﻿94 
  Nichols: 
  The 
  vegetation 
  of 
  Connecticut 
  

  

  * 
  

  

  decrease 
  in 
  the 
  amount 
  of 
  illumination 
  received 
  by 
  plants 
  growing 
  

   on 
  the 
  bottom, 
  and 
  the 
  intensity 
  (or 
  the 
  quality) 
  of 
  the 
  light 
  at 
  

  

  most 
  

  

  the 
  distribution 
  of 
  many 
  seaweeds. 
  Taken 
  collectively, 
  the 
  

   seaweeds 
  of 
  the 
  four 
  great 
  natural 
  groups 
  of 
  algae 
  (the 
  blue- 
  

   greens, 
  the 
  greens, 
  the 
  browns, 
  and 
  the 
  reds) 
  differ 
  considerably 
  

  

  from 
  

  

  The 
  blue-green 
  

  

  and 
  the 
  green 
  algae 
  demand 
  the 
  greatest 
  illumination 
  and 
  the 
  

   red 
  algae 
  the 
  least, 
  while 
  the 
  brown 
  algae 
  are 
  intermediate 
  In 
  their 
  

  

  r 
  

  

  light 
  requirements. 
  The 
  blue-greens 
  and 
  ereens 
  ; 
  

  

  most 
  

  

  ant 
  In 
  areas 
  which 
  are 
  above 
  low 
  tide 
  level 
  ; 
  toward 
  high 
  tide 
  mark 
  

   they 
  are 
  practically 
  the 
  only 
  forms 
  present. 
  The 
  browns, 
  in 
  

   large 
  part, 
  flourish 
  best 
  in 
  the 
  regions 
  just 
  above 
  and 
  just 
  below 
  

   low 
  tide 
  level. 
  The 
  reds 
  are 
  most 
  luxuriantly 
  developed 
  below 
  

   low 
  tide 
  mark; 
  in 
  deep 
  water 
  they 
  are 
  the 
  commonest 
  forms. 
  To 
  

   be 
  sure, 
  there 
  are 
  numerous 
  exceptions; 
  certain 
  of 
  the 
  red 
  algae, 
  

   under 
  favorable 
  conditions, 
  range 
  well 
  up 
  toward 
  high 
  tide 
  mark*; 
  

   certam 
  of 
  the 
  green 
  algae 
  grow 
  in 
  deep 
  water; 
  while 
  along 
  our 
  

  

  most 
  

  

  mem 
  

  

  Generally 
  speaking, 
  however, 
  the 
  vertical 
  distribution 
  of 
  marine 
  

   algae 
  along 
  the 
  coast, 
  at 
  least 
  below 
  low 
  tide 
  level, 
  is 
  closely 
  

   correlated 
  with 
  variations 
  In 
  llght.f 
  

  

  The 
  extreme 
  depths 
  at 
  which 
  autophytic 
  marine 
  algae 
  will 
  

   grow 
  depends 
  largely 
  on 
  the 
  clearness 
  of 
  the 
  water. 
  Some 
  species 
  

  

  more 
  

  

  J- 
  ' 
  "■ 
  ^ 
  ■ 
  — 
  -H 
  -^ 
  - 
  

  

  It 
  is 
  of 
  interest, 
  in 
  this 
  connection, 
  to 
  note 
  that 
  Chondrus 
  crispus, 
  one 
  of 
  

   the 
  most 
  characteristic 
  of 
  the 
  red 
  algae 
  along 
  the 
  Connecticut 
  coast 
  and 
  a 
  

   species 
  which 
  ranges 
  from 
  deep 
  water 
  up 
  to 
  low 
  tide 
  level, 
  frequently 
  loses 
  its 
  red 
  

   color 
  completely 
  when 
  growing 
  near 
  the 
  surface, 
  becoming 
  yellowish 
  ^green. 
  • 
  

  

  t 
  But 
  whether 
  it 
  is 
  the 
  quantity 
  of 
  the 
  light 
  or 
  its 
  quality 
  that 
  determines 
  the 
  

   depth 
  at 
  which 
  various 
  algae 
  will 
  grow 
  is 
  a 
  matter 
  of 
  dispute. 
  To 
  quote 
  from 
  B. 
  M. 
  

   Davis 
  ( 
  13). 
  "The 
  red 
  rays 
  of 
  sunlight, 
  it 
  is 
  claimed, 
  cannot 
  penetrate 
  much^below 
  

   7 
  fathoms, 
  and 
  the 
  light 
  at 
  greater 
  depths 
  is 
  mainly 
  composed 
  of 
  blue 
  and 
  green 
  ravs. 
  

   IS 
  feeble 
  m 
  yellow, 
  and 
  lacks 
  red 
  rays 
  entirely. 
  Certain 
  investigators 
  . 
  . 
  . 
  hold 
  that 
  

   the 
  quality 
  of 
  the 
  light 
  rather 
  than 
  its 
  intensity 
  determines 
  the 
  distribution 
  of 
  the 
  

   green, 
  brown, 
  and 
  red 
  algae. 
  According 
  to 
  this 
  view 
  the 
  green 
  algae 
  grow 
  under 
  

   bright 
  Illumination 
  because 
  they 
  require 
  the 
  maximum 
  of 
  red 
  rays, 
  while 
  the 
  red 
  

   algae 
  are 
  able 
  to 
  live 
  m 
  deeper 
  water 
  because 
  their 
  color 
  allows 
  them 
  to 
  absorb 
  

   the 
  green 
  rays 
  which 
  they 
  especially 
  need. 
  The 
  brown 
  algae 
  in 
  general 
  adjust 
  them- 
  

   selves 
  to 
  light 
  conditions 
  intermediate 
  between 
  these 
  extremes." 
  

  

  