His position: • No evidence of increasing lake clarity as a result of secchi measurements since 1946 • The interplay of stratification and plankton productivity are not «straightforward» • Challenges O'Reilly's assumption on the correlation of wind and productivity - the highest production is on the end of the lake with the lowest winds • A strong caution using diatoms as the productivity
proxy (it is one of two different lake modes) • No ability to link climate
change to productivity
changes • More productivity from river than allowed for
in Nature Geopscience article • Externally derived nutrients control productivity for a quarter of the year • Strong indications of overfishing • No evidence of a climate and fishery production link • The current productivity of the lake is within the expected range • Doesn't challenge recent
temp increase but cites temperature records do not show a temperature rise
in the last century • Phytoplankton chlorophylla seems to have not materially
changed from the 1970s to 1990s • Disputes O'Reilly's and Verbug's claims of increased warming and decreased productivity • Rejects Verburgs contention that
changes in phytoplankton biomass (biovolume),
in dissolved silica and
in transparency support the idea of declining productivity.