton was investigated between 18 April and 7 May 1983 in mesotrophic Lake Erken, Sweden. By using the lake as a batch culture, our aim was to estimate, via different methods, the production of phytoplankton and bacterioplankton in the lake and to compare these production estimates with the actual increase in phytoplankton and bacterioplankton biomass. The average water temperature was 3.5°C. Of the phytoplankton biomass, >90% was the diatom Stephanodiscus hantzchii var. pusillus, by the peak of the bloom. The 14C and 02 methods of estimating primary production gave equivalent results (r = 0.999) with a photosynthetic quotient of 1.63. The theoretical photosynthetic quotient predicted from the C/NO3 N assimilation ratio was 1.57. The total integrated incorporation of ['4C]bicarbonate into particulate material (>1 ,um) was similar to the increase in phytoplankton carbon determined from cell counts. Bacterioplankton increased from 0.5 x 109 to 1.52 x 10 cells liter-' (-0.5 ,ug of C liter-' day-).
Polar Biology, Mar 29, 2011
Seasonal Baltic Sea ice is structurally similar to polar sea ice and provides habitats for divers... more Seasonal Baltic Sea ice is structurally similar to polar sea ice and provides habitats for diverse ice organism assemblages that are integral to the biogeochemistry and ecology of the sea during winter. Temperature and inorganic nitrogen sources have been suggested to control bacterial growth, with increasing dependence on ammonium at low temperatures. To study the bacterial growth and preference for the nitrogen source, we conducted experiments at 0 and 4°C, using ammonium and nitrate as nitrogen sources at two coastal fast-ice stations in the Gulf of Finland and in the Gulf of Bothnia during three successive winters. The two study sites differ markedly in relation to the allochthonous dissolved organic matter supply from the catchment area. High levels of bacterial growth were recorded at both study sites, with community generation times of 15-37 h. The measured bacterial growth efficiencies of 20-58% suggest that the Baltic sea ice brines provide a rich medium for bacterial growth and efficient functioning of bacteria-based food webs. Our experiments with sea ice samples showed a preference for ammonium at both temperatures and high potential growth in both types of nitrogen supplies. No major differences in phosphorus depletion rates were found at the two temperatures, but rates were always highest when ammonium was added to the experiments. These experiments point out that ice maturity, presumably through changes in bacterial community structure, impacts nitrogen processes and that these processes are pronounced prior to melting of the ice.
Boreal Environment Research
ABSTRACT
Ecological Studies, 2001
7 Pelagic Plankton Growth and Resource Limitations in the Baltic Sea A. HAGSTROM, F. AZAM, J. KUP... more 7 Pelagic Plankton Growth and Resource Limitations in the Baltic Sea A. HAGSTROM, F. AZAM, J. KUPARINEN, and U.-L. ZWEIFEL 7.1 Introduction ... ties of allochthonous material enter the Baltic via rivers and streams and the net outflow of water through the Danish straits is ...
Phycological Research, 2014
The conversion processes of macroalgae for biofuels can be divided into thermochemical (dry) and ... more The conversion processes of macroalgae for biofuels can be divided into thermochemical (dry) and microbiological (wet) processes. The chemical composition of macroalgae together with the pre-treatment method, conversion conditions, and the characteristics of the microbes involved (wet processes) determine the yield and the properties of the biofuel produced. Macroalgae are often rich in carbohydrates, and therefore well suited for biogas, biobutanol and bioethanol productions. The content of triacylglycerols (TAGs) is the best indicator for the suitability of the alga for biodiesel production. TAGs have a high conversion rate to biodiesel, high percentage of fatty acids, and they lack phosphorus, sulfur and nitrogen. Macroalgae can have high metal concentrations, which can have an impact on conversion processes: metals may inhibit or catalyse the processes. High sulfur (especially in green algae) and nitrogen contents are also characteristic to macroalgae, and may be problematic in the production of biogas (NH3-toxicity) and the use of the oil and biodiesel (high concentrations of H2S and NOx-compounds). Macroalgae have proven to be suitable material for conversion processes, but further optimization of the processes is needed. At present, macroalgae are not economically, or in many cases not even environmentally, sustainable material when the whole production chain is considered. In this review we summarize information on the chemical composition of macroalgae in a prospect of biofuel production, and the current situation in the field of macroalgal-based biofuel production.
Encyclopedia of Environmental Microbiology, 2003
Polar Biology, 2008
Coastal fast ice and underlying water of the northern Baltic Sea were sampled throughout the enti... more Coastal fast ice and underlying water of the northern Baltic Sea were sampled throughout the entire ice winter from January to late March in 2002 to study the succession of bacterial biomass, secondary production and community structure. Temperature gradient gel electrophoresis (TGGE) and sequencing of TGGE fragments were applied in the community structure analysis. Chlorophyll-a and composition of autotrophic and heterotrophic assemblages were also examined. Overall succession of ice organism assemblages consisted of a low-productive stage, the main algal bloom, and a heterotrophic post-bloom situation, as typical for the study area. The most important groups of organisms in ice in terms of biomass were dinoXagellates, plasticidic Xagellates, rotifers and ciliates. Ice bacteria showed a speciWc succession not directly dependent on the overall succession events of ice organisms. Sequenced 16S rDNA fragments were mainly aYliated to -, -, and -proteobacterial phyla and Cytophaga-Flavobacterium-Bacteroides-group, and related to sequences from cold environments, also from the Baltic Sea. Temporal clustering of the TGGE Wngerprints was stronger than spatial, although lower ice and underlying water communities always clustered together, pointing to the importance of ice maturity and ice-water interactions in shaping the bacterial communities.
Polar Biology, 2011
Seasonal Baltic Sea ice is structurally similar to polar sea ice and provides habitats for divers... more Seasonal Baltic Sea ice is structurally similar to polar sea ice and provides habitats for diverse ice organism assemblages that are integral to the biogeochemistry and ecology of the sea during winter. Temperature and inorganic nitrogen sources have been suggested to control bacterial growth, with increasing dependence on ammonium at low temperatures. To study the bacterial growth and preference for the nitrogen source, we conducted experiments at 0 and 4°C, using ammonium and nitrate as nitrogen sources at two coastal fast-ice stations in the Gulf of Finland and in the Gulf of Bothnia during three successive winters. The two study sites differ markedly in relation to the allochthonous dissolved organic matter supply from the catchment area. High levels of bacterial growth were recorded at both study sites, with community generation times of 15-37 h. The measured bacterial growth efficiencies of 20-58% suggest that the Baltic sea ice brines provide a rich medium for bacterial growth and efficient functioning of bacteria-based food webs. Our experiments with sea ice samples showed a preference for ammonium at both temperatures and high potential growth in both types of nitrogen supplies. No major differences in phosphorus depletion rates were found at the two temperatures, but rates were always highest when ammonium was added to the experiments. These experiments point out that ice maturity, presumably through changes in bacterial community structure, impacts nitrogen processes and that these processes are pronounced prior to melting of the ice.
Polar Biology, 1992
We applied two methods to measure bacterio-plankton production, the [3H]-thymidine (TTI) and the ... more We applied two methods to measure bacterio-plankton production, the [3H]-thymidine (TTI) and the [3H]-leucine (LEU) incorporation into cold trichloro-acetic acid precipitate. Both methods gave similar results of the distribution of production in time and space (r2=0.82, n=66). Using empirically determined conversion factors the TTI gave production values from 21 to 125 mg Cm-2 day-1, which are within the range reported
Polar Biology, 1992
... Springer, Berlin, pp 277-283 Hewes CD, Sakshaug E, Reid FMH, Holm-Hansen O (1990) Micro-bial ... more ... Springer, Berlin, pp 277-283 Hewes CD, Sakshaug E, Reid FMH, Holm-Hansen O (1990) Micro-bial autotrophic and heterotrophic eucaryotes in ... Marcel Dekker, New York, pp 395 413 Lancelot C, Veth C, Mathot S (1991) Modelling ice-edge phyto-plankton bloom in the Scotia ...
Marine Ecology Progress Series, 1991
Several conversion factors are r e q w e d for the eshmation of bacterial biomass, net production... more Several conversion factors are r e q w e d for the eshmation of bacterial biomass, net production and carbon demand from epifluorescence microscopy and measurements of [3 H]-thymidlne and [3 H]-leucine incorporation rates. These conversion factors were evaluated simultaneously in mixed cultures of bacterial assemblages from the Weddell/Scoha Confluence of the Southern Ocean. The cultures were grown in the dark at + l 'C. Conversion factors were calculated for each culture by regression analyses of cumulative parameters. Average conversion factors were: 1.1 X 1018 cells per m01 thymidme incorporated into cold TCA precipitate, 7.5 X 1015 pm3 of biovolume per m01 leucine incorporated into cold TCA precipitate, 0 4 pgC biomass per wm3 of biovolume, and 40% carbon growth yield.
Marine Ecology Progress Series, 2012
Increasing biomasses of gelatinous zooplankton presumably have major implications for the structu... more Increasing biomasses of gelatinous zooplankton presumably have major implications for the structure and function of marine food webs at large; however, current data on lower trophic levels are scarce, as most studies have focused on the immediate effects on zooplankton and fish larvae only. We examined the short-term impact of larvae and adults of the invasive ctenophore Mnemiopsis leidyi on a summer planktonic food web in the estuarine southern Baltic Sea, with special emphasis on the microbial loop. Grazing by M. leidyi reduced the mesozooplankton biomass, followed by increased dinoflagellate biomass in treatments with M. leidyi. While chlorophyll a increased most in the treatments with M. leidyi, small phytoplankton and ciliates decreased in all treatments. M. leidyi had a slight effect on bacterial abundance, but not on bacterial production, ectoenzymatic activities, or community composition. Undetectable levels of phosphate and a gradual accumulation of dissolved organic carbon during the experiment suggested a malfunctioning microbial loop scenario. The experiment shows that direct and indirect short-term effects of M. leidyi on the estuarine food web are limited to higher trophic levels and indicates that top-down and bottom-up consequences of M. leidyi expansions on the microbial loop will likely depend on local nutrient conditions. KEY WORDS: Bacterioplankton · Nanoflagellates · Microbial loop · Trophic levels · Ciliates · Baltic Sea
Marine Biology, 1996
A one year field study of four stations in the Gulf of Bothnia during 1991 showed that the biomas... more A one year field study of four stations in the Gulf of Bothnia during 1991 showed that the biomass was ca. two times, and primary productivity ca. four times, lower in the north (Bothnian Bay) than in the south (Bothnian Sea) during the summer. Nutrient addition experiments indicated phosphorus limitation of phytoplankton in the Bothnian Bay and the coastal areas in the northern Bothnian Sea, but nitrogen limitation in the open Bothnian Sea. A positive correlation between the phosphate concentration and the production/biomass ratio of phytoplankton was demonstrated, which partly explained the differences in the specific growth rate of the phytoplankton during the summer. Differences in photosynthetic active radiation between the stations also showed a covariation with the primary productivity. The relative importance of nutrient or light limitation for photosynthetic carbon fixation could not, however, be conclusively determined from this study. Marked differences in phytoplankton species composition from north to south were also observed. The number of dominating species was higher in the Bothnian Sea than in the Bothnian Bay. The distribution of some species could be explained as due to nutrient availability (e.g. Nodularia spumigena, Aphanizomenon sp.), while salinity probably limits the distribution of some limnic as well as marine species.
Marine Biology, 1991
Growth and herbivory of heterotrophic dino flagellates (Gymnodinium sp.) from the Weddell Sea and... more Growth and herbivory of heterotrophic dino flagellates (Gymnodinium sp.) from the Weddell Sea and the Weddell/Scotia Confluence were studied in 1988 in 100-liter microcosms. The microcosms were screened through 200-#m or 20-#m mesh nets and incubated for 12 d at 1 °C under artificial light. Mean cell volume of dinoflagellates was 1000 to 1 500 #m 3, and that of their phytoplankton prey 360 to 430#m a. Dinoflagellate growth rate followed a Holling type II functional response, with a maximum growth rate of 0.3 d-1 and half-saturation food concentrations of 1.0#g chlorophyll a 1-1, 50 #g C 1-1, or 1 500 cells ml-1. Carbon budgets based on 14CO2 assimilation and biomasses of phytoplankton and heterotrophic dinofiagellates suggested a balance between phytoplankton grazing loss and dinoflagellate consumption, assuming a dinoflagellate carbon conversion efficiency of 40%. Applying this to the functional response yielded estimates of maximum ingestion rate (0.8 #g C pg-1 C d 1, or 6 pg C dinoflagellate -1 h -1) and maximum clearance (0.8 to 1.2x 105 body volumes h -1, or 80 to 120 nl ind. -1 h-l). The microcosm experiments suggested that heterotrophic dinoflagellates may contribute significantly to maintenance of low phytoplankton biomass in the Southern Ocean.
Journal of Freshwater Ecology, 2010
Thirty Microcystis colonies, belonging to three species (Microcystis aeruginosa, Microcystisflos-... more Thirty Microcystis colonies, belonging to three species (Microcystis aeruginosa, Microcystisflos-aquae, and Microcystis wesenbergii) were isolated from Lake Taihu and Lake Chaohu in China. Bacterial communities associated with the single Microcystis colonies were investigated using a seminested polymerase chain reaction-amplification along with denaturing gradient gel electrophoresis (DGGE). The bacterial communities of most colonies of the same Microcystis species in each lake tended to be similar. This indicates that species-specific associations may exist between colony-associated bacteria and Microcystis spp. Sequence analysis of dominant DGGE bands revealed that the dominant bacterial groups associated with Microcystis colonies were Alphaproteobacteria, Betaproteobacteria, Garnmaproteobacteria, Bacteroidetes, Firmicutes, Deinococcus-Thermus, and Gemmatimonadetes. Phylotypes related to Pseudomonas sp., Serratia sp., and Flexibacteraceae were dominant in colonies of M. wesenbergii, M jlos-aquae, and M aeruginosa, respectively.
ICES Journal of Marine Science, 1999
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Papers by Jorma Kuparinen