Seasonal variations in macrobenthic taxonomic diversity and the application of taxonomic distinctness indices in Bohai Bay,northern China

Taxonomic diversity indices have a number of desirable properties as indicators in the assessment of environmental quality, and have become an important measure in biodiversity studies. Macrobenthic taxonomic variations were studied in Bohai Bay, northern China, an area under threat from rapid human development. Four seasonal cruise datasets were collected between 2006 and 2007. Environmental conditions exhibited large fluctuations due to human development; nitrogen and phosphorus were the main environmental stressors. A total of 97 macrofauna taxa were identified belonging to 88 genera, 72 families, 36 orders, 14 classes, and nine phyla. Analysis of similarity indicated that there were significant assemblage differences across sampling stations as well as seasons. Four taxonomic indices, taxonomic diversity (Δ), taxonomic distinctness (Δ*), average taxonomic distinctness (Δ⁺), and variation in taxonomic distinctness (Λ⁺) were calculated using abundance data. Among the stations and seasons, there were greater variations in both Δ and Λ⁺ than in Δ* and Δ⁺. The funnel plot of Δ⁺ could identify disturbed stations to some extent, but was not always a strong indicator of disturbance. The Δ⁺ performance was better in autumn than in spring, but could not identify a disturbed station in autumn due to a low number of species. The efficiency of taxonomic distinctness may depend on taxa or the pollution indicators. Taxonomic distinctness indices can be effective at assessing environmental degradation when correctly applied; however, they are unsuitable for directly assessing environmental quality in a new area prior to efficiency testing.     

胶州湾海水、海洋生物体中重金属含量的研究

研究了胶州湾海水、海洋生物体中重金属含量.结果表明,沿岸河口地区海水中重金属污染主要受沿岸工业排放废水的影响;海洋生物体内重金属含量不仅受海水中的重金属含量大小的支配,温度对其也有一定的影响.海洋生物体中重金属含量为底栖生物大于鱼类,以沉积物为主要饵料的杂食性底栖动物内重金属含量大于鱼类;海洋生物对于Cu比其它重金属具有较强的富集能力.     

Assessment of long-term water quality variation affected by high-intensity land-based inputs and land reclamation in Jiaozhou Bay,China

With the interactive and accumulative effects of multiple pressures, the dissolved inorganic nitrogen concentration (C_DIN) is increasing considerably and is regarded as the dominant chemical pollutant in Jiaozhou Bay (JZB). To efficiently prevent water quality (WQ) deterioration, the relationships among the C_DIN in JZB with anthropogenic pressure indicators (APIs) and coastal carrying indicators (CCIs) were identified using long-term series data (1962–2012). First, the control indicators (CIs) were obtained by the application of a conceptual model analysis, and potential sources were identified by a factor analysis. Second, the key CIs were identified by a regression analysis. Finally, the effects of the key CIs on WQ were quantitatively assessed by numerical model experiments. The results showed that the CIs for the C_DIN variation contained both APIs, including terrigenous total nitrogen flux (F_TN) discharged into JZB, river runoff, sea area of reclamation, and the CCIs, including the water area of JZB (S_JZB), chlorophyll-a, dissolved oxygen, pH, salinity and seawater temperature. The APIs on WQ variation were greater than the CCIs. The F_TN and S_JZB were identified as the key CIs responsible for the variation in the C_DIN. The WQ simulation results showed that the increasing trend of the C_DIN was caused by the increase in the F_TN and the decrease in the S_JZB, and the combined effects induced by the two key CIs on the C_DIN variation was as high as 79%, higher their separate effects, indicating a synergistic interaction of the two key CIs on the WQ of JZB during the last 50 years. These results illustrated that both terrigenous nitrogen pollutant load control systems and a scientific plan for coastline utilization should be implemented to effectively improve the WQ of JZB.     

胶州湾海水,海洋生物体中重金属含量的研究

研究了胶州湾海水、海洋生物体中重金属含量 .结果表明 ,沿岸河口地区海水中重金属污染主要受沿岸工业排放废水的影响 ;海洋生物体内重金属含量不仅受海水中的重金属含量大小的支配 ,温度对其也有一定的影响 .海洋生物体中重金属含量为底栖生物大于鱼类 ,以沉积物为主要饵料的杂食性底栖动物内重金属含量大于鱼类 ;海洋生物对于Cu比其它重金属具有较强的富集能力 .     

The use of taxonomic distinctness to assess environmental disturbance of insect communities from running water

1. Taxonomic distinctness (or average taxonomic breadth) of a sample is a measure of diversity that has the great advantage of not being sensitive to variations in sampling effort, unlike measures of species richness. It can also be tested for departures from expectation and can thus be used to determine whether a site has suffered from a genuine loss of diversity. 2. Taxonomic distinctness or delta⁺ was measured using all insect species from three datasets obtained from running water habitats: reference or least disturbed sites from channel and bank habitats on rivers from the Australian state of Victoria; test sites distributed along a water quality gradient in Victoria and sites immediately below a series of dams in Victoria and New South Wales. The last two datasets comprised sites subject to a range of obvious disturbances. 3. At reference sites delta⁺ was generally within the range of expected values (95% confidence limits) for both habitats as would be anticipated for these essentially undisturbed sites. However, 13–14% of sites fell below the lower confidence limits. Sites in river basins with less cover of natural habitat had slightly but significantly lower delta⁺ values than those with more cover and these sites contributed to this anomaly. 4. Delta⁺ was inversely correlated with water quality (r = −0.54, P = 0.002) as measured by the first axis of a PCA of water quality variables. It was also inversely correlated with individual variables, such as turbidity and total phosphorous. 5. Delta⁺ was below expectation for 18 of the 19 dam sites and at 13 of these sites delta⁺ values were below the lower confidence limit. 6. Delta⁺ was a sensitive index of diversity that generally distinguished sites suffering from environmental disturbance. Only a few previous studies of river ecosystems have used delta⁺, which did not respond consistently to disturbance because either too few taxa at species or higher taxonomic levels were available or because longitudinal changes in species composition swamped the signal from delta⁺. Neither of these problems occurred with the current datasets. 7. Delta⁺ responded more readily to disturbance than number of species, perhaps because taxonomic distinctness reflects some of the multivariate nature of community samples, whereas number of species is blind to this aspect.     

Dominant chloramphenicol-resistant bacteria and resistance genes in coastal marine waters of Jiaozhou Bay,China

Studies of abundance, diversity and distribution of antibiotic-resistant bacteria and their resistance determinants are necessary for effective prevention and control of antibiotic resistance and its dissemination, critically important for public health and environment management. In order to gain an understanding of the persistence of resistance in the absence of a specific antibiotic selective pressure, microbiological surveys were carried out to investigate chloramphenicol-resistant bacteria and the chloramphenicol acetyltransferase resistance genes in Jiaozhou Bay after chloramphenicol was banned since 1999 in China. About 0.15–6.70% cultivable bacteria were chloramphenicol resistant, and the highest abundances occurred mainly in the areas near river mouths or sewage processing plants. For the dominant resistant isolates, 14 genera and 25 species were identified, mostly being indigenous estuarine or marine bacteria. Antibiotic-resistant potential human or marine animal pathogens, such as Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and Shewanella algae, were also identified. For the molecular resistance determinants, the cat I and cat III genes could be detected in some of the resistant strains, and they might have the same origins as those from clinical strains as determined via gene sequence analysis. Further investigation about the biological, environmental and anthropogenic mechanisms and their interactions that may contribute to the persistence of antibiotic-resistance in coastal marine waters in the absence of specific antibiotic selective pressure is necessary for tackling this complicated environmental issue.     

Spatial variation in ciliate communities with respect to water quality in the Delhi NCR stretch of River Yamuna,India

The River Yamuna emerges from Saptarishi Kund, Yamunotri and merge with River Ganges at Allahabad, India. Anthropogenic stress has affected the water quality of the river Yamuna drastically in the stretch traversing Delhi and its satellite towns (National Capital Region, NCR). In the present study, effect of water quality on the microbial life in the River Yamuna was analyzed using ciliate communities (Protista, Ciliophora) as bio-indicators. Water samples were collected from six sampling sites chosen according to the levels of pollution along the river and water quality was analysed using standard physicochemical factors. As the river traverses Delhi NCR, water quality deteriorates considerably as indicated by the Water Quality Index at the selected sampling sites. Seventy-four ciliate species representing nine classes were recorded. Based on the Shannon diversity index, maximum species diversity was found at the point where the river enters Delhi. The saprobity index showed the river water was beta-mesosaprobic when the river enters Delhi and alpha-mesosaprobic at downstream sites after the first major drain outfall. Significant relationship between the spatial variation in ciliate communities and abiotic parameters indicate that ciliates can be used as effective bioindicators of pollution in the River Yamuna.     

Marine organisms attached to seaweed surfaces in Jiaozhou Bay,China

Scanning electron microscopy of the surfaces of the seaweeds Laminaria japonica, haploid Porphyra yezoensis, Ulva pertusa and the diploid conchocelis of P. yezoensis and P. haitanensis revealed Vibrio and Micrococcus to be abundant on the surfaces of U. pertusa and P. yezoensis. Vibrio, Flavobacterium, Pseudomonas, Staphylococcus, Bacillus, Corynebacterium and other genera were isolated from the surfaces of L. japonica.D. Duan and X. Fei are with the Experimental Marine Biology Laboratory, Institute of Oceanology, Academia Sinica, Qingdao, 266071, China L. Xu and H. Xu are with the Department of Marine Biology, Ocean University of Qingdao, Qingdao, 266003, China.     

应用原生动物群落评价枯水期白洋淀的水质现状

应用PFU微型生物群落监测方法,对长期处于低水位状态下的白洋淀水质进行了综合评价。结果表明,白洋淀水域受府河污水的影响,淀内的内源性污染,对原生动物群落造成了极大的影响。与20世纪90年代的资料相比,淀内中心区4个采样点原生动物的群集种类数(1d)急剧下降,而丰度上升了1．28倍,表明内源性污染对白洋淀水质的影响加剧。     

Human impacts in soft‐sediment assemblages at Casey Station,East Antarctica: Spatial variation,taxonomic resolution and data transformation

Abstract Differences between marine soft‐sediment assemblages at disturbed (two waste dumps, a sewage outfall and a wharf) and control locations were found at Casey Station, Antarctica. These differences were significant against considerable background spatial variability. Core samples were collected by divers using a hierarchical, spatially nested sampling design incorporating four scales: (i) locations (thousands of metres apart); (ii) sites (hundreds of metres apart); (iii) plots (tens of metres apart); and (iv) among replicates within plots (approximately 1 metre apart). Control locations had greater species richness and diversity than disturbed locations and there were many taxa found at control locations that were not recorded at disturbed locations. Assemblages at disturbed locations were less variable than those at control locations. In contrast, populations of some dominant species were more variable at disturbed locations than at control locations. Significant variation in populations of individual taxa was also found at all scales and although greatest at the level of location, variation was also large at the smallest scale, between replicate cores, indicating significant small‐scale patchiness in populations of taxa. Patterns of assemblage structure were similar at fine (77 taxa) and medium (aggregated to 33 taxa) levels of taxonomic resolution, but changed at coarse levels of resolution (nine phyla). Soft‐sediment assemblages at Casey Station are markedly different from those reported from other areas of Antarctica. Assemblages at Casey are almost completely dominated by crustaceans (up to 99% total abundance) and polychaetes are rare or in very low abundances in most areas investigated in the region. This is also the first demonstration that small Antarctic research stations (population 20–50 people) may cause impacts that are detectable in the adjacent marine environment.     

Multi-locus sequence analysis, taxonomic resolution and biogeography of marine Synechococcus

Conserved markers such as the 16S rRNA gene do not provide sufficient molecular resolution to identify spatially structured populations of marine Synechococcus, or 'ecotypes' adapted to distinct ecological niches. Multi-locus sequence analysis targeting seven 'core' genes was employed to taxonomically resolve Synechococcus isolates and correlate previous phylogenetic analyses encompassing a range of markers. Despite the recognized importance of lateral gene transfer in shaping the genomes of marine cyanobacteria, multi-locus sequence analysis of more than 120 isolates reflects a clonal population structure of major lineages and subgroups. A single core genome locus, petB, encoding the cytochrome b(6) subunit of the cytochrome b(6) f complex, was selected to expand our understanding of the diversity and ecology of marine Synechococcus populations. Environmental petB sequences cloned from contrasting sites highlight numerous genetically and ecologically distinct clusters, some of which represent novel, environmentally abundant clades without cultured representatives. With a view to scaling ecological analyses, the short sequence, taxonomic resolution and accurate automated alignment of petB is ideally suited to high-throughput and high-resolution sequencing projects to explore links between the ecology, evolution and biology of marine Synechococcus.     

Length–weight relationships of fish species caught by bottom trawl in Jiaozhou Bay,China

Length–weight relationships (LWRs) were estimated for 31 fish species caught by bottom trawl surveys in Jiaozhou Bay on the west coast of the south Yellow Sea. Specimens were collected from September 2008 to August 2009 at monthly intervals. This study presents the first reference on LWRs for 15 of these species and new records of maximum total length for two species. Most of the b values fell within the expected range of 2.5–3.5. The mean value of b was 3.094 ± 0.064 (95% CL), which was significantly larger than 3.0, indicating a slight but significant tendency towards positive allometric growth in most of the fishes. Effects of the sex, season and growth phase were taken into account in this study. Results showed significantly different relationships between males and females in three of the species. Four species were found to have highly significant seasonal differences in the regression slope of b. Two different growth stanzas were detected using the double‐logarithmic plot of body weight vs total length for three species. The finding that the absolute residuals of b from 3.0 would become smaller with the increase in length‐range used was confirmed in this study.     

Diversity,Abundance, and Spatial Distribution of Sediment Ammonia-Oxidizing Betaproteobacteria in Response to Environmental Gradients and Coastal Eutrophication in Jiaozhou Bay,China

Ongoing anthropogenic eutrophication of Jiaozhou Bay offers an opportunity to study the influence of human activity on bacterial communities that drive biogeochemical cycling. Nitrification in coastal waters appears to be a sensitive indicator of environmental change, suggesting that function and structure of the microbial nitrifying community may be associated closely with environmental conditions. In the current study, the amoA gene was used to unravel the relationship between sediment aerobic obligate ammonia-oxidizing Betaproteobacteria (Beta-AOB) and their environment in Jiaozhou Bay. Protein sequences deduced from amoA gene sequences grouped within four distinct clusters in the Nitrosomonas lineage, including a putative new cluster. In addition, AmoA sequences belonging to three newly defined clusters in the Nitrosospira lineage were also identified. Multivariate statistical analyses indicated that the studied Beta-AOB community structures correlated with environmental parameters, of which nitrite-N and sediment sand content had significant impact on the composition, structure, and distribution of the Beta-AOB community. Both amoA clone library and quantitative PCR (qPCR) analyses indicated that continental input from the nearby wastewater treatment plants and polluted rivers may have significant impact on the composition and abundance of the sediment Beta-AOB assemblages in Jiaozhou Bay. Our work is the first report of a direct link between a sedimentological parameter and the composition and distribution of the sediment Beta-AOB and indicates the potential for using the Beta-AOB community composition in general and individual isolates or environmental clones in the Nitrosomonas oligotropha lineage in particular as bioindicators and biotracers of pollution or freshwater or wastewater input in coastal environments.Nitrification, the oxidation of ammonia to nitrate via nitrite, plays a critical role in the biogeochemical cycling of nitrogen and the formation of the large deep-sea nitrate reservoir (37, 46, 51). Because the N cycle may affect the global C cycle, shifts in N transformation processes may also affect the climate (30, 40). Nitrification is an important bioremediation process in human-perturbed estuarine and coastal ecosystems, where it may serve as a detoxification process for excess ammonia (14). If coupled to classical denitrification or anaerobic ammonium oxidation (anammox), these processes may remove most of the anthropogenic N pollution (51, 81). Bacterial nitrifiers may also cooxidize a variety of xenobiotic compounds (3, 49). On the other hand, nitrification may lead to enhanced production of the potent greenhouse gases nitric oxide (NO) and nitrous oxide (N₂O) (15). Because the input of excess ammonia stimulates the growth of ammonia-oxidizing microorganisms, research in coastal environments and ecosystems increasingly includes the study of microbial communities involved in nitrification.Marine nitrification is performed by chemolithoautotrophic proteobacteria and the newly discovered ammonia-oxidizing archaea (AOA) (47); nevertheless, reliable information on the individual contributions of each cohort to the process is still lacking (72) and the contributions likely vary in different environments (33, 51, 93). Beta- and gammaproteobacterial aerobic obligate ammonia-oxidizing bacteria (AOB) are known to catalyze the oxidization of ammonia to nitrite, the first and rate-limiting step of nitrification (3). Because of their monophyletic nature, diversity, and important environmental functionality, the betaproteobacterial AOB (Beta-AOB) have served as a model system in the study of fundamental questions in microbial ecology, including microbial community structure, distribution, activity, and environmental response (9, 49, 92).The growth of AOB is slow, and present isolates represent only a fraction of their natural diversity. Culture-independent molecular methods provide a more convenient and accurate approach for community analyses (76, 92). All AOB genomes contain at least one cluster of amoCAB genes encoding functional ammonia monooxygenase (AMO), which catalyzes the oxidation of ammonia to hydroxylamine (4). Because AmoA- and 16S rRNA-based phylogenies are congruent (73), the amoA gene has been extensively used as a molecular marker to explore and characterize the structure and diversity of AOB communities in a variety of estuarine and coastal environments (9, 10, 11, 13, 27, 32, 36, 43, 68, 88). Some of these studies indicated that local environmental factors such as salinity, pH, ammonium, and O₂ concentrations might be drivers for the formation of distinct AOB assemblages, in which individual lineages may have evolved differential ecophysiological adaptivity (4, 73, 85). Furthermore, differences in AmoA sequences may correlate with differences in isotopic discrimination during ammonia oxidation, implicating function-specific ammonia monooxygenases (15). Therefore, the AmoA sequences may provide information about the structure and composition of the AOB communities and their ecological function and response to environmental complexity and variability. Despite long-standing efforts, a complete understanding of these relationships is still lacking (9), especially in complex environments such as anthropogenic activity-impacted coastal areas.China consumes more than 20 million tons of N fertilizer each year, leading to a significant increase of coastal N pollution (38). Thus, the China coast is an important location for intense N biogeochemical cycling. Jiaozhou Bay is a large semienclosed water body of the temperate Yellow Sea in China. Eutrophication has become its most serious environmental problem, along with red tides, species loss, and contamination with toxic chemicals and harmful microbes (21, 23, 24, 28, 82, 91). In similar environments with a high input of nitrogenous compounds, surface sediment is a major site for nitrification due to a relatively high AOB abundance and activity (79).Although the China coast is important in N cycling and in related environmental and climatic issues, surprisingly very little is known, especially about the microbial processes and functions involved. On a global scale, it is currently not well understood how the AOB community structure, abundance, and distribution respond to coastal eutrophication, though partial knowledge is emerging (36, 49, 89). Recent studies indicated that spatial distribution and structure of the sediment AOA community could be influenced by a variety of environmental factors, of which continental input may play important roles in estuary and continental margin systems (22, 26). The sediment AOA community may serve as useful biotracers and bioindicators of specific environmental disturbance. Likewise, the sediment AOB community may also serve as biotracers or bioindicators of continental influence, such as eutrophication in coastal environments. In this study, the bacterial functional marker gene amoA was employed to test this hypothesis in the eutrophied Jiaozhou Bay.     

胶州湾六丝钝尾虾虎鱼的摄食生态特征

根据2011年2-11月在胶州湾海域进行的4个季节的底拖网调查,共收集624尾六丝钝尾虾虎鱼样品进行胃含物分析,对其摄食生态进行了初步研究.结果表明:六丝钝尾虾虎鱼摄食的饵料种类有40余种,其中优势饵料生物有日本鼓虾、经氏壳蛞蝓和细螯虾等.其食物组成存在明显的季节变化,除在4个季节均大量摄食虾类外,春季主要摄食腹足类,夏季主要以鱼类为食,秋季主要摄食虾类,冬季摄食桡足类和端足类等小型甲壳生物的比例较高,这主要与胶州湾饵料生物种类和数量的季节性变化有关.随着体长的增长,六丝钝尾虾虎鱼摄食的饵料生物由小型的桡足类逐渐转变为个体较大的经氏壳蛞蝓、绒毛细足蟹和日本鼓虾等,食物组成呈现出明显的体长变化.典范对应分析(CCA)表明,水温和盐度是影响六丝钝尾虾虎鱼摄食的主要因素,其次是体长和pH.     

Can annual cyclicity of protozoan communities reflect water quality status in coastal ecosystems?

With many advantages, many ecological parameters of protozoan communities have been successfully used as a useful bioindicator for bioassessment of water quality in Chinese marine waters. However, as regard the response of the annual cyclicity of protozoan communities to seasonal environmental stress, a further investigation was needed. In this study, the cyclicity of annual variations in community patterns of biofilm-dwelling protozoa was studied based on an annual dataset. Samples were monthly collected, using glass slide method, at four stations, within a pollution gradient, in coastal waters of the Yellow Sea, northern China during a 1-year period. The cyclicity patterns of the microbiota represented a significant spatial variation among four stations. The low value of cyclicity coefficients occurred in heavily polluted area, while the high values were in less stressed areas. Correlation analysis showed that the cyclicity measure was significantly related to environmental variables ammonia, transparency and dissolved oxygen. Thus, it is suggested that the annual cyclicity of protozoan communities may be used as a potential bioindicator of bioassessment in marine ecosystems.     

Ciliated protozoan communities and saprobic evaluation of water quality in the hilly zone of some tributaries of the Po River (northern Italy)

Ciliate protozoans were collected from five watercourses belonging to the hydrographic network of the North Apennines (Italy) and flowing into the middle lower section of the river Po from its right bank. Thirteen stations were selected in the meta- and hyporhithron section of the five studied rivers and samples from water–sediment interface were collected during a 1year period. A total of 175 species of ciliates belonging to 97 genera were found, of which 68 were bacterivorous, 58 were algivorous, 26 were omnivorous and 23 were carnivorous. Their distribution varied both with distance along the river and with the time. Community structures were analysed using some statistical methods and this allowed the determination of similarities among stations and relationships between species and stations. The saprobic index and valency methods were used to evaluate the water quality at the 13 stations. Comparisons between the five watercourses indicate that trophic state influences the composition of ciliate communities. The high similarity observed in the unpolluted stations enabled us to define the typical species and the community of the meta- hyporhithron zone. Conversely, polluted stations showed the lowest similarities. Our results confirm that in watercourses the organic load may be the dominating factor able to influence, if not eliminate the diversifying effects of other factors such as those which characterize the longitudinal zonation of the watercourses.     

Low sensitiveness of taxonomic distinctness indices to human impacts: Evidences across marine benthic organisms and habitat types

Ecological indicators likely constitute the mainstream tools in assessing the quality of aquatic ecosystems as they condense composite biological information into single measures, easier to handle for environmental managers and more understandable for non-scientific users. However, sampling settings can influence the performance of most indices, and their use is often constrained to specific habitat types. Average taxonomic distinctness (Δ⁺) and variation in taxonomic distinctness (Λ⁺) may represent promising tools in overcoming sampling bias, and potentially applicable to a wide range of environmental contexts. In marine systems, such metrics showed higher sensitivity than classical indices in discriminating among perturbed and unperturbed conditions, though a number of studies found Δ⁺ and Λ⁺ also varying along natural gradients, suggesting a lower ability to discern human-driven variations from natural variability than what expected. Here, analyzing existing data sets from previous impact assessment studies, we test the response of Δ⁺ and Λ⁺ in detecting the effects of different sources of anthropogenic disturbance on marine mollusks and polychaetes from Mediterranean soft sediments and hard substrates. Our results showed that neither classical univariate analyses on Δ⁺ and Λ⁺ values nor their associated statistical framework were able to discern among perturbed and unperturbed sites, highlighting a low sensitiveness of such metrics in detecting assemblage variations related to anthropogenic disturbance. Δ⁺ and Λ⁺ are based on presence/absence data, and assume impacts being likely to induce variations in taxonomic structures of assemblages. As a consequence, they could experience reduced discrimination power when impacts mostly affect relative abundances of organisms rather than assemblage composition, or drive species replacement within higher taxa. Our results also showed that habitat type could strongly affect taxonomic relatedness of species within assemblages, and that this effect can vary among different organisms, suggesting that the departures from expectation of Δ⁺ and Λ⁺ values might not be always univocally attributable to human perturbations, since possibly depending on habitat effects. Taxonomic distinctness indices can provide useful additional information on taxonomic diversity of assemblages, crucial to better address the wide concept of biological diversity. However, the effectiveness of such measures in disclosing the effects of human disturbance is still unclear, requiring further investigations especially on their potential application in defining the ecological status of coastal rocky systems.     

Size structures of microplankton biomass and production in Jiaozhou Bay, China

Seasonal investigations of size-fractionated biomass and productionwere carried out from February 1992 to May 1993 in JiaozhouBay, China. Microplankton assemblages were separated into threefractions: pico- (0.7–2 µm), nano- (2–20 µm)and netplankton (20–200 µm). The biomass was measuredas chlorophyll a (Chi a), paniculate organic carbon (POC) andparticipate organic nitrogen (PON). The production was determinedby ¹⁴C and ¹⁵N tracer techniques. The seasonal patterns in biomass,though variable, were characterized by higher values in springand lower values in autumn and summer (for Chi a only). Theseasonal patterns in production, on the other hand, were moreclear with higher values occurring in summer and spring, andlower values occurring in autumn and winter. Averaged over thewhole study period, the respective proportions of total biomassaccounted for by net-, nano- and picoplankton were 26, 45 and29% for Chi a, 32, 33 and 35% for POC, and 26, 32 and 42% forPON. The contributions to total primary production by net-,nano- and picoplankton were 31, 35 and 34%, respectively. Therespective proportions of total NH₄⁺–N uptake accountedfor by net-, nano- and picoplankton were 28, 33 and 39% in thedaytime, and 10, 29 and 61% at night. The respective contributionsto total NO₃^–-N uptake by net-, nano- and picoplanktonwere 37, 40 and 23% in the daytime, and 13, 23 and 64% at night.Some comprehensive ratios, including C/N biomass ratio, Chla/C ratio, C uptake/Chl a ratio, C:N uptake ratio and the f-ratio,were also calculated size separately, and their biological andecological meanings are discussed.     

香溪河水质空间分布特性研究

运用聚类分析和主成分分析对香溪河19个样点水质的理化特性进行研究,聚类分析表明,根据各采样点之间水质组分的相似性可将香溪河大致分为3个河段,分别属于不同的亚流域,各亚流域问的特征差异显著,对各河段水质的主成分分析表明,上述3河段的主要水质信息差异很大,第1河段(在河流上游)水质的信息主要体现为总碱度和硬度,第2河段(河流中游)主要体现为可溶性磷酸盐、总磷和氯离子,第3河段(河流下游)则为pH、亚硝酸盐氮、总氮和COD,文中结合香溪河流域地理环境背景,探讨了香溪河水质空间分布格局的成因,为分析流域水质状况及成因提供了一条简单有效的途径。     

Environmental quality assessment of water body and surface sediment in the sea area of Jiaozhou Bay wetland

Based on the investigation data from 48 sampling stations in the sea area of Jiaozhou Bay wetland in 2009, and by using Nemerow index, eutrophication index (EI), and Hakanson potential ecological risk index, an assessment was conducted on the environmental quality of water body and surface sediment in the sea area. According to the assessment on the 16 indicators including pH, dissolved oxygen (DO), dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorous (DIP), chemical oxygen demand (COD(Mn)), petroleum hydrocarbons, Cu, Zn, Pb, Cd, Hg, As, hexachlorocyolohexane (HCH), dichlorodiphenyltrichloroethane (DDT), coliform, and faecal coliform, the water quality was at moderate and serious pollution level in the tidal reach of Dagu River, at slight and moderate pollution level in the intertidal zone, and at slight pollution level in the shallow sea. The eutrophication level differed markedly with the regions, being very serious in the tidal reach of Dagu River (EI value 58.13-327.89), serious in the intertidal zone (EI value 1.34-19.96), and slight in the shallow sea (EI value 0.65-2.10). The surface sediments in the sea area were basically at slight pollution level. The sediment quality was at slight pollution level in the tidal reach of Dagu River, at slight and moderate pollution level in the intertidal zone, and at cleaner and slight pollution level in the shallow sea. The pollution parameter (C(f)(i)) and contamination index (Cd) of the heavy metals in the surface sediments were low, suggesting that the pollution degree was at a lower level. The Cu and Zn were the primary pollution factors in the sediments. The potential ecological risk parameter (E(r)(i)) and risk index (RI) of the heavy metals in the surface sediments were lower, indicating a slight ecological risk of heavy metals pollution.