In certain cases, the barrier progrades seaward, and this
may reduce contact with the sea (Cooper, 1997). However,
it should be noted that the rate and direction of the lagoon
evolution depend on many factors. According to Cooper
(1997), these factors may be divided into macroscale and
local or microscale variations. Macroscale controls
include sea-level changes, climate, and tectonic stability.
Local controls include fluvial sediment supply, longshore
drift, salinity, surrounding geology, costal morphology,
lagoon orientation, wave energy, and tidal range. Carter
et al. (1989) proposed a hierarchy of controls on the effect
of sea-level changes on coarse-grained barrier-lagoon
evolution. Such hierarchical arrangement of dependencies
shows the complexity and interrelationships between various factors.
Very often, lagoon evolves from an estuary or marine
embayment to a partially enclosed barrier-lagoon system
and then, with progressive infilling, to a marsh or
deltaic-filled lagoon, ending the cycle with a depositional
plain or with an eventual destruction by marine erosion
(Nichols, 1989). For example, the area of the Odra River
mouth, southern Baltic coast, is subjected to such an evolution since the late Pleistocene (Borówka et al., 2005;
Osadczuk et al., 2007).
Based on detailed studies of sedimentation processes in
one of the world’s largest lagoons (Laguna Madre, Texas),
Morton et al. (2000) have found that the historical average
annual accumulation rate in the lagoon (1 mm/year) is substantially less than the historical rate of relative sea-level
rise (4 mm/year). Lagoon submergence coupled with erosion of the western shore indicates that Laguna Madre is
being submerged slowly and migrating westward rather
than filling, as some have suggested.
According to Adlam (2014), the existence of numerous
examples of lagoons that remain unfilled suggests that a
discontinuity in their geologic evolution occurs before
maturity is reached. He has presented a new hypothesis
that geologic evolution of lagoons takes place in two
phases which are defined by changes in physical processes. The early phase aligns with the traditional view
but ends when a depth threshold is reached. In the late
phase, sedimentation is inhibited by the local energy
regime and can only proceed if the lagoon surface area is
reduced. Validation of the existence of these two distinct
process-based phases of geologic evolution will improve
the reliability of predictive models for lagoon shoreline
changes and rates of basin fill as well as reduce the risk
of misinterpreting past conditions from the geological
record.
Conclusions
The formation and evolution of coastal lagoons is controlled by many factors, including global, regional, and
local determinants at different levels of importance. Very
important is the hierarchy of the circumstances and processes that control the evolution of this environment.
A comprehensive model of lagoons’ evolution should take
into account as many factors as possible. The model
should include, in particular, such variables as geological
conditions; neotectonic movements; lagoon morphology
and its orientation; connection with the sea; sea-level
changes, tidal amplitude, and waves energy; climate and
local meteorological conditions; character of sediments
supply; sedimentation rate; salinity; primary production;
and anthropogenic influences. Although there were several attempts to create a comprehensive and universal
model of the lagoons’ evolution, unfortunately, it was
not created, so far, one that would take into account all
variables.
Bibliography
Adlam, K., 2014. Coastal lagoons: geologic evolution in two
phases. Marine Geology, 355, 291–296.
Alsharhan, A. S., and Kendall, C. G. St. C., 2003. Holocene coastal
carbonates and evaporites of the southern Arabian Gulf and their
ancient analogues. Earth-Science Reviews, 61, 191–243.
Anthony, A., Atwood, J., August, P., Byron, C., Cobb, S., Foster, C.,
Fry, C., Gold, A., Hagos, K., Heffner, L., Kellogg, D. Q., LellisDibble, K., Opaluch, J. J., Oviatt, C., Pfeiffer-Herbert, A., Rohr,
N., Smith, L., Smythe, T., Swift, J., and Vinhateiro, N., 2009.
Coastal lagoons and climate change: ecological and social ramifications in U.S. Atlantic and Gulf coast ecosystems. Ecology
and Society, 14(1), 8.
Barnes, R. S. K., 1980. Coastal Lagoons; The Natural History of a
Neglected Habitat. Cambridge: Cambridge University Press.
106 pp.
Bird, E. C., 1994. Physical setting and geomorphology of coastal
lagoons. In Kjerfve, B. (ed.), Coastal Lagoon Processes.
Elsevier Oceanography Series 60. Amsterdam: Elsevier Science
Publications B.V, 60, 9–40.
Bird, E. C., 2008. Coastal Geomorphology: An Introduction.
Chichester: Wiley. 411 pp.
Bird, C. E., Franklin, E. C., Smith, C. M., and Toonen, R. J., 2013.
Between tide and wave marks: a unifying model of physical
zonation on littoral shores. PeerJ, 1, e154, doi:10.7717/
peerj.154.
Borówka, R. K., Osadczuk, A., Witkowski, A., WawrzyniakWydrowska, B., and Duda, T., 2005. Late Glacial and Holocene
depositional sequences in the eastern part of the Szczecin
Lagoon (Great Lagoon) basin – NW Poland. Quaternary International, 130, 87–96.
Boyd, R., Dalrymple, R., and Zaitlin, B. A., 1992. Classification of
clastic coastal depositional environments. Sedimentary Geology,
80, 139–150.
Brito, A., Newton, A., Tett, P., and Fernandes, T., 2012. How will
shallow coastal lagoons respond to climate change?
A modelling investigation. Estuarine, Coastal and Shelf Science, 112, 98–104.
Carter, R. W. G., 1988. Coastal Environments: An Introduction to
the Physical, Ecological and Cultural Systems of Coastlines.
London: Academic.
Carter, R. W. G., Forbes, D. L., Jennings, S. C., Orford, J. D., Shaw,
J., and Taylor, R. B., 1989. Barrier and lagoon coast evolution
under differing relative sea level regimes: examples from Ireland
and Nova Scotia. Marine Geology, 88, 221–242.
Cooper, J. A. G., 1997. Lagoons and microtidal coasts. In Carter,
R. W. G., and Woodroffe, C. D. (eds.), Coastal Evolution. Late
Quaternary Shoreline Morphodynamics. Cambridge: Cambridge University Press.
390
LAGOONS
may reduce contact with the sea (Cooper, 1997). However,
it should be noted that the rate and direction of the lagoon
evolution depend on many factors. According to Cooper
(1997), these factors may be divided into macroscale and
local or microscale variations. Macroscale controls
include sea-level changes, climate, and tectonic stability.
Local controls include fluvial sediment supply, longshore
drift, salinity, surrounding geology, costal morphology,
lagoon orientation, wave energy, and tidal range. Carter
et al. (1989) proposed a hierarchy of controls on the effect
of sea-level changes on coarse-grained barrier-lagoon
evolution. Such hierarchical arrangement of dependencies
shows the complexity and interrelationships between various factors.
Very often, lagoon evolves from an estuary or marine
embayment to a partially enclosed barrier-lagoon system
and then, with progressive infilling, to a marsh or
deltaic-filled lagoon, ending the cycle with a depositional
plain or with an eventual destruction by marine erosion
(Nichols, 1989). For example, the area of the Odra River
mouth, southern Baltic coast, is subjected to such an evolution since the late Pleistocene (Borówka et al., 2005;
Osadczuk et al., 2007).
Based on detailed studies of sedimentation processes in
one of the world’s largest lagoons (Laguna Madre, Texas),
Morton et al. (2000) have found that the historical average
annual accumulation rate in the lagoon (1 mm/year) is substantially less than the historical rate of relative sea-level
rise (4 mm/year). Lagoon submergence coupled with erosion of the western shore indicates that Laguna Madre is
being submerged slowly and migrating westward rather
than filling, as some have suggested.
According to Adlam (2014), the existence of numerous
examples of lagoons that remain unfilled suggests that a
discontinuity in their geologic evolution occurs before
maturity is reached. He has presented a new hypothesis
that geologic evolution of lagoons takes place in two
phases which are defined by changes in physical processes. The early phase aligns with the traditional view
but ends when a depth threshold is reached. In the late
phase, sedimentation is inhibited by the local energy
regime and can only proceed if the lagoon surface area is
reduced. Validation of the existence of these two distinct
process-based phases of geologic evolution will improve
the reliability of predictive models for lagoon shoreline
changes and rates of basin fill as well as reduce the risk
of misinterpreting past conditions from the geological
record.
Conclusions
The formation and evolution of coastal lagoons is controlled by many factors, including global, regional, and
local determinants at different levels of importance. Very
important is the hierarchy of the circumstances and processes that control the evolution of this environment.
A comprehensive model of lagoons’ evolution should take
into account as many factors as possible. The model
should include, in particular, such variables as geological
conditions; neotectonic movements; lagoon morphology
and its orientation; connection with the sea; sea-level
changes, tidal amplitude, and waves energy; climate and
local meteorological conditions; character of sediments
supply; sedimentation rate; salinity; primary production;
and anthropogenic influences. Although there were several attempts to create a comprehensive and universal
model of the lagoons’ evolution, unfortunately, it was
not created, so far, one that would take into account all
variables.
Bibliography
Adlam, K., 2014. Coastal lagoons: geologic evolution in two
phases. Marine Geology, 355, 291–296.
Alsharhan, A. S., and Kendall, C. G. St. C., 2003. Holocene coastal
carbonates and evaporites of the southern Arabian Gulf and their
ancient analogues. Earth-Science Reviews, 61, 191–243.
Anthony, A., Atwood, J., August, P., Byron, C., Cobb, S., Foster, C.,
Fry, C., Gold, A., Hagos, K., Heffner, L., Kellogg, D. Q., LellisDibble, K., Opaluch, J. J., Oviatt, C., Pfeiffer-Herbert, A., Rohr,
N., Smith, L., Smythe, T., Swift, J., and Vinhateiro, N., 2009.
Coastal lagoons and climate change: ecological and social ramifications in U.S. Atlantic and Gulf coast ecosystems. Ecology
and Society, 14(1), 8.
Barnes, R. S. K., 1980. Coastal Lagoons; The Natural History of a
Neglected Habitat. Cambridge: Cambridge University Press.
106 pp.
Bird, E. C., 1994. Physical setting and geomorphology of coastal
lagoons. In Kjerfve, B. (ed.), Coastal Lagoon Processes.
Elsevier Oceanography Series 60. Amsterdam: Elsevier Science
Publications B.V, 60, 9–40.
Bird, E. C., 2008. Coastal Geomorphology: An Introduction.
Chichester: Wiley. 411 pp.
Bird, C. E., Franklin, E. C., Smith, C. M., and Toonen, R. J., 2013.
Between tide and wave marks: a unifying model of physical
zonation on littoral shores. PeerJ, 1, e154, doi:10.7717/
peerj.154.
Borówka, R. K., Osadczuk, A., Witkowski, A., WawrzyniakWydrowska, B., and Duda, T., 2005. Late Glacial and Holocene
depositional sequences in the eastern part of the Szczecin
Lagoon (Great Lagoon) basin – NW Poland. Quaternary International, 130, 87–96.
Boyd, R., Dalrymple, R., and Zaitlin, B. A., 1992. Classification of
clastic coastal depositional environments. Sedimentary Geology,
80, 139–150.
Brito, A., Newton, A., Tett, P., and Fernandes, T., 2012. How will
shallow coastal lagoons respond to climate change?
A modelling investigation. Estuarine, Coastal and Shelf Science, 112, 98–104.
Carter, R. W. G., 1988. Coastal Environments: An Introduction to
the Physical, Ecological and Cultural Systems of Coastlines.
London: Academic.
Carter, R. W. G., Forbes, D. L., Jennings, S. C., Orford, J. D., Shaw,
J., and Taylor, R. B., 1989. Barrier and lagoon coast evolution
under differing relative sea level regimes: examples from Ireland
and Nova Scotia. Marine Geology, 88, 221–242.
Cooper, J. A. G., 1997. Lagoons and microtidal coasts. In Carter,
R. W. G., and Woodroffe, C. D. (eds.), Coastal Evolution. Late
Quaternary Shoreline Morphodynamics. Cambridge: Cambridge University Press.
390
LAGOONS