ArticlePDF Available

Three-dimensional connectivity in the Gulf of California: An online interactive webpage


Abstract and Figures

This paper presents an online interactive webpage [] that provides users with results of both the three-dimensional connectivity and spatial dispersion of particles in the Gulf of California (GC). These results were originated by means of a three-dimensional numerical model of circulation adapted to the GC from which the advection of particles were generated between different regions of the gulf. Particle connectivity and dispersion results were generated for and are limited to temporal scales to seasonal tides, which may aid in the interpretation of larval connectivity and contaminants within the gulf.
Content may be subject to copyright.
Interactive webpage on three-dimensional connectivity 1
Lat. Am. J. Aquat. Res., 45(2): 322-328, 2017
DOI: 10.3856/vol45-issue2-fulltext-8
Research Article
Three-dimensional connectivity in the Gulf of California: an online
interactive webpage
Carolina Montaño-Cortés1, Silvio G. Marinone1 & Ernesto Valenzuela1
1Department of Physical Oceanography, Ensenada Center of Scientific
Research and Higher Education (CICESE), Tijuana, Mexico
Corresponding author: Silvio G. Marinone (
ABSTRACT. This paper presents an online interactive webpage [] that
provides users with results of both the three-dimensional connectivity and spatial dispersion of particles in the
Gulf of California (GC). These results were originated by means of a three-dimensional numerical model of
circulation adapted to the GC from which the advection of particles were generated between different regions
of the gulf. Particle connectivity and dispersion results were generated for and are limited to temporal scales to
seasonal tides, which may aid in the interpretation of larval connectivity and contaminants within the gulf.
Keywords: interactive webpage, three-dimensional connectivity, particles dispersion, Gulf of California.
Three-dimensional connectivity studies are an impor-
tant research topic for the different branches of
oceanography because they provide information about
the location of moving particles based on the
hydrodynamics of a water body.
This study considers connectivity to be that which
“connects” different areas to different times, describing
some type of trajectory. These trajectories can serve as
the basis for understanding contaminant propagation
and the dispersion of larvae from different marine
species and their nutrients and can aid in the sound
development of protected marine areas, among other
applications (Cudney-Bueno et al., 2009; Marinone et
al., 2008).
The objective of this study is to demonstrate the
manner in which an interactive online webpage
[] displays the
evolution of three-dimensional connectivity between
the areas composing the Gulf of California (GC), as
well as to present a visualization of the dispersion of
particles from a particular region based on the results
obtained through the HAMburg Shelf Ocean Model
(HAMSOM), which is an Eulerian numerical circu-
lation model, and a Lagrangian particle dispersion
model. Both models were validated as described in the
following section.
Corresponding editor: Nelson Silva
Particles underwent advection for eight weeks, being
released the first day of each month of the year through
a Lagrangian advection-diffusion model (Visser, 1997;
Proehl et al., 2005) over a field of Eulerian currents
obtained from a three-dimensional baroclinic circu-
lation model (HAMSOM) adapted to the GC by
Marinone (2003, 2008). The model has a spatial
horizontal resolution of ~1.3×1.5 km and 12 layers
vertically, and is forced by tides, winds, seasonal
warming and water flows at the surface, and seasonal
hydrography at the mouth of the gulf (Marinone 2003,
2006, 2008; Marinone & Lavín, 2005; Santiago-García
et al., 2014; Montaño, 2015). Given this forcing, there
is no interannual or mesoscale variability beyond that
which is obtained from nonlinear interactions between
the currents produced by tides and seasonal currents
produced by wind and forcing at the mouth. In
particular, at these scales, the trajectories of particles
are dominated by seasonal circulation, and tides only
produce oscillations along the length of a trajectory
(Marinone et al., 2008). For calculations, at different
scales, forcing in the numerical model will need to be
changed to produce circulation during, for example, an
El Niño event.
The particles release was performed within the 17
areas into which the Gulf of California was divided
2 Latin American Journal of Aquatic Research
Table 1. Names of the regions that correspond to the Gulf of California (Santiago-García et al., 2014). Names are shown
in both Spanish and English, as the webpage includes both options.
Spanish name
Upper Gulf
Alto Golfo
Buffer Zone
Conexión Alto Golfo y Remolino Estacional
Peninsular Eddies
Remolinos Peninsulares
Seasonal Eddy
Remolino Estacional
Sonora Coast
Delfín Basin
Cuenca Delfín
North of Tiburón Island
Norte de Isla Tiburón
East of Ángel de la Guarda Island
Ángel de la Guarda
Ballenas-Salsipuedes Channel
Canal de Ballenas
Sills Zone
Zona de los Umbrales
Central Peninsular Region
Región Peninsular Central
Guaymas Basin
Cuenca Guaymas
Central Continental Region
Región Continental Central
South Continental Region
Región Continental Sur
Farallón Basin
Cuenca Farallón
South Peninsular Region
Región Peninsular Sur
La Paz Bay
Bahía la Paz
(Table 1; according to Santiago-García et al., 2014).
The final positions of the particles were determined
(longitude, latitude and depth) at 2, 4, 6 and 8 weeks
after being released. Then, the results were presented in
connectivity matrices between the different areas,
including the average depths and standard deviation, as
well as in final position maps of all the particles and
histograms of the percentage of particles corresponding
to the different areas of arrival, as subsequently
The connectivity matrices quantify the particles that
reached different regions and those that returned or
remained in the area where they were released for each
of the final periods (2, 4, 6 and 8 weeks), shown as
percentages. For each connectivity matrix, Cij(t), i is the
horizontal axis, which defines the area of arrival or final
destination of the particles, j is the vertical axis, which
represents the provinces or release areas, and t is the
week at which the positions of released particles are
observed during the different months of the year. The
summation of the percentages in each of the rows of the
matrix represents the total release percentage of each
area, except when the particles leave the model domain.
(In the connectivity figures, cells with less than 5% of
the particles were excluded from the matrices for clarity
Associated to the connectivity matrices, the mean
and standard deviation of the depths reached by the
particles for each of the different cells of the matrix
were calculated. Based on the information attained,
matrices were developed for mean depth and standard
deviation, which maintain the same format as the
connectivity matrix. The sequence of matrices is such
that both the abscissa (x) and ordinate (y) axes group
the regions as north, large islands and south. These
divisions are presented in the figures as dashed lines.
The principal diagonal line represents the retention and
indicates the particles that ended up inside the release
To complement the portrayal of the connectivity
results, mean depth, and standard deviation matrices,
maps were developed of the final geographic position
of the particles at different times (2, 4, 6 and 8 weeks),
presented as color codes of depth at which each particle
was found. Similarly, histograms were used to represent
the connectivity percentages of a location compared to
all other regional divisions that compose the GC.
Therefore, for the model’s 12 layers, the results
represent all months of the year as well as the periods
of 2, 4, 6 and 8 weeks.
Model validation
The results obtained using the Eulerian and Lagrangian
models upon which the calculations presented for this
webpage are based have been validated in several
studies. The Eulerian model used by Marinone (2003)
reproduces several circulation phenomena from the
GC. For example, it adequately reproduces seasonal
circulation patterns, which consist of a reversible
rotation in the northern GC (NGC) that is anticyclonic
in the winter and cyclonic in the summer, as reported
by Lavín et al. (1997) and Carrillo et al. (2002), and a
similar circulation pattern in the southern part of the
Interactive webpage on three-dimensional connectivity 3
GC, as noted by Beier (1997). Similarly, Marinone
(2008) validates the numerical results of the deep
circulation present around the large islands obtained by
López et al. (2006), which consisted of a trajectory
from Umbral de San Esteban to the northern end of the
channel formed between Ángel de la Guarda Island and
the Baja California Peninsula (Ballenas-Salsipuedes
Channel, or BC), exhibiting convergence in deep areas
and divergence on the surface.
The tidal currents (barotropic and baroclinic), and
their harmonic components reproduced by the model,
exhibited similar behaviors with respect to the data
obtained by Marinone & Lavín (2005). The numerical
results were compared with 124 time series corres-
ponding to 62 stations, of which 68 time series
correspond to NGC, 31 correspond to the region of
large islands and 25 correspond to the central gulf. A
comparison indicates that the semidiurnal components
were better modeled than the diurnal components. For
example, in Table 2 from Marinone & Lavín (2005),
the semi-major axis of the modeled M2 exhibits an
underestimation of only 3.9%, whereas the underes-
timation for K1 is 26%. However, as mentioned in the
study, when examining the means of the semi-major
axis values together with their corresponding error bars,
there is markedly a high number of overlapping data
points, indicating better modeling than what is
indicated by the significant differences. The numerical
results obtained for sea level were validated with
respect to the observations of Ripa (1990) and Beier
(1997). The mean amplitude of the annual component
in the coastal stations was 18.8 ± 4.5 cm for the model,
whereas it was 18.6 ± 4.5 for the observations
(Marinone, 2003). The comparison of sea surface
temperatures obtained from the model with sea surface
temperatures obtained from the region studied by Soto-
Mardones et al. (1999) revealed that the evolution of
warm and cold water pools was reproduced in the
central part of the NGC, as well as the presence of a
lateral temperature gradient during the summer in the
southern part of the GC (Marinone, 2003). For further
validation of the currents obtained by the model, refer
to [].
The Lagrangian behavior obtained from particle
advection was also validated by comparing the results
obtained for the trajectories of buoys (ARGOS) released
in the NGC in September (1995) and March (1996) by
Lavin et al. (1997), where one cyclonic and one
anticyclonic rotation were observed. Additionally,
Calderon-Aguilera et al. (2003) described the
migratory patterns of the blue shrimp by associating the
circulation patterns during the summer in the northern
part of the GC. In that study, every day and during two
periods (July 1227, 1995 and June 30 to July 16,
1996), simultaneous samples of post-larval shrimp
were collected in two locations of the NGC (San Felipe
on the peninsula side, and Santa Clara on the
continental side of the GC). To simulate circulation, the
output of the HAMSOM model was used. From the
significant results, it was determined that the model
served as an important tool to explain why the post
larvae found in the continental sector were bigger
(apparently, they were older) than those found on the
peninsula side. Similarly, Cudney-Bueno et al. (2009)
used this model to evaluate the possible effects of the
reserve network of the upper gulf’s continental sector
on adjacent areas. The results of the model were
compared with oceanographic experiments and the
changes observed in the density of commercial juvenile
mollusks before and after establishing the reserves. In
that respect, the model suggested that San Jorge Island,
on the southern side, in particular, could be responsible
for exporting larvae to the reserves and fishing areas
along the coast. Munguia-Vega et al. (2014) hypothe-
sized that the source-sink metapopulation dynamic of
the Mycteroperca rosacea larvae in 17 zones
distributed across the Great Islands describes the
direction and frequency of larval dispersion based on
an oceanographic model (HAMSOM) that favors the
understanding of empirical genetic data.
The comparison of model results (Eulerian and
Lagrangian), with the described observations reported in
the different studies cited, lends qualitative confidence to
using this online tool to examine connectivity matrices
and dispersion patterns throughout a climatological
The webpage [http://conectividad-dispersion.cicese.
mx/] presents results for connectivity, dispersion, etc.
both in English and Spanish. The page content was
divided into four sections: the first (Start) provides a
brief explanation of the methodology of products
obtained as well as visualization options for the results
presented in the second section (Interactive Map). The
third section (Help) provides a brief explanation of how
to use the webpage as well as some concepts, and the
fourth section (Contacts) acknowledges collaborators
involved in developing the page.
Interactive map
In this section (Fig. 1), the user can select:
Matrix Connectivity matrices for mean depth and
standard deviation
Dispersion Maps of final particle positions and
To display the figures, one must first select the type
of graph: matrix or dispersion. This option is located in
4 Latin American Journal of Aquatic Research
Figure 1. Image of the webpage’s interactive map section.
Figure 2. Example of a connectivity matrix. The release was completed in March at the first layer (010 m). In this case,
the final time selected was the end of the sixth week.
the top central area of the webpage. Following,
examples of both types of figures are described.
a) Matrix
For this graph, the matrix type must be selected:
connectivity, mean depth or standard deviation; the
option is found at the top central part of the page. The
release options are found at the top right, in which the
user selects the depth (1 to 12 layers), the month (1 to
12 months) and the final visualization time (2, 4, 6 or 8
weeks). For example, Fig. 2 shows a connectivity
matrix for March, releasing particles at a depth range of
Interactive webpage on three-dimensional connectivity 5
Figure 3. Example of a particle’s final position map and its corresponding histogram. The release was performed in the
Central Peninsular Region (CP) in March at the first layer (010 m). In this case, the final time selected was the end of the
sixth week.
Figure 4. Example of a particle’s final position map and its corresponding histogram. The release was done in the Central
Peninsular Region (CP) in March at the first layer (0–10 m). In this case, the option “All” was selected, displaying the four
different final periods.
6 Latin American Journal of Aquatic Research
010 m and displaying the results for the sixth week
after release. In contrast, Fig. 2 shows that the particles
released in the Central Peninsular Region (CP) moved
towards the Sills Zone (SZ), Guaymas Basin (GB) and
Central Continental Region (CC), and a small
percentage of the particles are found in the same sector
in which they were released. Similarly, north of
Tiburón Island (TI), six weeks after release, the
particles moved towards the regions of GB, CC,
Farallón Basin (FB) and the South Continental Region
The data for each connectivity, mean depth and
standard deviation matrix may be downloaded by
selecting the option “Data” located in the top center of
the page. The format of the data is the same as that of
the figure, that is, the horizontal axis represents the
particle arrival location, and the vertical axis represents
release areas.
b) Dispersion
First, a release area must be selected; this is
accomplished using the map located at the upper left of
the page. This map shows the 17 regions into which the
GC was divided, each with its associated acronym. The
results are shown for the different depths of the GC and
for the 12 months of the year. However, in the case of
a particle’s final position, there are two options for
displaying the results: specific, by selecting 2, 4, 6 and
8 weeks; and general, by selecting “all”, whereby all
four results are displayed in a single image. Finally, in
the lower left of the page there is an option for
information, which provides the full name and number
of layers of the area selected.
Figures 3 and 4 show examples of a specific map
and a general map, respectively, of the final position of
the particles and their corresponding histogram. This
provides a visual representation of the steps described
previously. It is important to note that the dispersion
maps complement the matrix analysis.
Figure 3 shows the position of the particles six
weeks after being released in the CP, which more
precisely presents the particles’ paths, as well as depths
at which they are located. In this case, the majority of
the particles are found at depths greater than 40 m and
predominantly moved in the direction of the GB sector.
Fig. 4 depicts the four periods, permitting the trajectory
of the particles to be inferred. In this case, at the end of
the eighth week, a higher percentage of the particles
released moved towards the east of the CP, CC and GB
sectors. It was also observed that in the second region,
the majority of the particles were located at depths >50
m; however, in the following weeks, most of these
particles were located at depths <60 m.
Finally, it is possible to download the data from
each map depicting the particles’ final positions by
selecting the option “Data” located in the upper center
of the page. The format of this document is presented
in three columns (longitude, latitude, depth). The
heading of the first row provides the Julian hour of the
final positions, that is, the second, fourth, sixth and
eighth weeks correspond to the hours 336, 672, 1008
and 1344, respectively. The remaining rows provide the
positions of each particle.
The interactive online webpage developed in this study
presents the three-dimensional connectivity results
among 17 areas of the GC and the spatial distribution
of particles released from each of the areas. These
results were realized based on the advection of particles
obtained from a 12-layer three-dimensional numerical
model that was validated with respect to the primary
circulation characteristics of the GC. The associated
temporal scales are limited to model forcing, which
correspond to the seasonal variations in tides; therefore,
fluctuations in other frequencies are not considered for
the model used in this interactive webpage. The results
presented here are qualitative and should not be used as
a key tool for decision making. However, the results
offer an approximation of the connectivity and
dispersion patterns in the GC, which may help in the
understanding of dispersion patterns for marine
organism larvae as well as contaminants.
This study is part of the Masters of Science thesis of
CMC, who was supported by a CONACyT scholarship.
Financial support is part of the regular budget of the
CICESE and of project CONACyT No. 44055.
Beier, E. 1997. A numerical investigation of the annual
variability in the Gulf of California. J. Phys.
Oceanogr., 27(5): 615-632.
Calderon-Aguilera, L.E., S.G. Marinone & E.A. Aragón-
Noriega. 2003 Influence of oceanographic processes
on the early life stages of the blue shrimp (Litopenaeus
stylirostris) in the Upper Gulf of California. J. Mar.
Syst., 39: 117-128.
Carrillo, L., M.F. Lavín & E. Palacios-Hernández. 2002.
Seasonal evolution of the geostrophic circulation in the
northern Gulf of California. Estuar. Coast. Shelf Sci.,
54: 157-173.
Interactive webpage on three-dimensional connectivity 7
Cudney-Bueno, R., M.F. Lavín, S.G. Marinone, P.T.
Raimondi & W.W. Shaw. 2009. Rapid effects of
marine reserves via larval dispersal. PLoS ONE, 4(1):
Lavín, M.F., R. Durazo, E. Palacios, M.L. Argote & L.
Carrillo. 1997. Lagrangian observations of the
circulation in the northern Gulf of California. J. Phys.
Oceanogr., 27: 2298-2305.
López, M., J. Candela & M.L. Argote. 2006. Why does the
Ballenas Channel have the coldest SST in the Gulf of
California?. Geophys. Res. Lett., 33: 1-5.
Marinone, S.G. 2003. A three-dimensional model of the
mean and seasonal circulation of the Gulf of
California. J. Geophys. Res., 108(C10): 3325.
Marinone, S.G. 2006. A numerical simulation of the two-
and three-dimensional Lagrangian circulation in the
northern Gulf of California. Estuar. Coast. Shelf Sci.,
68: 93-100.
Marinone, S.G. 2008. On the three-dimensional numerical
modeling of the deep circulation around Ángel de la
Guarda Island in the Gulf of California. Estuar. Coast.
Shelf Sci., 80: 430-434.
Marinone, S.G. & M.F. Lavín. 2005. Tidal current ellipses
in a three-dimensional baroclinic numerical model of
the Gulf of California. Estuar. Coast. Shelf Sci., 64:
Marinone, S.G., M.J. Ulloa, A. Parés-Sierra, M.F. Lavín
& R. Cudney-Bueno. 2008. Connectivity in the
northern Gulf of California from particle tracking in a
three-dimensional numerical model. J Mar. Syst., 71:
Montaño, C.C. 2015. Conectividad tridimensional durante
verano en el norte del Golfo de California. Tesis
Maestría en Ciencias, Centro de Investigación
Científica y de Educación Superior de Ensenada, Baja
California, 60 pp.
Munguia-Vega, A., A. Jackson, S.G. Marinone, B.
Erisman, M. Moreno-Baez, A. Girón-Nava, T. Pfister,
O. Aburto-Oropeza & J. Torre. 2014. Asymmetric
connectivity of spawning aggregations of a comme-
cially important marine fish using a multidisciplinary
approach. Peer J. 2:e511. Doi:10.7717/peerj.511.
Proehl, J.A., D.R. Lynch, D.J. McGillicuddy & J.R.
Ledwell. 2005. Modeling turbulent dispersion on the
North Flank of Georges Bank using Lagrangian
particle methods. Cont. Shelf Res., 25: 875-900.
Santiago-García, M.W., S.G. Marinone & O.U. Velasco-
Fuentes. 2014. Three-dimensional connectivity in the
Gulf of California based on a numerical model. Prog.
Oceanogr., 123: 64-73.
Soto-Mardones, L., S.G. Marinone & A. Parés-Sierra.
1999. Time and spatial variability of sea surface
temperature in the Gulf of California. Cienc. Mar., 25:
Ripa, P. 1990. Seasonal circulation in the Gulf of
California. Ann. Geophys., 8: 559-564.
Visser, A.W. 1997. Using random walk models to
simulate the vertical distribution of particles in a
turbulent water column. Mar. Ecol. Prog. Ser., 158:
Received: 20 December 2015; Accepted: 27 December 2016
... Marine circulation in the central Gulf of California has been described by hydrodynamic models that characterize the preferential directions of currents at different depth levels in the water column (Marinone, 2003;Montaño-Cortés et al., 2017). In front of the Santa Rosalía mining district, the currents throughout the year show a southwesterly circulation direction between 100 and 150 m of depth, while, in the range of 0 to 10 m of depth, the circulation is towards the east (Marinone, 2003). ...
... In front of the Santa Rosalía mining district, the currents throughout the year show a southwesterly circulation direction between 100 and 150 m of depth, while, in the range of 0 to 10 m of depth, the circulation is towards the east (Marinone, 2003). In fact, the modeling of the release of particles along the central region of the Gulf of California, which includes the Santa Rosalía margin, suggests that the dispersion of the particles in the water column are from southwest to southeast and eastwards of the central Gulf of California (Montaño-Cortés et al., 2017). ...
... Marine circulation in the Gulf of California has been described by in situ measurements and models (e.g., Marinone, 2012 and citations here). However, at the Santa Rosalía margin, there is information on ocean circulation from numerical models and particle dispersion (Marinone, 2003;Marinone, 2012;Montaño-Cortés et al., 2017) that provide evidence to validate the direction of the residual sedimentary transport vectors that have been inferred from the textural tendencies of the surface sediments. ...
The transport of continental materials of natural and/or anthropic origin as well as their dispersion and final deposition in marine environments can be inferred from the analysis of the textural tendencies of sediments. The exploitation of copper ore (since the 19th century) in the Santa Rosalíamining district has caused the accumulation of potentially toxic elements (PTEs) in sediments off the western coast of the Gulf of California; however, after several decades of mining, little is known about the mobilization and final destination of these PTEs. In the present work, the net sedimentary transport and dispersion of Cu and Zn is inferred in front of the mining district of Santa Rosalía at the western margin of the Gulf of California. Net sedimentary transport is dominantly towards the southeast, with a change towards the east of the port of Santa Rosalía. The spatial distribution of Cu and Zn showed the same pattern as the net sediment transport,which suggests that the dispersion of PTEs is controlled by the textural tendencies of the sediments and their transport, corroborated by hydrodynamic models of the marine currents at the western margin of the Gulf of California.
... Fig. 2a shows the progression of the particles while Fig. 2b shows a few arbitrary trajectories for the same period. Although much information is inferable from these data, and numerous articles have used Lagrangian trajectories as the basis for the description of the integrated characteristics of numerical circulation models (e.g., Santiago-García et al., 2014;Montaño-Cortes et al., 2017), often these spaghetti-diagrams are difficult to interpret and synthesize. LaCasce (2008) presents an excellent review of statistical analyses from oceanic Lagrangian data. ...
... These matrices lump together information in a rough way, however, and often make analysis difficult (e.g. Marinone et al., 2008;Montaño-Cortes et al., 2017). ...
We propose a method for analyzing ocean currents using a statistical approach. The proposed technique is useful for analyzing global velocity fields and producing indices to describe the probable trajectories and destinations of particles embedded in such fields. Short-term Lagrangian integration of the velocities was used to generate transition matrices that define the system locally. A reshuffling algorithm, based on standard Markov Chain theory, was implemented to mix and synthesize the information involved in the global analysis. Iterative methods were then used to solve the resulting large and sparse linear systems. The method efficiently used local information (short-term Lagrangian integration) to infer global characteristics of the system. Two case studies were presented to emphasize the merits of the described scheme: one using modeled data from the Gulf of California, and another from the Gulf of Mexico.
... At mesoscale, overall connectivity patterns follow main current systems and its seasonal variations, as stated for a semi-enclosed sea such as the Gulf of California (Montaño-Cortés, Marinone, & Valenzuela, 2017;Munguia-Vega et al., 2014;Peguero-Icaza et al., 2011;Soria et al., 2014). It also holds for large areas such as the eastern Pacific (Lequeux et al., 2018;Romero-Torres, Treml, Acosta, & Paz-García, 2018) or the Gulf of Mexico/Caribbean sea (Murphy & Hurlburt, 1999;Sanvicente-Añorve et al., 2014). ...
Mexico harbors several types of coastal ecosystems both in the Atlantic (Gulf of Mexico and Caribbean) and in the Pacific (tropical and subtropical) on which the regional and national socio-economic development depends. They have been studied through several modeling approaches for management, conservation, and necessary ecological studies. In this chapter, we review and synthesize the most recent and relevant studies conducted, with particular emphasis on coral reefs. In the Caribbean, coral reefs are likely the most rapidly changing ecosystems with a net decline in the cover of reef-building corals accompanied by rapid increases of fleshy macroalgae over the last decades. Remaining coral communities are changing toward weedy coral species that are unlikely to support reef growth and thus provide important services to other species and humans. Since 2015 the Mexican Caribbean coast experienced a massive influx of drifting Sargassum spp. that accumulated on the shores, resulting in a build-up of decaying beach-cast material and near-shore murky brown waters (Sargassum-brown-tides), drastically modifying near-shore waters conditions by reducing light, oxygen (hypoxia or anoxia), and pH. The Gulf of Mexico’s coastal ecosystems have also been under significant threats because of human activities, such as gas and oil extraction, pollution, and fishing. Despite numerous studies conducted in the Pacific, biodiversity knowledge is still incomplete, highly biased toward specific habitats, and often narrow in taxonomic and spatial scope. Concurrently, ecological processes that drive biodiversity have been scarcely disentangled. In spite of sub-optimal conditions for coral calcification (lower alkalinity, upwelling, ENSO, high nutrients concentration) some coral reefs thrive in the Pacific. Calcification rate is disrupted with ENSO events (20–50% drop), but it is not correlated to historical changes in sea surface temperature and it might decrease between 15 and 22% due to ocean acidification.
... Geostrophic estimates show distinct two-way flow near bottom between PB and AR with a Pacific-ward flow to the east and inflows to the west [52]; thus, two-way larval exchange is possible, and the 75 km distance between PB and AR vent fields lies within the average dispersal distances for most worm, clam and crustacean larvae [18,53,54]. While the recent Lagrangian connectivity model of Montañ o-Cortés et al. [55] does not encompass the AR field, it illustrates particles crossing basin boundaries with some vertical component in four-and eight-week runs. Thus, the distinction of macrofauna between PB and AR locales suggests that community composition is related less to geographical proximity and larval supply than to habitat suitability. ...
Full-text available
Hydrothermal vent communities are distributed along mid-ocean spreading ridges as isolated patches. While distance is a key factor influencing connectivity among sites, habitat characteristics are also critical. The Pescadero Basin (PB) and Alarcón Rise (AR) vent fields, recently discovered in the southern Gulf of California, are bounded by previously known vent localities (e.g. Guaymas Basin and 218 N East Pacific Rise); yet, the newly discovered vents differ markedly in substrata and vent fluid attributes. Out of 116 macrofaunal species observed or collected, only three species are shared among all four vent fields, while 73 occur at only one locality. Foundation species at basalt-hosted sulfide chimneys on the AR differ from the functional equivalents inhabiting sediment-hosted carbonate chimneys in the PB, only 75 km away. The dominant species of symbiont-hosting tubeworms and clams, and peripheral suspension-feeding taxa, differ between the sites. Notably, the PB vents host a limited and specialized fauna in which 17 of 26 species are unknown at other regional vents and many are newspecies. Rare sightings and captured larvae of the ‘missing’ species revealed that dispersal limitation is not responsible for differences in community composition at the neighbouring vent localities. Instead, larval recruitment-limiting habitat suitability probably favours species differentially. As scenarios develop to design conservation strategies around mining of seafloor sulfide deposits, these results illustrate that models encompassing habitat characteristics are needed to predict metacommunity structure. © 2017 The Author(s) Published by the Royal Society. All rights reserved.
Full-text available
Fourteen years of satellite images (1983-1996) are used to examine the variability of sea surface temperature (SST) in the Gulf of California. The study focussed on the semiannual, annual and inter-annual scales and on the average. On average, SST decreases from the mouth to the head and its variability increases. The annual scale is responsible for most of the temporal variability, which oscillates in phase with minor north-south variations. The northern gulf shows the formation of warm anticyclonic eddies during winter and cold cyclonic eddies during summer. The spring transition shows a cyclonic eddy closer to the mainland side of the gulf; the autumn transition shows a net well-defined anticyclonic eddy. The SST around the island region is always colder than the rest of the gulf. The lateral variability in the central and southern regions is associated with upwelling phenomena. The semiannual and annual amplitudes increase to the north by a factor of two with respect to the southern region. On the interannual scale, the 1988-1989 and 1992-1993 events reach all the gulf. Both events appear first in the south and island regions, and the signals are more intense at the islands than the rest of the gulf. This behavior has not been reported before. The 1985, 1987 and 1990 events show a 'normal' evolution, i.e., the warm waters appear in the south and gradually progress into the gulf.
Full-text available
Understanding patterns of larval dispersal is key in determining whether no-take marine reserves are self-sustaining, what will be protected inside reserves and where the benefits of reserves will be observed. We followed a multidisciplinary approach that merged detailed descriptions of fishing zones and spawning time at 17 sites distributed in the Midriff Island region of the Gulf of California with a biophysical oceanographic model that simulated larval transport at Pelagic Larval Duration (PLD) 14, 21 and 28 days for the most common and targeted predatory reef fish, (leopard grouper Mycteroperca rosacea). We tested the hypothesis that source-sink larval metapopulation dynamics describing the direction and frequency of larval dispersal according to an oceanographic model can help to explain empirical genetic data. We described modeled metapopulation dynamics using graph theory and employed empirical sequence data from a subset of 11 sites at two mitochondrial genes to verify the model predictions based on patterns of genetic diversity within sites and genetic structure between sites. We employed a population graph describing a network of genetic relationships among sites and contrasted it against modeled networks. While our results failed to explain genetic diversity within sites, they confirmed that ocean models summarized via graph and adjacency distances over modeled networks can explain seemingly chaotic patterns of genetic structure between sites. Empirical and modeled networks showed significant similarities in the clustering coefficients of each site and adjacency matrices between sites. Most of the connectivity patterns observed towards downstream sites (Sonora coast) were strictly asymmetric, while those between upstream sites (Baja and the Midriffs) were symmetric. The best-supported gene flow model and analyses of modularity of the modeled networks confirmed a pulse of larvae from the Baja Peninsula, across the Midriff Island region and towards the Sonoran coastline that acts like a larval sink, in agreement with the cyclonic gyre (anti-clockwise) present at the peak of spawning (May-June). Our approach provided a mechanistic explanation of the location of fishing zones: most of the largest areas where fishing takes place seem to be sustained simultaneously by high levels of local retention, contribution of larvae from upstream sites and oceanographic patterns that concentrate larval density from all over the region. The general asymmetry in marine connectivity observed highlights that benefits from reserves are biased towards particular directions, that no-take areas need to be located upstream of targeted fishing zones, and that some fishing localities might not directly benefit from avoiding fishing within reserves located adjacent to their communities. We discuss the implications of marine connectivity for the current network of marine protected areas and no-take zones, and identify ways of improving it.
Full-text available
Random walk simulation has the potential to be an extremely powerful tool in the investigation of turbulence in environmental processes. However, care must be taken in applying such simulations to the motion of particles in turbulent marine systems where turbulent diffusivity is commonly spatially non-uniform. The problems associated with this non-uniformity are far from negligible and have been recognised for quite some time. However, incorrect implementations continue to appear in the literature. In this note computer simulations are presented to illustrate how and why these implementations are incorrect, and a simple technique that can properly simulate turbulent diffusion in the marine environment is discussed.
Full-text available
The observations of sea level at the annual frequency in the Gulf of California are reproduced both in amplitude and phase with a horizontal two-dimensional linear two-layer model. The main forcing agents through which variability is explained are wind stress and the action of the Pacific Ocean, which excites an internal wave in the mouth of the gulf. The surface heating is shown to play a secondary role. The response of the basin is qualitatively similar to that observed, that is, an energetic circulation in the upper layer (cyclonic in summer and anticyclonic in winter) compared to a weaker and opposite circulation in the bottom layer, as well as a transversely averaged horizontal heat flux equal both in amplitude and phase to that calculated with historical hydrographic data. The results of the simulation show that variability across the gulf is as important as the longitudinal variability.
Using a numerical model of the circulation of the Gulf of California, a description of the tidal ellipses parameters is given. The best modeled constituents are those of the semidiurnal band, while those of the diurnal band are underestimated. In general, tidal ellipse semimajor axes for the diurnal and semidiurnal bands increase from south to north with a maximum in the archipelago area. The annual and semiannual components are largest in the southern part. The eccentricity of the internal tide is larger than the barotropic tide, but in general the currents are mostly rectilinear with no preferred sense of rotation. It is found that the barotropic currents are more energetic than the baroclinic currents. The most energetic component is the barotropic M2 component, followed by the Ssa, S2, and Sa harmonics. For the internal currents the energy levels of the M2, Ssa, and Sa harmonics are about the same, and are much larger than the rest of the constituents.
ARGOS drifters deployed in the Northern Gulf of California in September 1995 showed the presence of a cyclonic gyre, while a second deployment in March 1996 revealed an anticyclonic gyre. A circulation pattern consisting of a seasonally reversing gyre had been proposed before on the basis of satellite images, geostrophic calculations, and numerical models, but so far no direct observations have been made to test its existence. In September the gyre was cyclonic, baroclinic, very well defined, stable, and strong; its mean speed and rotation time were 0.3 m s-1 and ∼7 days. In March the gyre had the same mean speed, but it was anticyclonic and displaced to the northwest of the summer position. The March gyre has barotopic and baroclinic characteristics, but the observed speeds are stronger than in numerical simulations. These data and a data bank analysis suggest that the summer gyre is a persistent summer feature, but the winter-spring situation remains ill-defined and requires further research.
An improved description of the seasonal variability of the geostrophic circulation in the northern Gulf of California is obtained from a historical hydrographic database larger than in previous studies. The evolution of the geostrophic circulation consists of: a cyclonic (summer) period, an anticyclonic (winter) period and two transition periods. The cyclonic (summer) period lasts from June to September (four months) and is characterized by a strongly baroclinic cyclonic gyre which dominates the circulation. The anticyclonic (winter) period starts in November and persists until April (six months); the anticyclonic geostrophic circulation is less robust than that in summer. The transition periods take of the order of one month, occurring around October and April–May, and are characterized by the simultaneous presence of both types of gyres. Empirical Orthogonal Function analysis shows a strong seasonal signal in the dynamic height for the first mode (97·2% of the total variance), whose spatial structure is a closed gyre, which oscillates between cyclonic during the summer months and anticyclonic the rest of the year. The results strengthen and extend those from previous work based on analysis of hydrographic data, on limited direct observations, on satellite image analysis, and on numerical modelling.
Moored and hydrographic observations at the three most important sills in the northern Gulf of California (NGC) are used to describe the circulation. At the deepest San Esteban (SE) sill (600 m), the mean along-gulf flow is weak and outward (toward the mouth of the gulf) in the entire water column, whereas the mean deep flow is inward and bottom-intensified at the San Lorenzo (SL) sill (400 m), which controls the southern entrance to the Ballenas Channel (BC). However, large tidal currents (>1 m/s during spring tides) in the SE sill drive a net inward bottom transport of 0.09 Sv (1 Sv = 1 × 106 m3/s), due to a tidal pumping process. At the SL sill the net transport is also about 0.09 Sv, but here the mean flow contributes more than the tides and both are into the gulf. At the northern BC sill, which controls the northward entrance to the BC, the mean near-bottom flow is southward, implying that the bottom water of this deep basin is renewed at both of its ends. Moreover, the mean surface flow at both ends of the BC is out of the channel and, hence, the convergence at the bottom is compensated by a divergence at the surface, generating a persistent upwelling (~5 m/day) within the channel. This circulation pattern primarily explains why the BC has the coldest SST and is one of the most biologically productive basins in the Gulf of California.
A three-dimensional nonlinear baroclinic model is used to model the circulation in the Ballenas Channel, Gulf of California, México, which was inferred from current meter observations over three sills that surround the area. The suggested circulation consists of deep inflow that follows two paths: the first one is a direct spill of water through San Lorenzo sill into Ballenas Channel, the second one, a larger route that starts at San Esteban sill, then flows north of the island passing over Tiburón and Delfín basins, and then turns to the south reaching the North Ballenas Channel sill and then spills into Ballenas Channel. Following the latter result, a previous modeling effort to reproduce the circulation was partially obtained, the long path was not reproduced and it was believed that finer horizontal resolution was needed. In this work, the bathymetric resolution was increased by a factor of three and the full path of this deep circulation is now obtained and corroborated.