New Zealand Journal of Marine and Freshwater Research abstracts
Factors influencing autotrophic and heterotrophic nanoflagellate abundance in
five water masses surrounding New Zealand
KARL A. SAFI
JULIE A. HALL
National Institute of Water & Atmospheric
Research Ltd
P. O. Box 11-115
Hamilton, New Zealand
Abstract The aim of this study was to measure nanoflagellate
abundance in New Zealand waters, and identify the key factors which both
influence, and are influenced by, nanoflagellate abundance. Nanoflagellate
populations were sampled in winter and spring 1993 from a series of sites
representing different water masses around the South Island of New Zealand.
Both numbers and biomass of heterotrophic (HNF) and autotrophic nanoflagellate
(ANF) populations were larger in spring by a factor of four. ANF were about
three times as abundant as HNF in both seasons. The physiochemical variables,
temperature, NH4-N, and urea combined with bacteria and picophytoplankton
numbers explained between 67 and 94% of the variation in nanoflagellate
abundance. In addition, there was evidence that variation in abundances between
seasons and water masses was influenced by food availability, predation, and
changes in species composition represented by large differences in cell
biovolume.
Keywords nanoflagellates; autotrophic; heterotrophic;
mixotrophic; abundance; microbial food web
New Zealand Journal of Marine and Freshwater Research, 1997: Vol. 31:
51-60
0028-8330/97/3101-0051 $2.50/0 (c) The Royal Society of New Zealand
PDF file of entire paper: medium quality (894K); (scanned from paper original: notes about this process)
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