5 Microphytobenthos in Contrasting Coastal
Ecosystems: Biology and Dynamics
D.M. PATERSON and S.E. HAGERTHEY
5.1 Contrasting Shores
The rocky intertidal foreshore has long been an area intensely studied by
ecologists, and the contrasts found between relative heights on the shore and
between shores of different aspects have developed into a series of classical
studies that outline the nature of the forces (exposure, competition, grazing)
that dominate rocky shore ecology (Raffaelli and Hawkins 1996). These hard
shores have natural advantages for scientists interested in intertidal ecology:
they are usually accessible; the sessile organisms are easily observed; and the
shores are relatively stable. However, the contrasts between sandy (noncohesive) and muddy (cohesive) shores are equally of interest, although the
shore themselves present more of a logistic challenge and hence contrasting
accounts of the shores are less generally available. Also, except in the specialised circumstance of sea grass meadows and mangals, the primary producers (microphytobenthos) that dominate depositional systems are far less
obvious than the intertidal macro algae found on hard substrata. The following chapter addresses some of the differences found between sandy and
muddy shores with emphasis on the dominant microphytobenthos.
5.2 The Microphytobenthos
The grouping of organisms together under the title "microphytobenthos"
reflects no coherent phylogenetic relationship and, although mainly protists,
the assemblage includes both prokaryotic and eukaryotic forms (Fig. 5.1). The
dominant forms are often diatoms (Bacillariophyceae) that are a large and
heterogeneous group of eukaryotic autotrophs, classified under the Heterokontophyta (van den Hoek et al. 1995). Estimates of species numbers vary
from tens to hundreds of thousands and there is also recent discussion over
Ecological Studies, Vol. 151
K. Reise (ed.) Ecological Comparisons
of Sedimentary Shores
© Springer-Verlag Berlin Heidelberg 2001
Ecosystems: Biology and Dynamics
D.M. PATERSON and S.E. HAGERTHEY
5.1 Contrasting Shores
The rocky intertidal foreshore has long been an area intensely studied by
ecologists, and the contrasts found between relative heights on the shore and
between shores of different aspects have developed into a series of classical
studies that outline the nature of the forces (exposure, competition, grazing)
that dominate rocky shore ecology (Raffaelli and Hawkins 1996). These hard
shores have natural advantages for scientists interested in intertidal ecology:
they are usually accessible; the sessile organisms are easily observed; and the
shores are relatively stable. However, the contrasts between sandy (noncohesive) and muddy (cohesive) shores are equally of interest, although the
shore themselves present more of a logistic challenge and hence contrasting
accounts of the shores are less generally available. Also, except in the specialised circumstance of sea grass meadows and mangals, the primary producers (microphytobenthos) that dominate depositional systems are far less
obvious than the intertidal macro algae found on hard substrata. The following chapter addresses some of the differences found between sandy and
muddy shores with emphasis on the dominant microphytobenthos.
5.2 The Microphytobenthos
The grouping of organisms together under the title "microphytobenthos"
reflects no coherent phylogenetic relationship and, although mainly protists,
the assemblage includes both prokaryotic and eukaryotic forms (Fig. 5.1). The
dominant forms are often diatoms (Bacillariophyceae) that are a large and
heterogeneous group of eukaryotic autotrophs, classified under the Heterokontophyta (van den Hoek et al. 1995). Estimates of species numbers vary
from tens to hundreds of thousands and there is also recent discussion over
Ecological Studies, Vol. 151
K. Reise (ed.) Ecological Comparisons
of Sedimentary Shores
© Springer-Verlag Berlin Heidelberg 2001