Streamflow modeling of five major rivers that flow into the Gulf of Mexico using SWAT

Determining hydrogeological properties of the rock materials that constitute an aquifer through stress tests or laboratory tests presents inherent complications. An alternative tool that has significant advantages is the study of the groundwater-level response as a result of the pore-pressure variation caused by the internal structure deformation of the aquifer induced by barometric pressure and solid Earth tide. The purpose of this study was to estimate the values of the physical/hydraulic properties of the geological materials that constitute the Guadalupe Valley Aquifer based on the analysis of the groundwater-level response to barometric pressure and solid Earth tide. Representative values of specific storage (1.27 × 10⁻⁶ to 2.78 × 10⁻⁶ m⁻¹), porosity (14–34%), storage coefficient (3.10 × 10⁻⁵ to 10.45 × 10⁻⁵), transmissivity (6.67 × 10⁻⁷ to 1.29 × 10⁻⁴ m²∙s⁻¹), and hydraulic conductivity (2.30 × 10⁻³ to 2.97 × 10⁻¹ m∙d⁻¹) were estimated. The values obtained are consistent with the type of geological materials identified in the vicinity of the analyzed wells and values reported in previous studies. This analysis represents helpful information that can be considered a framework to design and assess management strategies for groundwater resources in the overexploited Guadalupe Valley Aquifer.

In recent years, the recording of fish with vertebral malformations has attracted growing interest worldwide, as these malformations may be associated with exposure to xenobiotics. This study aimed to determine the presence and concentrations of pesticide residues (organochlorines and organophosphates) in coastal fish in Nayarit, Mexico, and to assess their potential association with vertebral malformations. From November 2013 to September 2021, 32 fish, with visible malformations were conveniently collected, an equal number of healthy specimens per species was selected for comparative analysis. The fish exhibited vertebral malformations of the following types: kyphosis, lordosis, and scoliosis in 9, 8 and 6 species, respectively, while the total number of malformations was higher across the sampled organisms. Furthermore, pesticide residues were detected in both healthy and malformed fish using gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). The samples analyzed contained at least one pesticide, with the group of healthy fish showing greater diversity of organochlorine compounds. The most frequent of these were p,p’-DDE, followed by p,p’-DDT (41%), p,p’-DDD (25%), and endrin (25%). The species C. raredonae and A. seemanni exhibited the greatest number of pesticides. The pesticides observed in malformed fish samples were p,p’-DDE (100%), p,p’-DDD (97%), p,p’-DDT (97%), endrin (50%), and BHC delta (31%). Chlorpyrifos was present (56% and 100% in healthy and malformed fish), with the highest frequency observed in A. seemanni and B. panamensis. The highest concentrations were observed in the DDT group. An association was also observed between vertebral malformations and concentrations of p,p’-DDE and chlorpyrifos in the species C. raredonae and A. guatemalensis. Multivariate analysis revealed a clear separation between malformed and healthy fish based on contaminant profiles.

Tropical cyclones can strongly perturb the upper ocean through intense wind stress, vertical mixing, Ekman pumping, sea surface cooling, and nutrient injection into the euphotic zone. These processes enhance phytoplankton biomass generation and produce delayed chlorophyll-a responses after storm passage. Here, we investigate the physical and biogeochemical response of the Eastern Tropical Pacific to Hurricane Norbert, a category 4 hurricane that crossed the Mexican Pacific in October 2008. We combine tropical cyclone best-track data from IBTrACS, ERA5 wind forcing, CROCO physical-biogeochemical simulations, satellite-derived sea surface temperature and chlorophyll-a products, and Argo float profiles located near the hurricane track. The results show that Norbert generated strong positive Ekman pumping, mixed-layer deepening, surface nitrate enrichment, and a delayed increase in chlorophyll-a concentration along portions of the storm trajectory. The model reproduced the main structure of sea surface temperature cooling more clearly than the chlorophyll-a response, indicating that the physical response was more directly controlled by hurricane forcing, whereas the biological response was modulated by nutrient availability, pre-existing stratification, light conditions, and regional circulation. Argo profiles confirmed post-storm changes in the vertical thermal structure and mixed-layer depth. These results indicate that major hurricanes in the eastern tropical Pacific can generate significant but spatially heterogeneous biogeochemical responses through the coupling between wind-driven mixing, nutrient entrainment, and phytoplankton growth.

Tropical cyclones can strongly perturb the upper ocean through intense wind stress, vertical mixing, Ekman pumping, sea surface cooling, and nutrient injection into the euphotic zone. These processes enhance phytoplankton biomass generation and produce delayed chlorophyll-a responses after storm passage. Here, we investigate the physical and biogeochemical response of the Eastern Tropical Pacific to Hurricane Norbert, a category 4 hurricane that crossed the Mexican Pacific in October 2008. We combine tropical cyclone best-track data from IBTrACS, ERA5 wind forcing, CROCO physical-biogeochemical simulations, satellite-derived sea surface temperature and chlorophyll-a products, and Argo float profiles located near the hurricane track. The results show that Norbert generated strong positive Ekman pumping, mixed-layer deepening, surface nitrate enrichment, and a delayed increase in chlorophyll-a concentration along portions of the storm trajectory. The model reproduced the main structure of sea surface temperature cooling more clearly than the chlorophyll-a response, indicating that the physical response was more directly controlled by hurricane forcing, whereas the biological response was modulated by nutrient availability, pre-existing stratification, light conditions, and regional circulation. Argo profiles confirmed post-storm changes in the vertical thermal structure and mixed-layer depth. These results indicate that major hurricanes in the eastern tropical Pacific can generate significant but spatially heterogeneous biogeochemical responses through the coupling between wind-driven mixing, nutrient entrainment, and phytoplankton growth.

Tropical cyclones can strongly perturb the upper ocean through intense wind stress, vertical mixing, Ekman pumping, sea surface cooling, and nutrient injection into the euphotic zone. These processes enhance phytoplankton biomass generation and produce delayed chlorophyll-a responses after storm passage. Here, we investigate the physical and biogeochemical response of the Eastern Tropical Pacific to Hurricane Norbert, a category 4 hurricane that crossed the Mexican Pacific in October 2008. We combine tropical cyclone best-track data from IBTrACS, ERA5 wind forcing, CROCO physical-biogeochemical simulations, satellite-derived sea surface temperature and chlorophyll-a products, and Argo float profiles located near the hurricane track. The results show that Norbert generated strong positive Ekman pumping, mixed-layer deepening, surface nitrate enrichment, and a delayed increase in chlorophyll-a concentration along portions of the storm trajectory. The model reproduced the main structure of sea surface temperature cooling more clearly than the chlorophyll-a response, indicating that the physical response was more directly controlled by hurricane forcing, whereas the biological response was modulated by nutrient availability, pre-existing stratification, light conditions, and regional circulation. Argo profiles confirmed post-storm changes in the vertical thermal structure and mixed-layer depth. These results indicate that major hurricanes in the eastern tropical Pacific can generate significant but spatially heterogeneous biogeochemical responses through the coupling between wind-driven mixing, nutrient entrainment, and phytoplankton growth.