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1.
Asaad Ahmed Nafees Ambreen Kazi Zafar Fatmi Muhammad Irfan Arif Ali Fujio Kayama 《Environmental geochemistry and health》2011,33(2):203-216
This study was designed to determine the association between chronic arsenic exposure through drinking groundwater and decrement
in lung function, particularly among individuals who do not have signs of arsenic lesions, among an adult population. This
was a comparative cross-sectional study conducted during the months of January to March 2009. One hundred participants ≥15 years
of age in each group, i.e. exposed (≥100 μg/l) and unexposed (≤10 μg/l) to arsenic, determined by testing drinking water samples
(using portable kits), were compared for effects on lung function using spirometry. A structured and validated questionnaire
was administered. Examination for arsenic skin lesions was also done. There was a decline in the mean adjusted FEV1 of 154.3 ml
(95% CI: −324.7, 16.0; p = 0.076), in mean adjusted FVC of 221.9 ml (95% CI: −419.5, −24.3; p = 0.028), and in FEV1/FVC ratio of 2.0 (95% CI: −25.3, 29.4; p = 0.884) among participants who were exposed to arsenic compared to those unexposed. A separate model comprising a total
of 160 participants, 60 exposed to arsenic concentrations ≥250 μg/l and 100 unexposed at arsenic concentrations of ≤10 μg/l,
showed a decrement in mean adjusted FEV1 of 226.4 ml (95% CI: −430.4, −22.4; p = 0.030), in mean adjusted FVC of 354.8 ml (95% CI: −583.6, −126.0; p = 0.003), and in FEV1/FVC ratio of 9.9 (95% CI: −21.8, 41.6; p = 0.539) among participants who were exposed to arsenic in drinking groundwater. This study demonstrated that decrement in
lung function is associated with chronic exposure to arsenic in drinking groundwater, occurring independently, and even before
any manifestation, of arsenic skin lesions or respiratory symptoms. The study also demonstrated a dose-response effect of
arsenic exposure and lung function decrement. 相似文献
2.
Polycyclic aromatic hydrocarbon (PAH) concentrations were determined in 16 topsoils (0–10 cm) collected across the site of
a former tar works in NE England. The soils were prepared in the laboratory to two different particle size fractions: <250 μm
(fraction A) and >250 μm to <2 mm (fraction B). Sixteen priority PAHs were analysed in the soils using in situ pressurised
fluid extraction (PFE) followed by gas chromatography—mass spectrometry (GC–MS). The average total PAH concentration in the
soils ranged from 9.0 to 1,404 mg/kg (soil fraction A) and from 6.6 to 872 mg/kg (soil fraction B). These concentrations are
high compared with other industrially contaminated soils reported in the international literature, indicating that the tar
works warrants further investigation/remediation. A predominance of higher-molecular-weight compounds was determined in the
samples, suggesting that the PAHs were of pyrogenic (anthropogenic) origin. Statistical comparison (t-test) of the mean total PAH concentrations in soil fractions A and B indicated that there was a significant difference (95%
confidence interval) between the fractions in all but two of the soil samples. Additionally, comparisons of the distributions
of individual PAHs (i.e. 16 PAHs × 16 soil samples) in soil fractions A and B demonstrated generally higher PAH concentrations
in fraction A (i.e. 65.8% of all individual PAH concentrations were higher in soil fraction A). This is important because
fraction A corresponds to the particle size thought to be most important in terms of human contact with soils and potential
threats to human health. 相似文献
3.
Restoration of foundation species promises to reverse environmental degradation and return lost ecosystem services, but a lack of standardized evaluation across projects limits understanding of recovery, especially in marine systems. Oyster reefs are restored to reverse massive global declines and reclaim valuable ecosystem services, but the success of these projects has not been systematically and comprehensively quantified. We synthesized data on ecosystem services associated with oyster restoration from 245 pairs of restored and degraded reefs and 136 pairs of restored and reference reefs across 3500 km of U.S. Gulf of Mexico and Atlantic coastlines. On average, restoration was associated with a 21-fold increase in oyster production (mean log response ratio = 3.08 [95% confidence interval: 2.58–3.58]), 34–97% enhancement of habitat provisioning (mean community abundance = 0.51 [0.41–0.61], mean richness = 0.29 [0.19–0.39], and mean biomass = 0.69 [0.39–0.99]), 54% more nitrogen removal (mean = 0.43 [0.13–0.73]), and 89–95% greater sediment nutrients (mean = 0.67 [0.27–1.07]) and organic matter (mean = 0.64 [0.44–0.84]) relative to degraded habitats. Moreover, restored reefs matched reference reefs for these ecosystem services. Our results support the continued and expanded use of oyster restoration to enhance ecosystem services of degraded coastal systems and match many functions provided by reference reefs. 相似文献
4.
Ping Li Xinbin Feng Guangle Qiu Lihai Shang Guanghui Li 《Environmental geochemistry and health》2009,31(6):683-691
The total mercury (T-Hg) and methyl mercury (Me-Hg) concentrations in the hair were measured to evaluate mercury (Hg) exposure
for the residents in Da-shui-xi Village (DSX) and Xia-chang-xi Village (XCX) in the Wanshan Hg mining area, Guizhou Province,
Southwestern China. The mean concentrations in the hair of DSX residents were 5.5 ± 2.7 μg/g and 1.9 ± 0.9 μg/g for T-Hg and
Me-Hg, respectively. The concentrations in the hair of XCX residents were 3.3 ± 1.4 μg/g and 1.2 ± 0.5 μg/g for T-Hg and Me-Hg,
respectively. Hair Me-Hg concentrations were significantly correlated to T-Hg (r = 0.42, P < 0.01) in the two sites; on average, hair Me-Hg concentration accounted for 40 and 44% of T-Hg for DSX and XCX residents,
respectively. Age has no obvious correlation with hair Hg and the hair Hg levels showed a significant gender difference, with
higher T-Hg and Me-Hg concentrations in the hair from males than females. The rice collected from the two sites showed high
levels of T-Hg and Me-Hg concentration. The results indicated a certain Hg exposure for the residents in DSX and XCX in the
Wanshan Hg mining area. 相似文献
5.
Fu-Lin Evelyn Chu Eric D. Lund Paul R. Littreal Kate E. Ruck Ellen Harvey Jean-René Le Coz Yanic Marty Jeanne Moal Philippe Soudant 《Marine Biology》2009,156(2):155-169
The kinetics and efficiency of sterol production and bioconversion of phytosterols in two heterotrophic protists Oxyrrhis marina and Gyrodinium dominans were examined by feeding them two different algal species (Rhodomonas salina and Dunaliella tertiolecta) differing in sterol profiles. R. salina contains predominantly brassicasterol (≅99%) and <2% cholesterol. The major sterols in D. tertiolecta are ergosterol (45–49%), 7-dehydroporiferasterol (29–31%) and fungisterol (21–26%). O. marina fed R. salina metabolized dietary brassicasterol to produce 22-dehydrocholesterol and cholesterol. O. marina fed D. tertiolecta metabolized dietary sterols to produce cholesterol, 22-dehydrocholesterol, brassicasterol and stigmasterol. G. dominans fed either R. salina or D. tertiolecta metabolized dietary sterols to make cholesterol, brassicasterol and a series of unknown sterols. When protists were fed R. salina, which contains cholesterol, the levels of cholesterol were increased to a magnitude of nearly 5- to 30-fold at the phytoplankton-heterotrophic
protist interface, equivalent to a production of 172.5 ± 16.2 and 987.7 ± 377.7 ng cholesterol per mg R. salina carbon consumed by O. marina and G. dominans, respectively. When protists were fed D. tertiolecta, which contains no cholesterol, a net production of cholesterol by the protists ranged from 123.2 ± 30.6 to 871.8 ± 130.8 ng
per mg algal C consumed. Cholesterol is not only the dominant sterol, but a critical precursor for many physiologically functional
biochemicals in higher animal. As intermediates, these heterotrophic protists increase the amount of cholesterol at the phytoplankton–zooplankton
interface available to higher trophic levels relative to zooplankton feeding on algae directly. 相似文献
6.
Seasonal aerial surveys were conducted in the waters of the central Spanish Mediterranean from 2001 to 2003 using the line transect sampling methodology to estimate cetacean abundance. The density of the three most abundant species, striped dolphin (Stenella coeruleoalba), bottlenose dolphin (Tursiops truncatus) and Risso’s dolphins (Grampus griseus), was estimated. In the case of the first two species, the density was estimated accounting for the proportion of submerged animals, while for Risso’s dolphin only the surface density could be estimated. The striped dolphin was the most abundant species in the study area with a mean density of 0.489 dolphins km−2 (95% CI = 0.339–0.705) and a mean abundance of 15,778 dolphins (95% CI = 10,940–22,756). This density is comparable to that obtained in the International Ligurian Sea Cetacean Sanctuary. Striped dolphins were observed throughout the whole year and no seasonal changes in the density were detected. The mean density of bottlenose dolphins was an order of magnitude lower than that of striped dolphins (0.041 dolphins km−2; 95% CI = 0.023–0.075) with a mean abundance of 1,333 dolphins (95% CI = 739–2,407). The Risso’s dolphin had a surface estimated density of 0.015 dolphins km−2 (95% CI = 0.005–0.046) and a mean abundance of 493 dolphins (95% CI = 162–1,498). These results provide valuable biological information useful to develop conservation plans and establish a baseline for future population trend studies. 相似文献
7.
Michael D. Arendt Albert L. Segars Julia I. Byrd Jessica Boynton J. David Whitaker Lindsey Parker David W. Owens Gaëlle Blanvillain Joseph M. Quattro Mark A. Roberts 《Marine Biology》2012,159(1):101-112
Satellite transmitters were attached to 25 reproductively active and four inactive adult male loggerhead sea turtles (86.6–107.0 cm
SCLmin) captured from the Port Canaveral, FL, USA shipping channel to assess horizontal and vertical distributions. During
the breeding period, male loggerheads aggregated (44% of 755 turtle days) in a 117.6 km2 core area that encompassed the shipping channel. Median dive duration during the breeding period was 27 min (IQR = 15–42
min) and males spent 4% (IQR = 3–5%) of the time at the surface, with significantly shorter dives associated with reproductively
active males. Migrant and resident males dispersed concurrently, with residents shifting > 30 km east across the continental
shelf over a more protracted departure schedule than migrants. Dive duration and time spent at the surface increased through
the fall. Cluster analysis revealed the strongest association for dive duration with sea state during and after the breeding
period, with significantly longer dives during more turbulent conditions. In contrast, univariate associations with surface
interval duration were not elucidated. 相似文献
8.
Tomoharu Eguchi Jeffrey A. Seminoff Robin A. LeRoux Peter H. Dutton Donna L. Dutton 《Marine Biology》2010,157(8):1869-1877
Longitudinal capture-mark-recapture data were used to estimate abundance and survival rates for green turtles (Chelonia mydas) in San Diego Bay, California, USA. These turtles were closely associated with warm effluent from a power plant during winter
months. The life stage distribution of green turtles in the bay ranged from post-pelagic juveniles to adults (44.0–110.4 cm
straight carapace length). During 99 capture sessions between December 2, 1990, and March 25, 2009, 96 individual green turtles
were caught. To estimate abundance and survival rates, robust-design mark-recapture models were fitted to capture-recapture
histories using software MARK. The estimated annual survival rate was 0.861 (SE = 0.147, 95% CI = 0.356–0.986), whereas annual
abundance ranged from 16 (SE = 6.3, 95% CI = 4–29) to 61 (SE = 13.2, 95% CI = 36–88). This study provides the first survival
rate and abundance estimates for a green turtle foraging population in the highly industrialized San Diego Bay. 相似文献
9.
To determine seasonal variability in mineralization dynamics of mussel biodeposits, we applied a multiple-element approach measuring mineralization rates of carbon (C), nitrogen (N), phosphorus (P) and silicate (Si) during three periods (March, August and November). The results of this study showed that mineralization rates vary between seasons and between elements and that mineralization dynamics were influenced by both temperature and biodeposit nutrient composition. Mineralization rates were 3.2 ± 0.4 mmol C, 0.17 ± 0.04 mmol N, 0.06 ± 0.02 mmol P and 3.91 ± 3.75 mmol Si per gram biodeposit (DW) per day, which represented 24 % of the particulate organic C and 17 % of the particulate organic N in mussel biodeposits. Seasonal variability was largest for Si mineralization with 60–80-fold higher rates measured in March compared to August and November. This difference is most likely related to the difference in biodeposit nutrient composition. It was furthermore shown that the labile fraction of biodeposits became mineralized after, respectively, 18, 9 and 13 days during the experimental periods in March, August and November. This indicates that temperature enhances biodeposit decomposition with approximately 2–3 times faster turnover at a 10 °C temperature interval (Q 10 ). 相似文献
10.
A surfactant mediated cloud point extraction (CPE) procedure has been developed to remove color from wastewater containing
malachite green using Triton X-100 as non-ionic surfactant. The effects of the concentration of the surfactant, temperature
and salt concentration on the different concentrations of dye have been studied and optimum conditions were obtained for the
removal of malachite green. The concentration of malachite green in the dilute phase was measured using UV–Vis spectrophotometer.
It was found that the separation of phases was complete and the recovery of malachite green was very effective in the presence
of NaCl as an electrolyte. The results showed that up to 500 ppm of malachite green can quantitatively be removed (>95%) by
CPE procedure in a single extraction using optimum conditions. 相似文献
11.
Safety assessments for radioactive waste disposal require estimations of the migration of radionuclides in soils. The influence
of humic acid (HA) on the sorption of uranium in its +4 oxidation state to kaolin has been examined from pH 4 to 8, with HA
concentrations of 15–200 ppm. In the absence of HA, 20–40% of the U(IV) was in solution, with more sorption occurring at higher
pH. The presence of HA solubilised up to 90% of the uranium with higher solubilities at higher HA concentrations and higher
pH values. Uranium sorption was mapped against HA sorption, and it was found that there was a lower level of U(IV) sorption
than can be accounted for by just measuring HA sorption. However, this effect got less marked as the pH rose. Sensitivity
analysis indicated that the fraction of surface-bound HA is the controlling parameter for modelling in these systems. 相似文献
12.
The rate of growth of any population is a quantity of interest in conservation and management and is constrained by biological
factors. In this study, recent data on life-history parameters influencing rates of population growth in humpback whales,
including survival, age at first parturition and calving rate are reviewed. Monte Carlo simulations are used to compute a
distribution of rates of increase (ROIs) taking into account uncertainty in biological parameter estimates. Two approaches
for computing juvenile survival are proposed, which taken into account along with other life-history data, resulted in the
following estimates of the rate of population growth: Approach A: mean of 7.3%/year (95% CI = 3.5–10.5%/year) and Approach
B: mean of 8.6%/year (95% CI = 5.0–11.4%/year). It is proposed that the upper 99% quantile of the resulting distribution of
the ROI for Approach B (11.8%/year) be established as the maximum plausible ROI for humpback whales and be used in population
assessment of the species. Possible sources of positive and negative biases in the present estimates are presented and include
measurement error in estimation of life-history parameters, changes in the environment within the period these quantities
are measured, density dependence or other natural factors. However, it is difficult to evaluate potential biases without additional
data. The methods presented in this study can be applied to other species for which life-history parameters are available
and are useful in assessing plausibility in the estimation of population growth rates from time series of abundance estimates. 相似文献
13.
Geographic patterns of non-carpeted floor dust loading in Syracuse, New York (USA) homes 总被引:1,自引:0,他引:1
Johnson DL Hunt A Griffith DA Hager JM Brooks J Stellalevinsohn H Lanciki A Lucci R Prokhorova D Blount SL 《Environmental geochemistry and health》2009,31(3):353-363
Residential floor dust loading was measured on the smooth floor surface of 488 houses in Syracuse, New York, during the summers
of 2003 and 2004. Using U.S. Environmental Protection Agency (EPA) wipe methods, pre-weighed Ghost Wipes, Lead Wipes, or Whatman
Filters were employed to collect duplicate samples from (predominantly) kitchens. The collection efficiency of the various
media was determined from multiple wipe tests and side-by-side comparisons. The results were normalized and aggregated at
the census tract level to determine whether spatial patterns of dust loading could be observed. Loading was found to be log-normally
distributed, with a geometric mean value of 0.311 g m−2 (29 mg of dust per square foot of floor); 95% of the observations fell in the range of 0.042–2.330 g m−2 (4–216 mg foot−2). The sampling for floor dust loading shows some bias for day of the week in which visits to the residential properties were
made. After a first-order correction for this effect, results were aggregated by census tract and mapped in a geographic information
system (GIS); strong spatial patterns can be identified in an inverse distance weighted mapping. The geographic patterns exhibit
a strong correlation with socio-economic/demographic covariates extracted from the 2000 census summaries. Dust mass on the
floors is positively correlated with renter-occupied properties and family size; it is negatively correlated with measures
of household income. 相似文献
14.
The combined effects of ocean warming and acidification were compared in larvae from two populations of the cold-eurythermal
spider crab Hyas araneus, from one of its southernmost populations (around Helgoland, southern North Sea, 54°N, habitat temperature 3–18°C; collection:
January 2008, hatch: January–February 2008) and from one of its northernmost populations (Svalbard, North Atlantic, 79°N,
habitat temperature 0–6°C; collection: July 2008, hatch: February–April 2009). Larvae were exposed to temperatures of 3, 9
and 15°C combined with present-day normocapnic (380 ppm CO2) and projected future CO2 concentrations (710 and 3,000 ppm CO2). Calcium content of whole larvae was measured in freshly hatched Zoea I and after 3, 7 and 14 days during the Megalopa stage.
Significant differences between Helgoland and Svalbard Megalopae were observed at all investigated temperatures and CO2 conditions. Under 380 ppm CO2, the calcium content increased with rising temperature and age of the larvae. At 3 and 9°C, Helgoland Megalopae accumulated
more calcium than Svalbard Megalopae. Elevated CO2 levels, especially 3,000 ppm, caused a reduction in larval calcium contents at 3 and 9°C in both populations. This effect
set in early, at 710 ppm CO2 only in Svalbard Megalopae at 9°C. Furthermore, at 3 and 9°C Megalopae from Helgoland replenished their calcium content to
normocapnic levels and more rapidly than Svalbard Megalopae. However, Svalbard Megalopae displayed higher calcium contents
under 3,000 ppm CO2 at 15°C. The findings of a lower capacity for calcium incorporation in crab larvae living at the cold end of their distribution
range suggests that they might be more sensitive to ocean acidification than those in temperate regions. 相似文献
15.
Abimbola AF Kehinde-Phillips OO Olatunji AS 《Environmental geochemistry and health》2007,29(2):163-167
The aim of this study was to assess the heavy metal content of the dust generated by the Sagamu cement factory and its attendant
health hazards on the immediate environment, especially on the inhabitants of the area. A total of 25 samples were collected
and analyzed using inductively coupled plasma-optical emission spectrometry. Records of medical ailments associated with heavy
metal toxicity were also compiled from the Obafemi Awolowo Teaching Hospital situated in the town.The results for some of
the selected heavy metals showed the following pattern: limestone: Cd (n.d.-1.7 ppm), Pb (42–48 ppm), Cu (3.0–11 ppm), Zn
(7.0–53 ppm) and Ni (3.0–8.0 ppm); shale: Cd (0.3–1.1 ppm), Pb (17–22 ppm), Cu (2.0–11 ppm), Zn (17–147 ppm) and Ni (3.0–18 ppm);
dusts: Cd (0.5–0.7 ppm), Pb (32–52 ppm), Cu (2–16 ppm), Zn (5–152 ppm) and Ni (2–17 ppm); soils: Cd (0.5–1.1 ppm), Pb (28–49 ppm),
Cu (22–35 ppm), Zn (43–69 ppm) and Ni (13.0–17 ppm). High levels of heavy metals were found in the rocks and soils. We propose
that the high levels of metals in the dust and soil were acquired from the raw materials used by the cement factory and from
active industrial discharge from this same factory. Medical records and the current health situation of the local residents
in the study area reveal that there have been increases in the prevalence of diseases linked to heavy metal toxicity in the
environment, especially those related to dust generation. 相似文献
16.
Stock heterogeneity was investigated in albacore tuna (Thunnus alalunga, Bonnaterre 1788), a commercially important species in the North Atlantic Ocean and Mediterranean Sea. Twelve polymorphic
microsatellite loci were examined in 581 albacore tuna from nine locations, four in the north-east Atlantic Ocean (NEA), three
in the Mediterranean Sea (MED) and two in the south-western Pacific Ocean (SWP). Maximum numbers of alleles per locus ranged
from 9 to 38 (sample mean, 5.2–22.6 per locus; overall mean, 14.2 ± 0.47 SE), and observed heterozygosities per locus ranged
from 0.44 to 1.00 (overall mean: 0.79 ± 0.19 SE). Significant deficits of heterozygotes were observed in 20% of tests. Multilocus
F
ST values were observed ranging from 0.00 to Θ = 0.036 and Θ′ = 0.253, with a mean of Θ = 0.013 and Θ′ = 0.079. Pairwise F
ST values showed that the SWP, NEA and MED stocks were significantly distinct from one another, thus corroborating findings
in previous studies based on mitochondrial DNA, nuclear DNA (other than microsatellites) and allozyme analyses. Heterogeneity
was observed for the first time between samples within the Mediterranean Sea. GENELAND indicated the potential presence of
three populations across the NEA and two separate populations in the Mediterranean Sea. Observed genetic structure may be
related to migration patterns and timing of movements of subpopulations to the feeding grounds in either summer or autumn.
We suggest that a more intensive survey be conducted throughout the entire fishing season to ratify or refute the currently
accepted genetic homogeneity within the NEA albacore stock. 相似文献
17.
Elizabeth J. Berens McCabe Damon P. Gannon Nélio B. Barros Randall S. Wells 《Marine Biology》2010,157(5):943-942
Prey selection was investigated in wild, resident common bottlenose dolphins, Tursiops truncatus, during the summer months in Sarasota Bay, Florida, USA. Stomach content analyses of 15 dolphins with extensive sighting
histories and well-documented distributions were used to determine prey use. Prey availability was assessed by purse seine
surveys. We compared the relative abundances of prey available to estimates of prey use at closely matching spatial and temporal
scales. G-tests determined that dolphins in this study significantly selected for prey at the species, family, and soniferous/non-soniferous
prey levels (G
adj
= 753.98–1,775.93, df = 1–21, p ≤ 0.01). While comprising only 6.3% of the total available prey, soniferous fishes accounted for 51.9% of the total prey
consumed. Manly’s standardized forage ratios and 95% Bonferroni confidence intervals determined significant positive selection
for soniferous prey and against non-soniferous prey (βS = 0.9461 vs. βNS = 0.0539). Dolphins selected against Gerridae, Clupeidae, and Sparidae (β ≤ 0.0014), as well as against all the species within those families (β ≤ 0.0190). It is likely that passive listening for soniferous prey provides an ecological or energetic advantage to cetaceans
utilizing this specific foraging technique. 相似文献
18.
Pistón M Silva J Pérez-Zambra R Dol I Knochen M 《Environmental geochemistry and health》2012,34(2):273-278
A multicommutated flow system was designed and evaluated for the determination of total arsenic and selenium by Hydride Generation
Atomic Absorption Spectrometry (HG-AAS). It was applied to the determination of arsenic and selenium in samples of natural
and drinking water. Detection limits were 0.46 and 0.08 μg l−1 for arsenic and selenium, respectively; sampling frequency was 120 samples h−1 for arsenic and 160 samples h−1 for selenium. Linear ranges found were 1.54–10 μg l−1 (R = 0.999) for arsenic and 0.27–27 μg l−1 (R = 0.999) for selenium. Accuracy was evaluated by spiking various water samples and using a reference material. Recoveries
were in the range 95–116%. Analytical precision (s
r
(%), n = 10) was 6% for both elements. Compared with the Standard Methods, APHA, 3114B manual method, the system consumes at least
10 times less sample per determination, and the quantities of acid and reducing agent used are significantly lower with a
reduction in the generation of pollutants and waste. As an additional advantage, the system is very fast, efficient and environmentally
friendly for monitoring total arsenic and selenium levels in waters. 相似文献
19.
Estimating abundance of killer whales in the nearshore waters of the Gulf of Alaska and Aleutian Islands using line-transect sampling 总被引:1,自引:0,他引:1
Alexandre N. Zerbini Janice M. Waite John W. Durban Rick LeDuc Marilyn E. Dahlheim Paul R. Wade 《Marine Biology》2007,150(5):1033-1045
Killer whale (Orcinus orca Linnaeus, 1758) abundance in the North Pacific is known only for a few populations for which extensive longitudinal data
are available, with little quantitative data from more remote regions. Line-transect ship surveys were conducted in July and
August of 2001–2003 in coastal waters of the western Gulf of Alaska and the Aleutian Islands. Conventional and Multiple Covariate
Distance Sampling methods were used to estimate the abundance of different killer whale ecotypes, which were distinguished
based upon morphological and genetic data. Abundance was calculated separately for two data sets that differed in the method
by which killer whale group size data were obtained. Initial group size (IGS) data corresponded to estimates of group size
at the time of first sighting, and post-encounter group size (PEGS) corresponded to estimates made after closely approaching
sighted groups. ‘Resident’-type (fish-eating) killer whales were more abundant than the ‘transient’-type (mammal-eating).
Abundance estimates of resident killer whales (991 [95% CI = 379–2,585] [IGS] and 1,587 [95% CI = 608–4,140] [PEGS]), were
at least four times greater than those of the transient killer whales (200 [95% CI = 81–488] [IGS] and 251 [95% CI = 97–644]
whales [PEGS]). The IGS estimate of abundance is preferred for resident killer whales because the estimate based on PEGS data
may show an upward bias. The PEGS estimate of abundance is likely more accurate for transients. Residents were most abundant
near Kodiak Island in the northern Gulf of Alaska, around Umnak and Unalaska Islands in the eastern Aleutians, and in Seguam
Pass in the central Aleutians. This ecotype was not observed between 156 and 164°W, south of the Alaska Peninsula. In contrast,
transient killer whale sightings were found at higher densities south of the Alaska Peninsula between the Shumagin Islands
and the eastern Aleutians. Only two sightings of ‘offshore’-type killer whales were recorded during the surveys, one northeast
of Unalaska Island and the other south of Kodiak Island. These are the first estimates of abundance of killer whale ecotypes
in the Aleutian Islands and Alaska Peninsula area and provide a baseline for quantifying the role of these top predators in
their ecosystem.
Electronic Supplementary Material Supplementary material is available in the online version of this article at and is accessible for authorized users.
相似文献
Alexandre N. ZerbiniEmail: |
20.
Eun Jung Choy Qtae Jo Hyo-Bang Moon Chang-Keun Kang Ju-Chan Kang 《Marine Biology》2007,151(1):157-165
The time-course of uptake and elimination of benzo(a)pyrene (BaP) for the Pacific oyster, Crassostrea gigas and reproduction damage and reproductive outputs were studied. Sexually immature C. gigas broodstock were fed for 28 days with live algae grown in four BaP solutions of 0, 50, 500, and 5,000 μg L−1 (hereafter, control, 50, 500, and 5,000 oysters) and were subsequently conditioned to maturation by a feeding with BaP-free
live algae under temperature manipulation for another 28 days. The 5,000 μg L−1 oysters gained a steady state concentration, around 30,000 ng g−1 d.w. for digestive gland, a week earlier compared to the 500 μg L−1 oysters. The earlier gain or longer persistence of the steady state concentration influenced elimination of BaP, with an
eliminating trend for 500 μg L−1 oysters, while no elimination for 5,000 μg L−1 oysters. The maternal persistence of the steady state concentration resulted in significant damages in the reproductive success
and their reproductive outputs in terms of the hatching rate and larval growth, survival, and settlement. The 50 μg L−1 oysters remained far below the steady state concentration, and showed a manifest eliminating behavior during the subsequent
BaP-free 28 day maturation period. The reproductive success and initial larval events of 50 μg L−1 oysters were comparable to those of control. However, the damage potential of the 50 μg L−1 oysters might be more significant if their maternal exposure continued beyond 28 days, since the accumulation profile at this
dose was linear. 相似文献