Lake Enriquillo Research Articles

Earthquake Swarms in Southern Hispaniola Revealed by Spatiotemporal Evolution of Seismicity from Multi-Station Template Matching

ABSTRACT Earthquake swarms have provided useful insights into driving mechanisms for triggered earthquakes. However, a majority of earthquake swarms consist of microseismicity in which observations sometimes are limited because of detection ability. Here, we apply a multi-station template matching technique to two temporary seismic networks and investigate microseismicity in southern Hispaniola. We detect a total of 6065 and 1366 new events for the 2010 and 2013–2014 datasets, respectively, using templates from pre-existing catalogs. The magnitude of completeness (Mc) of our updated catalogs drops from 1.7 to 1.2 and from 2.2 to 1.4 for the 2010 and 2013–2014, respectively, after combining new detections with the templates. With the improvement of seismic detections, the spatiotemporal distribution of the seismicity showcases three instances of earthquake swarms. The first one is located offshore on the Trois Baies fault, with over one thousand events triggered during mid-February to early March 2010, whereas the other one is distributed along the western Léogâne fault, which occurs within a day and shows many earthquakes with similar waveforms. The third one is found in the north of Lake Enriquillo in the Dominican Republic, which outlines a nearly vertical fault plane. Our updated earthquake catalogs and observations of these swarms provide necessary information for seismic hazard assessment in southern Hispaniola and will facilitate continued investigations of seismology in the area.

The Incredible and Sad Story of Boca de Cachón: How a Rural Community in the Hispaniola Is in a Prolonged, Heartless, and Predictable Climate Crisis

This article aims to briefly review the socio-economic impact caused by the flooding of Lake Enriquillo on the inhabitants of Boca Cachón due to the complex local phenomenon related to climate variability. Between 2003 and 2014, Boca de Cachón and the communities surrounding Lake Enriquillo were deeply affected by flooding of the Lake’s rising waters. Lake Enriquillo is the largest wetland in the Caribbean and the first designated RAMSAR site. In turn, Boca de Cachón could be considered the first human settlement formally displaced because of climate variability in the Dominican Republic and probably one of the first in the Americas in the twenty-first century. Boca de Cachón is a rural Municipal District located to the northwest of the municipality of Jimaní, with a population of around 3000 inhabitants on the southwest border with the Republic of Haiti and located in the Biosphere Reserve Jaragua-Bahoruco-Enriquillo. Given the future climatic scenarios for the Dominican Republic and the possible climate change that could exacerbate by excess or, by default, the socio-environmental problems in the Lake’s belt, it is necessary to support the communities in their capacity-building processes. The lessons learned from Boca de Cachón can serve as a learning space for adaptation processes in rural environments in the Caribbean region.

Lake Volume Data Analyses: A Deep Look into the Shrinking and Expansion Patterns of Lakes Azuei and Enriquillo, Hispaniola

This paper presents the development of an evenly spaced volume time series for Lakes Azuei and Enriquillo both located on the Caribbean island of Hispaniola. The time series is derived from an unevenly spaced Landsat imagery data set which is then exposed to several imputation methods to construct the gap filled uniformly-spaced time series so it can be subjected to statistical analyses methods. The volume time series features both gradual and sudden changes the latter of which is attributed to North Atlantic cyclone activity. Relevant cyclone activity is defined as an event passing within 80 km and having regional monthly rainfall averages higher than a threshold value of 87 mm causing discontinuities in the lake responses. Discontinuities are accounted for in the imputation algorithm by dividing the time series into two sub-sections: Before/after the event. Using leave-p-out cross-validation and computing the NRMSE index the Stineman interpolation proves to be the best algorithm among 15 different imputation alternatives that were tested. The final time series features 16-day intervals which is subsequently resampled into one with monthly time steps. Data analyses of the monthly volume change time series show Lake Enriquillo’s seasonal periodicity in its behavior and also its sensitivity due to the occurrence of storm events. Response times feature a growth pattern lasting for one to two years after an extreme event, followed by a shrinking pattern lasting 5–7 years returning the lake to its original state. While both lakes show a remarkable long term increase in size starting in 2005, Lake Azuei is different in that it is much less sensitive to storm events and instead shows a stronger response to just changing seasonal rainfall patterns.

Development of digital bathymetry maps for Lakes Azuei and Enriquillo using sonar and remote sensing techniques

AbstractThis article presents an improved algorithm for optimization and development of a digital bathymetric model (DBM) for Lake Azuei (LA) (Haiti) and Lake Enriquillo (LE) (Dominican Republic) using the ANUDEM method. Both sonar data and contour lines of the lakes’ layout extracted using Landsat imagery were compiled for bathymetry development. We show that the performance of the ANUDEM method was strongly dependent on the density and irregularity of the spatial distribution of the data. Changing the resolution of the output grids and deriving auxiliary topographically corrected contours improved the ANUDEM performance and minimized the systematic errors of the method. Statistical analysis showed no significant difference between measured and interpolated depths, characterized by a root mean square error of less than 0.71 m (LE) and 0.96 m (LA), and a median difference of −0.009 m (LE) and 0.012 m (LA) on average. The shape reliability analysis revealed a relationship between accuracy and the depth and slope values, increasing in the center of the lakes where they are deep and the slope is gentle.

The Tectonics and Active Faulting of Haiti from Seismicity and Tomography

AbstractOblique convergence of the Caribbean and North American plates has partitioned strain across a major transpressional fault system that bisects the island of Hispaniola. The devastating MW 7.0, 2010 earthquake that struck southern Haiti, rupturing an unknown fault, highlighted our limited understanding of regional fault segmentation and its link to plate boundary deformation. Here we assess seismic activity and fault structures across Haiti using data from 33 broadband seismic stations deployed for 16 months. We use traveltime tomography to obtain relocated hypocenters and models of Vp and Vp/Vs crustal structure. Earthquake locations reveal two clusters of seismic activity. The first corresponds to aftershocks of the 2010 earthquake and delineates faults associated with that rupture. The second cluster shows shallow activity north of Lake Enriquillo (Dominican Republic), interpreted to have occurred on a north‐dipping thrust fault. Crustal seismic velocities show a narrow low‐velocity region with an increased Vp/Vs ratio (1.80–1.85) dipping underneath the Massif de la Selle, which coincides with a southward‐dipping zone of hypocenters to a depth of 20 km beneath southern Haiti. Our observations of seismicity and crustal structure in southern Haiti suggests a transition in the Enriquillo fault system from a near vertical strike‐slip fault along the Southern Peninsula to a southward‐dipping oblique‐slip fault along the southern border of the Cul‐de‐Sac‐Enriquillo basin. This result, consistent with recent geodetic results but at odds with the classical seismotectonic interpretation of the Enriquillo fault system, is an important constraint in our understanding of regional seismic hazard.

The Cuban Crocodile (Crocodylus rhombifer) from Late Quaternary Underwater Cave Deposits in the Dominican Republic

Late Quaternary fossils representing a locally extinct population of the Cuban crocodile (Crocodylus rhombifer) are reported from two underwater caves in the Dominican Republic. A large fossil sample of C. rhombifer, from Oleg's Bat Cave near Bavaro in the southeastern Dominican Republic, consists of four nearly complete skulls, numerous isolated cranial elements and mandibles, and more than 100 postcranial bones representing most of the skeleton. These fossils were collected from a completely submerged portion of the cave at a depth of 11 m and about 100 m from the nearest entrance. A skull, mandibles, and two vertebrae of a Cuban crocodile were also found in a second cave called Ni-Rahu, northeast of Santo Domingo.We identify the fossil crocodile skulls from the Dominican Republic as Crocodylus rhombifer because they share the following characters with modern skulls of C. rhombifer from Cuba (as well as fossil skulls from Cuba, the Bahamas, and Cayman Islands): short, broad, and deep rostrum; large orbits; convex nasals along the midline (midrostral boss); prominent swelling on the lacrimals anterior and medial to the orbits; low but obvious ridges extending anteriorly from the lacrimals to the nasals and posteriorly from the lacrimals to the prefrontals and frontals, outlining a distinct diamond- or rhomboid-shaped structure; strongly concave interorbital region and cranial roof; high, narrow ridges on the internal margins of the orbits, extending from the prefrontals to the frontals and posteriorly to the postorbitals; prominent ridges along the lateral margins of the cranial roof on the postorbitals and squamosals, terminating as noticeable protuberances on the posterolateral corners of the squamosals; premaxillary/maxillary suture on the palate essentially horizontal or transverse to the long axis of the skull at the level of the first maxillary tooth; 13 teeth in the maxilla.Certain aspects of the ecology and anatomy of living Crocodylus rhombifer in Cuba, and carbon isotope data from fossil crocodile bones from both the Dominican Republic and the Bahamas, indicate that the Cuban crocodile is a terrestrially adapted predator. The fossil deposits in Oleg's Bat Cave and other underwater caves in the Dominican Republic lack freshwater vertebrates, such as fish and turtles, but contain abundant samples of hystricognath rodents, small ground sloths, and other terrestrial vertebrates, including large land tortoises, that apparently were the primary prey of the crocodiles. Bats are abundant in the fossil deposits in Oleg's Bat Cave, and may have been an additional food source. Bone collagen from a tibia of C. rhombifer from Oleg's Bat Cave yielded an AMS radiocarbon date of 6460 ±30 ryrBP (equivalent to 7320 to 7430 cal yrBP). The chronology for the local extinction of C. rhombifer in Hispaniola is currently unknown, except to document the presence of this species in the eastern Dominican Republic in the early Holocene. Radiocarbon dates and historical records confirm that Cuban crocodiles survived into the period of European colonization (post-1492) in the Bahamas and on Grand Cayman. The only species of crocodile currently found in Hispaniola, the American crocodile (C. acutus), occurs in coastal marine habitats and in two inland brackishwater lakes: Lago Enriquillo in the Dominican Republic and the nearby Etang Saumâtre in Haiti. C. acutus has no fossil record in Hispaniola or elsewhere in the West Indies, suggesting that this species may be a very recent (late Holocene) immigrant in the Antillean region. Crocodylus rhombifer has one of the most limited geographic ranges of any living crocodylian species, known only from freshwater swamps in south-central Cuba and the Isla de Juventud (Isla de Pinos) off the southwestern coast of Cuba. Locally extinct or extirpated populations of C. rhombifer from fossil deposits in the Dominican Republic, Grand Cayman, and the Bahamas document a considerably wider distribution for this spe

Impacto de las aguas superficiales en el aumento del nivel de las aguas del Lago Enriquillo

A partir del 2014 el lago Enriquillo, localizado en el suroeste de la República Dominicana, empezó a evidenciar un continuo crecimiento en el nivel de sus aguas llegando, de 265 km2 hasta alrededor de 375 km2. Esto duró hasta el 2013 cuando se empezó a observar un decrecimiento paulatino hasta el momento. Durante todo este tiempo se han venido llevando a cabo investigaciones para determinar la causa, o causas, que dieron lugar a este fenómeno. Aunque se han planteado varias hipótesis sobre dicha crecida aún no existe un consenso generalizado sobre la crecida del lago. Lo que se plantea en este trabajo de investigación es que, exceptuando el aporte de aguas superficiales a través de eventos extremos, la mayor cantidad de agua que drena en el lago Enriquillo es a través del subsuelo, ya que la mayoría de los ríos y canales alrededor del lago han estado secos durante los últimos dos años. Gran parte del agua que fluye desde las sierras de Neyba y Bahoruco, desde el Norte y Sur respectivamente, es utilizada para riego y ganadería, en menor escala. El lago Enriquillo no recibe aporte de aguas superficiales desde la parte Oeste, y en cuanto al Este solo drena de manera continua el canal Cristóbal, el cual tiene un flujo que en gran medida depende del manejo de una compuerta y del uso para agricultura.

Influence of Climatic Phenomena on Sedimentation and Increase of Lake Enriquillo in Dominican Republic, 1900-2014

From 2003 to 2013, Enriquillo Lake, Dominican Republic, showed an increase in water level of 13 meters, with its level changing from 42 to 29 meters below sea level (BSL). In 2003, its maximum depth was approximately 24 meters; in 2013, it was 37.1 meters. The water surface coverage increased from 194.9 to 391 km2, flooding agricultural areas and leaving hundreds of people homeless. In addition, salinity increased from 105 ‰ to 23.4 ‰, a decrease of 4.47 times comparable to the volume change, which increased 4.48 times according to topographic and bathymetric maps. These changes began with Tropical Storm Odette and occurred progressively through 15 additional tropical cyclones (TC) or hurricanes that struck Lake Enriquillo between 2003 and 2011. Other climatic phenomena that have great influence on the Caribbean climate include the following: North Atlantic Oscillation (NAO), Southern El Niño Oscillation (ENSO), the trade winds, North Atlantic Warm Pool, Multidecadal Oscillation, the anticyclone Caribbean Regulator Climate Centers (CRCCs), and the Bermuda-Azores High (Mendez-Tejeda et al. 2017). The sediment records deposited by the runoff from these phenomena were analyzed. These proxy records were used to determine the decadal fluctuations related to cyclonic systems and the resultant effect upon increasing the level of Lake Enriquillo (LE). The accumulation rate (TAS) was estimated by means of 210 (210Pb) lead radiochronology, elemental composition, and mineral and ignition loss. These results were correlated with the extreme climatic events that affected the Lake Enriquillo Basin (LEB) from 1900 and 2011.

Development of Geospatial and Temporal Characteristics for Hispaniola’s Lake Azuei and Enriquillo Using Landsat Imagery

In this paper, we used Landsat imagery for water body identification to create a novel 36-year surface area extent time series for lakes Azuei (Haiti) and Enriquillo (Dominican Republic) aimed at illuminating the dramatic temporal changes of these two lakes not just at yearly but at monthly or even sub-monthly scales. We used the Normalized Difference Water Index (NDWI) to extract water features and we also used spatial differentiation and thresholding techniques to remove clouds and associated shadows from the scene that were then passed through gap filling algorithms to complete and extract the lake extent polygons. We also explored the challenges that arrive from trying to combine RS-based Digital Elevation Model data with locally collected bathymetric data to yield a seamless representation of the topographic features of the rift valley that contains the two lakes. This “bathtub” model was then meshed with the lake extent polygons to compute lake volumes, maximum depths, and geospatially referenced lake levels rating curves. We used this data to examine the lakes and their geospatial characteristics in the context of the lakes’ growth/shrinking patterns. While we did not carry out a full hydrologic analysis we attempted to illuminate how specific lake levels cause what type of flooding and especially answered the questions if (a) Lake Azuei would ever spill into Lake Enriquillo, and (b) what the maximum lake levels need to be before spilling into neighboring watersheds.

Hydrodynamic Study of Lake Enriquillo in Dominican Republic

This study presents an analysis of the hydrochemical characteristics of Lake Enriquillo in the southwestern region of the Dominican Republic. This lake is hypersaline and endorheic. The climatology of the region is influenced by the Caribbean Regulator Climate Centers (CRCCs). Due to the endorheic nature of the basin, evaporation plays an extremely important role in its dynamics [1]. During the study period, in November 2002, the water level of Lake Enriquillo was 42 m below sea level (BLS), and the salinity level was 104.2‰. By 2014, the water level of the lake rose to 29 m below sea level, and the salinity decreased to 23.4‰, as a result of the high cyclonic activity in the Caribbean region.

Physicochemical analysis of Lake Enriquillo in Dominican Republic

The water level in Lake Enriquillo in the Dominican Republic (DR) has increased by an unprecedented amount over the last decade, inundating thousands of acres of farmland and more than a dozen villages and inflicting adverse social, environmental, and economic impacts on the nation. The Lake Enriquillo Basin (LEB), located near the towns of Independencia and Bahoruco in the southwest region of the DR, is bordered to the north by the Sierra de Neyba mountain range and to the south by the Sierra de Bahoruco mountain range. Lake Enriquillo is hypersaline and endorheic, with a water level that normally fluctuates between 40–50 m below sea level (BSL). However, since 2000, both Lake Enriquillo and Lake Azuei (Sumastre) in Haiti have experienced alarming water level increases, with Lake Enriquillo’s water level rising to 17.2 m BSL This article explores the changes in some of the important physicochemical parameters—such as salinity, dissolved oxygen, temperature, and pH—that have occurred in the period from 1977 to 2012. The highest salinity value occurred in 2012, at a value 103.1‰, with an average increase of 27.06‰, coinciding with the lake level of 17.2 m BSL. Changes in these parameters have caused damage to the ecosystem and the lives of people and species that inhabit the region.

Genetic diversity and differentiation of the Critically Endangered Hispaniolan palm Coccothrinax jimenezii M.M. Mejía & R.G. García based on novel SSR markers

Coccothrinax jimenezii M.M. Mejía & R.G. García is a Critically Endangered palm species restricted to Haiti (one population near the city of Gonaïves with 43 individuals) and the Dominican Republic (one population on the shores of Lago Enriquillo with 18 individuals). The species faces two major conservation challenges: (1) water level rise in the hypersaline Lago Enriquillo and (2) overexploitation of leaves for making brooms in Haiti. Six SSR microsatellite loci were used to access levels of genetic variation and the genetic structure of these two populations. Only the Gonaïves site had loci that deviated from Hardy–Weinberg Equilibrium (2 loci). Both populations exhibited a relatively large number of private alleles (13 in Lago Enriquillo and 14 in Gonaïves) and did not show evidence of genetic bottlenecks. Inbreeding coefficients were much larger in Gonaïves (Fis = 0.232) than in Lago Enriquillo (Fis = 0.093). We detected high genetic differentiation among these sites (Fst = 0.497) suggesting that additional taxonomic studies are needed to determine if individuals from these two sites should be recognized as belonging to two different taxa. Because of taxonomic uncertainties we recommend not to translocate individuals between sites in future conservation activities involving this species.

Uneven socio-ecologies of Hispaniola: Asymmetric capabilities for climate adaptation in Haiti and the Dominican Republic

This article adopts a “capabilities” approach to climate justice to examine a globally unique phenomenon: a decade of unprecedented surface area growth in Lake Azuéi (the largest lake in Haiti) and Lake Enriquillo in the Dominican Republic (the largest lake in the Caribbean region). The objective was to explore how two neighbouring communities and their governments respond to large-scale environmental change within connected but uneven political ecological contexts. Current climate change impacts in this bi-national island present an opportunity to better understand not only local climate justice but also how fragmented sovereignty, territoriality, and citizenship regimes may affect processes of climate adaptation. The researchers conducted 27 semi-structured interviews in the Dominican Republic and 11 in Haiti, with open ended questions. The data analysis explores impacts of the lakes’ growth; perceived causes and solutions; access to assistance; views on responsibility; and capacities for mobilization, bi-national cooperation, and international partnerships. The article argues that different capabilities for climate adaptation are shaped by historical path dependencies, local institutional contexts, and international linkages; and that attaining climate justice requires attention to these factors within a collective normative framework. The conclusion examines how climate science, research partnerships, and citizen participation might be leveraged to help build binational adaptation strategies grounded in a capabilities approach to climate justice.

On the Hydrometeorological Changes of a Tropical Water Basin in the Caribbean and Its Sensitivity to Midterm Changes in Regional Climate

AbstractGlobal climate change manifests in the Caribbean basin as increased SSTs, precipitation anomalies, and changes in atmospheric moisture content, among other effects. These regional climate changes have a profound impact on the local human, flora, and fauna populations. Such is the case of the Enriquillo basin, a highly sensitive ecosystem located in the southwestern region of the Caribbean island of Hispaniola. The major bodies of water in the basin, Lake Enriquillo and Lake Azuéi, show a shrinking and expanding pattern since the early 1980s. The surface area of Lake Enriquillo was observed to reach minimum values in 2004 (170 km2), shifting to a rapid expansion to its current levels (>350 km2 as of late 2013). Lake Azuéi is observed to grow at similar rates. This lake expansion could be attributed to regional climate change. Long-term regional climate data reflect increasing SSTs (~1°C), air temperatures (~0.37°C decade−1), dewpoint (~0.66°C decade−1), and precipitation (~30%); no reliable local precipitation records were found. Furthermore, local governments are being forced to issue evacuations, prompting one of the first cases of environmental refugees not caused by an extreme event (e.g., a hurricane or tsunami). The hypothesis of lake expansion in the Enriquillo basin as a regional response to climate change is further investigated with the use of an integrated regional atmospheric modeling system. Model results from simulations performed for years during the lakes’ lowest water levels (2003–04) and during their continued growth (2012–13) show increased total accumulated surface precipitation, atmospheric liquid water content, and an enhanced positive feedback system that produces orographic cloud cover in the surrounding tropical montane cloud forests as a consequence of the changing atmospheric and oceanic conditions.

Factors Contributing to the 2005-Present, Rapid Rise in Lake Levels, Dominican Republic and Haiti (Hispaniola)

Lakes Enriquillo and Azuei, the two largest lakes in Hispaniola and in the Caribbean, have risen 10 and 5 m respectively within the last 8 years. Higher lake levels have submerged towns, road systems, agricultural lands and utilities, and have threatened to submerge the major overland highway that connects the Dominican Republic and Haiti. In this study, we use CHIRP seismic data, satellite imagery, and regional meteorological data to quantify and assess controls on the recent lake level rises. Although data are limited, the analyses indicate that the lakes’ water level changes may be attributed to a combination of increased rainfall and natural or man-made changes to the hydraulic connectivity of the various water bodies within the drainage basin. We show that a weak correlation exists between changes in Lake Enriquillo’s and Azuei’s water levels and precipitation rates (0.2 and 0.08 respectively, 1984-2012) and that both lakes experience periods of anti-correlation where, for example, water level drops at Lake Azuei (~20 masl) coincide with water level rises at Lake Enriquillo (41 mbsl). From these observations, we propose that the lakes experience intermittent periods of hydraulic connectivity along reactivated or newly developed stratigraphic-controlled sub-surface transport pathways. We also note that moderately small earthquakes along the large active fault system that extends through both lakes may promote or limit hydraulic conductivity on decadal or shorter time scales. The extents to which recent earthquakes have triggered changes in groundwater flow at this site remain unclear but represent an important topic of future research.

The Dominican Republic reader: history, culture, politics

Eric Paul Roorda, Lauren Derby and Raymundo Gonzalez, eds. The Dominican Republic Reader: History, Culture, Politics. Durham, NC: Duke University Press, 2014. 536 pp.R E VIE W E D BY F .S.J. L E DG I S T E RTHERE ARE ONLY TWO LAND BORDERS IN THE INSULAR Caribbean, on the islands of Saint Martin and Hispaniola. The Dominican Republic sits east of the longer of the two of these. The Dominican Republic occupies two-thirds of Hispaniola, the second largest of the Antilles, and is home, as this fascinating book makes clear, to some of the extremes of the region: the highest point (Pico Duarte); the lowest (Lago Enriquillo); the oldest European structure in the Americas (the Torre de Homenaje in Santo Domingo); the oldest university in the Americas (the Universidad Autonoma de Santo Domingo); it is also the first place African slaves landed in the Americas.This collection of readings brings to life accounts, as the sub-title indicates, of the history, politics, and culture of the country from its pre-history down to the early twenty-first century. It enables the student to obtain an idea of the richness both of the history of the Dominican Republic, and of the complexity of Dominican identity as the country has battled to define itself in opposition to its western neighbour, Haiti, which is unquestionably the black republic not only of the Caribbean but of the Americas as a whole. Many of the readings, in particular those that deal with the history and politics of the Dominican Republic from the moment of the Haitian Revolution on, attend to the ways in which Dominicans have been ambivalent, if not downright hostile, regarding their own enslaved African roots and have sought to build an identity on an imagined memory of the original Taino inhabitants of the land. Race makes its presence felt not only in the manner in which Dominicans have avoided dealing with the African roots of their history, but also in the way in which the United States has seen the people of that country, including one episode in which Barbadians in the Dominican Republic complain about how US occupation troops in the 1920s suppressed their efforts to organise a branch of the Universal Negro Improvement Association (269-70).One of the things that reading this text brought back to me, in fact, was the memory of discovering that the Dominican teaching assistant in the Spanish Department at the University of the West Indies, Mona, in the days when I was a student, had 'Indio' on his cedula de identidad when he was clearly not an Amerindian, as did his friends from his homeland. One of the many basic facts about the country that this text unveils is the root of this historic self-deception that lies at the heart of the way that the people of the Dominican Republic define themselves.The history includes not only accounts of the Taino drawn from the work of Irving Rouse, but descriptions by Spanish conquistadors, including Columbus himself; an excerpt from Exquemelin's buccaneer history; one from Moreau de Saint-Mery's account of Saint-Domingue; the document with which the Dominicans proclaimed their own independence; reports by US officials, and American occupiers; one account by Jose Marti; reports favouring the Trujillo dictatorship, and statements by opponents; statements justifying the second American occupation, and those opposed; and a number of documents relating to the post-1978 emergence of democracy. …

Numerical modeling of seawater intrusion into endorheic hydrological systems

Several groundwater endorheic base levels are known in different parts of the world. Some of them allow seawater encroachment into them. Two examples of such groundwater systems, at Lake Asal in the Afar Depression of East Africa and Lago Enriquillo in the Dominican Republic, have been modeled using FEFLOW. The simulated flow pattern reproduces the seawater encroachment all the way from the sea to the endorheic base level. When the water in that base level undergoes concentration to brine through evaporation, the dense brine starts to flow below the encroaching seawater body in the opposite direction toward the sea. These processes reach steady-state conditions in a relatively short time of several hundred years.

The Lago Enriquillo fringing reef (Dominican Republic): a unique window into Holocene coral reef ecosystems of the Caribbean Sea

The Lago Enriquillo fringing reef (Dominican Republic): a unique window into Holocene coral reef ecosystems of the Caribbean Sea

The habitats of Leptochloopsis virgata in the Dominican Republic

This paper deals with the Leptochloopsis virgata esparto patches growing in the Dominican Republic. These communities thrive mostly in shaded areas, as happens in the southwest of the island and the Cibao valley, where xericity records are high and vegetative inactivity lasts for over 7 months. The Leptochloopsis virgata esparto patches tend to be located in the Caribbean- Atlantic Subprovince, on the Quaternary marls of the Cibao valley, Azua, Bani, Lago Enriquillo, and on the serpentines of Puerto Plata, with an ombrotype ranging from semiarid to subhumid, but with a semiarid and dry character in the areas colonized by the espartillo and a thermotype which always remains infra- tropical. The high percentage of endemic species and media give rise to a high number of endemic, ecologically and geobotanically, highly valuable habitats. This paper suggests two new alliances and four associations. These latter, at least, present an endemic character and, consequently, should be considered as priority habitats for preservation purposes, since they are located in man—altered areas and the risk of species extinction cannot be ignored.

Physical and chemical properties of hypersaline Lago Enriquillo, Dominican Republic

Physical and chemical properties of hypersaline Lago Enriquillo, Dominican Republic