D. Stanwellsmith et Dka. Barnes, BENTHIC COMMUNITY-DEVELOPMENT IN ANTARCTICA - RECRUITMENT AND GROWTH ON SETTLEMENT PANELS AT SIGNY ISLAND, Journal of experimental marine biology and ecology, 212(1), 1997, pp. 61-79
Identity, quantity and seasonal variation in recruiting invertebrate l
arvae were investigated at Signy Island, Antarctica. Nine settlement p
anels were deployed at each of three sites at depths ranging between f
ive and 25 m over a two year experimental period. Longer-term communit
y development was followed using three panels continuously immersed fo
r up to 21 months at each site, with monthly photographs taken in situ
. Shorter-term variations in recruitment were studied by regular repla
cement of triplicate panels, which enabled the measurement of seasonal
ity of recruitment onto artificial substrata in Antarctica, for the fi
rst time. Cyclostomatid and cheilostomatid bryozoans, and spirorbinid
polychaetes were the dominant colonising taxa both in terms of numbers
and area covered. Very low rates of colonisation were observed: < 2%
of the panels at 5 m, and < 6% of the panel areas at 25 m, were covere
d after 15 months. Whilst little seasonality of recruitment was observ
ed in spirorbinids, that of cheilostomatid bryozoans showed a signific
ant peak between June and February. Successful recuitment levels of co
lonising taxa suggested seasonal and interannual variation, although n
ot conclusively. Measurement of growth of individual bryozoan colonies
was assessed by image analysis of the in situ monthly photographs. Me
an growth ranging between 1.7 mm(2) (Lacerna eatoni) and 7.1 mm(2) (Ar
achnopusia inchoata) per month were recorded. There was considerable i
nter- and intra-specific variation of growth of the encrusting cheilos
tomatid species investigated and this is the first report of such meas
urements having been made in Antarctica. (C) 1997 Elsevier Science B.V
.