Effects of mesoscale processes on phytoplankton chlorophyll off Baja California

Using satellite sea surface height (SSH) and chlorophyll (CHL), the year 2000 is analyzed to characterize the effects of mesoscale circulation patterns on phytoplankton spatial variability in the California Current (CC) off Baja California. Satellite data are combined with and compared to in situ field measurements (chlorophyll-a and hydrographic variables) along vertical alongshore sections located similar to 130 km offshore between similar to 24.5 degrees -33 degrees N. Monthly average maps of SSH and surface geostrophic velocities depict the characteristics of mesoscale meanders and eddies, which correspond well with the subsurface hydrographic and velocity fields. Satellite-derived pigment (CHL) represent in situ fields in the upper 0-20 m (overall r = 0.53; p < 0.05), but their representation of peak values in Deep Chlorophyll Maxima (DCM) at similar to 50 m depth are inaccurate. DCM are traced in all three seasons (January-July), descending from near the surface (north of 31 degrees N) to 50 m over a large extent of the transect to the south, approximately following the 24.7-25.1 isopycnals as they and the isotherms deepen to the south. In January, phytoplankton chlorophyll concentrations in the DCM are relatively uniform, originating during upwelling events that occur farther north, then following the equatorward flow of the CC. During April and July, the discrete maxima in the DCM occur at the centers of cyclonic meanders and the chlorophyll concentrations inside these maxima are enhanced as a result of local coastal upwelling off Baja California. Phytoplankton blooms created by coastal upwelling spread offshore and subduct along the 24.7-25.1 isopycnals, creating the DCM along the inner part of the meandering jet.KEYWORDS: Current system, Satellite, Pigment, State, Temperature, El Nino, Salinity, Evolution, Interannual variability, Coastal transition zon

Seasonal and interannual variability of satellite-derived chlorophyll pigment, surface height, and temperature off Baja California

Mean fields, seasonal cycles, and interannual variability are examined for fields of satellite-derived chlorophyll pigment concentrations (CHL), sea surface height (SSH), and sea surface temperature (SST) during 1997–2002. The analyses help to identify three dynamic regions: an upwelling zone next to the coast, the Ensenada Front in the north, and regions of repeated meanders and/or eddy variability west and southwest of Point Eugenia. High values of CHL are found in the upwelling zone, diminishing offshore. The exception is the area north of 31°N (the Ensenada Front), where higher CHL are found about 150 km offshore. South of 31°N, the long-term mean dynamic topography decreases next to the coast, creating isopleths of height parallel to the coastline, consistent with southward geostrophic flow. North of 31°N the mean flow is toward the east, consistent with the presence of the Ensenada Front. The mean SST reveals a more north-south gradient, reflecting latitudinal differences in surface heating due to solar radiation. Harmonic analyses and EOFs reveal the seasonal and interannual patterns, including the region of repeated eddy activity to the west and southwest of Point Eugenia. A maximum CHL occurs in spring in most of the inshore regions, reflecting the growth of phytoplankton in response to the seasonal maximum in upwelling-favorable winds. SST and SSH anomalies are negative in the coastal upwelling zone in spring, also consistent with a response to the seasonal maximum in upwelling. When the seasonal cycle is removed, the strongest signal in the EOF time series is the response to the strong 1997– 1998 El Niño, with a weaker signal representing La Niña (1998–1999) conditions. El Niño conditions consist of low chlorophyll, high SSH, and high SST, with opposite conditions during La Niña

Atmosphere-ocean CO2 flux in the Gulf of California, Navachiste, Sinaloa

The CO2 fluxes were obtained in front of Navachiste Coastal System, Sinaloa in March 2017, a board a little ship from Laboratorio de Productividad Primaria y Sistema del Carbono (IPN-LPPSC)

<b>Chlorophyll-a, nutrients, sea surface temperature and salinity, off Campeche, Mexico</b>

Data from four oceanographic surveys were carried out from October 2017 to June 2018, to analyze the Sea Surface Temperature (SST), Sea Surface Salinity (SSS), Chlorophyll-a (Chla), and nutrients, such as Dissolved Inorganic Nutrients (DIN [NO3-+ NO2-+NH4+]), Total Nitrogen (TN), Total Phosphorous (TP) and SiO2, off Campeche, Mexico.</p

Atmosphere-ocean CO2 flux in the Gulf of California

The CO2 fluxes were obtained in three cruises in RV Mexican Navy Altair in September 2016 in Navachiste, Sinaloa and Guaymas, Sonora in the Gulf of California

Morphophysiological status of the yellow snapper Lutjanus argentiventris (Peters, 1869) in the Macapule Lagoon (Gulf of California, Mexico) in 2013-2015

In December 2013, June and December 2014, and July 2015, a total of 123 specimens of L. argentiventris were captured in the Macapule Lagoon with gillnets of 50 mm mesh size. The total length and weight of each specimen were recorded. The liver, stomach, and gutted weight were weighed to the nearest gram (g) and the data used to calculate the following morpho-physiological indices: 1) the Fulton's condition factor (CF) using the equation: CF = W~t~/L~t~3 * 100, where W~t~ = total weight and L~t~ = total length; 2) the hepatosomatic index (HSI) using the equation: HSI = W~h~/W~t~*100, where W~h~ = liver weight and W~t~ = total weight of the individual; and 3) the gastric repletion index (GRI) using the equation GRI = W~s~/W~t~ *100, where W~s~ = stomach weight and W~t~ = total weight. Parameters of the length-weight relationship of L. argentiventris were estimated using the equation: W = aL^b^, where W = weight of the fish (g), L = total length (cm), a = y-intercept or the initial growth coefficient, b = slope or the growth coefficient. Blood samples of 1±0.1 mL were extracted (only of fish larger than 10 cm total length) by caudal puncture with a disposable plastic syringe containing 0.5 mL of heparinized solution (Sigma-Aldrich). The blood samples were centrifuged at 9,500 g at 4ºC during 10 minutes to separate the blood cells from the plasma. Total protein concentrations were determined following Bradford's method (1976), which is based on the reaction of the amino groups with the dye Coomassie Blue G-250. Triglycerides, glucose, and cholesterol concentrations were determined with colorimetric commercial kits Randox, U.K (Apún-Molina et al., 2015);. Absorbance was determined with a microplate reader (Multiskan Go, Thermo Scientific UV, United States) and concentrations were calculated from a standard solution of substrates

Physicochemical measurements in the Macapule Lagoon (Gulf of California, Mexico) in 2013-2015

The Macapule Lagoon (25º 21' and 25º 24' N; 108º 30' and 108º 45' W) is part of the San Ignacio-Navachiste-Macapule lagoon system, located in the southern region of the Gulf of California (Fig. 1). In 2000, it has been declared an "Area of Reserve and Refuge for Migratory Birds and Wildlife – Gulf of California Islands". This lagoon is very productive due to its location in the Gulf of California (Lluch-Cota et al. 2007). Water temperature, dissolved oxygen, pH, and salinity were measured in situ with an YSI (55-12FT) probe and a portable refractometer (RHS-10ATC). Nutrient (nitrate, ammonium, and phosphate) concentrations were determined in the laboratory during each sampling month using a photometer (YSI, 9500)