Spatial variability of intertidal rocky shore assemblages in the northwest coast of Portugal

The spatial variability of rocky shore assemblages of the northwest Portuguese coast was studied in a total of 12 transects, visited twice between March and August 2003. Each transect was positioned from the upper to the lower shore and four replicate samples (50 × 50 cm) were taken at each visually identified assemblage. Multivariate analysis was used to test the null hypothesis of no significant differences among assemblages located on different heights along the transect and among assemblages located at the same height on different transects. The distribution pattern of organisms along the height was not consistent across transects and significant variability could be found in assemblages located at the same height on the shore. Globally, the variability from the lower to the upper shore (vertical axis) was larger than from transect to transect (horizontal axis) but the distribution pattern along height was clearer in sheltered transects than in exposed ones. The heterogeneity in composition between the visually identified assemblages, within the same transect, was, however, the major source of variability in the study area. In the rocky intertidal northwest coast of Portugal, where tidal amplitude is broad and extremely wave-exposed sites are scarce, height above chart datum was the most important factor determining the distribution and species composition of the assemblages. However, variability along the horizontal axis was also significant and should be considered in studies of spatial patterns of distribution of organisms within this area.     

Changes in a rocky shore community: An evaluation of monitoring

The basic aim of this study was to record the changes in the communities on a moderately exposed rocky shore by a programme of repeated non-destructive sampling (‘monitoring’) and to determine the causes of these changes. Possible causative factors were investigated by the combined approach of analysing detailed sea-temperature and meteorological data for the period of the study and establishing manipulative field experiments.Fixed quadrats (2 m by 1 m) at three levels were visited at 6–8 weekly intervals for 30 months and the abundance and spatial pattern of major species assessed. In the ‘High’ quadrat the balance between Fucus spiralis and F. vesiculosus changed, and an outburst of ephemeral algae occurred following a decline in overall canopy cover. In the ‘Mid’ quadrat F. vesiculosus decreased considerably from its initial cover and virtually disappeared by the end of the study. In the ‘Low’ quadrat F. vesiculosus increased from being absent to comprising 20% of the canopy, whilst Semmibalanus (= Balanus) balanoides and ‘understorey’ algae decreased in cover. Actinia equina, Nucella lapillus and Patella vulgata showed marked changes in number at all levels where they occurred.Only certain of these changes could be attributed to the physical environment—most were biologically controlled. For example, manipulative experiments showed that the blooms of ephemeral algae and the decline of Patella in the high-shore quadrat, and the decline of Actinia in the mid-shore quadrat, were due to decreases in the fucoid canopy. These canopy changes were, in turn, the result of biological cycles which are characteristic of these communities. However, even with the support of manipulative experiments, it was not possible to account for (or predict) all of the observed natural changes. The extent of these fluctuations poses a serious obstacle to the recognition of any but very gross pollution-induced effects. The conclusion must be that the monitoring of rocky shores as a means of detecting and measuring pollution is likely to be an unproductive investment of time and resources.     

New metric of microhabitat complexity predicts species richness on a rocky shore

Most habitat complexity–species diversity relationships are specific to the habitat type, taxonomic group and spatial scale investigated. There is a need for a biologically relevant metric of habitat complexity that is transferable across systems and scales. Here, we introduce a novel metric of landscape microhabitat complexity that may overcome such constraints. It is scaled to the size of individual organisms and it numerically captures structural elements of the habitat that are biologically relevant to individuals. Our model ecosystem to develop this metric was a rocky shore in Eastern Australia. Here species richness of invertebrates was linked to habitat complexity quantified by the new metric. Importantly, measurements made at the scale of the organism predicted species richness at the landscape scale. Testing the generality of this approach across different systems may prove useful in a broader conservation biology context.     

Temporal variability in the isotopic niches of rocky shore grazers and suspension‐feeders

Carbon and nitrogen stable isotope ratios were measured in rocky inter‐tidal suspension‐feeders (brown mussels and cape reef worms) and grazers (goat's eye limpets and cape sea urchins) to determine the influences of lifestyle and time on the diets of consumers. Niche partitioning between consumer species within the same feeding guild was assessed using isotopic niche area (a proxy for trophic niche). Specimens were collected monthly at a single site in Southeastern South Africa from July 2010 to June 2011. Temporal variations in isotopic signatures were generally greater in the suspension‐feeders compared with the grazers, isotopic niche widths were smaller in the suspension‐feeders and intra‐population variations in isotope signatures were larger in the grazers. No inter‐specific niche overlap (according to standard ellipse areas) was observed within either feeding guild unless standardization calculations were used. Temporal variations in the diets of all the consumers appeared uncoupled from temporal variability in the isotopic signatures of basal resources in the region; as such, shifts in the consumer diets most likely pertained to feeding behaviour and food preferences. Our data provide new insights into how syntopic rocky shore consumers coexist by partitioning their temporally variable food environment.     

舟山岩相潮间带动物群落结构的研究

本文应用数理统计方法研究了舟山海区岩岸潮间带中26个测站的春季动物群落结构。根据26个站的位置分为近岸区、近外海区和外海区3个区域。各站均以软体动物和甲壳动物为群落主要组成成分,群落种类组成数从近岸到外海呈增长趋势,且优势种亦从低盐种类向高盐种类演替。近岸区群落主要优势种为短滨螺Littorina brevicula、粗糙滨螺L.scabra、僧帽牡蛎Ostrea cucullata、白脊藤壶Balanus albicostatus等;近外海区为短滨螺、粒结节滨螺Nodilittorinaexigua、僧帽牡蛎、鳞笠藤壶Tetraclita squamosa squamosa、白脊藤壶等;外海区为粒结节滨螺,疣荔枝螺Purpura clavigera、条纹隔贻贝Septifer virgatus、日本笠藤壶T.japonica及藻类等。但群落个体密度和生物量从近岸到外海呈减少趋势。从近岸到外海,群落的Shannon-Wiener多样性指数H和Pielou均匀度J均增加,而McNaughton优势度D减少。群落结构从近岸到外海渐趋复杂。但整体上,舟山海区岩岸春季动物群落结构是比较简单的(绝大多数断面H值小于2.50,J值小于0.5。而D值大于0.6)。近外海区的群落结构比较相似于外海区的群落。根据平均聚类分析,这26个群落可以分为三个生态类型,即隐蔽性岩岸群落,半隐蔽性岩岸群落及开敞性岩岸群落。     

Horizontal spatial and temporal distribution patterns of nearshore larval fish assemblages at a temperate rocky shore

There have been no previous studies of the composition of nearshore larval fish assemblages along the coast of Portugal. We aimed to describe the composition and horizontal distribution patterns of larval fish assemblages and their temporal dynamics near a rocky reef at depths shallower than 13 m (inshore) and at two miles (3.70 km) from shore (offshore), as well as along transects perpendicular to the shoreline, from the reef to 10 miles offshore (18.52 km). Samples were taken using 5 min sub-surface trawls at the rocky shore of the Arrábida Marine Park (W Portugal). A total of 1021 larvae were collected, belonging to 61 taxa inshore and to 29 taxa offshore. Along transects, 626 larvae of 52 taxa were collected. Most larvae belonged to coastal species associated with rocky reefs. Total larval abundance and diversity were higher from May to July, which is consistent with the spawning activity of adults. Diversity and total larval abundance decreased significantly with increasing distance from shore, both in the inshore/offshore comparison and in the transects, where this decrease was evident at a very small spatial scale (within the first mile from the reef). Species assemblages differed in the pattern of distribution, with most species clearly associated to the extreme nearshore. The distribution patterns obtained were independent of the spawning mode of species. Results are discussed in the light of the possible physical mechanisms that can potentially act at the Arrábida Marine Park to facilitate larvae retention and the role of larval behaviour.     

The coral assemblages of an off‐shore deep Mediterranean rocky bank (NW Sicily,Italy)

In this study we characterized the deep assemblages dwelling at 200–250 m depth on a large shoal off Capo St. Vito Promontory (Northwestern coast of Sicily, South Tyrrhenian Sea) by means of ROV‐imaging. Two assemblages of suspension feeders, dominated by the gorgonian Callogorgia verticillata and by the black coral Leiopathes glaberrima, together with a tanatocoenosis of the colonial yellow scleractinian coral Dendrophyllia cornigera, were examined. The three main species were significatively distributed into two areas corresponding to different habitat preferences: a more elevated hardground hosting black corals and a gently sloping, silted rocky bottom hosting the other coral species. The study area is subjected to a heavy pressure from the professional fishery, resulting in the mechanical damage of numerous colonies, some of which are then overgrown by various epibionts including a parasitic bioluminescent zoanthid, new for the Mediterranean fauna, and tentatively identified as Isozoanthus primoidus. In the Mediterranean Sea, these deep off‐shore rocky banks are widely known among recreational and professional fishermen due to their rich fish fauna. However, there has been still little effort into quantifying and characterizing the extent of the impact and its consequences on the benthic communities, which may represent, as in this case, only a partial picture of their original structure and extent.     

Vertical distribution of two sympatric labrid fishes in the Western Mediterranean and Eastern Atlantic rocky subtidal: local shore topography does matter

Changes in the shore topography (e.g. slope) occur at a scale of hundreds of meters in several locations in the Lusitanian and the Mediterranean Sea provinces. We tested whether differences in the bottom inclination might affect the vertical distribution patterns of two sympatric coastal labrid fishes, the rainbow wrasse Coris julis and the ornate wrasse Thalassoma pavo. Visual censuses were used to determine the distribution and abundance of these labrid species in high (≥30°) and low (≤3°) slope rocky substrates covered by brown macroalgae and at two different depths (shallow, 4–7 m, and deep 14–20 m). Pectoral fin aspect ratio was used as an estimate of swimming performance to potentially explain the patterns observed. Despite the intrinsic biogeographical differences in the overall density of T. pavo and C. julis, on steep coasts the ornate wrasse dominated in shallow waters, whereas the two species coexisted both in shallow and deeper depths on gentle slope coasts. These distribution patterns were consistent across locations, and fin aspect ratio was not a good predictor of between‐habitat use for wrasses. We show that, under specific topographical conditions, the depth segregation pattern seems to be an interactive segregation (likely related to resource competition) rather than a result of selective segregation due to morphological differences in the pectoral fin. Significant ecological changes might occur in locations where the density of T. pavo has recently increased as a result of water warming.     

中国东南沿海和平水母科二新种

报道中国东南沿海和平水母科2新种,即八辐和平水母Eireneoctonemalis sp.nov.和黑疣真瘤水母Eutimakrampi sp.nov.。     

Two new species of Eirenidae from the coast of southeast China

Through the examination of 377 samples collected from the Taiwan Straits, two new species of Eirenidae, i. e. , Eirene octonemalis n. sp. and Eutima krampi n. sp. are described. All type specimens are deposited at the Department of Oceanography, Xiamen University.     

东海自由生活线虫两新种

描述了采自东海陆架沉积物中自由生活线虫Hopperia和Nemanema属的两个新种。新种大化感器霍帕线虫主要特征是螺旋形化感器5圈,较大;弓形交接刺近端宽大具有中肋,延伸至三分之一处;引带具有弯曲的引带突;6个乳突状的肛前辅器;锥柱状尾具有膨大的末端和尾端刚毛。新种小线虫的主要特征是身体大小是属内最小的;具有较大的椭圆形化感器;尾锥状;交接刺细,具有腹面翼膜,近端弯钩状;引带环形;1个肛前辅器乳突状,其上着生3条刚毛。更新完善了Hopperia属17个种的二岐检索表。     

Narrow banded wave propagation from very deep waters to the shore

A fully nonlinear Boussinessq-type model with several free coefficients is considered as a departure point. The model is monolayer and low order so as to simplify numerical solvability. The coefficients of the model are here considered functions of the local water depth. In doing so, we allow to improve the dispersive and shoaling properties for narrow banded wave trains in very deep waters. In particular, for monochromatic waves the dispersion and shoaling errors are bounded by ~ 2.8% up to kh = 100, being k the wave number and h the water depth. The proposed model is fully nonlinear in weakly dispersive conditions, so that nonlinear wave decomposition in shallower waters is well reproduced. The model equations are numerically solved using a fourth order scheme and tested against analytical solutions and experimental data.     

Enoplus taipingensis, a new species of marine nematode from the rocky intertidal seaweeds in the Taiping Bay, Qingdao

One new species of free-living marine nematodes Enoplus taipingensis sp.nov.from the rocky intertidal seaweeds in the Taiping Bay,Qingdao is described and illustrated with scanning electron microscopy observation and 18S rRNA gene sequence analysis.Enoplus taipingensis is characterized by special arrangement of lateral setae on the tail,three cervical setae,distal structure on the supplement,and much longer body length with bigger De Man ratio "a".Type specimens are deposited in the College of Marine Life Science,Ocean University of China.     

东海自由生活线虫两个新纪录种

在对东海的自由生活海洋线虫进行分类和多样性研究中,发现2个我国新纪录种并进行了描述.深海螺旋球咽线虫Spirobolbolaimus bathyalis Soetaert&Vincx,1988的主要鉴别特征为:体表具显著的环纹,头感觉器呈乳突状,化感器螺旋形,口腔中部具有一个背齿以及一对亚腹齿,咽前后各有一个咽球;具有...     

Waters of the western springs catchment,Auckland

Abstract

Aquifers occur in basalt deposits infilling valleys in the Western Springs catchment of Auckland City, and they discharge into small streams incised along the edges of major lava flows. Total run‐off from the area is >0.261 m³·s^?1. Analyses by standard methods of twelve subsurface and surface waters show that flowing groundwaters have a low level of pollution (dissolved oxygen x = 7.6 mg·l^?1, abuminoid nitrogen x = 0.038 mg·l^?1, and total solids x = 188 mg·l^?1). Surface waters and stagnant groundwater have high, but varying levels of biological activity. Although much of the dissolved solid content of all the waters (e.g., Ca²⁺, Mg²⁺, Na⁺, K⁺, SiO₂) is consistent with the chemistry of the rocks of the catchment, particularly the glassy volcanic tuffs, for surface waters various sources of pollution also make significant contributions (e.g., leaking sewers, sewage overflows, combustion of fossil fuels, fertilisers, zoo animals). Apart from its iron level, the moderate volume (～.0.13 m³·s^?1) of flowing groundwater is of suitable quality for domestic, industrial and irrigation needs.     

Two new species of Naticidae (Mollusca, Gastropoda) from the coast of China

Two new species of Naticidae （ Mollusca, Gastropoda） collected from the coast of China are described： Cryptonaitca huanghaien- s/s sp. nov. and Sinum vittatum sp. nov. The morphological characteristics between the new species were described and the related information was provided. The similarities and differences between the new species and related species were also compared and discussed. The new species Cryptonaitca huanghaiensis differed from Cryptonaitca hirasei and Cryptonaitca andoi in outer shape, operculum and radula. The new species Sinum vittatum is similar to Sinumjaponicum （Lischke, 1869）, but the shell of the former is flat-elliptical in shape, spire very small, slightly convex. While the latter is flat-globular in shape, apex light brown in color, without a brown band on the body whorl. The comparison results revealed that Cryptonaitca huanghaiensis and Sinum vittatum were two new species from the coast of China. Specimens studied were obtained from collections in the Marine Biological Museum, Chinese Academy of Sciences.     

Two new species of medusae (Cnidaria) from the coastal waters of the northern Beibu Gulf

Medusae in 116 samples collected from the coastal waters of the northern Beibu Gulf during four seasonal oceanographic cruises from October 2017 to August 2018 were analyzed. In total, 34 species were identified. Two of the species are new to science, Proboscidactyla pentacanalis Xu, Chen & Yang sp. nov. and Helgicirrha apapillata Xu, Chen & Wang sp. nov., and three species are newly recorded in the Beibu Gulf, i.e., Hydractinia vacuolata Xu & Huang, 2006, Proboscidactyla flavicirrat...     

Statistics of fluctuations in high-frequency low-grazing-angle backscatter from a rocky sea bed

This paper examines the fluctuations in low-grazing-angle 100-kHz backscatter from a rocky limestone sea bed near Copenhagen, Denmark, at horizontal ranges up to 420 m. The sea-bed reverberation was characterized by strong short spatial-scale variations in scattering strength and statistical parameters. The measured areal backscatter strengths were in the range from -50 to -24 dB at grazing angles less than 3/spl deg/, showing a strong local variability and grazing-angle dependence definitely not in accordance with Lambert's law. The observed echo-amplitude distributions varied between log-normal and Rayleigh models, with more Rayleigh-like probability density functions having higher scintillation indices and skewness (approaching values of 1.0 and 0.63, respectively). The scintillation index and skewness parameters were found to increase mildly with both horizontal range and water-current magnitude. A simple model using the coherent superposition of multiple scatterers was proposed to explain the observed scattering statistics. This model is based on the assumption that the sea bed is effectively immobile, with water-borne scintillation and micro-multipaths providing fluctuations in scatterer phase. This simple model shows that echo-amplitude fluctuations can deviate from the Rayleigh model through two mechanisms: 1) decreasing the levels of water-borne phase fluctuation and 2) increasing the nonuniformity of the sea-bed scatterer amplitudes.     

Two new species of the genus Nassarius(Gastropoda:Nassariidae) from the South China Sea

Two species of Nassarius Duméril, 1805 from the South China Sea are described and illustrated. The specimens are in the Nassariidae collection of the Marine Biological Museum of Chinese Academy of Sciences, Qingdao.Nassarius concavus sp. nov., from the sandy bottom at a depth of 180 m, resembles Nassarius glabrus Zhang and Zhang, 2014 in general shell morphology, but differs from the latter in having a smaller, more slender adult shell without axial ribs on the upper teleoconch whorls. Nassarius nanshaensis sp. nov., from the Nansha Islands at a depth of 56–147 m, is similar to Nassarius maxiutongi Zhang, Zhang and Li, 2019 in the shell sculpture, but differs in having a more slender shell with a higher spire, and fewer cusps on the rachidian tooth(9–11 vs. 13–17).