Mesoscale variability related to iron speciation in a coastal Ross Sea area (Antarctica) during summer 2014

Dissolved iron (Fe) distribution and speciation was determined in water samples (0–200?m) collected in a coastal area near Terra Nova Bay during the austral summer of 2014. Nutrients, dissolved oxygen, chlorophyll-a, phytoplankton composition and prokaryotic biomass distribution were investigated in combination with measurements of the physical properties of the water columns and its dynamics. The dFe value was above the limiting growth concentration, ranging from 0.52 to 4.51?nM, and it showed a spatial variability with a horizontal length scale of about 10?km, according to the variability of the water column physical properties and to iron sources. The organic ligands (L) maintained the concentrations of dFe at levels much higher than the inorganic solubility of Fe, keeping it available for phytoplankton and the log K’_FeL values found (from 22.1 to 23.6) highlighted the presence of complexes of differing stabilities.     

Zooplankton responses to hydrological and trophic variability in a Mediterranean coastal ecosystem (Lesina Lagoon,South Adriatic Sea)

Spatial and temporal variability in zooplankton was studied at eight stations located in the Lesina Lagoon (South Adriatic Sea) Salinity, temperature, dissolved oxygen and chlorophyll a (in the lagoon) at these stations were also assessed. The zooplankton community was characterised by clear seasonal oscillations and mostly represented by copepods and their larvae. The dominant copepod species were Calanipeda aquaedulcis and Acartia tonsa, which exhibited spatial–temporal segregation in the lagoon. C. aquaedulcis copepodites seemed to be better adapted to oligotrophic and oligohaline conditions compared with the A. tonsa population. The invasive species A. tonsa has completely replaced the formerly abundant Acartia margalefi. A positive correlation was found between abundances, total species numbers and trophic state. An increasing abundance trend was shown from the lagoon towards the sea. The highest diversity indices were recorded at the two channel inlets, during high tide due to the absence of a clear dominance of one or more coastal species and the co-occurrence of species of lagoon and marine origin.     

Effect of nitrogen supply on photosynthesis and carbonic anhydrase activity in the green seaweed Ulva rigida (Chlorophyta)

Photosynthesis rate and carbonic anhydrase (CA) activity have been studied in the green seaweed Ulva rigida C. Agardh (Chlorophyta) grown in seawater (SW) and SW supplemented with 40 M NH₄Cl (N-SW). Higher growth and maximal O₂ evolution rates were observed in N-SW- than in SW-grown sea-weeds. Western blot analysis of the total homogenates probed with antibodies raised against small subunits of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) showed crossreaction with a 15 kdalton polypeptide in both SW- and N-SW-grown plants, although the band was more intense in N-SW-grown plants. Carbonic anhydrase activities in the total homogenate and in the soluble protein fraction were higher in N-SW-grown plants. Although the pellets from both plants showed a considerable CA activity, the activity of CA in the thylakoid membranes was undetectable. The low nitrogen concentration is a major environmental factor that affects the level of RuBisCO and CA, and therefore CO₂ assimilation in U. rigida.     

Carbon and nitrogen exchange between sandy beach clams (Donax serra) and kelp beds in the Benguela coastal upwelling region

Carbon consumption and nitrogen requirements were estimated for populations of the sandy beach bivalve Donax serra on nine beaches of the west coast of South Africa. Subtidal populations composed mainly of adult clams were responsible for the bulk of standing stock (3538 g C m⁻¹), annual carbon consumption (13 444 g C m⁻¹ yr⁻¹), faeces production (6478 g C m⁻¹ yr⁻¹ ) and nitrogen regeneration (2525 g N m⁻¹ yr⁻¹). Kelp detritus, bacteria and kelp consumers' faeces available in the water column surpass several times the carbon and nitrogen requirements of intertidal and subtidal clam populations. Individual Donax serra pop ulations, in turn, may regenerate up to 3.2% of the total nitrogen requirements of all primary producers from kelp beds and 14% of the requirements of phytoplankton. These high standing stocks of clams are presumably supported mainly by organic matter originating from kelp which, in contrast to phytoplankton, is in constant supply and comprises the largest proportion of the annual production of particulate organic matter on this coast. Wide and shallow continental shelves with gentle slopes probably limit the penetration of upwelled waters to the nearshore waters, decreasing the influence of external inputs and increasing the importance of internal flows of nutrients and carbon within the nearshore zone. In this context, sandy beaches, rocky shores and kelp beds may be more closely interlinked compartments of a larger ecosystem encompassing the whole nearshore than traditionally thought. Received: 28 August 1996 / Accepted: 7 October 1996     

Age-specific responses to elevated salinity in the coastal marsh plant black needlerush (Juncus roemerianus Scheele) as determined through polyphasic chlorophyll a fluorescence transients (OJIP)

This study employed polyphasic chlorophyll a fluorescence transients (OJIP), a non-invasive marker of environmental stress in plants, to evaluate salt tolerance in three different Juncus roemerianus age classifications (6-, 24-, and 60-months). Following exposure to elevated salts (30 psu), the younger plants sustained growth, which was comparable to freshwater controls. While older (60-month) plants receiving only freshwater also grew over the 8-week study, the older salt-treated plants did not increase in size. Similarly, there were significant declines in variable chlorophyll a fluorescence parameters (F _v/F _m and F _v/F _o), electron transport flux per reaction center (ET_o/RC), and photosystem II performance index (PI_ABS) for 60-month J. roemerianus following salt treatment. These responses were not evident in the two younger salt-treated age classifications. Our results suggest that older J. roemerianus are less tolerant to rapid and sudden increases in salinity relative to younger plants and that this age-specific response may help explain observed discrepancies in salt tolerance in J. roemerianus.     

Succession and growth limitation of phytoplankton in the Gulf of Bothnia (Baltic Sea)

A one year field study of four stations in the Gulf of Bothnia during 1991 showed that the biomass was ca. two times, and primary productivity ca. four times, lower in the north (Bothnian Bay) than in the south (Bothnian Sea) during the summer. Nutrient addition experiments indicated phosphorus limitation of phytoplankton in the Bothanian Bay and the coastal areas in the northern Bothnian Sea, but nitrogen limitation in the open Bothanian Sea. A positive correlation between the phosphate concentration and the production/biomass ratio of phytoplankton was demonstrated, which partly explained the differences in the specific growth rate of the phytoplankton during the summer. Differences in photosynthetic active radiation between the stations also showed a covariation with the primary productivity. The relative importance of nutrient or light limitation for photosynthetic carbon fixation could not, however, the conclusively determined from this study. Marked differences in phytoplankton species composition from north to south were also observed. The number of dominating species was higher in the Bothnian Sea than in the Bothnian Bay. The distribution of some species could be explained as due to nutrient availability (e.g. Nodularia spumigena, Aphanizomenon sp.), while salinity probably limits the distribution of some limnic as well as marine species. The potentially toxic phytoplankton N. spumigena, Dinophysis acuminata and Chrysochromulina spp. were common in the Bothnian Sea but not in the Bothnian Bay. The pico- and nanoplankton biomass during late summer was higher than previously reported due to a revised carbon/volume ratio.     

Vegetation development in coastal foredunes in relation to methods of establishing marram grass (Ammophila arenaria)

In coastal foredunes marram grass (Ammophila arenaria) is used to stabilize windblown sand. The development of traditionally plantedAmmophila into a more natural foredune vegetation may take 5 – 10 yr. For economic reasons, traditional planting may be replaced by alternative techniques such as planting seeds or disk-harrowing rhizome fragments. In this paper, we compare the initial vegetation development of traditionally planted stands with stands established from seeds and from rhizomes. The experiments were conducted on an artificial foredune originating from dredged sea sand. The total experimental area covered more than 100 ha and the vegetation development was studied for 6 yr. The data were analysed bya priori grouping of plant species according to their ecology, as well as by Principal Components Analysis (PCA) and Redundancy Analysis (RA) of the percentage ground cover per plant species. Comparing ecological groups of plants showed that all planting methods delivered equal numbers of plant species that are indicative for coastal dunes. PCA and RA showed that methods based on the use of rhizome material resulted in a higher percentage cover of clonal perennials (Calammophila baltica, Festuca rubra ssp.arenaria, Carex arenaria andCirsium arvense) than the traditionally planted stands and the stands obtained from seeds. The latter two were characterized by the dominance of annuals, bi-annuals and (mostly nonrhizomatous) perennials. Initially, the rates of succession were highest in the stands obtained from rhizomes. However, after 3 – 6 yr there were no differences between the various stands. During the first four years, the percentage cover by rhizomatous foredune plants developed faster than that of annuals, bi-annuals and perennials. After 6 yr, the latter contributed almost as much to the percentage cover as the clonal species. Nomenclature: van der Meijden et al. (1990) for plant species. The plant species were classified into ecological groups according to van der Meijden et al. (1991) and Mennema et al. (1980).     

Effect of nitrogen supply on nitrogen uptake,accumulation and assimilation in Porphyra perforata (Rhodophyta)

Porphyra perforata J. Ag. was collected from a rocky land-fill site near Kitsilano Beach, Vancouver, British Columbia, Canada and was grown for 4 d in media with one of the following forms of inorganic nitrogen: NO ₃ ^- , NH ₄ ⁺ and NO ₃ ^- plus NH ₄ ⁺ and for 10 d in nitrogen-free media. Internal nitrogen accumulation (nitrate, ammonium, amino acids and soluble protein), nitrate and ammonium uptake rates, and nitrate reductase activity were measured daily. Short initial periods (10 to 20 min) of rapid ammonium uptake were common in nitrogen-deficient plants. In the case of nitrate uptake, initial uptake rates were low, increasing after 10 to 20 min. Ammonium inhibited nitrate uptake for only the first 10 to 20 min and then nitrate uptake rates were independent of ammonium concentration. Nitrogen starvation for 8 d overcame this initial suppression of nitrate uptake by ammonium. Nitrogen starvation also resulted in a decrease in soluble internal nitrate content and a transient increase in nitrate reductase activity. Little or no decrease was observed in internal ammonium, total amino acids and soluble protein. The cultures grown on nitrate only, maintained high ammonium uptake rates also. The rate of nitrate reduction may have limited the supply of nitrogen available for further assimilation. Internal nitrate concentrations were inversely correlated with nitrate uptake rates. Except for ammonium-grown cultures, internal total amino acids and soluble protein showed no correlation with uptake rates. Both internal pool concentrations and enzyme activities are required to interpret changes in uptake rate during growth.     

Effect of natural and synthetic organic-Fe(III) complexes in an estuarine mixing model on iron uptake and growth of a coastal marine diatom, Chaetoceros sociale

Cell growth of a coastal marine diatom, Chaetoceros sociale, in the presence of different premixed organic-Fe(III) complexes [EDTA-Fe(III) (100:1 and 2:1), citric-Fe(III) (100:1) and fulvic-Fe(III) (0.1, 0.2 and 1 ppm C)] and solid amorphous hydrous ferric oxide [am-Fe(III) or Fe(III) hydroxide] were experimentally measured in culture experiments at 10 °C under 3000 lux fluorescent light. Fulvic-Fe(III) (0.1 and 0.2 ppm C) and citric-Fe(III) (100:1) induced maximal cell yields of C. sociale. The order of cell yields was: fulvic-Fe(III) (0.1 and 0.2 ppm C) ≥ citric-Fe(III) (100:1) > EDTA-Fe(III) (2:1) ≫ solid am-Fe(III) > EDTA-Fe(III) (100:1) ≫ fulvic-Fe(III) (1 ppm C). The short-term iron uptake rates by C. sociale in fulvic-Fe(III) (0.1 and 0.2 ppm C) and citric-Fe(III) (100:1) media were about five to six times faster than those in EDTA-Fe(III) (100:1) and solid am-Fe(III) media. The dissociative precipitation rates of premixed organic-Fe(III) complexes in seawater at 10 °C were determined by simple filtration (0.025 μm) involving γ-activity measurements of ⁵⁹Fe. The order of estimated initial Fe(III) dissociative precipitation rates of these organic-Fe(III) complexes in seawater were nearly consistent with those of cell yields in the culture experiments and short-term iron uptake rates by C. sociale [except for fulvic-Fe(III) (1 ppm C) medium]. In fulvic-Fe(III) (0.1 and 0.2 ppm C), citric-Fe(III) (100:1) and EDTA-Fe(III) (2:1) media, the concentrations of dissolved organic-Fe(III) complexes in initial culture experiments are prone to supersaturate under the culture conditions. The supersaturated dissolved organic-Fe(III) complex in seawater supplies biologically available inorganic Fe(III) species in culture media through its dissociation at high pH and high levels of seawater cations. Therefore, the natural dissolved organic-Fe(III) complexes supplied by riverine input may play an important role in supplying bioavailable iron in estuarine mixing system and coastal waters. Received: 6 September 1998 / Accepted: 8 April 1999     

Physiological and behavioral responses of temperate seahorses (Hippocampus guttulatus) to environmental warming

The aim of the present study was to evaluate, for the first time, the effect of environmental warming on the metabolic and behavioral ecology of a temperate seahorse, Hippocampus guttulatus. More specifically, we compared routine metabolic rates, thermal sensitivity, ventilation rates, food intake, and behavioral patterns at average spring temperature (18 °C), average summer temperature (26 °C), temperatures that they endure during summer heat wave events (28 °C), and in a near-future warming scenario (+2; 30 °C) in Sado estuary, Portugal. Both newborn juveniles and adults showed significant increases in metabolic rates with rising temperatures. However, newborns were more impacted by future warming via metabolic depression (i.e., heat-induced hipometabolism). In adult stages, ventilation rates also increased significantly with environmental warming, but food intake remained unchanged. Moreover, the frequency of swimming, foraging, swinging, and inactivity did not significantly change between the different thermal scenarios. Thus, we provide evidence that, while adult seahorses show great resilience to heat stress and are not expected to go through any physiological impairment and behavioral change with the projected near-future warming, the early stages display greater thermal sensitivity and may face greater metabolic challenges with potential cascading consequences for their growth and survival.     

Somatic and population growth responses of Ceriodaphnia dubia and Daphnia pulex (Cladocera) to changes in food (Chlorella vulgaris) level and temperature

We quantified the combined effects of three food levels (0.01 x 10(6), 0.1 x 10(6) and 1.0 x 10(6) cells ml(-1)) and three temperature levels (15, 20 and 25 degrees C) on the somatic and the clonal population growth of two cladocerans Ceriodaphnia dubia and Daphnia pulex for 24 to 42 days. The somatic growth data showed that both the cladoceran species began to increase their body size within 3 days and remained stable beyond a week. Food density had a significant effect on the body size of C. dubia while for D. pulex, food level and temperature as well as their interaction had significant effect on the body size. The population growth of both the cladoceran species was affected by temperature. At 15 degrees C, C. dubia showed little growth at the highest food density, while at low food level, there was some increase in the population abundances, especially after a long lag phase of about 2 weeks. At 15 degrees C and under the lowest tested food level, the population of D. pulex did not increase beyond the inoculation density. Optimal population growth of D. pulex was observed at intermediate temperature and at 1.0 x 10(6) cells ml(-1) of food level while for C. dubia 25 degrees C and the highest food level yielded highest growth. At low food level and low temperature, the rate of population increase (r) of C. dubia was much lower than that of D. pulex at comparable conditions. On the hand, at higher food levels and temperature regimes, the r of D. pulex was much higher than that of C.dubia. Regardless of the food levels and temperature, the r of C. dubia varied from 0.03 to 0.07 while that of D. pulex varied from 0.01 to 0.08 day(1).     

Vegetation development in coastal foredunes in relation to methods of establishing marram grass ( Ammophila arenaria )

In coastal foredunes marram grass (Ammophila arenaria) is used to stabilize windblown sand. The development of traditionally plantedAmmophila into a more natural foredune vegetation may take 5–10 yr. For economic reasons, traditional planting may be replaced by alternative techniques such as planting seeds or disk-harrowing rhizome fragments. In this paper, we compare the initial vegetation development of traditionally planted stands with stands established from seeds and from rhizomes. The experiments were conducted on an artificial foredune originating from dredged sea sand. The total experimental area covered more than 100 ha and the vegetation development was studied for 6 yr. The data were analysed bya priori grouping of plant species according to their ecology, as well as by Principal Components Analysis (PCA) and Redundancy Analysis (RA) of the percentage ground cover per plant species. Comparing ecological groups of plants showed that all planting methods delivered equal numbers of plant species that are indicative for coastal dunes. PCA and RA showed that methods based on the use of rhizome material resulted in a higher percentage cover of clonal perennials (Calammophila baltica, Festuca rubra ssp.arenaria, Carex arenaria andCirsium arvense) than the traditionally planted stands and the stands obtained from seeds. The latter two were characterized by the dominance of annuals, bi-annuals and (mostly nonrhizomatous) perennials. Initially, the rates of succession were highest in the stands obtained from rhizomes. However, after 3–6 yr there were no differences between the various stands. During the first four years, the percentage cover by rhizomatous foredune plants developed faster than that of annuals, bi-annuals and perennials. After 6 yr, the latter contributed almost as much to the percentage cover as the clonal species.     

Primary and secondary stress responses of striped bass (Morone saxatilis) exposed to benzene

Striped bass (Morone saxatilis) were collected from the San Francisco Bay-Delta estuary in 1982, from areas distant from pollution sources. After acclimatization, plasma cortisol concentration (primary response) and blood biochemicals indicative of energy mobilization (secondary responses) were followed in individuals exposed to sublethal levels of benzene for up to 21 d. Despite the persistence of benzene in blood and liver tissues for the exposure duration, stress responses were moderate and returned to control values within the initial 7 d. Blood and liver rapidly accumulated benzene to approximately 20 times the exposure concentrations (0.1 and 1.0 ppm). Concentrations of cortisol and secondary response variables were not proportional to benzene exposure or to accumulation levels, however. Plasma cortisol concentrations increased two- to three-fold at 8 h and returned to control levels prior to 48 h exposure. Glucose, lactate, H⁺, protein and triglyceride concentrations were elevated during the initial 4 h to 7 d, with protein and triglyceride returning to normal levels prior to the other secondary response variables. From the perspective of the general adaptation syndrome (GAS), benzene activated the hypothalamo-pituitary-interrenal axis, resulting in clinical stress responses characteristics of an alarm reaction. The time-courses and amplitudes of primary and secondary responses to benzene suggest the sensory perception of a noxious agent eliciting mild, acute stress followed by adaptation.     

Phytoplankton and pigment distributions in an anticyclonic slope water oceanic eddy (SWODDY) in the southern Bay of Biscay

An anticyclonic slope water oceanic eddy (SWODDY), named AE6, was sampled in the southern Bay of Biscay from 12 to 31 August 1998 to assess changes in the abundance and composition of phytoplankton assemblages related to the mesoscale feature. SWODDY AE6 showed characteristic biological signatures. A twofold increase in chlorophyll a concentration was found at the eddy centre relative to surrounding waters. Picoplankton cells accounted for a lower fraction of total chlorophyll a values at the eddy centre (44–50%) than outside the eddy (54–61%). Microscopic cell counts and HPLC pigment analysis showed that diatoms were almost entirely confined to the eddy centre, but both techniques yielded different results when studying other phytoplankton groups. Microscopic cell counts indicated that the spatial distribution of diatoms, dinoflagellates and unidentified flagellates was significantly influenced by SWODDY AE6, showing maximum abundance inside the mesoscale feature. HPLC pigment analysis provided more detailed information about the composition of pico–nanoplanktonic organisms. Pigment data processed by means of the CHEMTAX program showed "chlorophytes", "haptophytes" and "dinoflagellates II" (having haptophyte-like pigments and gyroxanthin-diester) as the more abundant "pigment classes" at the eddy centre, whereas dominance of "chlorophytes" and higher contribution of "cyanobacteria" (type Synechococcus) were estimated in the surrounding waters.Communicated by S.A. Poulet, Roscoff     

The performance of nitrate-reducing Fe(II) oxidation processes under variable initial Fe/N ratios: The fate of nitrogen and iron species

•Bacterially-mediated coupled N and Fe processes examined in incubation experiments. •NO₃⁻ reduction was considerably inhibited as initial Fe/N ratio increased. •The maximum production of N₂ occurred at an initial Fe/N molar ratio of 6. •Fe minerals produced at Fe/N ratios of 1–2 were mainly easily reducible oxides. The Fe/N ratio is an important control on nitrate-reducing Fe(II) oxidation processes that occur both in the aquatic environment and in wastewater treatment systems. The response of nitrate reduction, Fe oxidation, and mineral production to different initial Fe/N molar ratios in the presence of Paracoccus denitrificans was investigated in 132 h incubation experiments. A decrease in the nitrate reduction rate at 12 h occurred as the Fe/N ratio increased. Accumulated nitrite concentration at Fe/N ratios of 2–10 peaked at 12–84 h, and then decreased continuously to less than 0.1 mmol/L at the end of incubation. N₂O emission was promoted by high Fe/N ratios. Maximum production of N₂ occurred at a Fe/N ratio of 6, in parallel with the highest mole proportion of N₂ resulting from the reduction of nitrate (81.2%). XRD analysis and sequential extraction demonstrated that the main Fe minerals obtained from Fe(II) oxidation were easily reducible oxides such as ferrihydrite (at Fe/N ratios of 1–2), and easily reducible oxides and reducible oxides (at Fe/N ratios of 3–10). The results suggest that Fe/N ratio potentially plays a critical role in regulating N₂, N₂O emissions and Fe mineral formation in nitrate-reducing Fe(II) oxidation processes.     

大型钢铁厂及其周边土壤多环芳烃污染现状调查、评价与源解析

采用气相色谱-质谱联机方法(GC-MS)分析了东北某钢铁厂及周边居住区、风景区共11个采样点表层土壤样品16种多环芳烃(PAHs),结果表明,钢铁工业区16种PAHs(∑PAHs)浓度范围为3.39×103—1.54×105ng·g-1,平均浓度3.21×104ng·g-1;居住区∑PAHs浓度范围为587—6.70×103ng·g-1,平均浓度3.82×103ng·g-1;风景区千山∑PAHs浓度385 ng·g-1.∑PAHs和Bap浓度均呈工业区>居住区>风景区趋势.与国内外其他研究结果相比,该钢铁工业区及其周边居住区土壤PAHs污染相对较为严重,11个采样点中有9个采样点土壤∑PAHs为严重污染,4个采样点苯并(a)芘(Bap)浓度超过加拿大土壤质量基准.利用特征比值法(Diagnostic Rate)和主成分分析法(Principal component analysis,PCA)对钢铁工业区及其周边地区土壤进行了源解析,结果表明,钢铁工业区土壤中PAHs主要来源于焦炉、燃煤、柴油燃烧等污染源,周边地区土壤除受工业污染源排放影响外,机动车汽油、柴油污染排放也有重要影响.     

Growth patterns of Codium fragile ssp. tomentosoides in response to temperature,irradiance, salinity,and nitrogen source

Seasonal patterns of growth, reproduction, and productivity of Codium fragile spp. tomentosoides (van Goor) Silva were monitored at 3 locations in Rhode Island. Maximal growth occurred during the summer and was more significantly correlated with temperature than any other factor measured in this study. Multiple correlation models suggested an interaction between temperature, irradiance, and available nitrogen. Maximal reproduction occurred in late summer and early fall. The maximal productivity, based on harvested quadrats, was 2. 10 g dry weight m^-2 day^-1. A large amount (up to 87.3%) of the annual production entered the detrital food chain during the winter by fragmentation of the thallus. Culture studies examined the effects of temperature (6° to 30°C), irradiance (7 to 140 E m^-2 sec^-1), daylength (8 h light: 16 h dark to 24 h light: O h dark) and salinity (6 to 48) on growth. Differentiated thalli grew over a broad range of experimental conditions, with maximal growth at 24°C, 24 to 30 S, a minimal irradiance of 28 E m^-2 sec^-1, and 16 h daylength. The effect of increasing daylength was due to increased total daily irradiance rather than to a true photoperiodic effect. Undifferentiated sporelings survived and grew in a narrower range of environmental conditions than thalli. c. fragile spp. tomentosoides grew equally well with nitrate, nitrite, ammonium, and urea as a nitrogen source. The addition of NaHCO₃ stimulated growth at levels of 2.4 to 4.8 mM, suggesting an inorganic carbon limitation in static cultures. This study supports the hypothesis that the in situ seasonal growth pattern of c. fragile spp. tomentosoides is primarily due to the interaction of temperature and irradiance.     

深圳表层土壤中多环芳烃的污染特征及来源

2007年1月采集深圳市36个土壤,采用气相色谱-质谱仪对其中的16种优先控制的多环芳烃(PAHs)进行分析.结果表明:16种PAHs的含量范围在67.77137.0 ng · g-1之间,平均值为664.7 ng · g-1,其中苯并[b]荧蒽的含量最高,致癌性PAHs占总量的51.9﹪.PAHs在深圳不同土地利用类型的土壤中的含量由高到低的次序为:菜园地,城区,果园地,林地.PAHs主要来源于燃烧来源,果园地、林地中的PAHs主要来源于长距离的大气迁移,部分城区土壤指示有石油来源.深圳市19.4﹪的土壤属重污染,重污染的土壤主要分布在菜园地和城区两类土壤中,城区表层土壤PAHs含量较国外其他城市低.结果对于认识PAHs在深圳土壤中的分布规律和环境迁移、以及如何控制PAHs污染具有重要的意义.