Höhere Wasserpflanzen

Gessner, Fritz

doi:10.1007/978-3-642-94798-8_62

Cited by 1 publication

(2 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Lindeman (1942) considered that productivity tends to increase towards the climax of any ecological succession extending from aquatic to terrestrial communities, with an intermediate minimum at the transition stage. However, emergent vegetation, characteristic of the transition, appears to produce as much, or more, than either completely aerial or submerged communities (see Table 4; Penfound, 1956;Gessner, 1959; E. P. Odum, 1959).…”

Section: Discussionmentioning

confidence: 99%

“…When the plant community is suspended in a deep mixed water, a large part of the effective biomass will be poorly illuminated and its respiration will depress the net photosynthesis of the community. It is also probable that the slow diffusion of carbon dioxide or carbonates in solution, compared with gaseous diffusion, acts against submerged plants (Burr, 1941 ;Gessner, 1960;StHlfelt, 1960). Emergent vegetation has the advantages of a gaseous source of carbon and ample water supplies.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Comparisons of Plant Productivity

1963

View full text Add to dashboard Cite

Ecosystems are the basic functional units in ecology, which include the organisms that form communities, and their environment; freshwater lakes and deciduous forests are two types of ecosystem (E. P. Odum, 1959). Comparisons of plant productivity 389( 2 ) Criteria and units Measurements used as evidence of the productivity of different communities may be published as standing crop, crop, yield, biomass, production or productivity, and are expressed according to a great variety of criteria and units. Such different entities cannot be compared directly and the problems of selecting conversion factors require detailed consideration.Results expressed in different units, such as lb./acre and kg./m.2, can be readily inter-converted by constants, but when different criteria are involved, such as dry weight and ash-free dry weight, conversion factors must be selected to suit the particular community.Conversions from volume have been used in preparing this article only for some forest and phytoplankton crops. They are particularly unreliable and are of limited importance. Volume is usually measured by displacement, which may be inaccurate when the plant contains collapsible air spaces or has adherent water (Westlake, 1961), or is calculated by mensuration, which is not easy for microscopic plants or for complicated shapes. Conversion factors (i.e. densities) for volume to fresh weight are very variable from species to species, usually depending on the proportion of air 25-2

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%