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21.
ABSTRACT.   Although breeding populations of Piping Plovers are well studied, their winter distribution is less clear. We studied the seasonal abundance of nonbreeding Piping Plovers ( Charadrius melodus ) during the winters of 2003–2004 and 2004–2005 on Little St. Simons Island (LSSI), Georgia. Our objectives were to determine the relative abundance of individuals from three breeding populations at LSSI, and identify possible differences among populations in arrival time, winter movements, or departure time. We observed up to 100 Piping Plovers during peak migration, and approximately 40 plovers wintered at LSSI. From July 2004 to May 2005, approximately 20% of the Great Lakes breeding population used LSSI. Plovers were not present at LSSI during June. All breeding populations of Piping Plovers had similar patterns of temporal occurrence on LSSI, suggesting no need for population-specific management plans at this site. Our results suggest that LSSI is among the most important wintering sites on the Atlantic coast for Piping Plovers, especially for individuals from the endangered Great Lakes population.  相似文献   
22.
Structural characteristics of the femur are compared in preagricultural (2200 B.C.–A.D. 1150) and agricultural (A.D. 1150–1550) subsistence strategy groups from the Georgia coast. Using an automated technique, cross-sectional geometric properties used in structural analyses (areas, second moments of area) were determined at midshaft and distal to the lesser trochanter in 20 adults from each group. A significant decline in magnitude of almost every geometric property occurs in the agricultural group. The differences between groups are reduced but still significant for many properties after standardizing for bone length differences. In addition, a remodeling of the femoral cortex to one of relatively smaller medullary and subperiosteal diameter, as well as a more circular cross-sectional shape, is characteristic of agricultural femora. Thus, while the relative cross-sectional area of bone remains the same, the spatial distribution of bone area is different in the two groups. The results strongly suggest a relative reduction in mechanical loadings of the femur in the agricultural group, implying different levels and possibly types of activity involving the lower limb in the two groups. The data are also compared with similar data available for the Pecos Pueblo (agricultural) sample. The comparison indicates that types of activity may have been more similar in the two agricultural samples, but that general levels of activity were more similar in the Pecos Pueblo and Georgia coast preagricultural samples.  相似文献   
23.
Many recent studies of cultural inheritance have focused on small-scale craft traditions practised by single individuals, which do not require coordinated participation by larger social collectives. In this paper, we address this gap in the cultural transmission literature by investigating diversity in the vernacular architecture of the Pacific northwest coast, where communities of hunter-fisher-gatherers constructed immense wooden long-houses at their main winter villages. Quantitative analyses of long-house styles along the coastline draw on a range of models and methods from the biological sciences and are employed to test hypotheses relating to basic patterns of macro-scale cultural diversification, and the degree to which the transmission of housing traits has been constrained by the region's numerous linguistic boundaries. The results indicate relatively strong branching patterns of cultural inheritance and also close associations between regional language history and housing styles, pointing to the potentially crucial role played by language boundaries in structuring large-scale patterns of cultural diversification, especially in relation to 'collective' cultural traditions like housing that require substantial inputs of coordinated labour.  相似文献   
24.
Five cyanobacterial species (Phormidium sp., Nostoc sp., Anabaena sp. Aphanothece conferta, and Synechocystis aquatilis) isolated from the Suez Canal coast at the city of Ismailia (Egypt) were tested for biodegradation of four hydrocarbon (HC) compounds: two aliphatic compounds (n‐octadecane and pristine) and two aromatic compounds (phenanthrene and dibenzothiophene). High degradation efficiencies for the two aliphatic compounds were measured for A. conferta (64% for n‐octadecane and 78% for pristine) and S. aquatilis (85% for n‐octadecane and 90% for pristane). However, the other biodegradation percentages ranged between weak and moderate percentages.  相似文献   
25.
26.
The relationship between the variables of reef fish community structure (fish richness, fish diversity and total number of fishes) and those of habitat complexity (total surface area, substratum diversity, topographic complexity, number of holes, percent cover of turf algae, zoanthids, millepores, massive corals, bare rock, encrusting calcareous algae, urchins, other sessile organisms and Sargassum) were examined on three different rocky shores (FA, FB and FT) at Arraial do Cabo, a tropical region located on Brazilian southeastern coast (23° S, 42° W). Fish abundance and vertical distribution were assessed by a visual census technique using strip transects. Percentage cover of benthic organisms and other substratum types were calculated by replicated transects using a chain laid down on the substratum. Topographic complexity was determined by the chain link method and number of holes were estimated by direct counts on replicated transects. More than 91 fishes belonging to 37 families were seen in all study sites during one year of visual census effort. FA and FB sites had similar fish community structure and habitat complexity characteristics, while FT showed different habitat characteristics and higher fish diversity and richness, plus total number of fishes. Vertical distribution of fishes along the rocky shores studied seemed to be predictable and was determined by factors such as feeding habits and behavior, availability of refuges and social interactions. The habitat variables that best explained the higher diversity and number of fishes observed in FT site were total surface area of rocky shores and the abundance of benthic sessile invertebrates; these conditions were typical of rocky shores more exposed to wave surge.  相似文献   
27.
Fluoride ion (F?) is a relevant component of concern due to its potential toxicity for humankind. This study clarifies the status of F? for human health in three polluted regions along the Egyptian Mediterranean Sea coast, and determining its contents in seawater and different fish tissues (muscle, skin, brain, and bone). Fluoride ion concentrations in different fish tissues had a descending trend of brain > skin > muscle > bone with averages of 26.8 ± 26.0, 24.8 ± 6.5, 12.7 ± 2.3, and 9.0 ± 1.6 μg F?/g wet wt, respectively. The bioconcentration factor for fluoride ion in different fish tissues was determined and multivariate analyses were conducted. The human health hazard assessment from fish consumption and seawater contact using hazard quotient (HQ) and ingestion and dermal absorption dose of whole body for different ages of females and males as well as the specified body parts (legs, arms, and hands) were calculated. Although the calculated daily intake values for ingestion of fish in the present study were lower than some established tolerable daily intake values, their hazard quotients were within 1 ≥ HQ < 10 and may reflect a possible fluoride adverse effect on human health from the consumption of the gathered fish species.  相似文献   
28.
The Oualidia lagoon provides important ecosystem services, such as fishing, aquaculture, tourism and high biological and ecological productivity. Many indices have been developed to evaluate environmental risks and to estimate the anthropogenic contribution of potentially toxic elements (PTE) in surficial sediments. The results show that the concentrations of the PTE found in surface sediments due to the anthropogenic activities in the area (urban effluents, aquaculture and agricultural areas) are significantly higher than those from the local background and sediment quality guidelines (SQGs). The potential ecological and biological risk index present satisfactory results. However, the sites near to the areas where anthropogenic activities are developed present 49% probability of toxicity, while the rest of the lagoon, present 9% to 21% probability of toxicity and low potential ecological risk, except for Hg where the risk was considered to be considerable. The PTE are mainly originated from the anthropogenic activities; nevertheless, anthropogenic contributions represent up to 69% of the total sediment of content, but it depends on the PTE: Cd (16%), Ni (38%), Zn (41%), Cr (43%), Cu (56%), Hg (68%), Pb (69%). Compared with the Sub-basin soils, the PTE are higher than 80%, hence the sub-basin feeds the lagoon by these elements (PTE).  相似文献   
29.
Annual productivity and excretion of organic compounds by epibenthic algae in a coastal Texas marsh were investigated using 14C techniques. Over the course of two years, productivity and extracellular release were measured bimonthly to assess the environmental factors affecting seasonal patterns. Annual productivity was estimated to be 71 gc·m?2, approximately 10% of the estimated net aerial productivity of the grass canopy in this area. The percentage of photoassimilated carbon released was fairly constant, and the rate of excretion appeared to be primarily dependent upon the rate of carbon fixation. Greater rates of release were observed with high salinity, low soil moisture conditions. It was estimated that up to 10% of the DOC in adjacent tidal creek water could be produced by this community and could represent an important source of nutrients for consumers in the system.  相似文献   
30.
Forty-seven sites along the Rhode Island coastline were sampled on a seasonal basis for the presence of the red alga Bangia atropurpurea (Roth) C. Ag. This species was found to be widely distributed, occurring at 94% of the hard, stable substrates sampled. Bangia populations were most, widespread in the winter (71% of sites) and least frequent in the summer (29% of sites). At one location, three high intertidal populations (average height 101 cm) and three low intertidal populations (average height 14 cm) were sampled monthly for two years. The upper intertidal populations appeared in September and persisted until at least May, whereas the lower populations were ephemeral, appearing for only a few months in late winter. The high intertidal populations were present on 85% of the sampling dates white the lower ones were observed on 25% of the sampling dates. Upper intertidal filaments reproduced exclusively by asexual monospores unlike those of the lower populations which were largely sexual. The maximum diameter of asexual and carpogonial filaments was 120 and 250 nm, respectively. Monosporagenesis was strongly correlated to temperature whereas gametogenesis was strongly correlated to photopriod.  相似文献   
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