New Zealand Journal of Marine and Freshwater Research abstracts
Photosynthetic parameters in water masses in the vicinity of the Chatham Rise,
South Pacific Ocean, during late summer
IAN HAWES
MARK GALL
MARK WEATHERHEAD
National Institute of Water & Atmospheric
Research Ltd
P. O. Box 8602
Christchurch, New Zealand
Abstract The relationship between photosynthesis (
P)
and light (
E) was determined for phytoplankton from the mixed layer and
the deep chlorophyll maximum (DCM) at 23 stations off the east coast of New
Zealand during February-March 1995. The stations encompassed three water
masses, Sub-tropical, Sub-antarctic and the Sub-tropical Convergence Zone. The
light-saturated rate of photosynthesis (
Pmax) and slope of the
light-limited portion of the curve ([[alpha]]) were determined using a light
gradient incubator. The absorption spectra of the phytoplankton assemblages
were used to calculate the maximum quantum efficiency of photosynthesis
([[phi]]max). A higher mixed-layer
Pmax in Sub-tropical water over
Sub-antarctic water (4.26 compared to 5.85 mg C (mg Chl
.a)
-1
h
-1) was consistent with the temperature difference of 4deg.C,
although there was also a taxonomic composition difference between these
waters. The highest variability of
Pmax and [[alpha]], as well as the
highest
Pmax values, were seen within the STC, but ranges for all water
masses overlapped. Physical conditions in the water masses were similar and no
correlations between any measured physical or chemical feature of the stations
and any
P-
E parameter could be identified.
Keywords New Zealand; photosynthesis-irradiance; P-E;
phytoplankton; quantum efficiency
New Zealand Journal of Marine and Freshwater Research, 1997: Vol. 31:
25-38
0028-8330/97/3101-0025 $2.50/0 (c) The Royal Society of New Zealand
PDF file of entire paper: medium quality (1075K); (scanned from paper original: notes about this process)
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