Der Chlorophyllgehalt im See und seine photosynthetische Valenz als geophysikalisches Problem

Photosynthesis Under Natural Conditions

“…In the first instance, such experiments allow the comparison of some photosynthetic indices using plant samples collected in different situations. Examples are provided by studies of the variation of photosynthetic capacity with latitude (e.g., 144,212) or season (12,64,127,162,182,257), and of differentiation between "sun" and "shade" material (10,20,207). The appli cation of such measurements to a reconstruction of photosynthetic activity in nature requires more extensive sampling and measurement of environmental variables than is usually made; direct comparisons of laboratory and field exposures (e.g., 220) are rarely attempted.…”

“…hr. (or its equivalent) at light-saturation (e.g., 62,63,64,90,123,262). Tropical examples of terrestrial plants studied do not appear to show particularly high photosynthetic rates at light-saturation [Stocker (2 11, 212), Walter (246,248), Zalensky (264), d. also (34,74)].…”

Photosynthetic Characteristics of Some Freshwater Plankton Diatoms in Relation to Underwater Radiation

“…Regarding variation in Pm, no detailed study appears to have been made based upon a single species. Gessner (1944Gessner ( , 1949 using chlorophyll-based values has described variations in mixed populations in relation to seasonal succession and photic adaptation.…”

“…The significance of such adaptation in relation to phytoplankton is little known, although various species or populations have been described as 'sun' ('strong light') or 'shade' ('weak light') forms on various grounds (e.g. Sagromsky, 1943;Findenegg, 1947;Gessner, 1949;Vollenweider, 1950;Gessner and Diehl, 1951). The early onset of light-saturation (i.e.…”

Phytoplankton and Marine Primary Production

“…The rate of photosynthesis at Imax divided by the concentration of chlorophyll-a has been used extensively in marine and fresh-water ecology (1) but values for this ratio vary at least fourfold, depending on species, nutrition, and prehistory of the population (53,62,63,65,68,(73)(74)(75)(76)(77)(78). The ratio is a r e asonably good index of comparative plant physiology and is the only parameter which can be measured simply and rapidly in the field.…”