Biology Reference
In-Depth Information
Fig. 17.1
(
a
) Cross section through a thallus of
Durvillaea antarctica
showing the gas-filled
honeycomb structure; (
b
) vesicles of
Sargassum horneri
, providing positive buoyancy to the algae;
and (
c
) raft of
S. horneri
floating in the eastern East China Sea
17.2.1 Global Distribution Patterns of Floating Seaweeds
The presence of floating algae at the sea surface strongly depends on their supply
from benthic source populations. Most reports of floating macroalgae come from
mid and high latitudes in both hemispheres (Kingsford
1992
; Helmuth et al.
1994
;
Hobday
2000a
; Macaya et al.
2005
; Komatsu et al.
2008
; Hinojosa et al.
2010
; Thiel
et al.
2011
) (Fig.
17.2
), where extensive benthic populations provide abundant
supply (L
uning
1990
; Graham et al.
2007
). For instance, in the northern hemisphere
algal rafts can be found in the NE Pacific where extensive subtidal kelp forests
along the Pacific coast of North America nourish abundant floating populations of
Macrocystis pyrifera
(Kingsford
1995
; Hobday
2000a
). In the NW Pacific a diverse
Sargassum
community is floating in coastal waters around Japan (Ohno
1984
;
Hirata et al.
2001
). In the N Atlantic pelagic
S. natans
and
S. fluitans
occur in the
Gulf of Mexico, the Gulf Stream, and in the Sargasso Sea (Parr
1939
) while floating
fronds of
Ascophyllum nodosum
and
Fucus vesiculosus
are common along the north-
ern N Atlantic
€
45
N (Tully and
´
C´idigh
1986
;Ing´lfsson
1998
; Vandendriessche
et al.
2006
;Muhlinetal.
2008
; Thiel et al.
2011
).
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