Semeniuk, V., Semeniuk, C. A., Tauss, C., Unno, J., and Brocx, M.,
2011. Walpole and Nornalup Inlets: Landforms, Stratigraphy,
Evolution, Hydrology, Water Quality, Biota, and Geoheritage.
Western
Australian
Museum,
Perth
(Monograph).
584 p. (ISBN 978-1-920843-37-3).
Silvestri, S., Defina, A., and Marani, M., 2005. Tidal regime, salinity and salt marsh plant zonation. Estuarine Coastal Shelf Science, 62, 119–130, doi:10.1016/j.ecss.2004.08.010.
Smit, C. J., 1984. Production of biomass by invertebrates and consumption by birds in the Dutch Wadden Sea areas. In Wolff,
W. J. (ed.), Ecology of the Wadden Sea, 2, part 6. Rotterdam:
Balkema, pp. 290–301.
Spalding, M., Kainuma, M., and Collins, L., 2010. World Atlas of
Mangroves. Malta: Earthscan, Guttenberg Press. ISBN 978-184407-657-4.
Staples, D. J., 1980. Ecology of juvenile and adolescent banana
prawns, Penaeus merguiensis in a mangrove estuary and adjacent off-shore area of the Gulf of Carpentaria. Australian Journal of Marine Freshwater Research, 31, 635–652.
Thiel, M., and Dernedde, T., 1994. Recruitment of shore crabs
Carcinus maenas on tidal flats: mussel clumps as an important
refuge for juveniles. Helgolander Meeresunters, 48, 321–332.
Tomlinson, P. B., 1986. The Botany of Mangroves. Cambridge:
Cambridge University Press.
Tsuchiya, M., and Nishihira, M., 1986. Islands of Mytilus edulis as
a habitat for small intertidal animals: effect of Mytilus age
structure on the species composition of the associated fauna
and community organization. Marine Ecology Progress Series,
31, 171–178.
Unno, J., and Semeniuk, V., 2011. Population dynamics of the
Western Australian soldier crab Mictyris occidentalis Unno
2008 in the Dampier Archipelago - 30 years of observations.
Crustaceana, 84, 905–937.
van Straaten, L. M. J. U., and Kuenen, PH. H., 1957. Accumulation
of fine grained sediments in the Dutch Wadden Sea. Geologie En
Mijnbouw (Nieuwe Series), 19e Jaargang, pp. 329–335.
Vargas, J. A., 1988. Community structure of macrobenthos and the
results of macropredator exclusion on a tropical intertidal mud
flat. Revista Biologia Tropical, 36, 287–308.
Verwey, J., 1954. On the ecology of distribution of cockle and mussel in the Dutch Wadden Sea, their role in sedimentation and the
source of their food supply. Archives Ne ´erlandaises de Zoologie,
10, 171–239.
Virnstein, R. W., 1977. The importance of predation by crabs and fishes
on benthic infauna in Chesapeake Bay. Ecology, 58, 1199–1217.
Wells, F. T., and Slack-Smith, S. M., 1981. Zonation of molluscs in
a mangrove swamp in the Kimberley, Western Australia. Western Australian Museum Publication, pp. 265–274. ISBN
0-7244-8355-1.
White, C. P., 1989. Chesapeake Bay – Nature of the EstuaryA Field Guide. Centreville: Tidewater Publishers.
Wolff, W. J. (ed.), 1983. Ecology of the Wadden Sea. Rotterdam:
A. A. Balkema.
Wood, E. J. F., 1967. Microbiology of Oceans and Estuaries.
Amsterdam: Elsevier.
Zwarts, L., 1981. Habitat selection and competition in wading birds.
In Smit, C. J., and Wolff, W. J. (eds.), Birds of the Wadden Sea.
Rotterdam: A. A. Balkema, pp. 271–279.
Cross-references
Estuarine Deltaic Wetlands
Mangroves
Saltmarshes
Sandflat
Soldier Crabs (Mictyridae)
Tidal Flat Salinity Gradient
TIDAL FLAT SALINITY GRADIENT
Vic Semeniuk and Christine Semeniuk
V & C Semeniuk Research Group, Warwick, WA,
Australia
Definition
A tidal flat salinity gradient is the systematic or progressive across-tidal-flat change in salinity in groundwater
(as pore water) and pellicular water due to the interacting
effects of inundation, evaporation, transpiration, sediment
types, and freshwater seepage.
Tidal flat salinity
During low tide, when tidal flats are exposed, water under
or within a tidal flat is subject to evaporation and
transpiration, resulting in its salinization, or to dilution
by freshwater seepage. During a low tide, there are two
sub-environments where tidal flat water resides (Figure 1):
1. in a shallow groundwater that is contiguous with the
open waters and whose water table falls and rises with
the rhythm of the tide; at slack-water low tide, this
water table can be $2–10 cm deep on low-gradient
muddy tidal flats and sandy tidal flats or located up to
30 cm depth on more steeply inclined sandy tidal flats;
at extremes, the water table can be at the surface on
very low-gradient tidal flats; the groundwater, which
also can be referred to as the phreatic zone, resides in
the pore spaces of the sediments – this is tidal flat pore
water.
2. as water films circumferential to sediment particles in
the wetted but undersaturated sediment above the
water table during low tide; this can be referred to as
the temporary vadose zone – this is tidal flat pellicular
water.
The salinity of tidal flat groundwater and pellicular
water varies spatially and temporally depending on the
location on the tidal flat relative to mean sea level
(MSL), the stage of the tide, the time length of exposure
of the tidal flat within a tidal cycle or between spring tides
and neap tide phases, and the salinity of the source water.
The salinity of the tidal flat groundwater tends to be relatively constant from tide to tide during a given season
and can even be constant over the entire year. However,
depending on the style of recharge into the pore waters
by flooding surface tides and a water table rising with
a tide, the salinity of the groundwater of estuarine tidal
flats can change seasonally. Although the water table of
the groundwater under tidal flats is shallow, it is separated
from the surface by a temporary vadose zone, and at low
tide generally, it is not in direct contact with the agencies
of solar-induced evaporation and wind shear. During
a flooding tide, the groundwater by rising into the temporary vadose zone salinized during the previous low-tide
period redissolves salt, hence raising its salinity. Plants
on the tidal flat, while clearly utilizing pellicular water in
678
TIDAL FLAT SALINITY GRADIENT
2011. Walpole and Nornalup Inlets: Landforms, Stratigraphy,
Evolution, Hydrology, Water Quality, Biota, and Geoheritage.
Western
Australian
Museum,
Perth
(Monograph).
584 p. (ISBN 978-1-920843-37-3).
Silvestri, S., Defina, A., and Marani, M., 2005. Tidal regime, salinity and salt marsh plant zonation. Estuarine Coastal Shelf Science, 62, 119–130, doi:10.1016/j.ecss.2004.08.010.
Smit, C. J., 1984. Production of biomass by invertebrates and consumption by birds in the Dutch Wadden Sea areas. In Wolff,
W. J. (ed.), Ecology of the Wadden Sea, 2, part 6. Rotterdam:
Balkema, pp. 290–301.
Spalding, M., Kainuma, M., and Collins, L., 2010. World Atlas of
Mangroves. Malta: Earthscan, Guttenberg Press. ISBN 978-184407-657-4.
Staples, D. J., 1980. Ecology of juvenile and adolescent banana
prawns, Penaeus merguiensis in a mangrove estuary and adjacent off-shore area of the Gulf of Carpentaria. Australian Journal of Marine Freshwater Research, 31, 635–652.
Thiel, M., and Dernedde, T., 1994. Recruitment of shore crabs
Carcinus maenas on tidal flats: mussel clumps as an important
refuge for juveniles. Helgolander Meeresunters, 48, 321–332.
Tomlinson, P. B., 1986. The Botany of Mangroves. Cambridge:
Cambridge University Press.
Tsuchiya, M., and Nishihira, M., 1986. Islands of Mytilus edulis as
a habitat for small intertidal animals: effect of Mytilus age
structure on the species composition of the associated fauna
and community organization. Marine Ecology Progress Series,
31, 171–178.
Unno, J., and Semeniuk, V., 2011. Population dynamics of the
Western Australian soldier crab Mictyris occidentalis Unno
2008 in the Dampier Archipelago - 30 years of observations.
Crustaceana, 84, 905–937.
van Straaten, L. M. J. U., and Kuenen, PH. H., 1957. Accumulation
of fine grained sediments in the Dutch Wadden Sea. Geologie En
Mijnbouw (Nieuwe Series), 19e Jaargang, pp. 329–335.
Vargas, J. A., 1988. Community structure of macrobenthos and the
results of macropredator exclusion on a tropical intertidal mud
flat. Revista Biologia Tropical, 36, 287–308.
Verwey, J., 1954. On the ecology of distribution of cockle and mussel in the Dutch Wadden Sea, their role in sedimentation and the
source of their food supply. Archives Ne ´erlandaises de Zoologie,
10, 171–239.
Virnstein, R. W., 1977. The importance of predation by crabs and fishes
on benthic infauna in Chesapeake Bay. Ecology, 58, 1199–1217.
Wells, F. T., and Slack-Smith, S. M., 1981. Zonation of molluscs in
a mangrove swamp in the Kimberley, Western Australia. Western Australian Museum Publication, pp. 265–274. ISBN
0-7244-8355-1.
White, C. P., 1989. Chesapeake Bay – Nature of the EstuaryA Field Guide. Centreville: Tidewater Publishers.
Wolff, W. J. (ed.), 1983. Ecology of the Wadden Sea. Rotterdam:
A. A. Balkema.
Wood, E. J. F., 1967. Microbiology of Oceans and Estuaries.
Amsterdam: Elsevier.
Zwarts, L., 1981. Habitat selection and competition in wading birds.
In Smit, C. J., and Wolff, W. J. (eds.), Birds of the Wadden Sea.
Rotterdam: A. A. Balkema, pp. 271–279.
Cross-references
Estuarine Deltaic Wetlands
Mangroves
Saltmarshes
Sandflat
Soldier Crabs (Mictyridae)
Tidal Flat Salinity Gradient
TIDAL FLAT SALINITY GRADIENT
Vic Semeniuk and Christine Semeniuk
V & C Semeniuk Research Group, Warwick, WA,
Australia
Definition
A tidal flat salinity gradient is the systematic or progressive across-tidal-flat change in salinity in groundwater
(as pore water) and pellicular water due to the interacting
effects of inundation, evaporation, transpiration, sediment
types, and freshwater seepage.
Tidal flat salinity
During low tide, when tidal flats are exposed, water under
or within a tidal flat is subject to evaporation and
transpiration, resulting in its salinization, or to dilution
by freshwater seepage. During a low tide, there are two
sub-environments where tidal flat water resides (Figure 1):
1. in a shallow groundwater that is contiguous with the
open waters and whose water table falls and rises with
the rhythm of the tide; at slack-water low tide, this
water table can be $2–10 cm deep on low-gradient
muddy tidal flats and sandy tidal flats or located up to
30 cm depth on more steeply inclined sandy tidal flats;
at extremes, the water table can be at the surface on
very low-gradient tidal flats; the groundwater, which
also can be referred to as the phreatic zone, resides in
the pore spaces of the sediments – this is tidal flat pore
water.
2. as water films circumferential to sediment particles in
the wetted but undersaturated sediment above the
water table during low tide; this can be referred to as
the temporary vadose zone – this is tidal flat pellicular
water.
The salinity of tidal flat groundwater and pellicular
water varies spatially and temporally depending on the
location on the tidal flat relative to mean sea level
(MSL), the stage of the tide, the time length of exposure
of the tidal flat within a tidal cycle or between spring tides
and neap tide phases, and the salinity of the source water.
The salinity of the tidal flat groundwater tends to be relatively constant from tide to tide during a given season
and can even be constant over the entire year. However,
depending on the style of recharge into the pore waters
by flooding surface tides and a water table rising with
a tide, the salinity of the groundwater of estuarine tidal
flats can change seasonally. Although the water table of
the groundwater under tidal flats is shallow, it is separated
from the surface by a temporary vadose zone, and at low
tide generally, it is not in direct contact with the agencies
of solar-induced evaporation and wind shear. During
a flooding tide, the groundwater by rising into the temporary vadose zone salinized during the previous low-tide
period redissolves salt, hence raising its salinity. Plants
on the tidal flat, while clearly utilizing pellicular water in
678
TIDAL FLAT SALINITY GRADIENT