Laurel Lindeman, Ecological Dynamics in
a Senescent Lake (Ph.D. Thesis, University
of Minnesota, 1941).
In his doctoral thesis, Raymond Lindeman developed
the "trophic dynamic" approach that
would be so influential to the formation of
ecosystem ecology in his widely cited "The
Trophic Dynamic aspects of Ecology" (1941).
For his thesis, he (and his wife Eleanor) conducted
a comprehensive analysis of the "food relations"
of Cedar Bog Lake outside of Minneapolis, MN.
Like in the Chinese proverb that he cited:
fish eats small fish;
Small fish eats water insects;
Water insects eat plants and mud."
Lindeman paid attention to the community relations
that has become central to limnology (the study
of lakes) and ecology (the study of communities).
He expanded a number of previous works, e.g.
F. A. Forel's "Le Leman" (1892), which
studied the general nature of food cycles into
a a study of trophic equilibrium and its relationship
to succession and climax formation.
Lindeman's diagram "The primary food-cycle
of Cedar Bog Lake," shows how nutrients
are incorporated into organic substances by
three agencies: autotrophic bacteria, algae,
and pondweeds. Each of these may die and decompose
by bacterial action into ooze, or may be eaten
by some animal. These nutrients then move around
the food cycle depicted.