Temporal and spatial variations in the distribution of macroalgal communities along the Yantai coast,China

To explore the impact of environmental variables on macroalgal communities, their temporal and spatial distributions were examined along the Yantai coast, China between April 2010 and March 2011. Macroalgae sampling was conducted monthly at four sites along the coast： Jiahe River estuary, Zhifu Island, Fisherman＇s Wharf, and Yangma Island. The species composition and abundance, and their relationship with environmental variables were assessed. Along the Yantai coast, 35 macroalgae species were identified, including 24 Rhodophyta spp., 7 Chlorophyta, and 4 Phaeophyta spp. Highest species numbers were recorded in the summer at all sampling sites, except in the Jiahe River estuary. Macroalgae biomass was the greatest in the summer. Year-round, the highest species number and dry biomass recorded at Fisherman＇s Wharf and Yangma Island was attributed to the substrate type. In summer, Ulva pertusa Kjellman was the dominant species identified along the Yantai coast, which indicates a risk ofmacroalgae blooms. Our results show that seawater temperature and nutrients appear to significantly affect the temporal and spatial patterns of macroalgal abundance along the Yantai coast. The effects of environmental variables on the macroalgae on the Yantai coast need further study.     

Spatial and seasonal distribution of intertidal macrobenthos with their biomass and functional feeding guilds in the Naf River estuary,Bangladesh

The Naf River estuary is one of the most productive ecological ecosystems in Bangladesh providing an important feeding area for fishes and other aquatic animals. However, detailed information on macrobenthic communities is rarely available in this area. Our study focused on the seasonal and spatial variability of macrobenthic community structure with their biomass and functional guilds. In total, fortyseven taxa were identified under nine major groups and seven functional feeding guilds. Among macrobenthic taxa, Polychaeta was dominant in both seasons and all over the estuary contributing 60% of total benthos.The mean abundance of macrobenthos was higher during the pre-monsoon(2 972±1 994 inds./m~2) than the monsoon(1 572±361 inds./m~2) being maximum at mid-estuary region and minimum at upper and lower estuary regions. Of the diversity indices, density(P=0.01, P=0.003), the number of taxa(P=0.000 3,P=0.000 9) and Margalefs Index(P=0.000 4, P=0.001) of macrobenthos were significantly different among stations and seasons. Shannon-Weiner index(P=0.009, P=0.12) and Pielou's evenness index(P=0.03,P=0.14) had significant differences among stations but not among seasons. Cluster analysis suggested that distribution of macrofauna is strongly influenced by seasonality. Among the feeding types, carnivorous were found to be dominant at the upper and mid-estuarine regions, and herbivorous were at lower estuarine regions. Carnivorous species were dominant in both seasons. Omnivores have shown to be the most abundant feeding type in terms of biomass though herbivores were highest during monsoon.     

Spatial distribution of penetration depth in Taihu Lake (China) during spring and autumn

In the context of remote sensing, sunlight penetration depth is the depth above which 90% of the diffusely reflected irradiance from a water body surface originates. Model algorithms to simulate water quality variables such as chlorophyll a, dissolved organic matter, suspended matter, and Secchi depth are sensitive to the variations of this variable. The penetration depth for Taihu Lake in China, a shallow and turbid lake, was calculated by using a multiple scattering model, and in situ optical measurements were carried out during May and October 2010. The results show that: 1) the penetration depth generally increased from west to east during spring and from southeast to northwest during autumn, reflecting the prevailing wind direction and; 2) there was strong dependence of the penetration depth on the concentration of suspended matter.     

Spatial and seasonal distribution of macroinvertebrates in high altitude reservoir (Beyler Reservoir, Turkey)

A highland reservoir in the West Black Sea region of Turkey which belongs to the Mediterranean climatic zone was examined.Both littoral and profundal zones were sampled from October 2009 to September 2010,to determine taxonomic composition,biodiversity and abundance of benthic invertebrates as well as the seasonal variation of these measures.A total of 35 taxa were identified,of which 12 belong to Chironomidae and 10 to Oligochaeta groups.The highest diversity and abundance of benthic macroinvertebrates were found at the littoral stations.Macroinvertebrates showed significant positive correlations with water temperature and NO₂ and NO₃ concentrations,and negative correlation with dissolved oxygen.     

Spatial distribution and changes of heavy metals of agricultural lands in typical pregrading coast in Dongtai City,Jiangsu Province,China

According to the historical changes of coastal lines, seven soil sampling districts, from land to sea, were arranged in Dongtai City, Jiangsu Province to sample soils from surface and profile. Concentrations of seven major heavy metals （HMs）, granularity, pH, organic matters and C/N of the soil samples were analyzed. Results show that concentrations of heavy metals in agricultural land present a certain spatial variance, decreasing from land to sea. Pollution assessment indicates that the agricultural soils were not polluted by HMs, but the potential pollution of Cu and Hg needs to be alerted. Different HMs accumulate in the surface and sub-surface of the soil profiles, and concentrations of Hg and Pb decrease significantly with the increment of soil depth. Concentrations of HMs exhibit a significantly negative correlation to pH, but have no significant relation with organic matters in soil. Principle component analysis show that the concentrations of HMs relate to the land use history. Concentrations of Hg, Ni and Cr in soil are closely related with land use history, and concentrations of Pb, Cu and Cr are affected by land use history as well as other factors. However, there is no significant relation between concentration of As and land use history.     

Complementary DNA sequencing (cDNA): an effective approach for assessing the diversity and distribution of marine benthic ciliates along hydrographic gradients

The Yellow Sea Cold Water Mass(YSCWM) is a distinct hydrographic phenomenon of the Yellow Sea,and the distribution pattern of meio-and macrobentho s diffe rs inside and outside of the YSCWM.However,such a pattern has never been observed in the microbenthic ciliate communities.Therefore,we hypothesized that benthic ciliates followed a similar distribution pattern as meio-and macrobentho s,but this pattern has not been uncovered by morphological methods.We evaluated the diversity and distribution of benthic ciliates at five stations along hydrographic gradients across the YSCWM and adj acent shallow water by using morphology and DNA and complementary DNA(cDNA) high-throughput sequencing of the V4 region of 18 S rRNA gene.Results showed that the diversity of benthic ciliate s detected by DNA(303 OTU s),and the cDNA(611 OTUs) sequencing was much higher than that detected by the morphological method(79 species).Morphological method detected roughly different ciliate communities inside and outside of the YSCWM,but without statistical significance.No clear pattern was obtained by DNA sequencing.In contrast,cDNA sequencing revealed a distinct distribution pattern of benthic ciliate communities like meioand macrobenthos,which coincided well with the results of the environmental parameter analysis.More than half of the total sequences detected by DNA sequencing belonged to planktonic ciliates,most(if not all) of which were recovered from historic DNA originating through the sedimentation of pelagic forms because none of them were observed morphologically.The irrelevant historic DNA greatly influenced the recovery of rare species and thus limited the understanding of the benthic ciliate diversity and distribution.Our research indicates that the methods used have significant effects on the investigation of benthic ciliate communities and highlights that cDNA sequencing has great advantages in estimating the diversity and distribution of benthic ciliates,as well as the potential for benthic environmental assessments.     

Phytoplankton distribution and community structure in the East China Sea (ECS) continental shelf

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Two new marine benthic diatom species of Hippodonta (Bacillariophyceae) from the coast of China: H. nanjiensis sp. nov. and H. qingdaoensis sp. nov.

The diversity and distribution of Hippodonta species on the coast of China are largely unknown due to limited investigations. In this paper, we report the detailed morphology and ultrastructure of two new species: H. nanjiensis sp. nov., collected from intertidal sandy sediments of Nanji Islands, the East China Sea and H. qingdaoensis sp. nov., collected from intertidal sandy sediments of the No. 1 Bathing Beach in Qingdao City, the Yellow Sea. Both species occur mainly in the middle part of the intertidal zone. H. nanjiensis possesses a unique large round central area. H. qingdaoensis differs from congeners in having a unique stria pattern, wherein the areolae in the middle transapical striae are less developed or absent on the primary side of the valve, and two areolae per stria are apparent under light microscopy(LM). This study expands our knowledge of Hippodonta diversity and distribution on the coast of China.     

Fouling characteristics of cnidarians (Hydrozoa and Anthozoa) along the coast of China

Journal of Oceanology and Limnology - Hydrozoans and anthozoans are an important component of a great variety of marine communities, particularly abundant and ubiquitous as part of the fouling...     

The Potential Vertical Distribution of Bigeye Tuna ( Thunnus obesus ) and Its Influence on the Spatial Distribution of CPUEs in the Tropical Atlantic Ocean

Understanding the potential vertical distribution of bigeye tuna(Thunnus obesus) is necessary to understand the catch rate fluctuations and the stock assessment of bigeye tuna. To characterize the potential vertical distribution of this fish while foraging and determine the influences of the distribution on longline efficiency in the tropical Atlantic Ocean, the catch per unit effort(CPUE) data were compiled from the International Commission for the Conservation of Atlantic Tunas and the Argo buoy data were downloaded from the Argo data center. The raw Argo buoy data were processed by data mining methods. The CPUE was standardized by support vector machine before analysis. We assumed the depths with the upper and lower limits of the optimum water temperatures of 15℃ and 9℃ as the preferred swimming depth, while the lower limit of the temperature(12℃) associated with the highest hooking rate as the preferred foraging depth(D12) of bigeye tuna during the daytime in the Atlantic Ocean. The preferred swimming depth and foraging depth range in the daytime were assessed by plotting the isobath based on Argo buoy data. The preferred swimming depth and vertical structure of the water column were identified to investigate the spatial effects on the CPUE by using a generalized additive model(GAM). The empirical cumulative distribution function was used to assess the relationship between the spatial distribution of CPUE and the depth of 12℃ isolines and thermocline. The results indicate that 1) the preferred swimming depth of bigeye tuna in the tropical Atlantic is from 100 m to 400 m and displays spatial variation; 2) the preferred foraging depth of bigeye tuna is between 190 and 300 m and below the thermocline; 3) the number of CPUEs peaks at a relative depth of 30 –50 m(difference between the 12℃ isolines and the lower boundary of the thermocline); and 4) most CPUEs are within the lower depth boundary of the thermocline levels(LDBT) which is from 160 m to 230 m. GAM analysis indicates that the general relationship between the nominal CPUE and LDBT is characterized by a dome shape and peaks at approximately 190 m. The oceanographic features influence the habitat of tropical pelagic fish and fisheries. Argo buoy data can be an important tool to describe the habitat of oceanic fish. Our results provide new insights into how oceanographic features influence the habitat of tropical pelagic fish and fisheries and how fisheries exploit these fish using a new tool(Argo profile data).     

Birds in rocky habitats of the Tatra Mountains (Carpathians): species diversity and multiple ecological relationships

Rocky habitats are regarded as biodiversity hot-spots.Along with high species diversity,diverse ecological relationships can be observed in these habitats.Large groups of bird species use rocks in various ways:as perching/roosting sites,breeding or foraging habitats,information exchange sites,display arenas or as sources of minerals and water.Because of the inaccessibility of these environments,their role and importance to animals has been underestimated.We evaluated the use of rocky habitats by birds in the Tatra Mountains(49°13'N,19°57'E,Carpathians,central Europe).Rocky habitats were used by 29 bird species,eight of which used cliffs directly(i.e.for nesting,foraging or resting).The number of species recorded as using cliffs was correlated with the surface area of the cliff face.A total of 20 forms of rocky habitat use were recorded,in five behavioural categories:vocalization,foraging,perching,flight and nesting.Prevailing behaviours were flying by a rock face,circling above the face,and vocalization on a tree/shrub growing next to a rock.Rocks provide a nesting habitat for specialized petrophilic species and permit the existence of numerous ecological relations between species and habitats.The results of this study show that rocky habitats support the diversity of ecological relationships.     

A taxonomical and ecological survey of rotiffer communities in Krottensee (Austria)

The composition and distribution of benthic, periphytic and planktonic rotifers in different habitats in Krottensee were investigated. Sixty-five rotifer taxa were identified, their relative abundance estimated. Classification of the data set by cluster analysis allowed the recognition of distinct habitat groups confined to acid bog ponds, macrophytes, sediments and open water. Five groups of rotifer taxa were identified on the basis of their habitat preferences and the occurrence of the taxa. Highest diversities were found on macrophytes and in acid bog ponds.     

空间信息格网框架体系和关键技术分析

空间信息格网 (SIG)是格网 (Grid)技术在数字城市等地球信息应用服务领域中的具体应用。本文首先分析了格网兴起的背景以及国内外在格网领域的研究进展 ,然后建立了格网三层体系结构 ,提出了格网操作系统中基于 XML 的格网资源描述语言的资源管理方法和多层格网节点分治式格网任务调度管理方法 ,最后提出了基于空间智能体的空间信息格网的体系结构 ,并且探讨了空间信息格网中空间信息连通性和一致性、空间信息格网的智能化等一系列重点问题。     

Spatial distribution of Dactylogyrus wunderi Bychowsky on gills of Abramis brama orientalis Berg (Leuciscinae) in Irtysh River, China

The spatial distribution of the monogenean Dactylogyrus wunderi Bychowsky,1931 on the gill filaments of the bream Abramis brama orientalis Berg(Leuciscinae) inhabiting the Irtysh River of Xinjiang,China was investigated from June to July 2012.D.wunderi was identified by sequencing a fragment of its ITS rDNA region.Sixty-five fish were examined,with 55% testing positive for monogenean infection.The prevalence of the parasite in the left and right gill arches was 46% and 48%,respectively.In fish with a large body length,the prevalence of the parasite and the infection intensity did not significantly differ between the right and left gill arches but both were slightly higher in the former.Among the three size groups of fish(small,medium and large) the prevalence and the intensity of infection were lowest in fish with small body lengths.The distribution of the monogenean population in the host gills showed an aggregate distribution,with little change in the degree of aggregation,suggesting that most hosts were either not or only slightly infected by D.wunderi and that the parasite infected only a few hosts.In addition,differences in D.wunderi infections between gill arches of A.brama orientalis were not significant(P>0.05).     

Spatial distribution and abundance of small fishes in Xiaosihai Lake, a shallow lake along the Changjiang (Yangtze) River, China

Spatial distribution and abundance of small fishes were studied in autumn 2007 in the Xiaosihai Lake, a shallow lake along the middle reach of the Changjiang (Yangtze) River. Based on the plant cover, the lake was divided into three major habitats: Myriophyllum spicatum habitat (MS habitat), Trapa bispinosa habitat (TB habitat), and non-vegetation habitat (NV habitat). A modified pop-net was used for quantitative sampling of small fishes in the three habitats, and the Zippin’s removal method was used for estimating densities of the small fishes. A total of 13 species belonging to 5 families were collected, with 11 species in MS habitat, 7 species in TB habitat, and 5 species in NV habitat. Habitat type had significant effect on the spatial distribution of small fishes. The Shannon-Wiener diversity index in the MS, TB and NV habitats were 1.28, 0.56 and 0.54, respectively. The total density and biomass of small fishes were significantly higher in the MS habitat (13.68 ind/m² and 4.44 g/m²) than in the TB habitat (1.41 ind/m² and 0.54 g/m²) and the NV habitat (1.08 ind/m² and 0.40 g/m²), and were not significantly different between the TB habitat and the NV habitat. Water depth had no significant effect on spatial distribution of the small fishes. It was suggested that vegetation type played an important role in habitat selectivity of small fishes, and the presence of submersed vegetation should be of significance in the conservation of small fish diversity.     

Spatial distribution and abundance of small fishes in Xiaosihai Lake, a shallow lake along the Changjiang(Yangtze) River, China

Spatial distribution and abundance of small fishes were studied in autumn 2007 in the Xiaosihai Lake, a shallow lake along the middle reach of the Changjiang (Yangtze) River. Based on the plant cover, the lake was divided into three major habitats: Myriophyllum spicatum habitat (MS habitat), Trapa bispinosa habitat (TB habitat), and non-vegetation habitat (NV habitat). A modified pop-net was used for quantitative sampling of small fishes in the three habitats, and the Zippin’s removal method was used for estimating densities of the small fishes. A total of 13 species belonging to 5 families were collected, with 11 species in MS habitat, 7 species in TB habitat, and 5 species in NV habitat. Habitat type had significant effect on the spatial distribution of small fishes. The Shannon-Wiener diversity index in the MS, TB and NV habitats were 1.28, 0.56 and 0.54, respectively. The total density and biomass of small fishes were significantly higher in the MS habitat (13.68 ind/m2 and 4.44 g/m2) than in the TB habitat (1.41 ind/m2 and 0.54 g/m2) and the NV habitat (1.08 ind/m2 and 0.40 g/m2), and were not significantly different between the TB habitat and the NV habitat. Water depth had no significant effect on spatial distribution of the small fishes. It was suggested that vegetation type played an important role in habitat selectivity of small fishes, and the presence of submersed vegetation should be of significance in the conservation of small fish diversity.     

Spatial distribution and diurnal variation of chemical oxygen demand at the beginning of the rainy season in the Changjiang （Yangtze） River Estuary

A field observation was carried out in the Changjiang （Yangtze） River Estuary from May 19 to 26, 2003. A total of 29 stations, including 2 anchored stations, were occupied through almost the whole salinity gradient. Based on the observation data, biogeochemistry of chemical oxygen demand （COD） was examined. Spatial distribution pattern of COD shows that it decreased downstream. The COD concentration varied generally within a narrow range of 1.24-1.60 mg/L in the zone around the river mouth, beyond which it decreased rapidly to 0.20 mg/L. In the mixed water zone, the fluctuation in COD was smaller at 2 m above the bottom layer than at the surface layer in 48 h. In the seawater zone, the 48-h fluctuation at the surface was the largest, followed by that of 5 m below the surface and 2 m above the bottom layers in a range of from 2.50 to 0.55 mg/L. Freshwater discharge was the dominant source of COD in the estuary. The average COD beyond the river mouth was 2.7 mg/L, which accorded with the Chinese seawater quality Grade I. Relationships between dissolved oxygen and biogeochemical parameters such as suspended particulate matter, dissolved organic matter and chlorophyll-a were also discussed.     

Population distribution,structure and growth condition of Antarctic krill （Euphausia superba Dana） during the austral summer in the Southern Ocean

Antarctic krill （Euphausia superba Dana） was collected using a High Speed Collector and an Isaac-Kidd midwater trawl （IKMT） net during the austral summer of 2007/2008 and 2008/2009 in the circumpolar and Prydz Bay regions of the Southern Ocean, respectively. Combined with the simultaneous recording of environmental factors, spatial distribution, population structure and growth condition of E. superba were studied. The abundance of E. superba in the Weddell Sea was higher than in Prydz Bay. However, the abundance of E. superba in both the Weddell Sea and Prydz Bay was lower than figures reported in previous krill surveys for the same time period. With respect to the total study area, E. superba displayed a normal growing state during the two expeditions. E. superba grew relatively poorly in some stations, which may be due to the late retreat of sea ice or lower chlorophyll a concentrations. The number of juvenile E. superba collected using the High Speed Collector was proportionally greater in stations located at the edge of the sea ice, while adults dominated in long-term non-ice regions. This phenomenon reflects the different distribution pattern between juvenile and adult krill. The population structure of E. superba differed between sea regions, which may affect recruitment.     

Middle and Late Cambrian trilobite communities from Fenghuang (Dama) of western Hunan, China

Middle and Late Cambrian trilobite faunas from the Dama section in western Hunanare are composed of 63 genera and subgenera, 84 species, and two forms of gen. et sp. indetermined. Which include a mixture of cosmopolitan agnostoids and polymeroids. Three new species,Hardyoides damaensis,Meringaspis damaensis and Rhyssometopus (Rodtrifinis) nitidus, are described by present author in 2004. Besides, Erixanium is recognised for the first time in study area, which is significant for biostratigraphical correlation of the Late Cambrian in the Austalo-Asia region. According to distribution regularity vertical, the Middle and Late Cambrian trilobites can be divided into 9 trilobite communities for the Dama section. Based on the trilobite communities analysis, the author concludes that from the east Mt. Lailong to Dama through Fenghuang, further east, reach in Chenxi,the palaeoenvironments were changed from a shallow-water of oxygen-rich (platform margin slope ) into a deep-water of oxygen-poor setting (basin).     

Middle and Late Cambrian trilobite communities from Fenghuang (Dama) of western Hunan, China

Middle and Late Cambrian trilobite faunas from the Dama section in western Hunanare are composed of 63 genera and subgenera, 84 species, and two forms of gen. et sp. indetermined. Which include a mixture of cosmopolitan agnostoids and polymeroids. Three new species, Hardyoides damaensis ,Meringaspis damaensis and Rhyssomelopus (Rodtrifinis ) nitidus, are described by present author in 2004. Besides, Erixanium is recognised for the first time in study area, which is significant for biostratigraphical correlation of the Late Cambrian in the Austalo-Asia region. According to distribution regularity vertical, the Middle and Late Cambrian trilobites can be divided into 9 trilobite communities for the Dama section. Based on the trilobite communities analysis, the author concludes that from the east Mt. Lailong to Dama through Fenghuang, further east, reach in Chenxi.the palaeoenvironments were changed from a shallow-water of oxygen-rich (platform margin slope) into a deep-water of oxygen-poor setting (basin).