East Coast Of Mexico Research Articles

Regional patterns of vegetation, temperature, and rainfall trends in the coastal mountain range of Chiapas, Mexico

Changes in atmospheric CO2, ocean temperature, and regional vegetation conditions in Mesoamerica indicate that significant trends in temperature and rainfall may have occurred in the Sierra Madre de Chiapas, Mexico. This is an important region for flora and fauna which could be affected by climate trends. We aimed to determine if and where climate trends had occurred in the Sierra Madre and lower elevation regions between 1990 and 2016 (27 years), if these trends were part of longer term (1960-2016 [57 years]) changes, and how changes in large-scale and regional/local conditions may be influencing these trends. In the Sierra Madre, overall minimum daily temperatures increased, maximum temperatures decreased, and the most significant mean temperature trends were cooler during the 27-yr period. Both the start and end of the wet season trended earlier in the year, and wet season rainfall increased significantly. Trends were not significant during the 57-yr period in the Sierra Madre; however, in the adjacent Pacific coast region, significant warmer temperature trends continued during this period. Within regions, there was large variation in temperature and rainfall changes and some local trends were opposite to the regional averages. Large-scale processes of warming sea surface temperatures in the east coast of Mexico, a change from the positive to negative phase of the Pacific Decadal Oscillation and increases in atmospheric CO2 may be influencing these trends. At the regional scale, increases in dense vegetation and evapotranspiration since 1990 may have created characteristics favoring a positive feedback of higher ocean-based moisture and vegetation-based precipitation cycling.

The contribution of tropical cyclones to the atmospheric branch of Middle America\u2019s hydrological cycle using observed and reanalysis tracks

Middle America is affected by tropical cyclones (TCs) from the Eastern Pacific and the North Atlantic Oceans. We characterize the regional climatology (1998–2016) of the TC contributions to the atmospheric branch of the hydrological cycle, from May to December. TC contributions to rainfall are quantified using Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) product 3B42 and TC tracks derived from three sources: the International Best Track Archive for Climate Stewardship (IBTrACS), and an objective feature tracking method applied to the Japanese 55-year and ERA-Interim reanalyses. From July to October, TCs contribute 10–30% of rainfall over the west and east coast of Mexico and central Mexico, with the largest monthly contribution during September over the Baja California Peninsula (up to 90%). TCs are associated with 40–60% of daily extreme rainfall (above the 95th percentile) over the coasts of Mexico. IBTrACS and reanalyses agree on TC contributions over the Atlantic Ocean but disagree over the Eastern Pacific Ocean and continent; differences over the continent are mainly attributed to discrepancies in TC tracks in proximity to the coast and TC lifetime. Reanalysis estimates of TC moisture transports show that TCs are an important moisture source for the regional water budget. TC vertically integrated moisture flux (VIMF) convergence can turn regions of weak VIMF divergence by the mean circulation into regions of weak VIMF convergence. We discuss deficiencies in the observed and reanalysis TC tracks, which limit our ability to quantify robustly the contribution of TCs to the regional hydrological cycle.

Mesophyllum erubescens (Corallinales, Rhodophyta)—so many species in one epithet

The name Mesophyllum erubescens has been applied to protuberant rhodolith specimens which sometimes occur abundantly, as well as to encrusting specimens in tropical and temperate waters in the Western Pacific, Indian and Western Atlantic Oceans. A DNA sequence, representing about 20% of the rbcL gene, was obtained from the 140 year old holotype specimen collected in the Fernando de Noronha Archipelago by the Challenger Expedition. This sequence was identical to field-collected topotype specimens as well as to specimens ranging south along the coast of Brazil. Sequences for psbA from these same Brazilian specimens and specimens from the east coast of Mexico were identical or differed by 1 base pair. In contrast, specimens called M. erubescens based on morpho-anatomical characters in the Pacific Ocean differed from Western Atlantic Ocean specimens by 2.5–13.1%, indicating that these represent numerous distinct species. All reports of non-geniculate coralline species said to be widely distributed across different oceans or in different biogeographic provinces based on morpho-anatomical characters need to be verified by DNA sequences.

Nitrogen and phosphorus resorption in a neotropical rain forest of a nutrient-rich soil

In tropical forests with nutrient-rich soil tree's nutrient resorption from senesced leaves has not always been observed to be low. Perhaps this lack of consistence is partly owing to the nutrient resorption methods used. The aim of the study was to analyse N and P resorption proficiency from tropical rain forest trees in a nutrient-rich soil. It was hypothesised that trees would exhibit low nutrient resorption in a nutrient-rich soil. The soil concentrations of total N and extractable P, among other physical and chemical characteristics, were analysed in 30 samples in the soil surface (10 cm) of three undisturbed forest plots at 'Estaci6n de Biologia Los Tuxtlas' on the east coast of Mexico (18 degrees 34' - 18 degrees 36' N, 95 degrees 04' - 95 degrees 09' W). N and P resorption proficiency were determined from senescing leaves in 11 dominant tree species. Nitrogen was analysed by microkjeldahl digestion with sulphuric acid and distilled with boric acid, and phosphorus was analysed by digestion with nitric acid and perchloric acid. Soil was rich in total N (0.50%, n = 30) and extractable P (4.11 microg g(-1) n = 30). As expected, trees showed incomplete N (1.13%, n = 11) and P (0.11%, n = 1) resorption. With a more accurate method of nutrient resorption assessment, it is possible to prove that a forest community with a nutrient-rich soil can have low levels of N and P resorption.

Effects of Seed Weight and Substrate on Germination and Growth of Non-toxic Jatropha curcas L. Seedings

Aims: We characterized the responses of non-toxic seedlings ofJatropha curcasL. to variation in seedweight and substrate during their germinat ion and growth. Study Design: Two analytical experiments using a randomized controlled trial approach were applied to consider the effects of seed weight and substrate. Place and Duration of Study:Non-toxic seeds from the east coast of Mexico were selected during two consecutive years and their seedlings were studied during one month after emergence. Methodology: The seeds were grouped into different weight categories (400 -499 -800

New species and new records of Crinipellis from tropical and subtropical forests of the east coast of Mexico

Crinipellis brunneoaurantiaca, C. pallidibrunnea and C. rubella are described as new species and their taxonomic position is discussed. The two former were collected in subdeciduous tropical forest and the latter in the montane cloud forest, all from the east coast of Mexico (central Veracruz). Crinipellis podocarpi, C. pseudostipitaria var. mesites, C. setipes, recorded in montane cloud forest, and C. tucumanensis, collected in subdeciduous tropical forest, also are discussed. Detailed macro- and microscopic descriptions, illustrations of distinctive microscopic characters and plates are presented for each species.

Variation in Anatomical Characteristics in Leaves of Pecan Seedstocks from Mexico and the United States

Leaf anatomical traits of Mexican and U.S. pecan [Carya illinoinensis (Wangenh.) K. Koch] seedstocks grown in a single location were studied to determine patterns of ecogeographic variation within the natural range. Stomatal density was uniform among open-pollinated seedlings of a common maternal parent with twofold differences in stomatal density separating some seedstocks. There was an inverse relationship between stomatal density and epidermal cell density. Stomatal density and stomatal index of Mexican seedstocks were related to longitude and annual precipitation of origin. Stomatal density increased along the longitudinal gradient toward the east coast of Mexico; seedstocks originating from areas on the east coast of Mexico had greater stomatal density than seedstocks originating from the drier areas on the west coast. Stomatal density and stomatal index did not follow a pattern along latitude or longitude in the U.S. seedstocks. Although isotopic carbon (13C) discrimination did not vary greatly in Mexican seedstocks, the reduction in stomatal density in pecan trees from areas with reduced annual precipitation suggest the presence of an anatomical feature to reduce water losses.

Floods over the U.S. Midwest: A Regional Water Cycle Perspective

Abstract The characteristics of situations of extremely high rainfall over the midwestern region of the United States during late spring and summer are investigated from the perspective of the regional water cycle using observations and observationally based analyses. The period of May–July has the greatest mean rainfall rates of the year and higher interannual variability than the periods either before or after. This is also a critical time of year for water resources and cultivation schedules in this agriculturally important region. Large-scale floods during this time of year are usually characterized by an enhanced source of moisture evaporating from low latitudes, specifically the Caribbean Sea. This is part of a fetch of moisture that extends from the Caribbean northward along the coast of Central America, over the Yucatan Peninsula, along the east coast of Mexico and the western Gulf of Mexico, and over Texas, where it links into the Great Plains low-level jet. In fact, heavy rainfall over much of the eastern half of the United States is associated with above-average Caribbean moisture supply. There is also indication of an enhanced source of moisture from the subtropical Pacific during Midwest flood events. Drought events appear to have a different spatial pattern of water cycle variables and circulation anomalies, and are not simply equal and opposite manifestations of flood events. While not a dominant source of moisture even during extreme events, the Caribbean region seems to be part of an important link for remote moisture, supplying floods over the Midwest.

The effects of ambient temperature and humidity on pregnancy rate in Beefmaster cows in a subtropical environment of Mexico

Pregnancy rates of a Beefmaster herd with improved management in the east coast of Mexico under intense heat load during most part of the year (THI range = 56–102) were evaluated, using the GENMOD procedure of SAS, with respect to temperature–humidity index (THI) prior or after artificial inseminations (AI; n = 2039 inseminations). There was a departure from linearity ( P < 0.05) between THI and conception rates, as maximum THI exceeded 92 units pregnancy rate decreased more rapidly, although conception rate changed only five percent points over the THI range found in this study. When heat stress was as it maximum the day of AI (THI = 88–96) lower or higher THI one or three days prior or after AI did not affect conception rates (47–56%). With lower heat load at AI (THI = 80–88) higher THI before or after neither modify conception rates (48–58%). Pregnancy rates of cows differed among seasons ( P < 0.01), peaking in the fall (62%) and decreasing in spring (44%). Inseminations per pregnancy were lower in summer and fall (1.5) than in other seasons (1.9–2.0; P < 0.01). There was a weak association between days open (average 242 days for 14,910 calvings) and monthly average THI during the study period, with longer intervals between parturition and pregnancy in cows calving in the fall. The main conclusions of this study were that pregnancy rate was mildly compromised by extreme heat load in Beefmaster cows in this subtropical environment, and that cooler or warmer temperatures prior or after AI bear no consequences for pregnancy rate during the warmest seasons for this breed of cattle.

The blunt-headed vine snake, Imantodes cenchoa (Linnaeus, 1758), in Minas Gerais, southeastern Brazil

The blunt-headed vine snake, Imantodes cenchoa, has a large distribution, occurring from the east coast of Mexico to Argentina. In Brazil, it is found from the Amazon in the north, to Santa Catarina in the south. In the state of Minas Gerais, southeastern Brazil, there are only two records of I. cenchoa in the literature. In the present study, a search for I. cenchoa from Minas Gerais was conducted in the main Brazilian herpetological collections, revealing a total of 13 localities with records of this species.

Morphometric Relationship of Weight and Length of Cultured Freshwater Snail, Pomacea patula (Baker, 1922), at Three Different Life Stages

Snails from the genus Pomacea live in the floodplain of rivers, swamps, and in water canals used for irrigation in tropical zones of the American Continent (Banarescu 1990); they are amphibious and herbivorous, and present some biological characteristics to be suggested as potential species for culture (Mendoza et al. 2002; Ramnarine 2003). There are few snails that are commercially cultured in Trinidad and Guyana (Ramnarine 2004), and Peru (IIAP 2000). The apple snail, Pomacea patula, is an edible freshwater mollusk originating from Catemaco Lake (Veracruz, east coast of Mexico), where is locally considered a very important fishery resource but in the past decades catches have declined, almost depleted, mainly by overexploitation and environmental degradation (Gonzalez-Soriano et al. 1997). Nowadays, P. patula is also found in the midcoast of the Mexican Pacific since was introduced almost 30 yr ago (JaimeVargas 1992). Most of the information reported for this species is related to its basic biology and ecology (Naranjo-Garcia and GarciaCubas 1985; Martinez-Garcia 1989) and there are only few reports about its nutrition under controlled conditions (Asiain and Olguin 1995; Garcia-Ulloa et al. 2006). In spite of the economic interest in cultivation of freshwater snails for human consumption, there is a lack of basic information about the morphometric characteristics of the P. patula species. The application of morphometric relationships in P. patula could be a simple alternative to estimate body weight from length measurements at different stages of its life development. The present study analyzes the length–weight relationship of P. patula ranging in weight from 0.1 to 66 g when cultured in our lab during nursery, grow-out, and broodstock production phases. This knowledge may simplify management practices in the different culture phases of this species.

Overview of Study Areas and UNAM-Iztacala Student Research

The State of Veracruz is located on the east coast of Mexico and consists of many shallow marine systems such as estuaries and coastal lagoons. These estuarine systems are ecological sites of great importance due to the interactions that occur between the intertidal zones and adjacent areas. This importance is reflected in the variety of natural components present in these sites as well as the large number of species that depend on this aquatic zone, such as birds, mammals, molluscs, crustaceans and fishes. Many of the crustaceans and fishes are consumed by the local inhabitants and distributed in commercial areas in Mexico City. It is estimated that Veracruz state is in fourth place in fisheries landings for the country, and contributes 10% of the total fisheries production. Academic personnel from the laboratories of Ecology and Zoology in the Facultad de Estudios Superiores Iztacala, Tlalnapantla, Mexico have focused their research efforts since 1988 on two of the systems in Veracruz state, the Tecolutla River and the lagoonal system of Alvarado. Research in both locations has resulted in a number of professional theses by undergraduate students in the Biology Department at UNAM-Iztacala.

Fall Migration Routes, Timing, and Wintering Sites of North American Ospreys as Determined by Satellite Telemetry

Abstract Satellite telemetry was used to determine fall migratory movements of Ospreys (Pandion haliaetus) breeding in the United States. Study areas were established along the lower Columbia River between Oregon and Washington; in north-central Minnesota; on Shelter Island, New York; and in southern New Jersey. Seventy-four adults (25 males, 49 females) were tracked from 1995 through 1999. Migration routes differed among populations but not by sex. Western Ospreys migrated through California and to a lesser degree other western states and wintered in Mexico (88%), El Salvador (6%), and Honduras (6%) (25.9°N to 13.0°N and 108.3°W to 87.3°W). Minnesota Ospreys migrated along three routes: (1) through the Central U.S. and then along the east coast of Mexico, (2) along the Mississippi River Valley, then across the Gulf of Mexico, or (3) through the southeastern U.S., then across the Caribbean. East Coast birds migrated along the eastern seaboard of the U.S., through Florida, and across the Caribbean. Midwest...

A numerical study of barotropic vortex motion near a large-scale mountain range with application to the motion of tropical cyclones approaching the Sierra Madre

The motion of an idealized vortex near a large-scale mountain range is examined by numerically integrating the single-layer shallow-water equations on an equatorial beta plane. Modification of the asymmetric circulation by divergent vorticity generation as the air is forced across the ridge greatly affects the motion of the vortex. Attention is focused on the role of the vortex structure, the mountainrange width and orientation, and the stratification of the model atmosphere in influencing the motion of the vortex. A scale analysis is used to explain the sensitivity of the vortex track to changes in the model's external parameters. The sensitivity of the model vortex track to the slope and orientation of the mountain range is used to help explain some features of the observed tracks of hurricanes that make landfall on the east coast of Mexico.

Isopods of the Genus Excorallana Stebbing, 1904 (Crustacea, Isopoda, Corallanidae) from the East Coast of Mexico with a Supplemental Description of E. subtilis

Eight species of Excorallana, E. acuticauda, E. delaneyi, E. oculata, E. sexticornis, E. subtilis, E. tricornis tricornis, E. warmingii, and Excorallana sp. are recorded for the eastern coast of Mexico. The range of E. delaneyi is extended south in the Gulf of Mexico. Excorallana oculata and E. subtiIis are reported for the first time in the Gulf. Based on specimens from the east coast of Mexico, a supplemental description of E. subtilis is presented and its taxonomy to other closely related species discussed. A key is provided to the adult males of the species of Excorallana now known to occur in the southwestern Gulf of Mexico and the Caribbean coast of Mexico.

Lower Cretaceous Shelf-Margin Carbonate Facies, Northwestern Gulf of Mexico: ABSTRACT

Lower Cretaceous carbonate sediments accumulated on a broad shallow-water shelf which completely encircled the Gulf of Mexico. Along the edge of this shelf, biogenic growth climaxed with a complex of rudist reefs, banks, bars, and islands. The shelf-margin trend has been recognized offshore north of Yucatan; along the east coast of Mexico in the Golden Lane and Poza Rica trend in the subsurface, and outcrops in the Sierra Madre Oriental; through Texas and Louisiana parallel with and approximately 100 mi inland from the present coastline; and offshore of Florida along the west Florida Escarpment. These shelf-margin deposits are best known from the subsurface Golden Lane and Poza Rica trend, the outcrop in the Sierra Madre Oriental, and the subsurface of south Texas, where t is commonly referred to as the Stuart City trend. Five major depositional environments have been recognized from the carbonate rocks of the south Texas Stuart City trend: shelf lagoon, shelf margin, upper shelf slope, lower shelf slope, and open marine. The shelf-lagoon facies include miliolid wackestone, mollusk wackestone, toucasid wackestone, and mollusk-miliolid grainstone. These facies accumulated under generally low-energy conditions in water depths from 0 to 20 ft (0 to 6 m). In contrast, the narrow band of shelf-margin carbonate beds is made up of algae-encrusted miliolid-coral-caprinid packstone, coral-caprinid boundstone, requienid boundstone, and rudist grainstone, all of which accumulated in moderate-energy to high-energy waters less than 15 ft (5 m) deep. Seaward of the shelf margin, the upper shelf-slope environment com rises the caprinid-coral wackestone and coral-stromatoporoid boundstone facies, and the lower shelf slope comprises the intraclast grainstone, echinoid packstone, and End_Page 416------------------------------ echinoid-mollusk wackestone facies. Farther seaward, in water depths greater than 60 ft (18 m), the open-marine environment is represented by the planktonic foram wackestone. Intraparticle, interparticle, and fracture porosity are present in the thick limestone section along the Stuart City shelf margin. Intraparticle porosity, in places reaching 20%, is common, although permeability in facies with intraparticle porosity is low. Facies with interparticle porosity greater than 5% have good permeability up to 10 md. Permeability in any facies may be enhanced by the presence of thin fractures which were common in several cores. Only four facies, however, have greater than 5% porosity and 5 md permeability--the algae-encrusted miliolid-coral-caprinid packstone, mollusk grainstone, rudist grainstone, and coral-stromatoporoid boundstone. Rudist grainstone is potentially the most consistent in terms of porosity and permeability, thickness, and lateral extent. End_of_Article - Last_Page 417------------

Seismic Stratigraphy and Geologic History of Campeche Escarpment, Gulf of Mexico: ABSTRACT

Interpretation of multifold seismic data from the Campeche Escarpment northwest of the Yucatan Peninsula shows geologic features that suggest the sequence of events in the evolution of the Gulf of Mexico. Profiles of the surface resemble topography typical of subaerial erosion, that is, a pediment surface. An inferred Jurassic salt layer that covers sediments in a downthrown basement block pinches out against the pediment surface. Updip of the salt pinchout and topographically higher are possible Late Jurassic carbonate banks or reefs which onlap the basement erosional surface. A major unconformity separating the carbonate seismic unit from the overlying slope-front-fill unit probably corresponds to a worldwide middle Cretaceous unconformity. Since Late Cretace us, deep-water turbidites emanating from the east coast of Mexico and northern Gulf Coast have dominated the study area. The scenario revealed at Campeche Escarpment suggests that an early Mesozoic mantle event (plume?) uplifted this once continental area and caused thinning of the crust to near oceanic thickness. Whether and how much of the Gulf of Mexico is underlain by thinned Paleozoic or Mesozoic continental crust, or true oceanic End_Page 487------------------------------ crust, is still uncertain. The central gulf and interior basins subsided after this period of crustal thinning. It was in these basins that the Sigsbee and Louann Salt were deposited. Later, as the basin margins subsided farther, carbonate sediments onlapped and covered these margins, marking 5 km of subsidence by the Cretaceous. Since the Cretaceous, clastics have infilled the northwestern Gulf, causing an additional 3 km of subsidence of the gulf basin, while the central Florida and Yucatan platforms have stabilized above sea level. End_of_Article - Last_Page 488------------

Floating-Type Offshore Drilling Vessels

After two decades of oil exploration on the world's continental shelf, various design types of mobile drilling rigs have evolved, namely the submersible, the jack-up, and the floater. The authors consider that the current stage of development of these rigs has sufficiently established design patterns which are worthy of investigation and review. The authors have selected the floater type for discussion and presentation as being of germane interest to the naval architect and marine engineer. Section 1 of the paper reviews the design aspects of floating drilling vessels by considering them in two groups: "surface hull" type and "column stabilized" type. Functional design requirements are discussed, including some fundamentals on rotary oil drilling to familiarize the naval architect with its basic techniques. Requirements and recommendations for deck areas and volumes are given, together with representative weights for drilling equipment and vessel weight summaries. Hydrostatic, stability, and motion characteristics are compared between the two types. Structural design, safety features, and logistic support systems are reviewed. Section 2 describes the offshore drilling vessel Reforma as typical of one of the large surface-hull-type rigs incorporating the latest drilling techniques and marine systems. The rig, one of a fleet of three, is owned and operated by Perforadora Mexico, S. A., a private drilling contractor under contract to Petroleos Mexicanos, off the east coast of Mexico.

On the propagation of the Lg phase

ABSTRACT Empirical determinations of the mean surface velocity of Lg indicate a range from 3.47 to 3.54 km/sec., with one set of velocities off the east coast of Mexico as low as 3.20 km/sec. Computations based on ray theory show that Lg with these velocities may be shear waves guided in the upper crust by an alternation of refractions and surface reflections. The slower velocities would result from shear waves traveling almost entirely in the sedimentary layer. Polarization of Lg is related to the angle at which the guided shear waves are incident at the surface. Calculations show that Lg would travel in a continental crust covered by a considerable thickness of water, thus supporting the hypothesis that the absence of Lg indicates that an oceanic crust underlies such bodies of water as the Gulf of Mexico. All computations were run on the Univac 1103 at Southern Methodist University.

Indians of the Mississippi Valley and the East Coast of Mexico

Indians of the Mississippi Valley and the East Coast of Mexico