Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

Net in Situ Growth Rates of Phytoplankton in an Oligotrophic, Tropical Shelf Ecosystem

Miles J. Furnas
Limnology and Oceanography
Vol. 36, No. 1 (Jan., 1991), pp. 13-29
Stable URL: http://www.jstor.org/stable/2837666
Page Count: 17
  • More info
  • Cite this Item
Net in Situ Growth Rates of Phytoplankton in an Oligotrophic, Tropical Shelf Ecosystem
Preview not available

Abstract

In situ growth rates of phytoplankton in tropical shelf waters of the Great Barrier Reef were measured with diffusion chambers. A broad disparity was observed between the growth responses of diatom species or assemblages $(\mu_max = 2-5 doublings d^-1)$ and assemblages of microflagellates, nonmotile ultraplankton, or phototrophic picoplankton $(\mu_max <2 doublings d^-1)$. Several diatom species or groups consistently grew faster than the community Chl doubling rate $(\mu_max = 1.6 doublings d^-1)$. Most dominant species and groups, regardless of taxonomic affiliation, exhibited the potential for high relative growth rates $(\mu/\mu_max >0.5)$ at ambient concentrations of dissolved inorganic $N<0.2 \mumol liter^-1$ and the time-averaged diurnal irradiances in situ $>50 \muEinst m^-2 s^-1$. If relative constancy in phytoplankton standing crop and composition is to be maintained, grazing rates must vary widely at the species level, but be broadly similar to growth rates over time scales of days. Although the full 40-80 m water column in the central Great Barrier Reef lies the euphotic zone, phytoplankton growth rates near the bottom seem to be light limited.

Page Thumbnails

  • Thumbnail: Page 
13
    13
  • Thumbnail: Page 
14
    14
  • Thumbnail: Page 
15
    15
  • Thumbnail: Page 
16
    16
  • Thumbnail: Page 
17
    17
  • Thumbnail: Page 
18
    18
  • Thumbnail: Page 
19
    19
  • Thumbnail: Page 
[20]
    [20]
  • Thumbnail: Page 
21
    21
  • Thumbnail: Page 
22
    22
  • Thumbnail: Page 
23
    23
  • Thumbnail: Page 
24
    24
  • Thumbnail: Page 
25
    25
  • Thumbnail: Page 
26
    26
  • Thumbnail: Page 
27
    27
  • Thumbnail: Page 
28
    28
  • Thumbnail: Page 
29
    29