Biology Reference
In-Depth Information
Chapter 9
Chemical Ecology of Seaweeds
Charles D. Amsler
9.1 Overview
Chemical ecology is the study of chemically mediated interactions between
organisms or between organisms and their environment. It is convenient to separate
these interactions into sensory chemical ecology and defensive chemical ecology.
However, sensory and defensive chemical interactions cannot always be separated
as waterborne signals released by seaweeds under attack by herbivores can be
sensed by neighboring algae and induce a defensive response in the unattacked
neighbors (Toth and Pavia
2000
). Moreover, seaweed defenses against biofouling
can function by interfering with chemical communication between bacteria on the
algal surface (Kjelleberg et al.
1997
).
Sensory chemical ecology can be subdivided into chemical communications
between organisms, be they intentional or not, and sensing and responding to the
abiotic chemical environment of the alga. There is a large body of literature on
seaweeds sensing and physiologically responding to their nutrient environment (see
Chap.
4
by Gordillo). However, in practice such studies have been outside the scope
of “chemical ecology” and this chapter follows the more narrow definition, which
does not include physiological responses to nutrients.
Defensive chemical ecology can likewise be subdivided, often by what is being
defended against. Most studies of seaweed chemical ecology as a whole involve
studies of defenses against predation, which from a mechanistic perspective are an
important focus of this chapter. They are discussed with respect to community
impacts in Chap.
8
by Iken. Chemical defenses can also be produced in response to
organisms that grow on or over seaweeds, referred to as
biofoulers
or
epibionts
,to
pathogenic organisms, and to competitors. Production of chemical defenses against
competitors is commonly referred to as
allelopathy
. These categories are not
C.D. Amsler (
*
)
Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35294-1170, USA
e-mail:
amsler@uab.edu
