Seasonal Changes in Chlorophyll‐containing Picoplankton Populations of Ten Lakes in Northern England

Abstract

Key features of photosynthetic picoplankton populations were compared during 1988 in ten lakes in northem England ranging from oligotrophic to slightly eutrophic; two of the three eutrophic lakes were shallow and lacked a thermocline. Measurements were made at 0.5 m depth of temperature, total chlorophyll a, chlorophyll-containing picoplankton cell density, mean picoplankton Celt volume and percentage of phycoerythrin-rich cells in the total picoplankton population. All lakes showed maxima for total chlorophyll concentration and picoplankton cell density in mid-to late summer. The maximum value for picoplankton density ranged from 3.4 x 103 (Esthwaite Water) to 1.3 x 106 cells ml-1 (Ennerdale Water).There was a significant negative relationship (p c 0.05) between log,,, of maximum picoplankton cell density and maximum total chlorophyll, the latter being taken as an indicator of lake trophic status. The ratio of maximum to minimum picoplankton density during the year in a particular lake ranged from 39 to 2360 and showed no obvious relationship to lake type. Overall, the seasonal range in picoplankton density was about one order of magnitude greater than the range in total chlorophyll a, but there were considerable differences between lakes.Phycoerythrin-rich picoplankton as a percentage of total picoplankton reached a maximum in summer in all lakes. Values were always very low (c 5 %) in the two shallow eutrophic lakes, but reached 97 % and over in the four most oligotrophic lakes. In two of the oligotrophic lakes, Wastwater and Ennerdale Water, phycoerythrin-rich picoplankton was a major component of the summer phytoplankton biomass.

Mass development of phytoplankton in the River Warta in Poznań (Poland) in the 21st century

“…The participation of APP as a component of the total phytoplankton biomass in the Warta was not significant. This confirms the observation of Hawley and Whitton (1991b), that relative contribution of APP to total phytoplankton biomass is the lowest when the trophic state is high. Autotrophic picoplankton is observed in waters of different trophic state, but studies show the sensitivity of APP to eutrophication, and also to water contamination, especially with heavy metals (Severn et al 1989;Weisse 1991;Weisse and Mindl 2002).…”

Picocyanobacterial community structure of freshwater lakes and the Baltic Sea revealed by phylogenetic analyses and clade-specific quantitative PCR

“…While some studies of temperate lakes have shown two peaks of picocyanobacteria abundance, one in spring and one in late summer (Weisse, 1993;, other lakes lack a spring peak, with only a summer or autumn population maximum (Pick & Agbeti, 1991;Maeda et al, 1992;Hawley & Whitton, 1991). Our data suggest that CWP lakes 9 and 124 exhibit one peak, in summer, for all clades with the exception of clade I.…”

Autotrophic and Heterotrophic Picoplankton in Wetlands: Differences with Lake Patterns

“…Large spring peaks were found in Lake Constance (WEISSE, 1993) and Lake Maggiore (STOCKNER et al, 2000) and are also common in eutrophic and hypertrophic lakes (SIME- NGANDO, 1995;VÖRÖS et al, 1991;JASSER, 1997), but not in warm-monomictic lakes (STOCKNER and SHORTREED, 1991;MALINSKY-RUSHANSKY et al, 1995). The seasonal patterns found in seven Danish lakes (SØNDERGAARD, 1991), several Canadian lakes (PICK and AGBETI, 1991), Lake Biwa, Japan (MAEDA et al, 1992) and in the northern English lakes (HAWLEY and WHITTON, 1991) all lack the spring peak, there being only a summer or autumn maximum. The bimodal pattern of APP abundance in PG was similar to that reported by JASSER (1997) in the shallow, dystrophic lake Flosek (Poland).…”