Bird, E., 2011. Coastal Geomorphology: An Introduction, 2nd edn.
West Sussex: Wiley.
Diez, G. J., 1996. Guı ´a Fı ´sica de Espan ˜a, 6. Las Costas. Madrid:
Alianza Editorial, pp. 91–339.
McManus, J., Diez, J. J., Duck, R. W., Escobar, V., Anderson, J. M.,
Esteban, V., and Paz, R., 1993. Comparison of Scottish Firths
and Spanish Rias. Bulletin International Association Engineering Geology, 47, 127–132.
Cross-references
Coastal Bays
Firth
Fjord
RIVER-DOMINATED ESTUARY
David M. Kennedy
Department of Resource Management & Geography,
The University of Melbourne, Parkville, VIC, Australia
Definition
A river-dominated estuary is one where fluvial processes
extend to the estuary mouth where only ephemeral marine
deposits occur.
Description
River-dominated estuaries tend to be shallow and
undergo a cycle of infill related to floods from the catchments in their hinterland. During a non-flood period,
a barrier is present at the seaward edge of the estuary
backed by small flood-tide deltas where cohesive muddy
and relatively steep channel banks are found. During
a flood, the channels erode and the flood-tide deltas and
barrier are often removed (Cooper et al., 1990; Cooper,
1993; Cooper, 2001). River-dominated estuaries where
the barrier is formed of gravel-size sediment are also
known as hapua (Hart, 2007; Kirk and Lauder, 2000).
River-dominated estuaries often occur on high-energy,
wave-dominated coasts, so they are unlikely to develop
into a delta (Cooper, 1993).
Bibliography
Cooper, J. A. G., 1993. Sedimentation in a river-dominated estuary.
Sedimentology, 40, 979–1017.
Cooper, J. A. G., 2001. Geomorphological variability among
microtidal estuaries from the wave-dominated South African
coast. Geomorphology, 40, 99–122.
Cooper, J. A. G., Mason, T. R., Reddering, J. S. V., and Illenberger,
W. K., 1990. Geomorphological effects of catastrophic flooding
on a small subtropical estuary. Earth Surface Processes and
Landforms, 15, 25–41.
Hart, D. E., 2007. River-mouth lagoon dynamics on mixed sand and
gravel barrier coasts. Journal of Coastal Research, SI 50,
927–931.
Kirk, R. M., and Lauder G. A., 2000. Significant coastal lagoon systems in the South Island, New Zealand. In Science for Conservation 146. Wellington: Department of Conservation, 47.
Cross-references
Tectonic Eustasy
Well-Mixed Estuary
ROCKY INTERTIDAL SHORES
M. G. Chapman and A. J. Underwood
Centre for Research on Ecological Impacts of Coastal
Cities, School of Biological Sciences, University of
Sydney, Sydney, NSW, Australia
Definition
An intertidal rocky shore is the area between low tide and
the highest reach of wave action on a rocky shoreline.
Introduction
Intertidal rocky shores in estuaries are a subset of all
intertidal rocky shores. They are occupied by the same
types of biota, which react to environmental factors and
interact with each other in similar ways, although features
of estuaries may impose modifications on these interactions. So, when discussing intertidal rocky shores in estuaries, it is necessary to consider general features of these
habitats (Stephenson and Stephenson, 1972; Menge and
Branch, 2001).
These habitats are occupied by a wide range of plants
and animals. The plants are predominantly algae, including large seaweeds and microscopic forms. The animals
are generally invertebrates, other than fish in pools, birds,
and mammals which forage on shores. The invertebrates
are very diverse at all taxonomic levels. In addition to
mobile animals that include herbivores, predators, and
scavengers, many animals are sessile filter feeders. What
makes rocky shores different from many other habitats is
the diversity of sessile animals (“ecosystem engineers,”
Jones et al., 1994) that create new, unique habitats. So,
in addition to seaweeds which provide habitat for smaller
species, animals, such as mussels, polychaetes, and ascidians, create large patches or reefs of unique habitat, which
are then occupied by a range of other fauna.
Distributions and abundances of species on rocky
shores
Although patterns, such as vertical zonation, are commonly described in the literature for rocky shores
(Barnes and Hughes, 1999), quantitative data have shown
that consistent broad-scale patterns of distribution are
shown for only a few species and in some places. Despite
strong gradients of submersion and emersion associated
with the tide, there are no clearly defined heights on the
shore where one assemblage of species abruptly changes
into another. Instead, although different species occupy
different heights, the change from the bottom to the top
of the shore is a continuum of changes in species, so that
the assemblage changes gradually.
ROCKY INTERTIDAL SHORES
507
West Sussex: Wiley.
Diez, G. J., 1996. Guı ´a Fı ´sica de Espan ˜a, 6. Las Costas. Madrid:
Alianza Editorial, pp. 91–339.
McManus, J., Diez, J. J., Duck, R. W., Escobar, V., Anderson, J. M.,
Esteban, V., and Paz, R., 1993. Comparison of Scottish Firths
and Spanish Rias. Bulletin International Association Engineering Geology, 47, 127–132.
Cross-references
Coastal Bays
Firth
Fjord
RIVER-DOMINATED ESTUARY
David M. Kennedy
Department of Resource Management & Geography,
The University of Melbourne, Parkville, VIC, Australia
Definition
A river-dominated estuary is one where fluvial processes
extend to the estuary mouth where only ephemeral marine
deposits occur.
Description
River-dominated estuaries tend to be shallow and
undergo a cycle of infill related to floods from the catchments in their hinterland. During a non-flood period,
a barrier is present at the seaward edge of the estuary
backed by small flood-tide deltas where cohesive muddy
and relatively steep channel banks are found. During
a flood, the channels erode and the flood-tide deltas and
barrier are often removed (Cooper et al., 1990; Cooper,
1993; Cooper, 2001). River-dominated estuaries where
the barrier is formed of gravel-size sediment are also
known as hapua (Hart, 2007; Kirk and Lauder, 2000).
River-dominated estuaries often occur on high-energy,
wave-dominated coasts, so they are unlikely to develop
into a delta (Cooper, 1993).
Bibliography
Cooper, J. A. G., 1993. Sedimentation in a river-dominated estuary.
Sedimentology, 40, 979–1017.
Cooper, J. A. G., 2001. Geomorphological variability among
microtidal estuaries from the wave-dominated South African
coast. Geomorphology, 40, 99–122.
Cooper, J. A. G., Mason, T. R., Reddering, J. S. V., and Illenberger,
W. K., 1990. Geomorphological effects of catastrophic flooding
on a small subtropical estuary. Earth Surface Processes and
Landforms, 15, 25–41.
Hart, D. E., 2007. River-mouth lagoon dynamics on mixed sand and
gravel barrier coasts. Journal of Coastal Research, SI 50,
927–931.
Kirk, R. M., and Lauder G. A., 2000. Significant coastal lagoon systems in the South Island, New Zealand. In Science for Conservation 146. Wellington: Department of Conservation, 47.
Cross-references
Tectonic Eustasy
Well-Mixed Estuary
ROCKY INTERTIDAL SHORES
M. G. Chapman and A. J. Underwood
Centre for Research on Ecological Impacts of Coastal
Cities, School of Biological Sciences, University of
Sydney, Sydney, NSW, Australia
Definition
An intertidal rocky shore is the area between low tide and
the highest reach of wave action on a rocky shoreline.
Introduction
Intertidal rocky shores in estuaries are a subset of all
intertidal rocky shores. They are occupied by the same
types of biota, which react to environmental factors and
interact with each other in similar ways, although features
of estuaries may impose modifications on these interactions. So, when discussing intertidal rocky shores in estuaries, it is necessary to consider general features of these
habitats (Stephenson and Stephenson, 1972; Menge and
Branch, 2001).
These habitats are occupied by a wide range of plants
and animals. The plants are predominantly algae, including large seaweeds and microscopic forms. The animals
are generally invertebrates, other than fish in pools, birds,
and mammals which forage on shores. The invertebrates
are very diverse at all taxonomic levels. In addition to
mobile animals that include herbivores, predators, and
scavengers, many animals are sessile filter feeders. What
makes rocky shores different from many other habitats is
the diversity of sessile animals (“ecosystem engineers,”
Jones et al., 1994) that create new, unique habitats. So,
in addition to seaweeds which provide habitat for smaller
species, animals, such as mussels, polychaetes, and ascidians, create large patches or reefs of unique habitat, which
are then occupied by a range of other fauna.
Distributions and abundances of species on rocky
shores
Although patterns, such as vertical zonation, are commonly described in the literature for rocky shores
(Barnes and Hughes, 1999), quantitative data have shown
that consistent broad-scale patterns of distribution are
shown for only a few species and in some places. Despite
strong gradients of submersion and emersion associated
with the tide, there are no clearly defined heights on the
shore where one assemblage of species abruptly changes
into another. Instead, although different species occupy
different heights, the change from the bottom to the top
of the shore is a continuum of changes in species, so that
the assemblage changes gradually.
ROCKY INTERTIDAL SHORES
507