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Publikasjoner (10 av 38) Visa alla publikasjoner
Båmstedt, U. (2019). Comparing static and dynamic incubations in primary production measurements under different euphotic and mixing depths. Hydrobiologia, 827(1), 155-169
Åpne denne publikasjonen i ny fane eller vindu >>Comparing static and dynamic incubations in primary production measurements under different euphotic and mixing depths
2019 (engelsk)Inngår i: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 827, nr 1, s. 155-169Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Since phytoplankton production is usually estimated from static incubations (fixed depths or light levels), a mesocosm study was performed to evaluate the significance of mixing depth, mixing intensity and load of humus of natural phytoplankton assemblages. Vertically rotated (dynamic) incubations usually gave higher results than static incubations in humus-rich water. Mixing intensity was of significant importance in one of 2years tested, but strong interaction effects with humus complicated the explanation. Differences in primary production between dynamic incubations did not fully reflect the received PAR dose, and increased humus and increased mixing depth increased the photo-assimilation efficiency. Different single-depth incubations did not provide a shortcut method to measure water-column primary production with high accuracy. Results diverged from theoretical estimates based on recent combined photo-biological and physical environmental models. The large variability in responses to mixing is supposed to reflect species-specific adaptations and pre-history regarding quantity (photons) and quality (spectral distribution) of the optical environment in an assemblage of different species. The proportional abundance of each species with its specific characters will therefore strongly influence bulk primary production. Due to such variable responses, clear guidelines for a best practice in primary production measurements cannot be given, based on the present results.

sted, utgiver, år, opplag, sider
SPRINGER, 2019
Emneord
Primary production, Dynamic incubation, Static incubation, Mixing depth, Euphotic zone, otoadaptation, NMAN KL, 1983, LIMNOLOGY AND OCEANOGRAPHY, V28, P801
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-154323 (URN)10.1007/s10750-018-3762-1 (DOI)000451426200011 ()
Tilgjengelig fra: 2018-12-18 Laget: 2018-12-18 Sist oppdatert: 2019-03-05bibliografisk kontrollert
Båmstedt, U. (2019). Productivity related to ambient photon flux for phytoplankton communities under different turbid conditions. Hydrobiologia, 837(1), 109-115
Åpne denne publikasjonen i ny fane eller vindu >>Productivity related to ambient photon flux for phytoplankton communities under different turbid conditions
2019 (engelsk)Inngår i: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 837, nr 1, s. 109-115Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Phytoplankton productivity standardized to chlorophyll a and photon flux (mg C mg chl. a(-1) mol photons(-1)) of natural communities from northern Bothnian Sea under dynamic (vertically rotating) incubations and different optical conditions was studied during four mesocosm experiments between April 2013 and April 2016. The standardized productivity showed a positive exponential relationship with calculated optical depth (P<0.001 in all four cases) although a considerably weaker one for one of the series where the community was pre-adapted to the same optical condition as used in the measurements. This series also showed a lower regression slope than the three non-adapted series, which in turn showed identical regression slopes, thus indicating a similar response on the standardized productivity to short-term changes in average ambient photon flux and mixing depth. These results indicate that phytoplankton communities in environments with episodic inflow and mixing of humus-rich water can partly compensate for the reduced photon flux by increased production efficiency.

sted, utgiver, år, opplag, sider
Springer, 2019
Emneord
Primary production, Mixing depth, Optical depth, Photosynthetic efficiency, Blackwater environments
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-161572 (URN)10.1007/s10750-019-3964-1 (DOI)000472486800008 ()
Tilgjengelig fra: 2019-07-25 Laget: 2019-07-25 Sist oppdatert: 2019-08-14bibliografisk kontrollert
Båmstedt, U. & Larsson, H. (2018). An indoor pelagic mesocosm facility to simulate multiple water-column characteristics. International Aquatic Research, 10(1), 13-29
Åpne denne publikasjonen i ny fane eller vindu >>An indoor pelagic mesocosm facility to simulate multiple water-column characteristics
2018 (engelsk)Inngår i: International Aquatic Research, ISSN 2008-4935, E-ISSN 2008-6970, Vol. 10, nr 1, s. 13-29Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Mesocosms are important research tools in aquatic ecology because they close the gap between laboratory studies at the individual or lower organization level and field studies at the population and ecosystem level. However, most mesocosm studies regarding the pelagic environment do not consider the effects of physical factors like water-column stratification, turbulence and mixing. Neglecting such factors might bias the results compared to the natural system. Using a unique indoor mesocosm facility, we present results on how different water-column stratifications can be made and how they act as barriers for exchange between water layers. Turbulent mixing, simulated by vertically rotating incubation vessels, is shown to be of high importance for primary production, generating up to nine times higher production in humus-rich water than incubation vessels at fixed depths. Convective stirring is shown to be an attractive method for generating different turbulence conditions, and different temperature settings can be used to get turnover times from 84 h or more down to 17 min for a 5-m water parcel. We also demonstrate how an anoxic bottom layer can be achieved by stimulating heterotrophic bacteria through addition of bioavailable organic carbon.

sted, utgiver, år, opplag, sider
Springer, 2018
Emneord
Aquatic mesocosm, Turbulent mixing, Primary production, Pycnocline strength, Light spectrum, Bacterial oxygen depletion, Thermal convection
HSV kategori
Forskningsprogram
miljövetenskap
Identifikatorer
urn:nbn:se:umu:diva-143856 (URN)10.1007/s40071-017-0185-y (DOI)2-s2.0-85044211868 (Scopus ID)
Tilgjengelig fra: 2018-01-11 Laget: 2018-01-11 Sist oppdatert: 2019-03-05bibliografisk kontrollert
Degerman, R., Lefébure, R., Byström, P., Båmstedt, U., Larsson, S. & Andersson, A. (2018). Food web interactions determine energy transfer efficiency and top consumer responses to inputs of dissolved organic carbon. Hydrobiologia, 805(1), 131-146
Åpne denne publikasjonen i ny fane eller vindu >>Food web interactions determine energy transfer efficiency and top consumer responses to inputs of dissolved organic carbon
Vise andre…
2018 (engelsk)Inngår i: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 805, nr 1, s. 131-146Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Climate change projections indicate increased precipitation in northern Europe, leading to increased inflow of allochthonous organic matter to aquatic systems. The food web responses are poorly known, and may differ depending on the trophic structure. We performed an experimental mesocosm study where effects of labile dissolved organic carbon (DOC) on two different pelagic food webs were investigated, one having zooplankton as highest trophic level and the other with planktivorous fish as top consumer. In both food webs, DOC caused higher bacterial production and lower food web efficiency, i.e., energy transfer efficiency from the base to the top of the food web. However, the top-level response to DOC addition differed in the zooplankton and the fish systems. The zooplankton production increased due to efficient channeling of energy via both the bacteria land the phytoplankton pathway, while the fish production decreased due to channeling of energy mainly via the longer and less efficient bacterial pathway. We conclude that the added DOC either acted as a subsidy by increasing the production of the top trophic level (mesozooplankton), or as a sink causing decreased top consumer production (planktivorous fish).

Emneord
Food web efficiency, Carbon transfer, Allochthonous dissolved organic carbon, Mesocosm, Planktivorous fish
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-102789 (URN)10.1007/s10750-017-3298-9 (DOI)
Forskningsfinansiär
Ecosystem dynamics in the Baltic Sea in a changing climate perspective - ECOCHANGE
Merknad

Originally published in manuscript form with title Food web interactions determine transfer efficiency and top consumer responses to increased allochthonous carbon input

Tilgjengelig fra: 2015-05-05 Laget: 2015-05-05 Sist oppdatert: 2019-03-05bibliografisk kontrollert
Båmstedt, U. & Brugel, S. (2017). A cost-precision model for marine environmental monitoring, based on time-integrated averages. Environmental Monitoring & Assessment, 189(7), Article ID 354.
Åpne denne publikasjonen i ny fane eller vindu >>A cost-precision model for marine environmental monitoring, based on time-integrated averages
2017 (engelsk)Inngår i: Environmental Monitoring & Assessment, ISSN 0167-6369, E-ISSN 1573-2959, Vol. 189, nr 7, artikkel-id 354Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Ongoing marine monitoring programs are seldom designed to detect changes in the environment between different years, mainly due to the high number of samples required for a sufficient statistical precision. We here show that pooling over time (time integration) of seasonal measurements provides an efficient method of reducing variability, thereby improving the precision and power in detecting inter-annual differences. Such data from weekly environmental sensor profiles at 21 stations in the northern Bothnian Sea was used in a cost-precision spatio-temporal allocation model. Time-integrated averages for six different variables over 6 months from a rather heterogeneous area showed low variability between stations (coefficient of variation, CV, range of 0.6-12.4%) compared to variability between stations in a single day (CV range 2.4-88.6%), or variability over time for a single station (CV range 0.4-110.7%). Reduced sampling frequency from weekly to approximately monthly sampling did not change the results markedly, whereas lower frequency differed more from results with weekly sampling. With monthly sampling, high precision and power of estimates could therefore be achieved with a low number of stations. With input of cost factors like ship time, labor, and analyses, the model can predict the cost for a given required precision in the time-integrated average of each variable by optimizing sampling allocation. A following power analysis can provide information on minimum sample size to detect differences between years with a required power. Alternatively, the model can predict the precision of annual means for the included variables when the program has a pre-defined budget. Use of time-integrated results from sampling stations with different areal coverage and environmental heterogeneity can thus be an efficient strategy to detect environmental differences between single years, as well as a long-term temporal trend. Use of the presented allocation model will then help to minimize the cost and effort of a monitoring program.

sted, utgiver, år, opplag, sider
Springer, 2017
Emneord
Environmental surveys, Cost of precision, Optimal allocation, Seasonal variability, Marine environments, Coastal ecology
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-138552 (URN)10.1007/s10661-017-6064-6 (DOI)000404652900051 ()28647904 (PubMedID)
Tilgjengelig fra: 2017-09-14 Laget: 2017-09-14 Sist oppdatert: 2018-06-09bibliografisk kontrollert
Winder, M., Bouquet, J.-M., Bermudez, J. R., Berger, S. A., Hansen, T., Brandes, J., . . . Thompson, E. M. (2017). Increased appendicularian zooplankton alter carbon cycling under warmer more acidified ocean conditions. Limnology and Oceanography, 62(4), 1541-1551
Åpne denne publikasjonen i ny fane eller vindu >>Increased appendicularian zooplankton alter carbon cycling under warmer more acidified ocean conditions
Vise andre…
2017 (engelsk)Inngår i: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 62, nr 4, s. 1541-1551Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Anthropogenic atmospheric loading of CO2 raises concerns about combined effects of increasing ocean temperature and acidification, on biological processes. In particular, the response of appendicularian zooplankton to climate change may have significant ecosystem implications as they can alter biogeochemical cycling compared to classical copepod dominated food webs. However, the response of appendicularians to multiple climate drivers and effect on carbon cycling are still not well understood. Here, we investigated how gelatinous zooplankton (appendicularians) affect carbon cycling of marine food webs under conditions predicted by future climate scenarios. Appendicularians performed well in warmer conditions and benefited from low pH levels, which in turn altered the direction of carbon flow. Increased appendicularians removed particles from the water column that might otherwise nourish copepods by increasing carbon transport to depth from continuous discarding of filtration houses and fecal pellets. This helps to remove CO2 from the atmosphere, and may also have fisheries implications.

sted, utgiver, år, opplag, sider
John Wiley & Sons, 2017
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-137976 (URN)10.1002/lno.10516 (DOI)000404993100016 ()
Tilgjengelig fra: 2017-08-02 Laget: 2017-08-02 Sist oppdatert: 2018-06-09bibliografisk kontrollert
Båmstedt, U. & Wikner, J. (2016). Mixing depth and allochthonous dissolved organic carbon: controlling factors of coastal trophic balance. Marine Ecology Progress Series, 561, 17-29
Åpne denne publikasjonen i ny fane eller vindu >>Mixing depth and allochthonous dissolved organic carbon: controlling factors of coastal trophic balance
2016 (engelsk)Inngår i: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 561, s. 17-29Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

ABSTRACT: The interacting effects of different mixing depths and increased allochthonous dissolved organic carbon (DOC) on the ratio of heterotrophic to autotrophic production (i.e. trophic balance) was evaluated in a mesocosm study with a stratified water column. An autumn plankton community from the northern Bothnian Sea showed significantly decreased phytoplankton production and somewhat increased bacterial production with added DOC. In addition, increased mixing depth further reduced phytoplankton production. With a deep pycnocline and added DOC, the system became net-heterotrophic, with an average bacteria-to-phytoplankton production ratio of 1.24. With a deep pycnocline without added DOC, the trophic balance was changed to 0.44 (i.e. autotrophic). With a shallow pycnocline, the system remained net-autotrophic irrespective of DOC addition. We propose that increased precipitation in northern Europe due to climate change may result in changed density stratification and increased allochthonous DOC transport to the sea, leading to more heterotrophic coastal aquatic ecosystems. Such a scenario may entail reduced biological production at higher trophic levels and enhanced CO2 emission to the atmosphere.

sted, utgiver, år, opplag, sider
Oldendorf/Luhe: , 2016
Emneord
marine, ecology, climate, production, plankton, mesocosm, trophic, balance, dissolved organic carbon, stratification
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-128844 (URN)10.3354/meps11907 (DOI)000391695800002 ()
Tilgjengelig fra: 2016-12-16 Laget: 2016-12-16 Sist oppdatert: 2019-03-06bibliografisk kontrollert
Båmstedt, U. & Martinussen, M. B. (2015). Ecology and behavior of Bolinopsis infundibulum (Ctenophora; Lobata) in the Northeast Atlantic. Hydrobiologia, 759(1), 3-14
Åpne denne publikasjonen i ny fane eller vindu >>Ecology and behavior of Bolinopsis infundibulum (Ctenophora; Lobata) in the Northeast Atlantic
2015 (engelsk)Inngår i: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 759, nr 1, s. 3-14Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Results from field surveys with net sampling and video profiling, combined with laboratory experiments on feeding and growth, revealed the ecological function of Bolinopsis infundibulum in northern temperate coastal waters. B. infundibulum reaching a peak abundance of around 250 ctenophores m(-2), in mid-May, followed by a dramatic reduction over the next few weeks, presumably explained by predation from the ctenophore Beroe cucumis. The field data on maximum individual body height in the population indicated an instantaneous growth rate of 0.129 d(-1). Newly hatched cydippid larvae showed an average instantaneous growth rate of 0.240 d(-1) over 4 weeks, whereas ctenophores in the size range of 4.4-9.8 mm height gave instantaneous growth rates between 0.10 and 0.20 d(-1). B. infundibulum disappeared from surface water in mid-June, but big individuals were found in deeper water, where they preyed on copepods. The results indicate that the new generation of the year was recruited from February onwards. Laboratory predation and digestion experiments showed a continuous increase in predation rate with increased prey abundance, throughout the tested range of 5-400 copepods l(-1), and a digestion time increasing from 39 min with a single copepod ingested to 73 min with 8 copepods ingested.

sted, utgiver, år, opplag, sider
Springer, 2015
Emneord
Bolinopsis infundibulum, Ctenophores, Growth rate, Predation rate, Behavior, Digestion rate, erwintering, Life cycle
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-109364 (URN)10.1007/s10750-015-2180-x (DOI)000360672400002 ()
Tilgjengelig fra: 2015-09-25 Laget: 2015-09-25 Sist oppdatert: 2018-06-07bibliografisk kontrollert
Sjoqvist, C., Kremp, A., Lindehoff, E., Båmstedt, U., Egardt, J., Gross, S., . . . Godhe, A. (2014). Effects of Grazer Presence on Genetic Structure of a Phenotypically Diverse Diatom Population. Microbial Ecology, 67(1), 83-95
Åpne denne publikasjonen i ny fane eller vindu >>Effects of Grazer Presence on Genetic Structure of a Phenotypically Diverse Diatom Population
Vise andre…
2014 (engelsk)Inngår i: Microbial Ecology, ISSN 0095-3628, E-ISSN 1432-184X, Vol. 67, nr 1, s. 83-95Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Studies of predator-prey systems in both aquatic and terrestrial environments have shown that grazers structure the intraspecific diversity of prey species, given that the prey populations are phenotypically variable. Populations of phytoplankton have traditionally considered comprising only low intraspecific variation, hence selective grazing as a potentially structuring factor of both genetic and phenotypic diversity has not been comprehensively studied. In this study, we compared strain specific growth rates, production of polyunsaturated aldehydes, and chain length of the marine diatom Skeletonema marinoi in both grazer and non-grazer conditions by conducting monoclonal experiments. Additionally, a mesocosm experiment was performed with multiclonal experimental S. marinoi populations exposed to grazers at different levels of copepod concentration to test effects of grazer presence on diatom diversity in close to natural conditions. Our results show that distinct genotypes of a geographically restricted population exhibit variable phenotypic traits relevant to grazing interactions such as chain length and growth rates. Grazer presence affected clonal richness and evenness of multiclonal Skeletonema populations in the mesocosms, likely in conjunction with intrinsic interactions among the diatom strains. Only the production of polyunsaturated aldehydes was not affected by grazer presence. Our findings suggest that grazing can be an important factor structuring diatom population diversity in the sea and emphasize the importance of considering clonal differences when characterizing species and their role in nature.

sted, utgiver, år, opplag, sider
Springer, 2014
HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-112711 (URN)10.1007/s00248-013-0327-8 (DOI)000330982500008 ()24272280 (PubMedID)
Tilgjengelig fra: 2015-12-14 Laget: 2015-12-14 Sist oppdatert: 2019-03-06bibliografisk kontrollert
Haraldsson, M., Båmstedt, U., Tiselius, P., Titelman, J. & Aksnes, D. L. (2014). Evidence of Diel Vertical Migration in Mnemiopsis leidyi. PLoS ONE, 9(1), e86595
Åpne denne publikasjonen i ny fane eller vindu >>Evidence of Diel Vertical Migration in Mnemiopsis leidyi
Vise andre…
2014 (engelsk)Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, nr 1, s. e86595-Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The vertical distribution and migration of plankton organisms may have a large impact on their horizontal dispersal and distribution, and consequently on trophic interactions. In this study we used video-net profiling to describe the fine scale vertical distribution of Mnemiopsis leidyi in the Kattegat and Baltic Proper. Potential diel vertical migration was also investigated by frequent filming during a 24-hour cycle at two contrasting locations with respect to salinity stratification. The video profiles revealed a pronounced diel vertical migration at one of the locations. However, only the small and medium size classes migrated, on average 0.85 m h(-1), corresponding to a total migration distance of 10 m during 12 h. Larger individuals (with well developed lobes, approx. >27 mm) stay on average in the same depth interval at all times. Biophysical data suggest that migrating individuals likely responded to light, and avoided irradiance levels higher than approx. 10 mu mol quanta m(-2) s(-1). We suggest that strong stratification caused by low surface salinity seemed to prohibit vertical migration.

HSV kategori
Identifikatorer
urn:nbn:se:umu:diva-86839 (URN)10.1371/journal.pone.0086595 (DOI)000330283100187 ()
Tilgjengelig fra: 2014-03-13 Laget: 2014-03-11 Sist oppdatert: 2018-06-08bibliografisk kontrollert
Organisasjoner
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0003-0220-9492