Mexico Waters Research Articles

Petroleum hydrocarbons in semipermeable membrane devices deployed in the Northern Gulf of Mexico and Florida keys following the Deepwater Horizon incident.

The Deepwater Horizon (DWH) oil spill from April to July of 2010 contaminated Gulf of Mexico waters through release of an estimated 4.1 × 106 barrels of oil. Beginning in June of 2010, semipermeable membrane devices (SPMDs) were deployed near areas with sensitive marine habitats (Alabama Alps and Western Shelf) potentially exposed to that oil. Elevated TPAH50 concentrations, flux rates and similarity of histograms and diagnostic ratios for polycyclic aromatic hydrocarbons (PAH) from SPMDs to weathered floating oil collected during the DWH spill indicates the Alabama Alps habitats were affected. While not affected by oil from the DWH spill, the temporal pattern of PAH contamination of SPMDs deployed near the Western Shelf between July 2010 and March 2011 could indicate prevailing currents affected contaminant transport to the Western Shelf Area (East and West Flower Garden, Sonnier, and Stetson Banks) from non-DWH sources, including oil and gas exploration, shipping, and Mississippi River effluent.

Response to Comment on "Legacy nitrogen may prevent achievement of water quality goals in the Gulf of Mexico".

Ballard et al argue that our prediction of a 30-year or longer recovery time for Gulf of Mexico water quality is highly uncertain, and that much shorter time lags are equally likely. We demonstrate that their argument, based on the use of a two-component regression model, does not sufficiently consider fundamental watershed processes or multiple lines of evidence suggesting the existence of decadal-scale lags.

Humpback whale calls detected in tropical ocean basin between known Mexico and Hawaii breeding assemblies.

Humpback whales migrate in winter from northern feeding grounds to geographically separate breeding assemblies in near-shore waters of Mexico and Hawaii. Currently assessed as distinct populations warranting separate management, their shared song composition and interchange of photo-identified whales question this paradigm. To investigate a potential connection an autonomous Wave Glider performed a 6965.5 km, 100-day (round trip) acoustic survey from Hawaii toward Mexico circa 20° N, from January 15 to April 25, 2018. The 2272 h of recordings included humpback whale calls to approximately midway from Hawaii to Mexico. Explanations include an undocumented migration route, offshore assembly, or mid-season travel between assemblies.

Comparison of oribatid mites from agricultural soils with contrasting irrigation types in Hidalgo State, Mexico: a case study

The objective of this work is to know the structure (composition and density) of the community of the oribatid mites and their relationship to edaphic parameters in 2 agricultural parcels with different type of irrigation. It constitutes the first work done with oribatid mites in agricultural plots irrigated with waste water in Mexico. Two agricultural parcels were selected: one is irrigated with waste water (San Salvador) and the other with well water (El Bondho) from the municipality of San Salvador. The density of oribatids in San Salvador was higher than that from El Bondho (2,360 and 1,935 ind/m2, respectively). The maximum abundances in percentages in San Salvador were for 3 species: Tectocepheus velatus elegans (48%), Scheloribates sp. (15%) and Oppiella nova (13%); but for El Bondho, there were only 2 species: Zygoribatula connexa (74%) and Ramusella sp. (10%). Due to soil conditions by the irrigation type, results gave information, on one hand, about the tolerance of some species like O. nova, R. ardua, and T. velatus elegans to heavy metals, and on the other hand, about the low resistance to heavy metals of Epilohmannia pallida and Z. connexa , which were present in the less polluted parcel, but are tolerant to saline soils. Results can be useful to support the use of some species of oribatid mites as bioindicators in ecosystems with similar conditions.

Pathogenic potential of non-typhoidal Salmonella serovars isolated from aquatic environments in Mexico.

River water has been implicated as a source of non-typhoidal Salmonella (NTS) serovars in Mexico. To dissect the molecular pathogenesis and defense strategies of seven NTS strains isolated from river water in Mexico. The genome of Salmonella serovars Give, Pomona, Kedougou, Stanley, Oranienburg, Sandiego, and Muenchen were sequenced using the whole-genome shotgun methodology in the Illumina Miseq platform. The genoma annotation and evolutionary analyses were conducted in the RAST and FigTree servers, respectively. The MLST was performed using the SRST2 tool and the comparisons between strains were clustered and visualized using the Gview server. Experimental virulence assay was included to evaluate the pathogenic potential of strains. We report seven high-quality draft genomes, ranging from ~ 4.61 to ~ 5.12Mb, with a median G + C value, coding DNA sequence, and protein values of 52.1%, 4697bp, and 4,589bp, respectively. The NTS serovars presented with an open pan-genome, offering novel genetic content. Each NTS serovar had an indistinguishable virulotype with a core genome (352 virulence genes) closely associated with Salmonella pathogenicity; 13 genes were characterized as serotype specific, which could explain differences in pathogenicity. All strains maintained highly conserved genetic content regarding the Salmonella pathogenicity islands (1-5) (86.9-100%), fimbriae (84.6%), and hypermutation (100%) genes. Adherence and invasion capacity were confirmed among NTS strains in Caco-2 cells. Our results demonstrated the arsenal of virulence and defense molecular factors harbored on NTS serovars and highlight that environmental NTS strains are waterborne pathogens worthy of attention.

In (Not so) Deep Water: The Texas–New Mexico Water War and the Unworkable Provisions of the Rio Grande Compact

In the 2018 Supreme Court case, Texas v. New Mexico, Texas claimed that New Mexico breached its obligations under the Rio Grande Compact of 1938 by allowing groundwater pumping in New Mexico south of Elephant Butte Reservoir. The Rio Grande Compact is one of many interstate water compacts in the western United States. The Compact requires Colorado and New Mexico to pay river water to the respective downstream states based on 1929 river conditions. The Supreme Court jurisprudence over interstate water disputes has wavered between concepts of equity (through the Court’s power of equitable apportionment) and contract law, which makes it difficult to predict how the Court will eventually hold in the Texas–New Mexico dispute. Regardless of how the Court holds, the underlying problem of unworkable provisions of the Rio Grande Compact will continue to present problems. Interstate water compacts have a common flaw of failing to consider changing factors that affect water availability such as decreased precipitation and snowcap runoff as well as increased temperatures, evaporation and population growth, which all result in lower river flows. The Rio Grande Compact must be amended and restructured to provide for considerations of climatic factors and changes that affect river flows and water availability. The Rio Grande Compact should borrow some concepts from the Utton Transboundary Resource Center’s Model Interstate Water Compact, but the Model Compact fails to address the important climatic factors. Without the consideration of these factors, the sustainability of interstate water resources will diminish entirely. The Rio Grande Compact and its Commission must be structured to consider these climatic factors and provide for the best interest of the Rio Grande itself as a vital and diminishing natural resource.

Population connectivity of pelagic megafauna in the Cuba-Mexico-United States triangle

The timing and extent of international crossings by billfishes, tunas, and sharks in the Cuba-Mexico-United States (U.S.) triangle was investigated using electronic tagging data from eight species that resulted in >22,000 tracking days. Transnational movements of these highly mobile marine predators were pronounced with varying levels of bi- or tri-national population connectivity displayed by each species. Billfishes and tunas moved throughout the Gulf of Mexico and all species investigated (blue marlin, white marlin, Atlantic bluefin tuna, yellowfin tuna) frequently crossed international boundaries and entered the territorial waters of Cuba and/or Mexico. Certain sharks (tiger shark, scalloped hammerhead) displayed prolonged periods of residency in U.S. waters with more limited displacements, while whale sharks and to a lesser degree shortfin mako moved through multiple jurisdictions. The spatial extent of associated movements was generally associated with their differential use of coastal and open ocean pelagic ecosystems. Species with the majority of daily positions in oceanic waters off the continental shelf showed the greatest tendency for transnational movements and typically traveled farther from initial tagging locations. Several species converged on a common seasonal movement pattern between territorial waters of the U.S. (summer) and Mexico (winter).

Genetic Diversity and Structure of Channel Catfish from Continental Waters of Mexico

AbstractMexico is the native site of 10 species of the genus Ictalurus, among which the Channel Catfish I. punctatus has great presence in worldwide aquaculture. Wild populations of catfish not only constitute a biological resource but have a great potential for aquaculture. Recently, this species was classified as an invasive organism by the Mexican government. The aim of this study was to determine the structure and genetic diversity of Channel Catfish belonging to native and introduced freshwater populations within Mexico. Using 11 DNA microsatellite loci, we analyzed 292 fish sampled from four rivers and five reservoirs. Observed heterozygosity values ranged between 0.66 and 0.80. The genetic distance analysis showed low to high differentiation among populations (overall genetic differentiation index FST = 0.14). Bayesian coancestry analysis identified two ancestral groups. A single management population on central Tamaulipas can be suggested. The findings of the present study provide the basis for future characterization of productive traits of Mexican Channel Catfish populations in order to use the species as a breeding source for aquaculture. The lower Rio Grande population is one of the most ancient and ecologically relevant Channel Catfish populations in Mexico, and this study identifies it as the most vulnerable. Free‐living populations of Channel Catfish, although they have been heedlessly spread, constitute a valuable natural resource that deserves our best effort to preserve.

Dancing with the Turquoise Waters of Mexico–Embodied Experiences and Observations for Environmental Justice

Abstract This article explores the author’s embodied experiences in and with the turquoise waters of Mexico. This journey started with an exploration of the healing potential of water through water therapy and dance. It led towards a search for ways to protect these precious water ecosystems against climate change, deforestation of waterfront ecosystems and pollution. The autoethnographic research process thus developed into a dialogue about environmental justice. Employing visual ethnography and visual arts, the author utilises photography of her dance in and with the turquoise waters of Mexico. She hopes that this article will inspire new thoughts about these precious water ecosystems and actions to protect them so they can remain pure and vivid for future generations. :

Regulatory Challenges for the Use of Reclaimed Water in Mexico: A Case Study in Baja California

In Mexico, water planning is based on the National Water Law, the core of which is Integrated Water Resources Management (IWRM). The municipality provides wastewater treatment and reuse, and an integrated approach is mandatory for these processes. However, a traditional (non-integrated) management regime has prevailed in water legislation, resulting in pollution and the inefficient use of water. The objectives of this research were to analyze the Mexican legal framework and international guidelines in the use of reclaimed water for agricultural irrigation and environmental discharges, and to evaluate challenges facing reclaimed water in the Maneadero Valley, Baja California, as a case study. Results show that wastewater reuse was implemented in the absence of integrative planning and assessment of the potential impacts on the environment and public health. In addition, gaps between decisions linked to the legal attributes of the relevant institutions were identified. Defined roles across the three levels of authority, transparent and congruent funding, coherent water-quality requirements and the strengthening of stakeholder participation are needed to adopt integrated water resource management for reclaimed water use. The alignment of common goals on public health, environmental protection and agricultural development between authorities and the different sectors is crucial to bridge these challenges.

The morphological and phylogenetic characterization for the dinoflagellate Margalefidinium fulvescens (=Cochlodinium fulvescens) isolated from the Jiaozhou Bay, China

The dinoflagellate genus Margalefidinium has been split from Cochlodinium as a new genus recently and Margalefidinium fulvescens is one of the five Margalefidinium species. Margalefidinium fulvescens is toxic and has been reported from the coastal waters of USA, Canada, Mexico, China, Japan, Indonesia, Korea, Pakistan and Spain. Here we provide the morphological and phylogenetic characterization for an isolate of it from the Jiaozhou Bay, Qingdao, China. Our results showed that the vegetative cells were subspherical to ellipsoidal, 34-60 m in length, and 19-41 m in width. Both single cell forms and colonies in chains of 2, 4, or 8 cells were observed in cultures, but chain forms with 2 or 4 cells were observed more often in the field samples. The cingulum was rather deep, encircling the cell approximately twice, but the sulcus was rather narrow, surrounding the cell about one turn. The nucleus was spherical and located at the central epicone. The chloroplasts were granular, brownish, and scattered peripherally. An orange pigmented body also appeared in the epicone. The apical groove appeared vase-like as previously described. Under epi-fluorescence microscopy, a pumpkin-like structure was clearly observed, in which cells were embedded. Cells were observed to exit from the structure, which led us to a hypothesis that the structure may provide cells a shelter to avoid predation or to respond to other stresses. The phylogenetic analyses based on partial LSU rDNA sequences indicated that M. fulvescens from the Jiaozhou Bay was grouped with M. fulvescens populations from other origins and closely related to the clade of M. polykrikoides. Our morphological observations and phylogenetic analyses together confirmed the presence of M. fulvescens in China and our monitoring has also observed the species dominant in the dinoflagellate community of the Jiaozhou Bay in the early autumn of 2015, which alerted us to continually monitor this bloom-forming species in the region.

Groundwater geochemistry fluctuations along a fresh-saltwater gradient on the carbonate islands of the lower Florida Keys

Climate change will have long-lasting effects on the availability of fresh water on small, carbonate islands that have isolated fresh groundwater lenses, particularly as sea level rises and rainfall regimes shift. The carbonate islands of the Florida Keys provide an ideal location to study the effect of variable rainfall on the aqueous geochemistry of the islands' groundwater. In a rainfall-driven carbonate system, the expectation is that limestone dissolution will occur within the vadose zone resulting in increased ions in the groundwater. However, geochemical processes are also affected by the salinity of groundwater and the extent of the mixing zone between fresh and salt water. We chose two islands to conduct the study of the shallow groundwater: the largest island in the lower Florida Keys, Big Pine Key (BPK), and a smaller island, Upper Sugarloaf Key (SLK). From May 2011 through April 2012, monthly groundwater samples were collected from 24 shallow (1 m deep) wells located along a fresh to saline gradient on both islands. Groundwater chemistry was compared with rainfall amounts from a weather station on BPK. Saturation indices for aragonite and calcite, generated with geochemical modeling in PHREEQC, were compared to conservative mixing between Gulf of Mexico water and freshwater. Equilibrium to supersaturated conditions with respect to carbonate minerals dominated in all of the groundwater samples. Saturation indices varied with rainfall with the most supersaturated samples observed after a large rain event and samples approaching equilibrium after the longest period without rainfall. Calcium in excess of what would be expected from conservative mixing of fresh water and seawater was observed in all groundwater samples and was elevated at near-shore locations, especially on BPK. Contrary to expectations, dissolution resulting from mixing of freshwater and seawater was not supported in the shallow groundwater. Instead, dissolution within the narrow vadose zone from rain events likely resulted in the excess calcium in the groundwater. Seasonal fluctuations in groundwater composition were primarily observed on the smaller island and were related to the fresh water balance, changing rapidly after a heavy rain event, and suggest that a size threshold has been surpassed for a stable lens. Rising seas will further decrease lens extent and vadose zone depth, reducing the potential for future limestone dissolution.

Limited recruitment of an ecologically and economically important fish, Paralabrax clathratus, to an invasive alga

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 602:213-224 (2018) - DOI: https://doi.org/10.3354/meps12673 Limited recruitment of an ecologically and economically important fish, Paralabrax clathratus, to an invasive alga Samuel C. Ginther*, Mark A. Steele California State University Northridge, Department of Biology, Northridge, CA 91330-8303, USA *Corresponding author: samuel.ginther@csun.edu ABSTRACT: Some invasive species have devastating ecological impacts on native species, whereas others have little effect. The macroalga Sargassum horneri recently invaded the waters of California (USA) and Mexico, and in some places has largely replaced an important native macroalga, the giant kelp Macrocystis pyrifera. To explore the potential impacts of the invasive alga on populations of an ecologically and economically important fish, the kelp bass Paralabrax clathratus, we tested whether recruitment of kelp bass onto macroalgae differed between the invasive S. horneri and native M. pyrifera. Field surveys by scuba divers on naturally occurring S. horneri and M. pyrifera at Santa Catalina Island revealed that kelp bass recruits were ~30 times more abundant on individual M. pyrifera than on individual S. horneri. To assess the cause of this pattern, we conducted a field experiment in which plots containing 3 treatments (M. pyrifera only, S. horneri only, and M. pyrifera and S. horneri together) were isolated over a sandy bottom, which limited post-settlement movement of recently settled kelp bass among macroalgae. Kelp bass recruitment was similar for the 2 treatments containing M. pyrifera, but no recruits were observed on S. horneri, regardless of whether the alga was alone or paired with M. pyrifera. Additionally, we found a strong spatial gradient in recruitment among the experimental plots that was explained by the abundance of larger, cannibalistic conspecifics. This study presents the first evidence that invasive S. horneri may negatively impact an important reef fish. KEY WORDS: Sargassum horneri · Macrocystis pyrifera · Kelp bass · Santa Catalina Island Full text in pdf format PreviousNextCite this article as: Ginther SC, Steele MA (2018) Limited recruitment of an ecologically and economically important fish, Paralabrax clathratus, to an invasive alga. Mar Ecol Prog Ser 602:213-224. https://doi.org/10.3354/meps12673 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 602. Online publication date: August 23, 2018 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2018 Inter-Research.

Rare Earth Elements Geochemistry and Nd Isotopes in the Mississippi River and Gulf of Mexico Mixing Zone

Rare earth elements (REE) concentrations were measured in surface waters collected across the salinity gradient in the Mississippi River estuary (i.e., Mississippi River plume, MRP), which includes the near-shore portion of the Louisiana Shelf. In addition, the neodymium (Nd) isotope compositions of two river water samples, and the acid leachable fractions of the associated suspended particulate matter (SPM), were quantified to compare Mississippi River water, and SPM with Gulf of Mexico waters. Despite the spatial limitations associated with sampling due to the size of the Mississippi River system, this study provides some important insights into the REE geochemistry of the MRP. The Mississippi River and its estuarine waters are enriched in the heavy REE (HREE) compared to the light REE (LREE) when normalized to shale composites. All water samples from the estuary also exhibit substantial negative Ce anomalies. In contrast to the majority of other estuaries investigated, removal of REE in the low salinity reaches of the Mississippi River estuary is less substantial. For example, approximately 50% of the river borne Nd is removed in the low salinity region (S < 10) of the Mississippi River estuary compared to the estimated global average of ca. 70% removal of Nd for estuaries worldwide. We propose that the relatively low REE removal in the Mississippi estuary reflects the high pH (~8) of the Mississippi River, where REE complexation with carbonate ions and natural organic ligands act to stabilize REE in solution. The Nd isotope composition of Mississippi River water near its outflow to the Gulf of Mexico is eNd(0)= -10.5. The acid leachable fraction of the associated SPM is more radiogenic (-9.95 ≤ eNd(0) ≤ -9.77), and closer to the generally more radiogenic Gulf of Mexico (eNd(0) = -9.0). Sequential extraction of the Mississippi River bank sediment reveals substantially different Sm/Nd ratios for the operationally defined fractions of the sediment, which suggests variations in Nd isotope compositions between the labile fractions and the bulk sediment.

Bottled water in Mexico: The rise of a new access to water paradigm

Providing a case of bottled water as the main source of drinking water for a nation, this article looks at the unfolding of this development in Mexico and locates it into the mainstream debate about how to achieve sustainable development goals (SDGs) Target 6.1: universal and equitable access to safe and affordable drinking water for all. This is timely and relevant due to the 2017 amplification of the indicators defining access to improved sources of water to include the use of bottled water, under the broader category of “packaged water.” This signifies that populations that rely on bottled water as a complement to tap water, independent of the frequency and quality of this service, will be considered to have achieved the target. In only two decades, the phenomenon of bottled water has grown from a high‐end, niche consumer good to a global industry valued at $170 billion and climbing. The industry now stands poised to show how the private sector can be involved in achieving global targets, such as SDG 6.1, while earning large profits. In Mexico, 2017 estimates show 73% of the national population relies on bottled water as their unique source of drinking water, up from 61% in 2010. The article will trace the industry's history in Mexico rising out of an earthquake, a cholera epidemic, a financial crisis and the actions of the bottled water corporations. The profitability of this particular model of water delivery has attracted large‐scale investment by multinational food and beverage corporations and banks as well a recent explosion of small‐scale neighborhood water shops selling relatively small quantities of water. Today, this Mexican model is actively being replicated in other regions. Using a literature review and interviews with key informants from CONAGUA, Mexico's national water commission, the article traces four “lines of flight” of the origin and development of the bottled water industry in Mexico. The article reviews the current expansion of market actors and the published strategies of the dominant multinational corporations, to show the various configurations of the bottled water industry that are competing for the future of water delivery. The paper concludes by suggesting that the consequences of this trend deserve renewed examination by the water research community.This article is categorized under: Engineering Water &gt; Planning Water Human Water &gt; Water Governance

Macondo oil in northern Gulf of Mexico waters – Part 1: Assessments and forensic methods for Deepwater Horizon offshore water samples

Forensic chemistry assessments documented the presence of Macondo (MC252) oil from the Deepwater Horizon (DWH) spill in offshore water samples collected under Natural Resource Damage Assessment (NRDA) protocols. In ocean depths, oiled water was sampled, observed, photographed, and tracked in dissolved oxygen (DO) and fluorometry profiles. Chemical analyses, sensor records, and observations confirmed the shifting, rising oil plume above the wellhead while smaller, less buoyant droplets were entrapped in a layer at ~1000–1400 m and advected up to 412 km southwest. Near-surface oil samples showed substantial dissolution weathering from oil droplets rising through the water column, as well as enhanced evaporative losses of lighter n-alkanes and aromatic hydrocarbons. Dispersant effects from surface applications and injected at the wellhead were seen in oil profiles as enhanced weathering patterns (increased dissolution), thus implying dispersants were a functionally effective mediation treatment. Forensic assessment methods are detailed in the Supplemental information (SI).

Macondo oil in northern Gulf of Mexico waters – Part 2: Dispersant-accelerated PAH dissolution in the Deepwater Horizon plume

During the Deepwater Horizon blowout, unprecedented volumes of dispersant were applied both on the surface and at depth. Application at depth was intended to disperse the oil into smaller microdroplets that would increase biodegradation and also reduce the volumes buoyantly rising to the surface, thereby reducing surface exposures, recovery efforts, and potential stranding. In forensically examining 5300 offshore water samples for the Natural Resource Damage Assessment (NRDA) effort, profiles of deep-plume oil droplets (from filtered water samples) were compared with those also containing dispersant indicators to reveal a previously hypothesized but undocumented, accelerated dissolution of the polycyclic aromatic hydrocarbons (PAH) in the plume samples. We interpret these data in a fate-and-transport context and conclude that dispersant applications were functionally effective at depth.

Diversidad, patrones de distribución y “hotspots” de los equinoideos irregulares (Echinoidea: Irregularia) de México

Diversity, distribution patterns and hotspots of the irregular equinoids (Echinoidea: Irregularia) of Mexico.Irregular echinoids can be found in almost all marine habitats, from the polar to the equatorial regions, and from the intertidal zone to great depths; some species have a cosmopolitan distribution, but most are geographically restricted, and all live in very particular habitats to a greater or lesser degree in Mexico has 153 species distributed within the coastal limits. Geographic barriers (terrestrial barriers and large ocean basins) and ocean current patterns act as primary modulators of the distribution of echinoids; however, there are factors that define the local distribution. The purpose of this work is to analyze the diversity of irregular echinoids in Mexico, as well as to explain the patterns of distribution and to explore the hotspots through panbiogeography as units of high richness. The study area covers all the territorial waters of Mexico in the Pacific Ocean, Atlantic and Caribbean Sea. To obtain the geographical coordinates we used the distribution data of 68 species of irregular echinoids recorded at different depths. We reviewed the specimens deposited in five scientific collections, in addition to the revision of other records from online databases: 1. National Collection of Echinoderms “Ma. Elena Caso Muñoz” of the Instituto de Ciencias del Mar y Limnología (ICML), of the Universidad Nacional Autónoma de México (UNAM); 2. Regional Collection of Invertebrates of the Academic Unit Mazatlán, ICML, UNAM. 3. Invertebrate Zoology Collection, Smithsonian Museum of Natural History, Washington, D.C., United States of America, (USA); 4. Invertebrate Collection, Museum of Comparative Zoology, University of Harvard, Boston, Massachusetts; 5. Invertebrate Zoology, Peabody Museum, Yale University, New Haven, Connecticut; National Information System on Biodiversity (SNIB-CONABIO) and Global Biodiversity Information (GBIF). The generalized tracks were performed by the analysis of endemicity based on the optimization method, using the NDM/VNDM program with a 2° x 2° latitude/longitude grid. Hotspots were obtained by overlapping the generalized tracks using the ArcView program. The best represented was family Brissidae, with 15 species, most of them belonging to the genus Brissopsis, followed by the family Mellitidae (with 12 species), half of them belongs to the genus Encope. The families of irregular sea urchins with a smaller number of species were: Echinoneidae, Plexechinidae, Palaeotropidae and Paleopneustidae, each represented by a single species. The following general patterns of distribution were recognized: 1) groups of widely distributed species and 2) restricted species living in the first few meters of depth (0-20m). Nine consensus areas or generalized tracks were obtained in the Endemicity Analysis and 47 hotspots were recognized. Three areas with high specific wealth were obtained: West Coast of the Gulf of Mexico, Bank of Campeche/Mexican Caribbean and Gulf of California. The Gulf of California area has the highest diversity of irregular echinoids. This is the first approximation in the study of the panbiogeography of echinoderms of Mexico. Rev. Biol. Trop. 65(Suppl. 1): S42-S59. Epub 2017 November 01.

Does Saving Lives Win Votes? Evaluating the Electoral Consequences of Providing Clean Water in Mexico

Politicians often struggle to claim credit for programmatic policies and therefore use personalized benefits to win elections. Non-programmatic strategies that target individual voters provide a greater electoral return, even if the technocratic provision of public goods would better serve citizens’ needs. Mexico’s PRI historically relied on such targeting to win elections and used social welfare spending to reinvigorate this practice after its poor 1988 electoral results. Thus, claims that Programa Agua Limpia (PAL), a clean water program, was technocratic merit skepticism. This paper assesses such claims and whether the resulting health improvements had electoral consequences. Analysis indicates that electoral considerations did not influence PAL. Furthermore, this program increased support for the PRI. A dollar spent on PAL may have yielded better electoral returns then larger particularistic social welfare programs concurrently implemented by the PRI. Our analysis illuminates the conditions under which politicians can garner electoral returns for providing public goods.

Water Quality Assessment of Large‐scale Bioenergy Cropping Scenarios for the Upper Mississippi and Ohio‐Tennessee River Basins

AbstractThe Upper Mississippi River Basin and Ohio‐Tennessee River Basin comprise the majority of the United States Corn Belt region, resulting in degraded Mississippi River and Gulf of Mexico water quality. To address the water quality implications of increased biofuel production, biofuel scenarios were tested with a Soil and Water Assessment Tool (SWAT) model revision featuring improved biofuel crop representation. Scenarios included corn stover removal and the inclusion of two perennial bioenergy crops, switchgrass and Miscanthus, grown on marginal lands (slopes &gt;2% and erosion rates &gt;2 t/ha) and nonmarginal lands. The SWAT model estimates show water quality is not very sensitive to stover removal. The perennial bioenergy crops reduce simulated sediment, nitrogen (N), and phosphorus (P) yields by up to 60%. Simulated sediment and P reductions in marginal lands were generally twice that occurring in the nonmarginal lands. The highest unit area reductions of N occurred in the less sloping tile‐drained lands. Productivity showed corn grain yield was independent from stover removal, while yields of the two perennial bioenergy crops were similar in the marginal and nonmarginal lands. The results suggest planning for biofuel production in the Corn Belt could include the removal of stover in productive corn areas, and the planting of perennial bioenergy crops in marginal land and in low‐sloped tile‐drained areas characterized by high N pollution. Editor's note: This paper is part of the featured series on SWAT Applications for Emerging Hydrologic and Water Quality Challenges. See the February 2017 issue for the introduction and background to the series.