Stone temperature and moisture variability under temperate environmental conditions: implications for sandstone weathering

Temperature and moisture conditions are key drivers of stone weathering processes in both natural and built environments. Given their importance in the breakdown of stone, a detailed understanding of their temporal and spatial variability is central to understanding present-day weathering behaviour and for predicting how climate change may influence the nature and rates of future stone decay.
Subsurface temperature and moisture data are reported from quarry fresh Peakmoor Sandstone samples exposed during summer (June–July) and late autumn / early winter (October–December) in a mid-latitude, temperate maritime environment. These data demonstrate that the subsurface thermal response of sandstone comprises numerous short-term (minutes), low magnitude fluctuations superimposed upon larger-scale diurnal heating and cooling cycles with distinct aspect-related differences. The short-term fluctuations create conditions in the outer 5–10 mm of stone that are much more ‘energetic’ in comparison to the more subdued thermal cycling that occurs deeper within the sandstone samples.
Data show that moisture dynamics are equally complex with a near-surface region (5–10 mm) in which frequent moisture cycling takes place and this, combined with the thermal dynamism exhibited by the same region may have significant implications for the nature and rate of weathering activity. Data indicate that moisture input from rainfall, particularly when it is wind-driven, can travel deep into the stone where it can prolong the time of wetness. This most often occurs during wetter winter months when moisture input is high and evaporative loss is low but can happen at any time during the year when the hydraulic connection between near-surface and deeper regions of the stone is disrupted with subsequent loss of moisture from depth slowing as it becomes reliant on vapour diffusion alone.
These data illustrate the complexity of temperature and moisture conditions in sandstone exposed to the ‘moderate’ conditions of a temperate maritime environment. They highlight differences in thermal and moisture cycling between near-surface (5–10 mm) and deeper regions within the stone and contribute towards a better understanding of the development of structural and mineralogical heterogeneity between the stone surface and substrate.

Seep communities from two mud volcanoes in the deep eastern Mediterranean Sea: faunal composition, spatial patterns and environmental control

The Mediterranean Sea constitutes a unique environment to study cold-seep ecosystems due to the presence of different geodynamic settings, from an active margin along the Mediterranean Ridge (MR) to a passive margin in the Nile Deep-Sea Fan (NDSF). We attempted to identify the structure of benthic communities associated with the Napoli and Amsterdam mud volcanoes (MVs) located on the MR and to establish the links between faunal distribution and environmental conditions at different spatial scales. Comparison between the 2 MVs revealed that the faunal distribution seemed to be mainly controlled by the characteristics of the microhabitats. On both geological structures, the variability between the different microhabitats was higher than the variability observed between replicates of the same microhabitat, and the distribution of macro-fauna was apparently linked to gradients in physico-chemical conditions. The peripheral sites from Napoli were generally more oxygenated and harboured lower species richness than the active sites. The reduced sediment microhabitat from Amsterdam presented the highest methane concentrations and was mainly colonised by symbiont-bearing vesicomyid bivalves and heterotrophic dorvilleid polychaetes. Overall, a higher taxonomic diversity was observed on Napoli. Sub-stratum type was hypothesised to be the second factor influencing faunal distribution. The results of this study highlight the high heterogeneity of faunal communities associated with seep ecosystems within this region and the need to pursue investigations at various spatial and temporal scales.

High interannual variability in connectivity and genetic pool of a temperate clingfish matches oceanographic transport predictions

Adults of most marine benthic and demersal fish are site-attached, with the dispersal of their larval stages ensuring connectivity among populations. In this study we aimed to infer spatial and temporal variation in population connectivity and dispersal of a marine fish species, using genetic tools and comparing these with oceanographic transport. We focused on an intertidal rocky reef fish species, the shore clingfish Lepadogaster lepadogaster, along the southwest Iberian Peninsula, in 2011 and 2012. We predicted high levels of self-recruitment and distinct populations, due to short pelagic larval duration and because all its developmental stages have previously been found near adult habitats. Genetic analyses based on microsatellites countered our prediction and a biophysical dispersal model showed that oceanographic transport was a good explanation for the patterns observed. Adult sub-populations separated by up to 300 km of coastline displayed no genetic differentiation, revealing a single connected population with larvae potentially dispersing long distances over hundreds of km. Despite this, parentage analysis performed on recruits from one focal site within the Marine Park of Arrábida (Portugal), revealed self-recruitment levels of 2.5% and 7.7% in 2011 and 2012, respectively, suggesting that both long- and short-distance dispersal play an important role in the replenishment of these populations. Population differentiation and patterns of dispersal, which were highly variable between years, could be linked to the variability inherent in local oceanographic processes. Overall, our measures of connectivity based on genetic and oceanographic data highlight the relevance of long-distance dispersal in determining the degree of connectivity, even in species with short pelagic larval durations.

Benthic macrofauna structure in the northeast area of Todos os Santos Bay, Bahia State, Brazil: patterns of spatial and seasonal distribution

Structure of intertidal and subtidal benthic macrofauna in the northeastern region of Todos os Santos Bay (TSB), northeast Brazil, was investigated during a period of two years. Relationships with environmental parameters were studied through uni-and multivariate statistical analyses, and the main distributional patterns shown to be especially related to sediment type and content of organic fractions (Carbon, Nitrogen, Phosphorus), on both temporal and spatial scales. Polychaete annelids accounted for more than 70% of the total fauna and showed low densities, species richness and diversity, except for the area situated on the reef banks. These banks constitute a peculiar environment in relation to the rest of the region by having coarse sediments poor in organic matter and rich in biodetritic carbonates besides an abundant and diverse fauna. The intertidal region and the shallower area nearer to the oil refinery RLAM, with sediments composed mainly of fine sand, seem to constitute an unstable system with few highly dominant species, such as Armandia polyophthalma and Laeonereis acuta. In the other regions of TSB, where muddy bottoms predominated, densities and diversity were low, especially in the stations near the refinery. Here the lowest values of the biological indicators occurred together with the highest organic compound content. In addition, the nearest sites (stations 4 and 7) were sometimes azoic. The adjacent Caboto, considered as a control area at first, presented low density but intermediate values of species diversity, which indicates a less disturbed environment in relation to the pelitic infralittoral in front of the refinery. The results of the ordination analyses evidenced five homogeneous groups of stations (intertidal; reef banks; pelitic infralittoral; mixed sediments; Caboto) with different specific patterns, a fact which seems to be mainly related to granulometry and chemical sediment characteristics.

A spatial approach for the epidemiology of antibiotic use and resistance in community-based studies: the emergence of urban clusters of Escherichia coli quinolone resistance in Sao Paulo, Brasil

Background: Population antimicrobial use may influence resistance emergence. Resistance is an ecological phenomenon due to potential transmissibility. We investigated spatial and temporal patterns of ciprofloxacin (CIP) population consumption related to E. coli resistance emergence and dissemination in a major Brazilian city. A total of 4,372 urinary tract infection E. coli cases, with 723 CIP resistant, were identified in 2002 from two outpatient centres. Cases were address geocoded in a digital map. Raw CIP consumption data was transformed into usage density in DDDs by CIP selling points influence zones determination. A stochastic model coupled with a Geographical Information System was applied for relating resistance and usage density and for detecting city areas of high/low resistance risk. Results: E. coli CIP resistant cluster emergence was detected and significantly related to usage density at a level of 5 to 9 CIP DDDs. There were clustered hot-spots and a significant global spatial variation in the residual resistance risk after allowing for usage density. Conclusions: There were clustered hot-spots and a significant global spatial variation in the residual resistance risk after allowing for usage density. The usage density of 5-9 CIP DDDs per 1,000 inhabitants within the same influence zone was the resistance triggering level. This level led to E. coli resistance clustering, proving that individual resistance emergence and dissemination was affected by antimicrobial population consumption.

Impacts of land-use pattern on soil water-content variability on the Loess Plateau of China

Long-term vegetation restoration carried out on the slopes of the Loess Plateau of China employed different spatial and temporal land-use patterns but very little is known about the effects of these patterns on soil water-content variability. For this study the small Donggou catchment was selected to investigate soil water-content distributions for three spatial scales, including the entire catchment area, sampling transects, and land-use systems. Gravimetric soil water contents were determined incrementally to a soil depth of 1.20 m, on 10 occasions from April to October, 2007, at approximately 20-day intervals. Results indicated that soil water contents were affected by the six land-use types, resulting in four distinct patterns of vertical distribution of soil moisture (uniform, increasing, decreasing, and fluctuating with soil depth). The soil water content and its variation were also influenced in a complex manner by five land-use patterns distributed along transects following the gradients of five similar slopes. These patterns with contrasting hydrological responses in different components, such as forage land (alfalfa)-cropland-shrubland or shrubland-grassland (bunge needlegrass)-cropland-grassland, showed the highest soil water-content variability. Soil water at the catchment scale exhibited a moderate variability for each measurement date, and the variability of soil water content decreased exponentially with increasing soil water content. The minimum sample size for accurate data for use in a hydrological model for the catchment, for example, required many more samples for drier (69) than for wet (10) conditions. To enhance erosion and runoff control, this study suggested two strategies for land management: (i) to create a mosaic pattern by land-use arrangement that located units with higher infiltration capacities downslope from those with lower soil infiltrabilities; and (ii) raising the soil-infiltration capacity of units within the spatial mosaic pattern where possible.

COMPETITION AMONG EUCALYPTUS TREES DEPENDS ON GENETIC VARIATION AND RESOURCE SUPPLY

Genetic variation and environmental heterogeneity fundamentally shape the interactions between plants of the same species. According to the resource partitioning hypothesis, competition between neighbors intensifies as their similarity increases. Such competition may change in response to increasing supplies of limiting resources. We tested the resource partitioning hypothesis in stands of genetically identical (clone-origin) and genetically diverse (seed-origin) Eucalyptus trees with different water and nutrient supplies, using individual-based tree growth models. We found that genetic variation greatly reduced competitive interactions between neighboring trees, supporting the resource partitioning hypothesis. The importance of genetic variation for Eucalyptus growth patterns depended strongly on local stand structure and focal tree size. This suggests that spatial and temporal variation in the strength of species interactions leads to reversals in the growth rank of seed-origin and clone-origin trees. This study is one of the first to experimentally test the resource partitioning hypothesis for intergenotypic vs. intragenotypic interactions in trees. We provide evidence that variation at the level of genes, and not just species, is functionally important for driving individual and community-level processes in forested ecosystems.

Serial conditional discrimination and temporal bisection in rats selectively lesioned in the dentate gyrus

In positive serial conditional discrimination, animals respond during a target stimulus when it is preceded by a feature stimulus, but they do not respond when the same target stimulus is presented alone. Moreover, the feature and target stimuli are separated from each other by an empty interval. The present work aimed to investigate if two durations (4 or 16s) of the same feature stimulus (light) could modulate the operant responses of rats to different levers (A and B) during a 5-s target stimulus (tone). In the present study, lever A was associated with the 4-s light, and lever B was associated with the 16-s light. A 5-s empty interval was included between the light and the tone. In the same training procedure, the rats were also presented with the 5-s tone without the preceding light stimuli. In these trials, the responses were not reinforced. We evaluated the hippocampal involvement of these behavioral processes by selectively lesioning the dentate gyrus with colchicine. Once trained, the rats were submitted to a test using probe trials without reinforcement. They were presented with intermediate durations of the feature stimulus (light) to obtain a temporal bisection curve recorded during the exposure to the target stimuli. The rats from both groups learned to respond with high rates during tones preceded by light and with low rates during tones presented alone, which indicated acquisition of the serial conditional discrimination. The rats were able to discriminate between the 4- and 16-s lights by correctly choosing lever A or B. In the test, the temporal bisection curves from both experimental groups showed a bisection point at the arithmetic mean between 4 and 16s. Such processes were not impaired by the dentate gyrus lesion. Thus, our results showed that different durations of a feature stimulus could result in conditional properties. However, this processing did not appear to depend on the dentate gyrus alone. (C) 2011 Published by Elsevier B.V.

Valproic acid has temporal variability in urinary clearance of metabolites

The reasons for the intra- and interindividual variability in the clearance of valproic acid (VPA) have not been completely characterized. The aim of this study was to examine day-night changes in the clearance of 3-oxo-valproate (3-oxo-VPA), 4-hydroxy-valproate (4-OH-VPA), and valproic acid glucuronides under steady state. Six diurnally active healthy male volunteers ingested 200 mg sodium valproate 12 hourly, at 0800 and 2000, for 28 days. On the last study day, two sequential 12-h urine samples were collected commencing at 2000 the evening before. Plasma samples were obtained at the end of each collection. Following alkaline hydrolysis, urine was analyzed for concentrations of VPA, 3-oxo-VPA, and 4-OH-VPA. A separate aliquot was assayed for creatinine (CR). The plasma concentrations of VPA, 3-oxo-VPA, 2-en-VPA, and CR were determined. The analysis of VPA and its metabolites was performed by CC-MS. There was an increase in plasma 3-oxo-VPA concentration at 0800, sampling as compared to 2000 sampling (p < .05). The urinary excretion of 3-oxo-VPA and VPA glucuronides were decreased between 2000 and 0800, compared to between 0800, and 2000, by 30% and 50% respectively (p < .05). These results indicate a nocturnal decrease in renal clearance of 3-oxo-VPA rather than a decrease in the beta -oxidation of VPA at night. These differences were not explained by differences between the sampling periods in CR excretion. These results indicate the importance of collecting samples of 24-h duration when studying metabolic profiles of VPA.

Climatic patterns and physical controls of chlorophyll-a in the Northeast Atlantic

Tese de Doutoramento, Física, 17 de Dezembro de 2013, Universidade dos Açores.

Spatial analysis of crime evolution in Portugal between 1995 and 2013

The main objective of this survey was to perform descriptive analysis of crime evolution in Portugal between 1995 and 2013. The main focus of this survey was to analyse spatial crime evolution patterns in Portuguese NUTS III regions. Most important crime types have been included into analysis. The main idea was to uncover relation between local patterns and global crime evolution; to define regions which have contributed to global crime evolution of some specific crime types and to define how they have contributed. There were many statistical reports and scientific papers which have analysed some particular crime types, but one global spatial-temporal analysis has not been found. Principal Component Analysis and multidimensional descriptive data analysis technique STATIS have been the base of the analysis. The results of this survey has shown that strong spatial and temporal crime patterns exist. It was possible to describe global crime evolution patterns and to define crime evolution patterns in NUTS III regions. It was possible to define three to four groups of crimes where each group shows similar spatial crime dynamics.

Spatio-temporal patterns of tuberculosis incidence in Ribeirão Preto, State of São Paulo, southeast Brazil, and their relationship with social vulnerability: a Bayesian analysis

INTRODUCTION: The purpose of this ecological study was to evaluate the urban spatial and temporal distribution of tuberculosis (TB) in Ribeirão Preto, State of São Paulo, southeast Brazil, between 2006 and 2009 and to evaluate its relationship with factors of social vulnerability such as income and education level. METHODS: We evaluated data from TBWeb, an electronic notification system for TB cases. Measures of social vulnerability were obtained from the SEADE Foundation, and information about the number of inhabitants, education and income of the households were obtained from Brazilian Institute of Geography and Statistics. Statistical analyses were conducted by a Bayesian regression model assuming a Poisson distribution for the observed new cases of TB in each area. A conditional autoregressive structure was used for the spatial covariance structure. RESULTS: The Bayesian model confirmed the spatial heterogeneity of TB distribution in Ribeirão Preto, identifying areas with elevated risk and the effects of social vulnerability on the disease. We demonstrated that the rate of TB was correlated with the measures of income, education and social vulnerability. However, we observed areas with low vulnerability and high education and income, but with high estimated TB rates. CONCLUSIONS: The study identified areas with different risks for TB, given that the public health system deals with the characteristics of each region individually and prioritizes those that present a higher propensity to risk of TB. Complex relationships may exist between TB incidence and a wide range of environmental and intrinsic factors, which need to be studied in future research.

Estudio de los modos de vida e historia biológica de las poblaciones humanas de la región central de argentina desde el registro bioarqueológico. Lifestyles and biological history of human populations of the central region of argentina from bioarchaeological record.

Se pretende aportar al estudio de la estructura, historia biológica y estilos de vida de las poblaciones que habitaron la región central de Argentina durante el Holoceno, desde una perspectiva que combina los aportes teóricos y metodológicos de la Genética del paisaje y la Bioarqueología. Interesa a) identificar barreras de diferenciación morfológica entre poblaciones, b) poner a prueba modelos poblacionales para explicar la variación observada e identificar las variables que contribuyan a dicha diferenciación, c) evaluar la congruencia de los resultados obtenidos, d) reconstruir los patrones de movilidad residencial de las poblaciones, e) estudiar sus patrones dietarios considerando diferencias temporales y espaciales, f) identificar indicadores de diversos tipos de estrés (nutricional, funcional), así como traumas, g) estudiar las historias tafonómicas del registro bioarqueológico regional, y h) proponer un modelo para explicar el poblamiento y la evolución local de las poblaciones que habitaron esta región, a partir de la información arqueológica y bioantropológica. Para el análisis de los patrones espaciales de variación biológica se trabajará a partir del registro de rasgos epigenéticos craneales, medidas lineales y datos obtenidos a partir de morfometría geométrica sobre fotografías en 2D sobre muestras arqueológicas procedentes de esta región y de otras regiones geográficas de la Argentina. Para el análisis de la estructura de la población se trabajará a partir del cálculo de la matriz R para datos morfológicos y sus estimaciones derivadas (distancia D², Fst, coordenadas principales) y la aplicación del modelo de Harpending y Ward. Desde la genética del paisaje, se realizarán análisis de autocorrelación espacial, barreras genéticas y análisis geoestadísticos (kriging). Para el estudio de los modos de vida a partir del registro bioarqueológico se relevarán patologías dento-alveolares y alteraciones vinculadas con la salud bucal tales como desgaste dental –a nivel micro y macroscópico- caries, abscesos, pérdidas dentales antemortem, cálculos, hipoplasias, marcadores esqueletales de salud y lesiones traumáticas. Se analizarán isótopos estables (δ13C, δ15N, 86Sr y 87Sr) en restos óseos humanos de diversos sitios arqueológicos con el objetivo de reconstruir patrones dietarios y analizar la movilidad residencial y migración de las poblaciones. Paralelamente, se establecerán procedimientos de control tafonómico de los restos óseos, y se harán análisis específicos para estudiar las historias tafonómicas y evaluar el grado de integridad de los contextos de depositación y de las colecciones en general. Estimamos que el análisis de los patrones espaciales y temporales de variabilidad morfológica craneofacial, así como el estudio de las dietas a partir de información isotópica y bioarqueológica, de las migraciones y la movilidad residencial de las poblaciones a partir de isótopos de estroncio, la reconstrucción de comportamientos y actividades cotidianas a partir de marcadores de estrés músculo-esqueletal, en un marco cronológico y espacial constituye un aporte novedoso y eficaz que permitirá incrementar de manera substancial la información sobre la evolución de las poblaciones originarias del centro del territorio argentino. The aim of this project is to study the structure, biological history and lifestyles of the people that inhabitated the central region of Argentina during the Holocene, from a perspective that combines theoretical and methodological contributions of Landscape Genetics and Bioarchaeology. To analyze the spatial patterns of biological variation we consider epigenetic cranial traits, linear measurements and data obtained from geometric morphometric on 2D photographs. Morphological variation will be focused on landscape genetics (autocorrelation, genetic barriers and geostatistical analysis –kriging-) and population structure (matrix R, D², Fst, principal coordinates, Harpendig and Ward model). For the study of lifestyles from bioarchaeological record we consider alveolar pathologies and disorders related to oral health such as tooth wear, micro and macroscopic level, caries, abscesses, antemortem tooth loss, hypoplasia, markers skeletal health and traumatic injuries, as well as taphonomic processes. Stable isotopes will be analyzed (δ13C, d15N, 86Sr and 87Sr) in human skeletal remains from various archaeological sites in order to reconstruct and analyze dietary patterns of residential mobility and migration of populations. It will be established procedures of taphonomic control on skeletal remains, analysis to study taphonomic histories and assess the degree of completeness of depositional context and collection, in general terms. We consider that analysis of spatial and temporal patterns of variability in craniofacial morphology and the study of health and diets from isotopic and bioarchaeological data, migration and residential mobility patterns from strontium isotopes, as well as activity patterns from stress markers is a novel and effective contribution that will substantially increase the information about the local evolution of populations that inhabitated the center of Argentina.

Defining habitat characteristics influencing the distribution, density and growth of Plaice (Pleuronectes Platessa) and Dab (Limanda Limanda) on west of Ireland nursery grounds

Plaice (Pleuronectes platessa, L.) and dab (Limanda limanda, L.) are among the most abundant flatfishes in the north-eastern Atlantic region and the dominant species in shallow coastal nursery grounds. With increasing pressures on commercial flatfish stocks in combination with changing coastal environments, better knowledge of population dynamics during all life stages is needed to evaluate variability in year-class strength and recruitment to the fishery. The aim of this research was to investigate the complex interplay of biotic and abiotic habitat components influencing the distribution, density and growth of plaice and dab during the vulnerable juvenile life stage and to gain insight in spatial and temporal differences in nursery habitat quality along the west coast of Ireland. Intraspecific variability in plaice diet was observed at different spatial scales and showed a link with condition, recent growth and morphology. This highlights the effect of food availability on habitat quality and the need to consider small scale variation when attempting to link habitat quality to feeding, growth and condition of juvenile flatfish. There was evidence of trophic, spatial and temporal resource partitioning between juvenile plaice and dab allowing the co-existence of morphologically similar species in nursery grounds. In the limited survey years there was no evidence that the carrying capacity of the studied nursery grounds was reached but spatial and interannual variations in fish growth indicated fluctuating environments in terms of food availability, predator densities, sediment features and physico-chemical conditions. Predation was the most important factor affecting habitat quality for juvenile plaice and dab with crab densities negatively correlated to fish condition whereas shrimp densities were negatively associated with densities of small-sized juveniles in spring. A comparison of proxies for fish growth showed the advantage of Fulton’s K for routine use whereas RNA:DNA ratios proved less powerful when short-term environmental fluctuations are lacking. This study illustrated how distinct sets of habitat features can drive spatial variation in density and condition of juvenile flatfish highlighting the value of studying both variables when modeling habitat requirements. The habitat models generated in this study also provide a powerful tool to predict potential climate and anthropogenic impacts on the distribution and condition of juveniles in flatfish nurseries. The need for effective coastal zone management was emphasized to ensure a sustainable use of coastal resources and successful flatfish recruitment to the fishery.

Population dynamics of 0-group flounder (Platichthys flesus L.) in Galway Bay, West of Ireland and the value of flounder from shore angling tourism in Ireland

The economic value of flounder from shore angling around Ireland was assessed. Flounder catches from shore angling tournaments around Ireland were related to domestic and overseas shore angling expenditure in order to determine an economic value for the species. Temporal trends in flounder angling catches, and specimen (trophy) flounder reports were also investigated. Flounder was found to be the most caught shore angling species in competitions around Ireland constituting roughly one third of the shore angling competition catch although this did vary by area. The total value of flounder from shore angling tourism was estimated to be of the order of €8.4 million. No significant temporal trends in flounder angling catches and specimen reports were found. Thus there is no evidence from the current study for any decline in flounder stocks. The population dynamics of 0-group flounder during the early benthic stage was investigated at estuarine sites in Galway Bay, west of Ireland. Information was analysed from the March to June sampling period over five years (2002 to 2006). Spatial and temporal variations in settlement and population length structure were analysed between beach and river habitats and sites. Settlement of flounder began from late March to early May of each year, most commonly in April. Peak settlement was usually in April or early May. Settlement was recorded earlier than elsewhere, although most commonly was similar to the southern part of the UK and northern France. Settlement was generally later in tidal rivers than on sandy beaches. Abundance of 0-group flounder in Galway Bay did not exhibit significant inter -annual variability. 0-group flounder were observed in dense aggregations of up to 105 m'2, which were patchy in distribution. Highest densities of 0-group flounder were recorded in limnetic and oligohaline areas as compared with the lower densities in polyhaline and to a lesser extent mesohaline areas. Measurements to of salinity allowed the classification of beaches, and tidal river sections near the mouth, into a salinity based scheme for length comparisons. Beaches were classified as polyhaline,the lower section of rivers as mesohaline, and the middle and upper sections as oligohaline. Over the March to June sampling period 0-group flounder utilised different sections at different length ranges and were significantly larger in more upstream sections. During initial settlement in April, 0-group flounder of 8-10 mm (standard length, SL) were present in abundance on polyhaline sandy beaches. By about 10mm (SL), flounder were present in all polyhaline, mesohaline and (oligohaline) sections. 0-group flounder became absent or in insignificant numbers in polyhaline and mesohaline sections in a matter of weeks after first appearance. From April to June, 0-group flounder of 12-30mm (SL) were found in more upstream locations in the oligohaline sections. About one month (May or June) after initial settlement, 0-group flounder became absent from the oligohaline sections. Concurrently, flounder start to reappear in mesohaline and polyhaline areas at approximately 30mm (SL) in June. The results indicate 0-group flounder in the early benthic stage are associated with low salinity areas, but as they grow, this association diminishes. Results strongly suggest that migration of 0-group flounder between habitats takes place during the early benthic phase.