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-Location of Gulf of California (A) and Bay of La Paz (B) with sampling stations and transect. Bathymetry (thin gray line) is showed in meter.
Source publication
Internal waves in the Bay of La Paz, southern Gulf of California, Mexico, are evidenced by variations in vertical profiles of chlorophyll-a and temperature, which showed vertical displacements between down-up cast profiles, and by satellite images. The maximum peaks in the natural fluorescence of chlorophyll-a and the thermocline depth were used to...
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... Bay of La Paz is situated in the eastern portion of the Baja California peninsula; it is the biggest basin within the GC and is one of the most important ecosystems due to its high biodiversity and productivity (Durán-Cam- pos et al. 2019) (Fig. 1). It connects with the GC through Boca Grande in the northern portion and San Lorenzo Channel in the southeast margin (Fig. 1). The bathymetry shows, at the central portion, a region with a maximum depth of 420 m in Alfonso Basin, which decreases gradually to the south. An important feature in the study area is the presence of a ...
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... situated in the eastern portion of the Baja California peninsula; it is the biggest basin within the GC and is one of the most important ecosystems due to its high biodiversity and productivity (Durán-Cam- pos et al. 2019) (Fig. 1). It connects with the GC through Boca Grande in the northern portion and San Lorenzo Channel in the southeast margin (Fig. 1). The bathymetry shows, at the central portion, a region with a maximum depth of 420 m in Alfonso Basin, which decreases gradually to the south. An important feature in the study area is the presence of a bathymetric sill along Boca Grande with ~250 m depth (Molina-Cruz et al. 2001). According to Lavín et al. (2009), the water masses ...
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... this study, we use information gathered during the research cruise "PALEo-xII" onboard the R/v "El Puma" of the National Autonomous university of Mexico during summer 2004 (June 10 to 19) in the Bay of La Paz. Six fixed stations were selected inside the bay, representing the bathymetric gradient in the area (Fig. ...
Citations
... This particular geomorphology, as a whole, constantly modifies the gulf's water circulation, promoting mixing, which fertilizes the euphotic zone and enhances productivity (Álvarez-Borrego 2012). The gulf also exhibits complex hydrodynamic processes, including strong tidal mixing and fronts (Lavin & Marinone 2003) and the occurrence of mesoscale eddies (Salas de León et al. 2011), and internal waves (Coria-Monter et al. 2019b). These processes have been related to the induction of nutrients into the euphotic zone with a noticeable impact on whole planktonic ecosystems. ...
In 2014, an unexpected and unusual warm patch of ocean water was discovered in the northeast Pacific Ocean (PO) that moved south, reaching the Mexican coasts; this patch, returning in 2019, was nicknamed "the Blob". This paper aimed to assess the impacts of this phenomenon on the sea surface temperature (SST) and chlorophyll-a (CHLA) levels in the Gulf of California (GC), a high-productivity region. Daily satellite images of SST and CHLA with a spatial resolution of 1 km/pixel were obtained for 2014, 2017, and 2019 from the Moderate Resolution Imaging Spectroradiometer (MODIS). Two disc-shaped areas of around 25 km in diameter were selected in the southern portion of the GC to assess the variability of both parameters quantitatively. An additional site was selected in the PO for comparison and, thus, to better characterize and have a complete vision of these events. The results showed that in the PO, during the periods in which the Blob occurred, the SST values were higher concerning the neutral year (2017), and the levels of CHLA were very low (barely 0.15 mg m-3). Within the GC, the results showed the presence of a strong seasonal variability, with maximum values of SST (>30°C) and the lowest concentrations of CHLA (<2 mg m-3) during the summer, with maximum concentrations of CHLA (~10 mg m-3) observed during the winter months. Contrary to expectations, no dramatic changes in SST and CHLA were observed during the years impacted by the Blob. This apparent absence of negative impacts could be related to different mechanisms in the gulf that "protect" to avoid climate disruptions. The presence of complex geomorphology and hydrodynamic processes at different scales induce mixing and fertilizing of the euphotic layer. Could these factors protect the southern gulf from the negative impacts of the Blob?
... Bahía de La Paz presents a variety of oceanographic processes that affect NPP, such as vortices and hydraulic jumps, which operate on different spatio-temporal scales [18,19] and affect organisms from plankton to marine mammals [20,21]. According to Verdugo-Diaz [22], the average NPP in BLP is relatively high (350 g C m −2 year −1 ). ...
... In addition, meteorological events (e.g., tropical cyclones, and climatic phenomena) in BLP that affect ecological cycles [23,24] also affect NPP. These include El Niño events [25] and the recently identified large mass of relatively warm water in the Pacific Ocean off the coast of North America, known as "The Blob" [19] also affect NPP. ...
... The Blob was an anomalously warm water mass (∼500 km wide and 90 m deep) that developed in the northwest Pacific and spread southward, persisting through 2014 and 2015 [64][65][66][67]. The Blob caused anomalous heating in the study area from the end of 2013 until 2016, although it ended in 2015 due to the presence of the ENSO of 2015-2016 [19]. Similarly, the results of the RSD seemed to indicate that the BLP entered a warm phase that lasted for several years, beginning at the end of 2013 with the presence of The Blob that was followed by the ENSO event. ...
The use of information of net primary productivity (NPP) from remote ocean color sensors is increasingly common in marine sciences. The resulting information has been used to explain variations in productivity at different spatio-temporal scales and in the presence of climate phenomena, such as the El Niño Southern Oscillation, and global warming. Satellite remote sensing data were analyzed in Bahía de La Paz (BLP), Mexico, to determine the spatio-temporal variation in NPP. In addition, in situ hydrographic data were obtained to characterize the water properties in the bay. The satellite data agree with in situ measurements, validating the satellite observations over this region. The NPP generally presented seasonal variation with maximum values in winter-spring and minimum values in summer–autumn. The variance explained by NPP from the measured variables was ranked as Chl-a < DEN < SST < PAR < WSC. The highest NPP values generally occurred when subtropical subsurface (SsStW) water was relatively shallow. Due to divergence and mixing processes, this water provided nutrients to the euphotic zone, and consequently an increase in NPP and changes in plankton biomass were observed. The annual trends of the variation in hydrographic data with respect to that of remote sensing data were similar; however, it is necessary to increase the number of data validation studies. The remote sensing and in situ measurements allowed for the main biophysical variables that modulate NPP in different time scales to be identified. The satellite-derived NPP data classifies the BLP as a high productivity zone with 432 g C m−2 year−1. The use of satellite NPP data is satisfactory and should be incorporated into marine primary productivity studies.
... This region has been characterized as highly dynamic, mainly due to the confluence of oceanographic processes that are present inside the basin at different scales and induce mixing within the water column and enhance the nutrient concentration in the euphotic layer, thus inducing high levels of CHLA. This process involves internal waves [10] and mesoscale cyclonic eddies [11], which in turn regulate the biological productivity in the region, particularly that of phytoplankton. ...
... The bay and the gulf are connected through two openings, with different dynamics; in the north, the Boca Grande is the main source of exchange for surface waters between the gulf and the bay because it is wide and deep, while in the southern part of the bay, the San Lorenzo channel joins the bay to the gulf through a shallow and narrow opening. The bay reaches its maximum depth (420 m) in the central area, in a marginal basin named the Alfonso Basin, which is highly dynamic due to the oceanographic processes that occur there, including internal waves and the presence of a quasipermanent cyclonic eddy [10,11]. This region is also highly dynamic in terms of its seasonal pattern of winds, with the prevalence of high velocity (>10 m s -1 ) and persistent northwesterly winds during the winter, and the occurrence of low wind speed conditions (<5 m s -1 ) associated with frequent calm periods during the summer [17]. ...
As the pigment present in all photosynthetic phytoplankton species, chlorophyll-a (CHLA) is the most common indicator of the phytoplankton biomass in any aquatic ecosystem, and thus the quantification of its seasonal variability is key to understanding the dynamics of the marine ecosystem. Based on in-situ observations systematically gathered during four seasons in different years, this paper reports the surface CHLA concentrations in the central part of the Bay of La Paz, Gulf of California, Mexico. The in-situ data are compared and supported by satellite observations at 1 km/pixel of resolution from the Moderate Resolution Imaging Spectroradiometer. The results show clear seasonal variability, with the highest values recorded during winter time, while the lowest values were recorded during summer. Spring and fall represented seasons of transition. Satellite observations were consistent with the variability observed in in-situ data. The seasonal variability observed could be related to different mechanisms including the local atmospheric forcing, which induces wind-driven mixing and changes in the heating/cooling of the water column. The results presented here contribute to our understanding of the phytoplankton population dynamics in the Bay of La Paz, a highly productive region that supports different species with great importance both ecologically and economically.
An evaluation of the vertical distribution of chlorophyll-a (Chl-a) levels, as an indicator of phytoplankton biomass, has strong repercussions in any marine ecosystem since it allows evaluating its productive potential and the amount of matter that is available for the higher trophic levels of the pelagic food web. This short communication aims to report the vertical distribution patterns of Chl-a levels and some selected hydrographic parameters during autumn in the Bay of La Paz, the biggest and deepest coastal environment inside the Gulf of California, a site also recognized for its high biodiversity. Two oceanographic research cruises were carried out during November 2014 and 2016. A CTD probe configured with dissolved oxygen and active fluorescence sensors, all pre-calibrated by the manufacturer, was used to acquire high-resolution data along the water column. The results showed two distribution patterns of Chl-a: 1) deep peaks (>60 m depth, with concentrations >6 mg m-3) associated with the bottom at nearshore stations, and 2) maximum concentration peaks associated with the thermocline/pycnocline with concentrations up to 7.40 mg m-3 observed at deep stations. A multivariate statistical analysis confirmed the role played by some physical variables in the distribution patterns described. The results shown in this study complement the previous research and fill in the existing gaps for the transition periods between the warm and the cold.
