Biology Reference
In-Depth Information
Chapter 11
Intimate Associations Between Epiphytes,
Endophytes, and Parasites of Seaweeds
Philippe Potin
11.1
Introduction
Most, but not all, seaweeds studied in natural ecosystems are plagued by epiphytes,
endophytes or other eukaryotic parasites that cause no or few apparent disease
symptoms. Hence, such intimate associations can range from mutualism through
commensalism to parasitism in a continuous manner (Correa
1994
). In shallow
hard-bottom marine habitats, seaweeds compete for substrate, nutrients, and light
(see Chap.
7
by Edwards and Connell). A planktonic bank of seaweed spores and
propagules is periodically and widely distributed in the coastal zone that is ready
to settle in all appropriate microhabitats (Wahl and Mark
1999
; Lotze et al.
2000
).
In this context, epibiotism (using other organisms as substrates) illustrates compe-
tition for space (e.g., Menge
1991
; Underwood
2000
; Wahl and Mark
1999
).
Epibiotic associations comprise a substrate organism (basibiont) and one or several
attached species (epibionts). This chapter focuses on associations between
seaweeds, and therefore it corresponds to associations between algal basiphytes
and epiphytes. A wide variety of algae colonizes other algae representing a contin-
uum between epiphytism and endophytism. Such interactions begin with nonran-
dom patterns of settlement and recruitment (Gonzalez and Goff
1989
; Pearson and
Evans
1989
,
1990
) and artificial substrata are often preferred over nearby living
surfaces for epiphytes (Wahl and Mark
1999
) very likely depending on the previous
colonization of these surfaces by specific bacterial biofilms (Goecke et al.
2010
, see
also Chap.
10
by Friedrich). Therefore, host specificity was considered as an
exception in such interactions. However, the presence of epiphytes, endophytes,
and eukaryotic parasites in marine macrophytes results from complex interactions
P. Potin (
*
)
CNRS, Universit´ Pierre et Marie Curie-Paris 6, UMR 7139, Station Biologique BP74,
29682 Roscoff, France
e-mail:
philippe.potin@sb-roscoff.fr
