Mexico Waters Research Articles

Abundance, distribution, and fluxes of dissolved organic carbon (DOC) in four small sub-tropical rivers of the Tampa Bay Estuary (Florida, USA)

The delivery of organic carbon (C) from rivers to the coastal ocean via estuaries is recognized as an important component of the global C budget however, smaller river systems are often overlooked and modern flux estimates are not very different from historical estimates. Here, the seasonal (wet vs. dry) concentration and fluxes of dissolved organic C (DOC) were measured in five small sub-tropical rivers that drain into the Tampa Bay (FL, USA) estuary. DOC distributions were highly variable among riverine, mesohaline, and marine end-member samples in all river catchments and no significant differences were observed among or between DOC concentrations with respect to river catchment, season, or year of sampling. In general, DOC mixed non-conservatively during the wet seasons, and conservatively during the dry seasons, with the estuarine reaches of each river serving as a sink of DOC. Fluxes were strongly tied to discharge irrespective of season, and the estuaries removed 15–65% of DOC prior to export to coastal Bay and Gulf of Mexico waters. DOC concentrations were similar to others reported for low-elevation sub-tropical rivers, and a combination of elevation, residence time, and climate appear to control the abundance and variability of DOC in sub-tropical vs. tropical river systems. The characterization of DOC in small, sub-tropical rivers, which share characteristics with both their temperate and tropical counterparts, is critical for quantitatively constraining the importance of these systems in local-to-regional scale ocean C budgets. In addition to geomorphic properties, the role of past, present, and future land cover and other environmental change in small coastal rivers also exerts control on the quantity and flux of DOC in these systems.

Agua embotellada en México: de la privatización del suministro a la mercantilización de los recursos hídricos

Recently, the human right to water paradigm has brought along heated debates with regards to the vital liquid’s marketization. In an era when drinking water supply for human consumption is under serious threat due to climatic change, when the world debate is centred on topics of water (in) security, it comes as a surprise that bottled water consumption in Mexico has had such an exponential growth, given its position as one of the countries with the highest degree of water insecurity worldwide. In this article, I present an analysis of the process of privatization of water supply in Mexico, focusing specifically on the extraction, bottling and distribution of bottled water. Using the policy regime framework as an analytical tool, in the article I show that growing consumption of bottled water in Mexico is the result of the convergence of specific ideas with regards to tap water drinkability, a weakened institutional structure that yields against the enormous pressure of multinational bottled water supply companies, and the huge strength both marketing-wise and politically-wise that water bottling corporations are able to harness. The analysis presented here shows that academic discussions on privatization of water supply in Mexico have put aside the enormous growth of bottled water as a business, with the resulting marketization of water resources.

Data Availability for Red Snapper in Gulf of Mexico and Southeastern U.S. Atlantic Ocean Waters

AbstractRed Snapper Lutjanus campechanus populations support (or have supported) important commercial and recreational fisheries in Gulf of Mexico and southeastern U.S. Atlantic Ocean waters. Stock assessment results and related regulatory actions are contentious in both regions. We assessed the relative availability of information to support Red Snapper assessment and management between the two regions by performing a literature review and comparing the number of region‐specific, Red Snapper–focused peer‐reviewed publications. One hundred and ten publications (over the period 1982–2013) were identified in this search, with 94% focused on Gulf of Mexico waters. We then assessed the available information on juvenile (≤150 mm total length) Red Snapper. Twenty‐eight peer‐reviewed publications focused entirely or partially on juvenile Red Snapper in Gulf of Mexico waters. None documented the occurrence of juvenile Red Snapper in southeastern U.S. Atlantic Ocean waters. For the Gulf of Mexico, more than 50,000 records of juvenile Red Snapper were identified in a single trawl survey database. For southeastern U.S. Atlantic Ocean waters, a comprehensive search of fishery‐independent survey databases (totaling >75,000 individual gear deployments and occurring across the range of habitats, depths, and seasons in which juvenile Red Snapper were collected in the Gulf of Mexico trawl survey) and institutional collections identified only 132 records of juvenile Red Snapper. These results highlight the need for additional information on Red Snapper in southeastern U.S. Atlantic Ocean waters and on the connectivity between Gulf of Mexico and southeastern U.S. Atlantic Ocean Red Snapper populations to support Red Snapper population assessment and fishery management.Received August 6, 2014; accepted November 13, 2014

Abundance and variety of birds associated with point sources of water in southwestern New Mexico, U. S. A.

Developed waters may improve arid landscapes for birds, but their efficacy requires further study. I counted birds along five 300-m transects originating at point sources of water in a New Mexico grassland, and compared results with those from transects without water. Total birds were nearly three times more abundant on transects with water, but differences were greater in spring and winter than during the wet summer period. Twenty-two of 25 common species trended toward greater abundance on transects with water, eight of these at statistically significant levels, including Gambel's Quail, Mourning Dove, House Finch, and a variety of wintering sparrows. Sixty-four percent of detections along transects with water occurred <50 m from the water sources, at which birds regularly drank. Results suggest 1) that water attracted birds, especially in dry seasons, and 2) that proximity to water may influence the abundance and composition of avian assemblages in arid landscapes.

The price Texas pays for Mexico’s water debt

The Lower Rio Grande Valley of Texas is not only a cultural gem but also a significant contributor to our state’s economy. Since the region is largely dependent upon the Rio Grande for its water supply, it is critical that those states and nations with which we share common borders comply with state, federal, and international agreements regarding the river. Since the early 1990s, Mexico has consistently failed to meet its obligations to the treaty signed in 1944 that allocates waters in the lower reach of the Rio Grande. Mexico’s repeated failure to comply with the treaty has caused severe economic hardship to Texas communities and farmers. Despite numerous efforts, Mexico continues to resist entering into a productive discussion and commitment to honor the treaty. A meaningful resolution to this issue will require active participation from the U.S. Department of State, the White House, and Texas officials. Citation: Rubinstein C. 2015. The price Texas pays for Mexico's water debt. Texas Water Journal. 6(1):1-10. Available from: https://doi.org/10.21423/twj.v6i1.7015.

Population Genetic Structure of Spotted Eagle Rays,Aetobatus narinari,off Sarasota, Florida and the Southeastern United States

The Spotted Eagle Ray, Aetobatus narinari, is a semi-pelagic myliobatoid recognized as near threatened by the World Conservation Union. A decreasing population trend, K-selected life history, and primarily inshore, coastal habitat renders this species susceptible to over-exploitation by targeted fisheries, drift netting, and capture as bycatch. Recent molecular investigations and subsequent taxonomic recognition as a species complex have left a large deficiency in current knowledge of A. narinari and a complete absence of data concerning population structure and genetic health for the northwestern Atlantic Ocean. Our study is the first to examine fine-scale structure on a regional basis in the Gulf of Mexico and coastal Atlantic waters off the United States. Individuals sampled non-invasively from four sites, Sarasota, FL (n = 143), the Everglades, FL (n = 36), Ft. Pierce, FL (n = 8), and the southeastern U.S. Atlantic coast (n = 24), were genotyped across eight microsatellite loci. Standard tests...

Primer registro del pez de aguas profundas Harriotta raleighana (Chondrichthyes: Rhinochimaeridae) en la costa de Jalisco, Pacífico mexicano

This is the first record of the deep-sea fish Harriotta raleighana, known as longnosed chimaera, in the south of Bahía de Banderas, Jalisco, in the Central Mexican Pacific. Deep waters, up to more than a 1 000m, characterize the south of this bay. The collected specimen is probably a female, which was found dead floating in the surface of the water, a few meters from the beach. Reports about this species in the Mexican Pacific are sporadic, and collected accidentally, or recently, by using submersibles. This species has a worldwide distribution in deep-sea areas of template waters. In the Pacific it is distributed in California, although it has been observed in the Gulf of California and in the tropical waters of Mexico the only previous report southern of Jalisco was close to Manzanillo, Colima in 2007. Measurements and biological data, which allow the comparison with other specimens found in Mexico, are included.

Public Participation in Mexico's Water Management … or Not?

Public Participation in Mexico's Water Management … or Not?

Reproductive biology of &lt;I&gt;Mugil curema&lt;/I&gt; and &lt;I&gt;Mugil cephalus&lt;/I&gt; from western Gulf of Mexico waters

The present study examined variation in sex ratio (SR), fecundity, gonadosomatic index (GSI), condition index (K), and weight-length relationship in white mullet, Mugil curema (Valenciennes, 1836), and striped mullet, Mugil cephalus (Linnaeus, 1758) collected from eight locations in western Gulf of Mexico waters. Fish were sampled from commercial mullet fishers during two consecutive fishing seasons (November�March), beginning in 2008. Significant male- and female-dominance was detected for both species depending on location, with greater female dominance for white mullet and male dominance for striped mullet. In general, geographic differences in relative fecundity, GSI, and K in the present study were minor. However, several of these values were lower than values previously reported for the same study region from the early 1990s. We suggest that the differences may be related to increases in commercial fishing intensity.

Deepwater Horizon oil in Gulf of Mexico waters after 2 years: transformation into the dissolved organic matter pool.

Recent work has shown the presence of anomalous dissolved organic matter (DOM), with high optical yields, in deep waters 15 months after the Deepwater Horizon (DWH) oil spill in the Gulf of Mexico (GOM). Here, we continue to use the fluorescence excitation-emission matrix (EEM) technique coupled with parallel factor analysis (PARAFAC) modeling, measurements of bulk organic carbon, dissolved inorganic carbon (DIC), oil indices, and other optical properties to examine the chemical evolution and transformation of oil components derived from the DWH in the water column of the GOM. Seawater samples were collected from the GOM during July 2012, 2 years after the oil spill. This study shows that, while dissolved organic carbon (DOC) values have decreased since just after the DWH spill, they remain higher at some stations than typical deep-water values for the GOM. Moreover, we continue to observe fluorescent DOM components in deep waters, similar to those of degraded oil observed in lab and field experiments, which suggest that oil-related fluorescence signatures, as part of the DOM pool, have persisted for 2 years in the deep waters. This supports the notion that some oil-derived chromophoric dissolved organic matter (CDOM) components could still be identified in deep waters after 2 years of degradation, which is further supported by the lower DIC and partial pressure of carbon dioxide (pCO2) associated with greater amounts of these oil-derived components in deep waters, assuming microbial activity on DOM in the current water masses is only the controlling factor of DIC and pCO2 concentrations.

Acute aquatic toxicity studies of Gulf of Mexico water samples collected following the Deepwater Horizon incident (May 12, 2010 to December 11, 2010)

The potential for the Deepwater Horizon MC-252 oil incident to affect ecosystems in the Gulf of Mexico (GOM) was evaluated using Americamysis bahia, Menidia beryllina and Vibrio fischeri (Microtox® assay). Organisms were exposed to GOM water samples collected in May–December 2010. Samples were collected where oil was visibly present on the water surface or the presence of hydrocarbons at depth was indicated by fluorescence data or reduced dissolved oxygen. Toxicity tests were conducted using water-accommodated fractions (WAFs), and oil-in-water dispersions (OWDs). Water samples collected from May to June 2010 were used for screening tests, with OWD samples slightly more acutely toxic than WAFs. Water samples collected in July through December 2010 were subjected to definitive acute testing with both species. In A. bahia tests, total PAH concentrations for OWD exposures ranged from non-detect to 23.0μgL−1, while WAF exposures ranged from non-detect to 1.88μgL−1. Mortality was >20% in five OWD exposures with A. bahia and three of the WAF definitive tests. Total PAH concentrations were lower for M. beryllina tests, ranging from non-detect to 0.64μgL−1 and non-detect to 0.17μgL−1 for OWD and WAF exposures, respectively. Only tests from two water samples in both the WAFs and OWDs exhibited >20% mortality to M. beryllina. Microtox® assays showed stimulatory and inhibitory responses with no relationship with PAH exposure concentrations. Most mortality in A. bahia and M. beryllina occurred in water samples collected before the well was capped in July 2010 with a clear decline in mortality associated with a decline in total PAH water concentrations.

Multidecadal Evidence of Recovery of Nearshore Red Drum Stocks off West‐Central Florida and Connectivity with Inshore Nurseries

AbstractThe importance of defining and quantifying ontogenetic movements and connectivity between juvenile and adult fish populations, especially for exploited species, has been well documented. Furthermore, the persistence of strong year‐classes can be used to track the success of regulations that contribute to the increased survival and escapement of fish into the adult population. Size and age structures of Red Drum Sciaenops ocellatus were documented within the Tampa Bay estuary, in southwest Florida, using haul seines and trammel nets (1989–2008), and in nearshore Gulf of Mexico waters using a commercial purse seine (2005–2008). In the estuary, juvenile Red Drum (&lt;100‐mm TL) were collected from low‐salinity backwater areas, and peaks in the annual relative abundance were apparent. In the estuary, Red Drum older than age 4 (&gt;800‐mm TL) were rare. Red Drum from nearshore gulf waters ranged from 2 to 35 years of age (674–1,074‐mm TL), but most were greater than age 4. After back‐calculating ages from Red Drum collected in the estuary and in nearshore gulf waters, we found that specific year‐classes of Red Drum, driven by strong juvenile recruitment, were disproportionately represented in the adult spawning stock. We evaluated the long‐term effectiveness of fishing regulations as a tool for rebuilding local adult Red Drum stocks by comparing data on size and age structures with results from earlier research conducted in the same geographic area. Adult Red Drum in nearshore waters off Tampa Bay were significantly longer, heavier, and older than were individuals collected a decade earlier, suggesting rebuilding of local Red Drum stocks. These observations validate the utility of long‐term, multigear monitoring efforts to track populations from the estuary to nearshore coastal waters.Received June 27, 2013; accepted April 1, 2014

Skistodiaptomus pallidus (Copepoda: Diaptomidae) establishment in New Zealand natural lakes, and its effects on zooplankton community composition

The North American calanoid copepod Skistodiaptomus pallidus is an emerging invader globally, with non-indigenous populations recorded from constructed waters in New Zealand, Germany and Mexico since 2000. We examined the effects of S. pallidus establishment on the zooplankton community of a natural lake, Lake Kereta, where it was first recorded in late-2008, coincident with releases of domestically cultured grass carp (Ctenopharyngodon idella) . Although not present in any of our samples prior to August 2008, S. pallidus was found in all samples collected in the subsequent five years. ANOSIM indicated zooplankton community composition significantly differed between samples collected before and after S. pallidus invasion, whether the invader was included in the analysis or not. Zooplankton species affected most greatly were the copepods Calamoecia lucasi and Mesocyclops sp., which decreased in their relative importance, and the cladocerans Bosmina meridionalis and Daphnia galeata, which increased. Rotifer species were relatively unaffected. As the length of grass carp released were >6.5 cm, direct predatory effects by this species on the zooplankton community are unlikely. Associated reductions in macrophyte biomass could explain increases in the relative abundances of planktonic cladocerans (B. meridionalis and D. galeata). However, the effect of macrophyte reduction by grass carp on zooplankton communities is considered to be limited elsewhere, while the reduced macrophyte biomass cannot explain the decrease in relative abundance of the native planktonic calanoid copepod C. lucasi. Competition between C. lucasi and S. pallidus is the most compelling explanation for the reduction in importance of the native calanoid copepod species. Skistodiaptomus pallidus appears to have undergone a “boom-and-bust” cycle in Lake Kereta, increasing in relative abundance in the first three years following establishment, before declining in importance.

Solar production of singlet oxygen from crude oil films on water

Abstract Photochemical production of singlet oxygen from thin oil films over seawater and pure water was measured with furfuryl alcohol as a selective chemical probe. Oil was collected from the surface of the Gulf of Mexico following the deepwater horizon spill and from other sources. The loss of furfuryl alcohol and the formation of 6-hydroxy(2H)pyran-3(6H)-one were monitored. Total singlet oxygen formation was studied using high furfuryl alcohol concentrations and varying exposure time. The total amount of singlet oxygen produced in 1 h irradiations of thin oil films (100 mg, 60 microns thick) over Gulf of Mexico water and pure water were 1.9 ± 0.4 × 10−5 and 1.6 ± 0.3 × 10−5 mol, respectively. After initial tests were performed, titanium dioxide (TiO2) nanomaterials were added to the system in two different concentrations to study the effects of singlet oxygen formation in the presence of a photocatalyst. The addition of TiO2 nanoparticles did not significantly change the observed formation rate of singlet oxygen. Steady state concentrations of photoproduced singlet oxygen were also determined and found to be near 1 × 10−12 M in water under thin films of oil, which is considerably greater than values previously observed for pure seawater. This study illustrates that oil is a source of singlet oxygen when exposed to sunlight. The fate of oil and other dissolved species will be heavily dependent on the formation and reaction of singlet oxygen in thin oil films on water.

A survey of deepwater horizon (DWH) oil-degrading bacteria from the Eastern oyster biome and its surrounding environment.

The deepwater horizon (DWH) accident led to the release of an estimated 794,936,474 L of crude oil into the northern Gulf of Mexico over an 85 day period in 2010, resulting in the contamination of the Gulf of Mexico waters, sediments, permeable beach sands, coastal wetlands, and marine life. This study examines the potential response of the Eastern oyster’s microbiome to hydrocarbon contamination and compares it with the bacterial community responses observed from the overlaying water column (WC) and the oyster bed sediments. For this purpose, microcosms seeded with DWH crude oil were established and inoculated separately with oyster tissue (OT), mantle fluid (MF), overlaying WC, and sediments (S) collected from Apalachicola Bay, FL, USA. Shifts in the microbial community structure in the amended microcosms was monitored over a 3-month period using automated ribosomal intergenic spacer region analysis, which showed that the microbiome of the OT and MF were more similar to the sediment communities than those present in the overlaying WC. This pattern remained largely consistent, regardless of the concentration of crude oil or the enrichment period. Additionally, 72 oil-degrading bacteria were isolated from the microcosms containing OT, MF, WC, and S and identified using 16S ribosomal RNA gene sequencing and compared by principal component analysis, which clearly showed that the WC isolates were different to those identified from the sediment. Conversely, the OT and MF isolates clustered together; a strong indication that the oyster microbiome is uniquely structured relative to its surrounding environment. When selected isolates from the OT, MF, WC, and S were assessed for their oil-degrading potential, we found that the DWH oil was biodegraded between 12 and 42%, under the existing conditions.

Florida Gulf Bay Scallop (Argopecten Irradians Concentricus) Population Genetic Structure: Form, Variation, and Influential Factors

Knowledge of changes in the interdependence of a species' populations for continued existence (connectivity) and of the forces driving connectivity patterns is critical for management and conservation of the species. Population genetics can be used to investigate population connectivity. Combining population genetics with climatic, environmental, and biological (external) factors that can influence population structure and connectivity can lead to a greater understanding of the forces influencing population dynamics. We deciphered the population genetic structure and connectivity patterns of bay scallops (Argopecten irradians concentricus Lamarck) from Florida Gulf of Mexico waters using allozyme-locus and mitochondrial DNA population genetics data from samples representing four consecutive generations. We evaluated bay scallop population genetic relationships within the context of habitat, hydrodynamic, and environmental variation, and concomitant spatial patterns in the abundance of adult and recently recruited scallops to infer the influence of these factors on bay scallop population structure. Florida Gulf bay scallops form a hierarchical, mixed-model, source-sink metapopulation with intergenerational variation in connectivity that seems to be influenced by the factors we considered. An El Niño event that occurred during 1 y caused climatic and environmental change that greatly reduced subpopulation connectivity, allowing us to understand more completely the potential relative importance of the other external factors on change in metapopulation connectivity over time. Our study illustrates the value of using multiple genetic markers, sampling for multiple years, and integrating data from multiple external factors for understanding the population genetic structure of species for adaptive management.

Redes de política y diseño de estrategias para superar la crisis del agua. Los casos de los acuíferos del Valle de León, Guanajuato, y del Valle de Aguascalientes (México)

Este artículo se basa en un estudio que muestra la disputa entre proyectos políticos en torno a la gestión del agua en dos acuíferos del centro de México afectados por sobreexplotación. Los casos se refieren al acuífero del Valle de León, Guanajuato, y del Valle de Aguascalientes. Analíticamente la atención se pone en el tipo de relaciones entabladas entre los actores públicos y privados involucrados en la gestión del agua subterránea, así como en los arreglos institucionales que moldean dichas relaciones a partir de la perspectiva llamada “análisis de redes de política pública”. El presente trabajo tiene el objetivo de resaltar no sólo el conflicto distributivo del agua en México, sino el de identificar condiciones estructurales de la persistencia de la crisis del agua. Los resultados de esta investigación permiten expresar dos ideas generales en este sentido: Primero, las políticas y estrategias basadas en la perspectiva que ve al agua como un bien económico son insuficientes y parciales al dejar fuera soluciones basadas en una mayor justicia distributiva y comprometidas con la sustentabilidad del medio ambiente; y segundo, el desarrollo de soluciones efectivas a la crisis del agua requerirá la consolidación de arreglos institucionales basados en reglas del juego que configuren un sector agua más inclusivo y que incida integralmente en las estrategias de desarrollo local.

Response to Comment on “Toxicity and Mutagenicity of Gulf of Mexico Waters During and After the Deepwater Horizon Oil Spill”

Response to Comment on “Toxicity and Mutagenicity of Gulf of Mexico Waters During and After the Deepwater Horizon Oil Spill”

Comment on “Toxicity and Mutagenicity of Gulf of Mexico Waters During and After the Deepwater Horizon Oil Spill”

Comment on “Toxicity and Mutagenicity of Gulf of Mexico Waters During and After the Deepwater Horizon Oil Spill”

Petroleum films exposed to sunlight produce hydroxyl radical

Sunlight exposed oil films on seawater or pure water produced substantial amounts of hydroxyl radical as a result of irradiation. Oil was collected from the surface of the Gulf of Mexico following the Deepwater Horizon spill and exposed to simulated sunlight in thin films over water. Photochemical production of hydroxyl radical was measured with benzoic acid as a selective chemical probe in the aqueous layer. Total hydroxyl radical formation was studied using high benzoic acid concentrations and varying exposure time. The total amount of hydroxyl radical produced in 24h irradiations of thin oil films over Gulf of Mexico water and pure water were 3.7×10−7 and 4.2×10−7moles respectively. Steady state concentrations of hydroxyl radical were measured using a competition kinetics approach. Hydroxyl radical concentrations of 1.2×10−16 to 2.4×10−16M were observed for seawater and pure water under oil films. Titanium dioxide (TiO2) nanomaterials were added to the system in an effort to determine if the photocatalyst would enhance oil photodegradation. The addition of TiO2 nanoparticles dramatically changed the observed formation rate of hydroxyl radical in the systems with NP water at pH 3, showing increased formation rate in many cases. With photocatalyst, the steady state concentration of radical decreased, predominantly due to an increase in the hydroxyl radical scavenging rate with oxide present. This study illustrates that oil is a strong and important source of hydroxyl radical when exposed to sunlight. The fate of oil and other dissolved species following oil spills will be heavily dependent on the formation and fate of hydroxyl radical.