﻿RELATION 
  OF 
  AQUATIC 
  PLAIS^TS 
  TO 
  SUBSTRATUM. 
  525 
  

  

  direct 
  ratio 
  proportional 
  to 
  the 
  amount 
  of 
  its 
  gross 
  rooted 
  vegetation." 
  

   In 
  the 
  final 
  paragraph 
  of 
  that 
  part 
  of 
  his 
  paper 
  which 
  deals 
  with 
  this 
  

   subject, 
  Kofoid 
  (1903, 
  p. 
  502) 
  recognizes 
  that 
  the 
  distinction 
  should 
  be 
  

   drawn 
  between 
  rooted 
  and 
  nonrooted 
  vegetation, 
  and 
  suggests 
  that 
  

   experimental 
  proof 
  is 
  desirable 
  for 
  the 
  generalization 
  which 
  he 
  ad- 
  

   vances. 
  Such 
  experimental 
  proof 
  1 
  had 
  already 
  offered 
  (Pond, 
  11)01) 
  

   in 
  a 
  preliminary 
  note, 
  to 
  which 
  Kofoid 
  does 
  not 
  refer, 
  though 
  he 
  refers 
  

   to 
  Pieters 
  (1901, 
  p. 
  73, 
  footnote), 
  in 
  which 
  this 
  note 
  is 
  cited. 
  (See 
  

   also 
  Pond, 
  1902, 
  p. 
  89.) 
  

  

  If 
  we 
  accept 
  the 
  conclusions 
  reached 
  in 
  this 
  paper 
  that 
  gross 
  rooted 
  

   vegetation 
  is 
  favorable 
  to 
  plankton 
  production, 
  and 
  if 
  we 
  further 
  

   accept 
  the 
  current 
  argument 
  that 
  fish 
  production 
  is 
  dependent 
  on 
  

   plankton 
  production, 
  the 
  practical 
  application 
  of 
  the 
  results 
  of 
  this 
  in- 
  

   vestigation 
  are 
  simple. 
  In 
  the 
  stocking 
  of 
  ponds 
  for 
  fish 
  culture 
  care 
  

   should 
  be 
  taken 
  to 
  have 
  a 
  good 
  soil 
  for 
  the 
  bottom; 
  not 
  a 
  stiff 
  clay 
  nor 
  

   sand, 
  but 
  a 
  good 
  loamy 
  soil, 
  such 
  as 
  is 
  favorable 
  for 
  land 
  plants. 
  The 
  

   species 
  allowed 
  to 
  grow 
  should 
  be 
  those 
  which 
  are 
  known 
  to 
  possess 
  

   roots 
  and 
  to 
  be 
  very 
  dependent 
  upon 
  the 
  soil, 
  such 
  as 
  Valllsueria 
  

   spiralis^ 
  the 
  so-called 
  eelgrass, 
  and 
  Potamogeton^ 
  or 
  pond 
  weeds; 
  not 
  

   forms 
  without 
  roots, 
  such 
  as 
  CercttophyUum^ 
  or 
  those 
  less 
  dependent 
  

   upon 
  the 
  soil. 
  In 
  natural 
  lakes 
  choked 
  with 
  a 
  growth 
  of 
  Cemto- 
  

   phylluin, 
  the 
  removal 
  of 
  this 
  form 
  and 
  the 
  substitution 
  for 
  it 
  of 
  rooted 
  

   plants 
  offer 
  possible 
  means 
  of 
  increasing 
  the 
  supply 
  of 
  edible 
  fish. 
  

  

  The 
  povert}^ 
  of 
  the 
  Great 
  Lakes 
  in 
  plankton 
  may 
  be 
  attributed 
  to 
  

   several 
  causes. 
  One 
  of 
  these 
  is, 
  doubtless, 
  the 
  relatively 
  small 
  shore 
  

   area 
  in 
  these 
  waters 
  occupied 
  by 
  rooted 
  aquatics. 
  The 
  comparatively 
  

   short 
  shore 
  line, 
  the 
  narrowness 
  of 
  the 
  shore 
  area, 
  and 
  the 
  mechanical 
  

   action 
  of 
  the 
  waves, 
  all 
  tend 
  to 
  limit 
  the 
  growth 
  of 
  rooted 
  plants, 
  

   hence 
  to 
  limit 
  the 
  productive 
  capacity 
  of 
  the 
  lake 
  in 
  plankton 
  and, 
  

   according 
  to 
  the 
  current 
  belief, 
  in 
  fishes. 
  

  

  BIBLIOGRAPHY. 
  

  

  Artari 
  (1901). 
  Zur 
  ErniihrungsphyHiologie 
  der 
  Griinen 
  Algen. 
  Berichte 
  der 
  

  

  Deutschen 
  Botanisclien 
  Gesellschaft, 
  XIX, 
  7. 
  

   Brandt 
  (1899). 
  Ueber 
  den 
  Stoffwechsel 
  im 
  Meere, 
  I. 
  Wissenschaftliche 
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  untersuchnngen. 
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  von 
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  deutschen 
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  in 
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  Biologischen 
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  auf 
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  Abth. 
  

  

  Kiel., 
  N. 
  F., 
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  (1902). 
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  den 
  Stoffwechsel 
  im 
  Meere, 
  II. 
  Ibid., 
  VI, 
  25-79. 
  

  

  Coulter 
  (1900). 
  Plant 
  Relations, 
  171. 
  

  

  Davis 
  (1901). 
  Contributions 
  to 
  the 
  Natural 
  History 
  of 
  Marl. 
  Journal 
  of 
  Geology, 
  

  

  IX, 
  505. 
  

   EvERMANN 
  (1902.) 
  The 
  Feeding 
  Habits 
  of 
  the 
  Coot 
  and 
  other 
  Water 
  Birds. 
  The 
  

  

  Osprey, 
  I, 
  57-64. 
  

   FoREL 
  (1902). 
  Le 
  Leman, 
  Monographie 
  Limnologique, 
  t. 
  3, 
  Hv. 
  1, 
  441 
  pages, 
  227 
  

  

  text 
  figures, 
  1 
  map. 
  

   Frank 
  (1890). 
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  78. 
  

   HocHREUTiNER 
  (1896). 
  Etudes 
  sur 
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  Phanerogames 
  Aquatiques 
  du 
  Rhone 
  et 
  du 
  

  

  Port 
  du 
  Geneve. 
  Revue 
  Generale 
  de 
  Botanique, 
  T. 
  VIII, 
  158. 
  

  

  