Cold-Temperate Seaweed Communities of the Southern Hemisphere - Seaweed Biology - page 288

14.1.5 Sub-Antarctic Islands Region

The sub-Antarctic islands region consists of the island groups of Prince Edward
(Prince Edward and Marion Islands), Crozet, Kergu´len, Heard (included also in
the Antarctic region), and Macquarie (sometimes regarded in the Southern New
Zealand region) Islands. The sub-Antarctic islands near New Zealand include
Snares, Auckland, Campbell, Bounties, Antipodes, and Chatham Islands
(Fig. 14.1 ). The location of the Southern Ocean islands in relation to the APF
influences strongly their climatic conditions. Overall, these islands exhibit particu-
larly cool, wet, and windy climates (Bergstrom and Chown 1999 ). The surface
water temperatures along the coasts of the sub-Antarctic islands range 3-11 Cin
winter and 5-14 C in summer, depending on the geographical location (Luning
1990 ).

14.2 Structure and Function of Seaweed Communities

14.2.1 Southwestern South America Region (Chile)

The southeastern Pacific coast can be divided into three biogeographic provinces:
(1) the Peruvian province (from Peru to 30 S) with high presence of warm-
temperate biota, (2) the Magellan province (from 40-42 Sto56 S) with dominance
of sub-Antarctic cold-temperate elements, and (3) the intermediate area (from 30 S
to 40-42 S) with mixed components from both provinces. According to Briggs
(1974, cited in L uning 1990 ) the cold-temperate region in the south-eastern Pacific

is limited to the north at around 40 S (see also Chap. 18 by Bartsch et al.). Recent
evidence (Strub et al. 1998 ; Camus 2001 ; Thiel et al. 2007 ) suggests that this region
extends to around 30 S due to the influence of the Humboldt Current. In general, the
seaweed flora in this region presents a remarkable degree of endemism (32%)
(Santelices 1980 ), although recent accounts indicate increases in subtropical and
alien species (Meneses and Santelices 2000 ; Castilla et al. 2005 ). Due to the higher
occurrence of cold-temperate species, the total number of species increases south-
wards (Santelices 1980 ; Santelices and Marquet 1998 ). According to a recent
update, the Magellan and Tierra del Fuego regions in the southern part of South
America comprise 234 seaweed species (red 60%, brown 22%, green 18%)
(Ram´rez 2010 ). The species composition shows a break point around the latitude
42 S (Meneses and Santelices 2000 ).
In the wave-exposed coast at 30-55 S latitudes, the zonation and the structure of
seaweed communities are characterized by the presence of Porphyra columbina
and filamentous and foliose green algae such as Ulva intestinalis at upper littoral
zones (Santelices 1989 ;G´mez and Huovinen 2011 ) (Fig. 14.2 ). In the mid-littoral,
coarsely branched red algae such as Mazzaella laminarioides and Nothogenia
fastigiata dominate. The red alga Gelidium sp. and the brown alga Petalonia fascia

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