Lam, P., Jensen, M. M., Lavik, G., McGinnis, D. F., Muller, B.,
Schubert, C. J., Amann, R., Thamdrup, B., and Kuypers,
M. M. M., 2007. Linking crenarchaeal and bacterial nitrification
to anammox in the Black Sea. PNAS, 104, 7104–7109.
Murray, J. W., 1991. The 1988 Black Sea Oceanographic Expedition:
introduction and summary. Deep-Sea Research, 38, S655–S661.
Renaud, M. L., 1986. Hypoxia in Louisiana coastal waters during
1983: implications for fisheries. Fisheries Bulletin, 84, 19–26.
Savchuk, O., 2010. Large-scale dynamics of hypoxia in the Baltic
Sea. In Yakushev, E. V. (ed.), Chemical Structure of Pelagic
Redox Interfaces: Observation and Modeling. Berlin/Heidelberg: Springer. Handbook of Environmental Chemistry,
Vol. 22, pp. 137–160.
Stunzhas, P. A., 2005. Application of continuous oxygen profiles to
redox zone studies in a coastal anticyclonic eddy. Oceanology,
45, 93–101.
Trouwborst, R. E., Brian, G. C., Tebo, B. M., Glazer, B. T., and
Luther, G. W., III, 2006. Soluble Mn(III) in suboxic zones.
Science, 313, 1955–1957.
Vaquer-Sunyer, R., and Duarte, C. M., 2008. Thresholds of hypoxia
for marine biodiversity. PNAS, 105, 15452–15457.
Yakushev, E., and Newton, A., 2013. Introduction: redox interfaces
in marine waters. In Yakushev, E. V. (ed.), Chemical Structure of
Pelagic Redox Interfaces: Observation and Modeling. Berlin/
Heidelberg: Springer. Handbook of Environmental Chemistry,
pp. 1–12.
Zubkov, M. V., Sazhin, A. F., and Flint, M. V., 1992. The microplankton organisms at the oxic- anoxic interface in the pelagial
of the Black Sea. FEMS Microbiology Ecology, 101, 245–250.
Cross-references
Anoxia, Hypoxia, and Dead Zones
Dissolved Oxygen
Oxygen Depletion
Water Quality
RESIDENCE TIME
Lisa V. Lucas
United States Geological Survey, Menlo Park, CA, USA
Definition
Residence time is defined as (1) the time taken by a water
parcel or particle to leave a defined region of interest
(Zimmerman, 1976; Delhez et al., 2004; de Brauwere
et al., 2011) or (2) the time for the mass of a scalar
(or the volume of freshwater; Dyer, 1997; Geyer, 1997)
within a water body to be renewed, given a known renewal
rate (Bolin and Rodhe, 1973; Geyer et al., 2000).
Essential concepts, applications, and methods of
estimation
“Residence time” is a commonly used term to generally convey time spent by water, dissolved substances, or particles
within a defined region or water body. However, specific
definitions and mathematical descriptions of this transport
timescale vary considerably in the literature, as pointed
out by others (Takeoka, 1984; Monsen et al., 2002;
Sheldon and Alber, 2002). The definitions provided above
are two of the most common and differ significantly from
each other in their underlying assumptions, precise meanings, and methods of estimation. Care is needed in the selection and description of residence time and other transport
timescale definitions and calculation methods, as estimated
values and suitability for the scientific question at hand
can vary substantially between approaches (Bolin and
Rodhe, 1973; Monsen et al., 2002).
Following from the first definition above (i.e., the time
taken by a water parcel or particle to leave a defined
domain), residence time is a function of space and time of
release, since particles originating at different locations and
times within a water body require different amounts of time
to leave (Monsen et al., 2002; Delhez et al., 2004). Defined
in this way, residence time (time for a parcel originating at
location x to exit a domain) is the complement of “age”
(time the parcel took to reach x after entering the domain);
the sum of the two timescales is called “transit time”
(Takeoka, 1984; Sheldon and Alber, 2002). In tidal systems,
ambiguity in the application of this definition may arise due
to the fact that fluid elements may leave the region of interest
on one phase of the tide and then reenter when the tide
reverses. Therefore, many authors have employed a strict
interpretation of this definition: the time required for
a parcel to leave the domain for the first time (Monsen
et al., 2002; Delhez et al., 2004; de Brauwere et al., 2011).
Because the cumulative amount of time spent within
a water body (over successive tidal visits) may be of ecological interest, a variation on the residence time concept –
“exposure time” – has been defined and computed with
numerical models (e.g., Monsen et al., 2002; de Brauwere
et al., 2011). A variety of numerical approaches is employed
to assess this first type of residence time, including Lagrangian particle tracking (Monsen et al., 2002), forward Eulerian
(de Brauwere et al., 2011), and time-reversed Eulerian
(Delhez et al., 2004) methods, the latter approaches
making use of numerical tracers. Models representing
a broad range of complexity have been implemented
for this purpose, including box (Zimmerman, 1976),
one-dimensional (Vallino and Hopkinson, 1998),
two-dimensional (de Brauwere et al., 2011), and threedimensional (Shen and Haas, 2004) models.
The second residence time definition (i.e., the time for
scalar renewal) represents an integrative timescale
describing general exchange characteristics of water bodies without addressing spatial variability (Monsen et al.,
2002). Under steady-state conditions, residence time
defined in this way takes the simple form M/F, where
M is total scalar mass in a domain and F is the scalar rate
of renewal (Bolin and Rodhe, 1973; Geyer et al., 2000).
If freshwater renewal is of particular interest, freshwater
volume may substitute for M and freshwater flow rate
for F (Dyer, 1997; Geyer, 1997). These integrative timescales are also known as “flushing times” (Monsen et al.,
2002; Sheldon and Alber, 2002) or “turnover times”
(Bolin and Rodhe, 1973; Sheldon and Alber, 2006).
502
RESIDENCE TIME
Schubert, C. J., Amann, R., Thamdrup, B., and Kuypers,
M. M. M., 2007. Linking crenarchaeal and bacterial nitrification
to anammox in the Black Sea. PNAS, 104, 7104–7109.
Murray, J. W., 1991. The 1988 Black Sea Oceanographic Expedition:
introduction and summary. Deep-Sea Research, 38, S655–S661.
Renaud, M. L., 1986. Hypoxia in Louisiana coastal waters during
1983: implications for fisheries. Fisheries Bulletin, 84, 19–26.
Savchuk, O., 2010. Large-scale dynamics of hypoxia in the Baltic
Sea. In Yakushev, E. V. (ed.), Chemical Structure of Pelagic
Redox Interfaces: Observation and Modeling. Berlin/Heidelberg: Springer. Handbook of Environmental Chemistry,
Vol. 22, pp. 137–160.
Stunzhas, P. A., 2005. Application of continuous oxygen profiles to
redox zone studies in a coastal anticyclonic eddy. Oceanology,
45, 93–101.
Trouwborst, R. E., Brian, G. C., Tebo, B. M., Glazer, B. T., and
Luther, G. W., III, 2006. Soluble Mn(III) in suboxic zones.
Science, 313, 1955–1957.
Vaquer-Sunyer, R., and Duarte, C. M., 2008. Thresholds of hypoxia
for marine biodiversity. PNAS, 105, 15452–15457.
Yakushev, E., and Newton, A., 2013. Introduction: redox interfaces
in marine waters. In Yakushev, E. V. (ed.), Chemical Structure of
Pelagic Redox Interfaces: Observation and Modeling. Berlin/
Heidelberg: Springer. Handbook of Environmental Chemistry,
pp. 1–12.
Zubkov, M. V., Sazhin, A. F., and Flint, M. V., 1992. The microplankton organisms at the oxic- anoxic interface in the pelagial
of the Black Sea. FEMS Microbiology Ecology, 101, 245–250.
Cross-references
Anoxia, Hypoxia, and Dead Zones
Dissolved Oxygen
Oxygen Depletion
Water Quality
RESIDENCE TIME
Lisa V. Lucas
United States Geological Survey, Menlo Park, CA, USA
Definition
Residence time is defined as (1) the time taken by a water
parcel or particle to leave a defined region of interest
(Zimmerman, 1976; Delhez et al., 2004; de Brauwere
et al., 2011) or (2) the time for the mass of a scalar
(or the volume of freshwater; Dyer, 1997; Geyer, 1997)
within a water body to be renewed, given a known renewal
rate (Bolin and Rodhe, 1973; Geyer et al., 2000).
Essential concepts, applications, and methods of
estimation
“Residence time” is a commonly used term to generally convey time spent by water, dissolved substances, or particles
within a defined region or water body. However, specific
definitions and mathematical descriptions of this transport
timescale vary considerably in the literature, as pointed
out by others (Takeoka, 1984; Monsen et al., 2002;
Sheldon and Alber, 2002). The definitions provided above
are two of the most common and differ significantly from
each other in their underlying assumptions, precise meanings, and methods of estimation. Care is needed in the selection and description of residence time and other transport
timescale definitions and calculation methods, as estimated
values and suitability for the scientific question at hand
can vary substantially between approaches (Bolin and
Rodhe, 1973; Monsen et al., 2002).
Following from the first definition above (i.e., the time
taken by a water parcel or particle to leave a defined
domain), residence time is a function of space and time of
release, since particles originating at different locations and
times within a water body require different amounts of time
to leave (Monsen et al., 2002; Delhez et al., 2004). Defined
in this way, residence time (time for a parcel originating at
location x to exit a domain) is the complement of “age”
(time the parcel took to reach x after entering the domain);
the sum of the two timescales is called “transit time”
(Takeoka, 1984; Sheldon and Alber, 2002). In tidal systems,
ambiguity in the application of this definition may arise due
to the fact that fluid elements may leave the region of interest
on one phase of the tide and then reenter when the tide
reverses. Therefore, many authors have employed a strict
interpretation of this definition: the time required for
a parcel to leave the domain for the first time (Monsen
et al., 2002; Delhez et al., 2004; de Brauwere et al., 2011).
Because the cumulative amount of time spent within
a water body (over successive tidal visits) may be of ecological interest, a variation on the residence time concept –
“exposure time” – has been defined and computed with
numerical models (e.g., Monsen et al., 2002; de Brauwere
et al., 2011). A variety of numerical approaches is employed
to assess this first type of residence time, including Lagrangian particle tracking (Monsen et al., 2002), forward Eulerian
(de Brauwere et al., 2011), and time-reversed Eulerian
(Delhez et al., 2004) methods, the latter approaches
making use of numerical tracers. Models representing
a broad range of complexity have been implemented
for this purpose, including box (Zimmerman, 1976),
one-dimensional (Vallino and Hopkinson, 1998),
two-dimensional (de Brauwere et al., 2011), and threedimensional (Shen and Haas, 2004) models.
The second residence time definition (i.e., the time for
scalar renewal) represents an integrative timescale
describing general exchange characteristics of water bodies without addressing spatial variability (Monsen et al.,
2002). Under steady-state conditions, residence time
defined in this way takes the simple form M/F, where
M is total scalar mass in a domain and F is the scalar rate
of renewal (Bolin and Rodhe, 1973; Geyer et al., 2000).
If freshwater renewal is of particular interest, freshwater
volume may substitute for M and freshwater flow rate
for F (Dyer, 1997; Geyer, 1997). These integrative timescales are also known as “flushing times” (Monsen et al.,
2002; Sheldon and Alber, 2002) or “turnover times”
(Bolin and Rodhe, 1973; Sheldon and Alber, 2006).
502
RESIDENCE TIME