Biomass and structure of planktonic communities along an air temperature gradient in subarctic Sweden

Abstract

1. Air temperature will probably have pronounced effects on the composition of plankton communities in northern lake ecosystems, either via indirect effects on the export of essential elements from catchments or through direct effects of water temperature and the ice-free period on the behaviour of planktonic organisms. 2. We assessed the role of temperature by comparing planktonic communities in 15 lakes along a 6°C air temperature gradient in subarctic Sweden. 3. We found that the biomass of phytoplankton, bacterioplankton and the total planktonic biomass were positively related to air temperature, probably as a result of climatic controls on the export of nitrogen from the catchment (which affects phytoplankton biomass) and dissolved organic carbon (affecting bacterioplankton biomass). 4. The structure of the zooplankton community, and top down effects on phytoplankton, were apparently not related to temperature but mainly to trophic interactions ultimately dependent on the presence of fish in the lakes. 5. Our results suggest that air temperature regimes and long-term warming can have strong effects on the planktonic biomass in high latitude lakes. Effects of temperature on the structure of the planktonic community might be less evident unless warming permits the invasion of fish into previous fishless lakes.

The habitat template of phytoplankton morphology-based functional groups

“…In general this group representatives have low optimum Temps (Kim et al, 2009;Jansson et al, 2010) and are more important in cold oligotrophic conditions (Kristlansen & Takahashi, 1982;Izaguirre et al, 2003), as well as in mesotrophic clear-water plant dominated lakes . Low explained variance can be a consequence of poor representation of lakes with this group.…”

Phytoplankton response to a changing climate

“…Increasing runoff can also modify the resource ratio in certain types of systems, depending on the nature of the geochemistry in the catchment and thus modifying the competitive advantage of phytoplankton species. For example, phytoplankton and bacterioplankton biomass is related to air temperature that controls the export of nitrogen and dissolved organic carbon from the catchment across subarctic Swedish lakes, indicating that climate may affect the balance between phytoplankton and bacterial production (Jansson et al, 2010). For coastal regions, enhanced upwelling due to an increasing Fig.…”

Morphology-based classification of functional groups for potamoplankton

“…To examine the relationships of dominant-group biomass and zooplankton abundance, leastsquares linear regression was used. Given the risk of spurious correlation (Jansson et al, 2010), relative comparisons of phytoplankton and zooplankton were prudent to make rather than focusing on the individual r 2 values. Statistical analyses were performed with SPSS 20.0.…”