A toxic Pseudo-nitzschia bloom in Todos Santos Bay,northwestern Baja California,Mexico

A toxic Pseudo-nitzschia spp. bloom in the Todos Santos Bay area (31.8°N), Mexico, is described. This is the southernmost report of the presence of domoic acid (DA) in the California Current System and it is also the first report of the distribution of toxic Pseudo-nitzschia species and DA on the Baja California west coast. The maximum cell abundance of Pseudo-nitzschia was 3.02 × 10⁵ cells L^?1 and the maximum concentration of DA in particulate matter (pDA) was 0.86 μg L^?1. P. australis constituted the major proportion of cells identified as Pseudo-nitzschia. The environmental conditions associated with wind-driven upwelling were the cause for the accumulation of toxic cells. Maximum pDA and cell concentration were detected around 14 °C. The ratio of the concentration of macronutrients seemed to be the important factor for the accumulation of P. australis. The highest cell abundance was detected in areas with a high Si(OH)₄ to N ratio in the entire water column. Therefore, the relative increase of silicate concentration related to upwelling conditions was the probable cause for the accumulation of P. australis. Maximum photosystem II (PSII) quantum efficiency of charge separation (F_v/F_m) was negatively correlated to the pDA to fucoxanthin ratio. This ratio was used in this work as an index of cellular DA content. Therefore, the photosynthetic competence of the cells might be an important factor that affected their DA cellular content.     

Association of Vibrio cholerae with plankton in coastal areas of Mexico

The El Niño event of 1997/1998 provided an opportunity to carry out a field experiment in which the relationship of sea surface temperature and the association of Vibrio cholerae with marine plankton could be assessed in Mexican coastal and estuarine areas. Plankton samples were collected from May 1997 through June 1999. Sites included the Mexican ports of Veracruz, Coatzacoalcos and Frontera in the Gulf of Mexico and Ensenada, Guaymas, Mazatlán, Manzanillo, Acapulco and Oaxaca in the Pacific Ocean. Sampling was also accomplished during two oceanographic cruises in the Yucatan channel of the Caribbean Sea. Bacteriological analyses for V. cholerae serogroups O1 and O139 were carried out. Also, the taxonomic structure of the plankton populations was determined. Vibrio cholerae O1 was detected only in Veracruz samples collected during April, May and June 1999, when La Niña climatic conditions prevailed. It is concluded that V. cholerae O1 in Mexico derives from its marine and estuarine origin and not from sewage contamination. The significant number of Acartia tonsa copepodites and V. cholerae copepodite-positive samples suggests a significant role of this copepod in the occurrence and distribution of V. cholerae in coastal areas of Mexico.     

Copepod daily egg production and growth rates in Bahia Magdalena, Mexico

The hydrography, chlorophyll (Chl) a and egg production of thecopepods Paracalanus parvus (Claus), Acartia lilljeborgii Giesbrecht,Acartia clausi Giesbrecht and Centropages furcatus were estimateddaily between 7 February and 5 March 1998 in Bahía Magdalena,Baja California Sur, México. Temperature was homogeneousthroughout the water column during the study (20°C). Positiveanomalies of the sea surface temperature were recorded 10 monthsbefore and during the sampling period compared with a temperature–timeseries, 1982–1989. Chlorophyll a concentration indicatedoligotrophic conditions with <10 Chl a mg m^–2 from15 m depth to the surface during the first half of the study,with a pulse of moderate concentration in the second part. Theegg production of these copepod species was usually suboptimal,and not correlated with Chl concentration or temperature. Eachgenus responded differently to Chl a and to environmental variables.The rate of input of turbulent kinetic energy to the ocean bythe winds, indicated by the cube of the wind speed, was negativelycorrelated to copepod egg production, suggesting that turbulencecan disperse phytoplankton patches and may affect the carboninput to these copepod populations. Turbulence and a previouslong warming event observed several months before the winterseason were probably the most important factors in limitingcopepod production and growth rates.     

Spatial patterns and GIS habitat modelling of fish in two French Mediterranean coastal areas

The spring and summer distribution of adults and larval fish stages of Sparids and Scorpaenids was studied in two sites in the western Mediterranean. Fish adults and larvae of those two taxa were identified and sorted according to their life stages in order to study their distribution and develop suitable habitat maps. Study areas were located on French coastal waters, the “Côte Bleue” Marine Park (CBMP) has an east-west orientation with substratum dominated by Posidonia beds and the Marine Reserve of Cerbère-Banyuls (MRCB) runs north–south and is dominated by rocky substrates. Generalised Additive Models (GAM) combined with Geographic Information System (GIS), were used to model the suitable habitats for fish larvae and adults. During spring months, waters exhibit low Sea Surface Temperatures (SST), low Photosynthetically Active Radiation (PAR), high values of Sea Surface Chlorophyll-a concentration (Chl-a), and mostly negative values of Sea Level Anomaly (SLA) indicating anticyclonic eddies. During summer months, waters have higher values of SST, lower values of Chl-a and positive values of SLA indicating cyclonic eddies. The results revealed different environmental responses in the distribution of fish adults and larvae in the CBMP and MRCB. Suitable habitats for adult were mainly dependent on the substrate types (Posidonia meadows and sand) and they were found close to the coast, whereas fish larvae were dependent on environmental cues (Chl-a, SLA, SST) with a sparse spatial distribution.     

Microbial identification of the Nichupte-Bojorquez coastal lagoon in Cancun,Mexico

The microbial community of the Nichupte-Bojorquez lagoon system located in Cancun, Mexico was evaluated using surface-water samples that were collected before and after the hurricane Wilma impacted the area on October 2005. The analysis was done using a culture-independent molecular approach involving Amplified Ribosomal DNA Restriction Analysis, and CLuster ANalysis of Sequences. A total of 61 16S ribosomal RNA genes were differentially selected and screened. The results show a bacterial profile dominated by Cytophaga-Flavobacteria/Flexibacter-Bacteroidetes group; the Bacteroidetes group in particular. The second most abundant group was assigned to the Proteobacteria group and a minor proportion of bacteria that belongs to the Cyanobacteria and Bacilli classes. Our study gives the first insight into the bacterial community adapted to this heavily polluted but occasional oligotrophic coastal lagoon; no substantial differences were, however, found.     

Spat collection studies on pearl oysters Pinctada mazatlanica and Pteria sterna (Bivalvia,Pteriidae) in Bahia de La Paz,South Baja California,Mexico

The present work deals with the temporal and bathymetrical variations of the epifaunal community associated with two species of pearl oysters (Pinctada mazatlanica and Pteria sterna) during a seed collecting season from June to November 1989. A total of 63 items (species, genera and/or families) were recorded; their variations in presence and abundance were followed during three periods (June–July, August–September and October–November). The collectors were examined for different immersion times (2, 4, 6 and 8 weeks) for each period. Community structure was compared through the Brillouin Index, the Morisita Index and the Importance Value.We define the chronology of spatfall for both species of pearl oysters and their bathymetrical distribution. Relationships between these species and the epifaunal community present into the collectors were analysed, searching for possible noxious effects on the survival of juvenile pearl oysters, and identifying index species related with their spatfall. A strategy for starting massive seed collection of both species is established, particularly for P. mazatlanica.     

Conservation strategies for coastal wetlands in the Gulf of California,Mexico

Wetlands worldwide, the fisheries they support, and the communities that depend on them are threatened by habitat modification. We describe strategies being used for wetland conservation in the Gulf of California, Mexico, their effectiveness, and challenges for implementation. We base our analysis on the authors’ experience working for local environmental non-governmental organizations and available literature. The strategies discussed include public and private policy instruments such as Environmental Impact Evaluations, environmental land easements, concessions and transfer agreements, Natural Protected Areas, and international agreements such as the Ramsar convention and the North American Wetlands Conservation Act. We present examples from the Gulf of California that highlight some of the challenges to wetland conservation. These challenges range from governmental failure to enforce existing environmental legislation, lack of verification of requirements for development projects, to low economic penalties for wetland modification or destruction. We found that in the Gulf of California successful conservation of coastal wetlands required a combination of policy instruments and relied on integrating science, management, and public participation through partnerships between non-governmental institutions, academic institutions, community stakeholders, and government agencies.     

Schistosomal glomerulopathy and changes in the distribution of histological patterns of glomerular diseases in Bahia, Brazil

Distinct patterns of glomerular lesions, including membranoproliferative glomerulonephritis and focal segmental glomerulosclerosis, are associated with infection by Schistosoma mansoni or Schistosoma japonicum. Evidence suggests that immune complex deposition is the main mechanism underlying the different forms of schistosomal glomerulonephritis and that immune complex deposition may be intensified by portal hypertension. The relationship between focal segmental glomerulosclerosis and schistosomiasis remains poorly understood. A clinicopathologic classification of schistosomal glomerulopathies was proposed in 1992 by the African Association of Nephrology. In Brazil, mass treatment with oral medications has led to a decrease in the occurrence of schistosomal glomerulopathy. In a survey of renal biopsies performed in Salvador, Brazil, from 2003-2009, only 24 (4%) patients were identified as positive for S. mansoni infection. Among these patients, only one had the hepatosplenic form of the disease. Focal segmental glomerulosclerosis was found in seven patients and membranoproliferative glomerulonephritis was found in four patients. Although retrospective studies on the prevalence of renal diseases based on kidney biopsies may be influenced by many patient selection biases, a change in the distribution of glomerulopathies associated with nephrotic syndrome was observed along with a decline in the occurrence of severe forms of schistosomiasis.     

Linking fish consumption patterns and health risk assessment of mercury exposure in a coastal community of NW Mexico

We aimed at characterizing the methylmercury (MeHg) exposure through fish consumption in two populations (common general and fishing-related population (FRP)) using a probabilistic health risk assessment in children, women of childbearing age, and adults in Mazatlán. The hazard quotients (HQs) were obtained from fish consumption, defined through a survey, and the levels of mercury in fishery products, obtained from published information. The average fish ingestion rate (IR_food) was higher in the FRP (167.85 g d^?1) than in the general population (GP) (140.9 g d^?1). However, HQs were significantly (p < 0.05) higher in the GP (ranging from 0.18 to 10.91) compared to the FRP (0.20 to 2.48); significant differences were also found among groups of both populations. Remarkably, children in both populations exhibited the highest proportions of risk, reaching up to 97% in GP. For all populations, fish consumption was the most important variable influencing MeHg exposure. Overall, for MeHg exposure, there is no safe level of fish consumption without risk, and actions should be taken to mitigate possible risk; further research with current data is needed to assess potential health risks associated with MeHg exposure, particularly in children.     

Community structure and association of waterbirds with spatial heterogeneity in the Bahia Magdalena-Almejas wetland complex, Baja California Sur, Mexico

Community structure and association of waterbirds with spatial heterogeneity in the Bahia Magdalena-Almejas wetland complex, Baja California Sur, Mexico. To test the hypothesis that spatial heterogeneity determines waterbird diversity in a coastal wetland, we compared waterbird density, diversity, and species composition among various habitats and landscapes units in Bahia Magdalena-Almejas, Baja California Sur, Mexico. Based on diversity patterns and bird distribution, we assessed the effect of coastal development on the waterbird community structure. To gather information on habitat features and waterbird populations we conducted waterbird censuses in 329 habitat segments along the internal coastline of the study area, from February 2002 to February 2003. We performed non-parametric analyses to test the null hypothesis of no diference on waterbird density, and diversity among landscape units and seasons. The species composition was evaluated using ordination techniques. Waterbird density was higher in winter and autumn in the three lagoons of the study area, particularly in the insular coast, sandy beach and dunes; it was higher in the few segments of antropic sustrate. Diversity was significantly higher in mangrove habitat along the peninsular coast, and in mangrove-dunes association on the insular coast. Although modification of coastal natural habitat and boat transit disturbance had no influence on waterbird density or diversity, the highest richness of waterbirds occurred in well preserved areas. Species composition analysis showed differences between Santo Domingo Channel and Magdalena Bay. Pelagic and mangrove habitat had a species composition difference higher than those associations in other habitats. Such differences in species assemblages by habitat and landscape units suggest that communities are structured according to the range of available natural resources in structurally complex habitats, and that dominant piscivorous waterbird species were favored in this community.     

Bacterial diversity, composition and dynamics in and around recreational coastal areas

A comparative study on the composition of bacterial communities in a coastal area in the West Mediterranean receiving the impact of recreation-derived activities (from a marina and a beach) was performed by terminal-restriction fragment length polymorphism (T-RFLP) of 16S rDNA along spatial and temporal scales. Interpolation of concentration of hydrophobic compounds, chlorophyll and bacterial cells in seawater over the geography of the sampling area using geographic information systems techniques (GIS) allowed the delineation of two different habitats: bay and marina (with low and high levels of impact respectively), and a transition zone between them. Accordingly, the 16S rDNA T-RFLP profiles of bacterial communities in the area differed mainly spatially, with gradual changes in community composition and structure when approaching the beach and marina. Bacterial communities in impacted areas had higher diversity and equitability, as well as different composition. The main bacterial populations inferred in bay samples, which were members of the Alphaproteobacteria (mainly SAR11 and Roseobacter groups), were replaced by a different population of the Roseobacter clade, and members of the Gammaproteobacteria and Bacteroidetes in more impacted areas. There were also differences in the dynamics of bacterial communities. While temporal variations in bacterial communities in bay samples were lower and mainly determined by temperature, an important factor for the functioning of this ecosystem, variation in impacted areas was more irregular, not so much temperature-driven, and in the case of the transition zone (beach) reflected the use of the coast during warmer periods.     

Wildlife uses and hunting patterns in rural communities of the Yucatan Peninsula, Mexico

Background

Use of plant resources and ecosystems practiced by indigenous peoples of Mesoamerica commonly involves domestication of plant populations and landscapes. Our study analyzed interactions of coexisting wild and managed populations of the pitaya Stenocereus pruinosus, a columnar cactus used for its edible fruit occurring in natural forests, silviculturally managed in milpa agroforestry systems, and agriculturally managed in homegardens of the Tehuacán Valley, Mexico. We aimed at analyzing criteria of artificial selection and their consequences on phenotypic diversity and differentiation, as well as documenting management of propagules at landscape level and their possible contribution to gene flow among populations.

Methods

Semi-structured interviews were conducted to 83 households of the region to document perception of variation, criteria of artificial selection, and patterns of moving propagules among wild and managed populations. Morphological variation of trees from nine wild, silviculturally and agriculturally managed populations was analyzed for 37 characters through univariate and multivariate statistical methods. In addition, indexes of morphological diversity (MD) per population and phenotypic differentiation (PD) among populations were calculated using character states and frequencies.

Results

People recognized 15 pitaya varieties based on their pulp color, fruit size, form, flavor, and thorniness. On average, in wild populations we recorded one variety per population, in silviculturally managed populations 1.58 ± 0.77 varieties per parcel, and in agriculturally managed populations 2.19 ± 1.12 varieties per homegarden. Farmers select in favor of sweet flavor (71% of households interviewed) and pulp color (46%) mainly red, orange and yellow. Artificial selection is practiced in homegardens and 65% of people interviewed also do it in agroforestry systems. People obtain fruit and branches from different population types and move propagules from one another. Multivariate analyses showed morphological differentiation of wild and agriculturally managed populations, mainly due to differences in reproductive characters; however, the phenotypic differentiation indexes were relatively low among all populations studied. Morphological diversity of S. pruinosus (average MD = 0.600) is higher than in other columnar cacti species previously analyzed.

Conclusions

Artificial selection in favor of high quality fruit promotes morphological variation and divergence because of the continual replacement of plant material propagated and introduction of propagules from other villages and regions. This process is counteracted by high gene flow influenced by natural factors (pollinators and seed dispersers) but also by human management (movement of propagules among populations), all of which determines relatively low phenotypic differentiation among populations. Conservation of genetic resources of S. pruinosus should be based on the traditional forms of germplasm management by local people.     

A new species of picramnia (Picramniaceae) from the Atlantic coastal forest of southern Bahia, Brazil

A new species ofPicramnia (Picramniaceae) is described, illustrated, and compared to related Amazonian species. The new species,Picramnia coccinea, is known only from three localities in three adjacent municipalities near Ilhéus, Bahia, and constitutes another example of endemism in the southern Bahian flora.     

Ecological restoration in coastal areas in the Netherlands: concepts,dilemmas and some examples

This chapter gives an overview of attempts in the Netherlands to restore coastal ecosystems and habitats, and explains how scientific and non-scientific information has been used to meet the goals. Indications for successes and failures of management measures taken so far, as well as dilemmas to cope with, are given. Up to now only small scale restoration projects have been executed, while large scale projects generally are not further then the thinking or planning phase. A special type of `restoration projects' are the large civil engineering works, particularly in the south-west of the Netherlands. Although these works were not planned and executed as restoration projects, but designed for safety against flooding from the sea, they have led to significant changes in the boundary conditions of the systems concerned. For restoration projects yet to be executed one can learn very much from these developments, particularly regarding the sensitivity of coastal systems for changes in boundary conditions and about the (im)possibilities to `steer' ecological developments. Physical, chemical and biological processes form the basis of restoration measures of coastal habitats, and this means that a thorough knowledge of these processes is essential. Coastal ecosystems are the result of complex interactions of large-scale and small-scale processes, implying a holistic approach in scientific investigations. Consequently, restoration of these systems primarily has to be realised by influencing the basic processes. This is the only way to preserve or regain in a sustainable way ecological values, such as species composition. Focusing only at one particular species (e.g. breeding terns) or a specific habitat (e.g. a salt marsh) may easily ignore the underlying processes. In general, coastal restoration should focus on the redirection of processes towards a desired status by stimulating certain process parameters. Monitoring of the results and, if necessary, gradual readjustment of the governing factors, is an essential part of this approach.     

Abundance and diversity of microfungi in three coastal beaches of Mexico

The abundance and diversity of species of microfungi was investigated on the beaches of Delfines, Km 24 Veracruz-Alvarado Highway, and El Coco, located on the coasts of the Caribbean Sea, Gulf of Mexico, and the Pacific Ocean, respectively. On each beach a sample composed of sand, subtidal wood or washed-up detritus with moist sand was collected. The samples were analyzed by three different methods, resulting in a total of 1,160 occurrences that fluctuated between 340 and 441 occurrences/sample. The number of species/sample fluctuated between 20 and 32. A total of 52 species was found, of which 12 were marine, and 40 nomarine, of terrestrial origin, and of these 15 were ascomycetes, 34 were hyphomycetes, 2 were blastomycetes and one was a coelomycete. The abundance distribution showed few species with high or low values, with the greates proportion having intermediate values. In order to compare species diversity among the samples frequency curves were utilized, based on the number of species expected from samples taken at random; the results showed that the beach at El Coco was richest in species.     

Research on antibodies to arbovirus in the serum of residents of the village of Corte de Pedra, Valencia, Bahia

A serological survey for research on antibodies to arbovirus was carried out on 288 residents of the rural zone of the village of Corte de Pedra, Valen?a, Bahia. It was observed that 3.8% of the sample population presented HI and N antibodies against Flaviviruses (Ilhéus 6, St. Louis 2, Yellow fever 3 and Rocio 1). One person, who had previously lived in the Amazon region, had antibodies to Mayaro. The authors were unable to detect either N antibodies for Piry virus in a random sample of 75 persons or CF antibodies against viruses of the Changuinola and Phlebotomus groups and ungrouped BE AR 408005 and BE AR 421710 in another random sample of 28 individuals. Complementary studies should be conducted in order to define the transmission of the different viruses in the area.