Distribution and development of under-ice phytoplankton in 90-m deep water column of Lake Päijänne (Finland) during spring convection

Kiili, Mari; Pulkkanen, Merja; Salonen, Kalevi

doi:10.1007/s10452-009-9262-7

Cited by 27 publications

(29 citation statements)

References 20 publications

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“…eutrophic Lake Ormajä rvi was at first a sink for CO 2 but became a source in mid-August. There was no spring peak in CO 2 flux in Lake Ormajä rvi, but our measurements on CO 2 concentration (results not shown) revealed an underice peak in late March, which disappeared by the time of first flux sampling, presumably due to under-ice photosynthesis (Tulonen et al 1994;Kiili et al 2009). The role of photosynthesis can also be suspected on the basis of slightly higher oxygen concentration just beneath the ice cover.…”

Section: Discussionmentioning

confidence: 63%

Carbon gas fluxes from a brown‐water and a clear‐water lake in the boreal zone during a summer with extreme rain events

Ojala

Bellido

Tulonen

et al. 2010

Limnology & Oceanography

104

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We studied CO 2 and CH 4 fluxes from two boreal lakes with differing trophic status (chlorophyll a 17.8 vs. 48.7 mg m 22 ) and water color (100 vs. 20 mg Pt L 21 ) throughout an open-water period when summer precipitation doubled, using both floating chambers and concentration gradients. Fluxes measured in chambers were higher, but irrespective of the method, both lakes were heterotrophic and were annual sources of carbon gases to the atmosphere. However, with the annual CO 2 flux of 6.85 (chambers) or 5.43 mol m 22 (gradients), the humic lake had notably higher emissions than the clear-water lake, where the fluxes were 3.97 and 3.38 mol m 22 , respectively. The annual CH 4 flux from the clear-water lake was 28.5 (chambers) or 20.5 mmol m 22 (gradients) and from the humic lake 20.7 or 16.2 mmol m 22 , respectively. There were interlake differences in seasonal patterns, but the most obvious changes in fluxes occurred during or just after the rains. In the humic lake, the resulting peak in CO 2 and CH 4 flux was responsible for 46% and 48% of the annual flux, respectively. Before the rains, the clear-water lake was a small sink of CO 2 or had near-zero efflux but afterwards became a source of CO 2 . In the humic lake, biological mineralization explained the majority of the fluxes, whereas in the clear-water lake the association between the biological processes and fluxes was less pronounced.

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Section: Discussionmentioning

confidence: 63%

Carbon gas fluxes from a brown‐water and a clear‐water lake in the boreal zone during a summer with extreme rain events

Ojala

Bellido

Tulonen

et al. 2010

Limnology & Oceanography

104

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“…The water temperature in deeper water of lakes range from 1 to 4°C; Fig. 1 Reading of automatic measurement station at Lake Kilpisjärvi in December during a polar night small deviations from the temperature of maximum density, however, result in dramatic variation in winter hydrodynamics (e.g., Kiili et al 2009;Vehmaa and Salonen 2009). Thus, the mixing conditions prior to the freezing of a lake have a major influence on the water circulation regime and hence indirectly also on the lake biology.…”

Section: Coupling Of Physical and Biologic Processes Under Icementioning

confidence: 98%

Perspectives in winter limnology: closing the annual cycle of freezing lakes

et al. 2009

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Winter has traditionally been considered as an ecologically insignificant season and, together with technical difficulties, this has led winter limnology to lag behind summer limnology. Recently, rapidly expanding interest in climate warming has increased water research in winter. It has also become clear that neither winter conditions of lakes nor underice communities are as static as often supposed. Although interannual differences in water temperature are small, close to the maximum density temperature, they may have profound effect on under-ice hydrodynamics. Thus, stochastic variations in weather, particularly those preceding the time of freezing and ice melting, may have important consequences for hydrodynamics which then affect the distributions and conditions of microorganisms and probably further to higher trophic levels. Even fish distributions can be dictated by under-ice conditions and their activities as well as behavior can sometimes approach those in summer. Life in freshwater ice is one of the least studied aspects of winter limnology and recent studies suggest that a thorough evaluation is needed. Altogether there are strengthening signs that winter should be considered as an integral part in the functioning and dynamics of lakes affecting quantitative and qualitative characteristics of aquatic communities in summer. There are great prospects that more thorough understanding of the prevailing limnological conditions in winter will improve our understanding of lake ecosystems in their entirety, and there is no doubt that such an approach requires multidisciplinary and long-term studies at different spatial scales.

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“…On the other hand, increase in the depth of the mixed layer often finally leads to circulation of algae to deeper layers (e.g. Kiili et al 2009) so that light climate for the algae deteriorates.…”

Section: Introductionmentioning

confidence: 98%

Radiation transfer and heat budget during the ice season in Lake Pääjärvi, Finland

et al. 2009

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Lake Pääjärvi, a boreal Finnish lake, was investigated in winter for weather conditions, structure and thickness of ice and snow, solar radiation, and under-ice current and temperature. Heat budget of Lake Pääjärvi in January-March was governed by terrestrial radiation losses of 20-35 W m -2 recompensed by ice growth of 0.5-1.0 cm day -1 . In April, snow melted, albedo decreased from 0.8 to \0.1, and the mean ice melt rate was 1.5 cm day -1 . Internal melting and surface melting were about equal. The mean turbulent heat loss was small. The heat flux from the water to ice was about 5 W m -2 in winter, increasing to 12 W m -2 in the melting season. The light attenuation coefficient was 1.1 m -1 for the congelation ice (black ice) in winter, compared with 1.5 m -1 for the lake water, and it was up to 3 m -1 for candled congelation ice in spring, and about 10 m -1 for superimposed ice (white ice) and snow. Gas bubbles were the main factor that reduced the transparency of ice. The radiation penetrating the ice heated the water body causing convective currents and horizontal heat transfer. This increased the temperature of the water body to about 3°C before the ice break-up. After the snow had melted, the euphotic depth (the depth of 1% surface irradiance) was estimated as 2.0 m, only two-thirds that in summer.

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Distribution and development of under-ice phytoplankton in 90-m deep water column of Lake Päijänne (Finland) during spring convection

Cited by 27 publications

References 20 publications

Carbon gas fluxes from a brown‐water and a clear‐water lake in the boreal zone during a summer with extreme rain events

Carbon gas fluxes from a brown‐water and a clear‐water lake in the boreal zone during a summer with extreme rain events

Perspectives in winter limnology: closing the annual cycle of freezing lakes

Radiation transfer and heat budget during the ice season in Lake Pääjärvi, Finland

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