A biological study of Durvillaea antarctica (Chamisso) Hariot and D ...

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the rock surface. Area E (1 x 2 m) on First Slope was cleared in
May 1972 and is visible in F'ig. 5.10. AXea F (1.5 x 3 m) on Second
Slope vTas cleared in July 1974. These areas were subsequently
checked for any colonisation by DupviZZaea.
(e)
The purpose of this experiment was to see if growth "las localised
in certain regions of D. antaY'ctica laminae. It involved punching
snlall holes at carefully measured intervals along blades or maio.t"
divisions of blades, and using the holes as reference points to
measure growth 7.ate and direction in different regions.
Fift.een small D. antarctica growing at Iron Gate St:ceam, and
25 cape form specimens at Oaro Reef were tagged and measured. Their
totai lengths ranged from 0.3 to 1.2 m. A leather worker's hand punch
was used to punch small holes (4 rom diameter) at 20 mm intervals in a
vertical line up the centre of major divisions of the blades of the
Iron Gate laminae, and up the undivided blades of the Oaro
Sever~ll
other specimens at. Oaro had a line of holes punched horizonta.lly
across the blade (i.e. at right angles to the stipe), and five
specimens at Iron Gate Stream had holes punched at 20 rom in'cervals
around the lamina margin at approximately 5 rom in from the edge.
The positions of these holes, the number of holes punched and the
distance bebleen the most distal hole and the end of the blade or
thong (where appropriate) was recorded for each specimen.
Iron Gate
specimens were punched in January 1972, the OcU:-O specimens in October
1973, the specimens collected after lO~ and 8 months respectively,
The distances between holes were remeasured, each interhole dist.anG€:
being numbered sequentially f:mHl the stipe, Co.:ne was 'taken to ho'le
if the holes had remained in line. The length and Hidth of each
hole was measured with calipers I and their outlines lvere traced.
Re-sul ts are presented in Chapter 7 F Section 2.