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1.
舟山枸杞水域的污损生物生态   总被引:1,自引:0,他引:1  
本文系1988年9月~1989年9月在舟山枸杞乌里西岙水域进行挂板试验的结果。共获污损生物135种,其中,近岸的油库码头获77种,远岸的养殖筏获110种。动物以亚热带高盐性种类为主,三角藤壶Balanustrigunus、小海葵Actinia、柯氏分胞孔苔虫Celleporinacostazii、西方三胞苔虫Tricelariaoccidentalis、艾氏美熄Cltiaedwardsi、广口小桧叶螅Sertularellamiurrensis等占优势,藻类常见的有长石莼Ulvalinza、肠浒苔Enteromorphyintestinalis和日本多管藻Polysiphoniajaponica。枸杞污损生物的附着期主要在夏季,附着量也以夏季最大。不同地点附着量的差异极大。夏季由于近岸三角藤壶大量附着,故生物量明显大子远岸,其他季节均是远岸大于近岸。夏季近岸三角藤壶的覆盖面积达100%,生物量达18119g/m2,占污损生物总生物量的98%。故夏季是污损生物防除的主要季节,三角藤壶是防除的主要对象。与1975~1976年嵊山污损生物进行比较,发现两地污损生物的种类组成和群落结构极为相似,说明10多年以来嵊山  相似文献   
2.
文章描述了云南寒武纪早期澄江生物群小细丝海绵属一新种——螺旋小细丝海绵(Leptomitella spiralis sp. nov.)。新种 具有横向骨针束围绕海绵体呈螺旋状排列的典型特征,明显区别于属内其他种;此外,在外部形态和骨针类型上与属内其他种 也存在较大差异。新种的发现增加了Leptomitella种间形态结构的多样性,也为海绵动物的早期演化及寒武纪海绵动物辐射演 化研究提供新的化石资料。  相似文献   
3.
Invertebrate colonization of lakes following the uplift of land from the sea was studied in four lakes, currently situated between 39 and 24 m a.s.l., on the central Norwegian coast. The lakes were isolated from the sea between 9500 and 7700 years B.P. Animal and algal remains picked from core samples showed that the first colonizers preserved as fossils were usually members of the Chironomidae, Daphnidae/Chydoridae, Acarina, Porifera (Ephydatia mülleri and Spongilla lacustris), Bryozoa (Cristatella mucedo and Plumatella spp.) and Charophyta (Chara sp.). Of the chironomids, the genus Chironomus was present in the oldest lacustrine layers of all four lakes, but other genera recorded at the marine/lacustrine boundary were Dicrotendipes, Procladius (?), Einfeldia, Microtendipes, and Glyptotendipes. Remains of the caddis fly family Limnephilidae were also present in the earliest lacustrine sediments in Kvennavatnet and Kvernavatnet. The oldest invertebrate fauna is typical for mesotrophic lakes. However, chironomids and mites have been present in this area from at least about 10?500 years B.P. A diverse chironomid community was established between 300 and 800 years after isolation from the sea at Kvernavatnet on the island of Hitra, while only between 80 and 120 years passed before a comparably diverse community developed at Kvennavatnet on the mainland coast. A similar development of the invertebrate fauna occurred in Kvennavatnet, Kvernavatnet and Storkuvatnet. However, Litjvatnet deviates greatly from the ‘normal’ pattern because a tsunami disturbed the bottom sediments and fauna. The tsunami, a gigantic sea wave, was caused by a submarine slide from the Norwegian continental slope. It reached Litjvatnet, today located 24 m a.s.l., but was not traced in Storkuvatnet at 30 m a.s.l. This event happened about 7200 years B.P.  相似文献   
4.
The South African coastline has been invaded by numerous alien species. Rare pre-invasion (1980) and post-invasion datasets (2001 and 2012) exist for Marcus Island, a small land-tied island in Saldanha Bay, South Africa. These snapshot datasets of the island’s intertidal invertebrate community were complemented with monitoring across seasons, from 2014 to 2016. Invertebrate communities were compared among the summers of 1980, 2001, 2012, 2014, 2015 and 2016 to assess interannual differences, while invertebrates and algae were monitored quarter-annually to assess seasonal changes. In addition, the population dynamics of the alien mussel Mytilus galloprovincialis were monitored. Differences in invertebrate communities between consecutive summers were significant but much smaller than changes induced by the arrival of alien species. Invertebrate and seaweed communities differed among years and shore zones but not among seasons, whereas species diversity differed among years, seasons and shore zones, with zones having the strongest influence. The invasion by M. galloprovincialis, and ensuing spatial and temporal variability in its recruitment, emerged as the most important factor influencing community composition, overshadowing interannual and seasonal changes. This work highlights that the impacts of alien species can be distinguished from natural variability by combining long-term monitoring with surveys at finer temporal scales. This is an important step in extending our understanding of the impacts of marine alien species.  相似文献   
5.
The study of epibionts on habitat engineering ascidians is of increasing interest because changes in the population structure of the latter may affect associated communities, especially in the case of commercially exploited species. The solitary ascidian Microcosmus sabatieri lives on rocky cliffs in the Eastern Mediterranean and is harvested in certain Aegean areas. Its hard, wrinkled tunic is usually fouled by various epibionts both sessile and motile. Sponges are an important component of this complex and their biomass may be higher than that of the ascidian itself, strongly affecting diversity and abundance of the motile epifauna. The aim of this study was to examine in detail the structure of the epibiotic sponge assemblage on ascidians collected from their main fishing grounds in the South Aegean Sea. A rich (41 species) and taxonomically diverse sponge assemblage was found, while only eight species contributed 80% of the total sponge cover. Most of the epibiotic sponges commonly grow on the surrounding sublittoral cliffs. The encrusting sponge growth form prevailed in cover of the ascidian tunic, while two massive species dominated in terms of frequency of appearance and abundance. Ascidian dimensions, weight and volume were significantly correlated with sponge diversity, abundance and cover area, thus structuring the epibiotic sponge assemblage. Spatial patterns in sponge cover were not clear, but a general declining NW to SE trend in sponge richness, abundance and cover appeared in accordance with previous records. Sponge distribution on the ascidian tunic presented a clear pattern related with characteristic features of the ascidian: the posterior zone supported the richest and most expansive sponge fauna. The ecosystem-engineering process performed by the ascidian is enhanced by the diverse epibiotic sponge assemblage, thus further increasing habitat complexity in this space-limited, temperate, sublittoral, rocky environment.  相似文献   
6.
The calcareous sponge Paraleucilla magna (Porifera, Calcarea) has been the subject of several studies in the last decade. It was first described along the Brazilian coast, where it is considered cryptogenic, and was subsequently found in the Mediterranean, where it is considered invasive. The wide artificial distribution of this species allows us to compare different aspects of the biology of an introduced species in different locations. Here, we analysed the effects of selected environmental parameters on the reproductive dynamics of P. magna in Rio de Janeiro (Brazil) over 18 months and compared our results with those obtained for the same species in the Mediterranean Sea. Specimens were collected monthly and analysed through histological methods. The density of reproductive elements in each month was calculated, and the effects of environmental parameters (photoperiod, precipitation, temperature, phytoplankton and bacterioplankton) were analysed using a regression tree analysis. Paraleucilla magna was reproductive throughout the study period. The densities of the reproductive elements (oocytes, embryos and larvae) showed no seasonality, and this species presented one of the highest reproductive efforts documented to date in the phylum Porifera (99.0 oocytes · mm?3; 89.0 embryos · mm?3; 319.0 larvae · mm?3). The main environmental parameters related to the reproduction of P. magna were temperature, photoperiod and bacterioplankton. Temperature was the main driver associated with the densities of oocytes and embryos, while bacterioplankton was the main driver of larvae (positive relationships). In Rio de Janeiro, larvae were present and continuously released. This strategy is different from that observed in the Mediterranean, where a larger larval output was observed but only during the summer months. Our results show that P. magna is a species with a strong invasive potential, considering its high and continuous reproductive effort. This high fecundity stimulated by high temperatures may be a key factor contributing to the growth of P. magna populations and its invasion of new areas.  相似文献   
7.
Four similar sponges of different colors, all unknown to science, were collected in submarine caves of New Caledonia. We aimed at determining whether the four chromotypes represented different species or phenotypic variations of a unique new species. We used an integrative taxonomic approach combining morphologic, molecular and metabolomic analyses. The main traits that define these specimens are a skeleton made of monolophose, trilophose and tetralophose calthrops only, high chemical diversity and a high abundance and diversity of prokaryotic symbionts. The symbiotic community includes two unique prokaryote morphotypes, which are described for the first time in Homoscleromorpha, and appeared to be vertically transmitted. Although several features slightly differ among chromotypes, the most parsimonious conclusion was to propose a single new species Plakina kanaky sp. nov. Our phylogenetic analysis indicated the paraphyly of the Plakina genus, with P. kanaky sp. nov. belonging to a clade that includes Plakina jani and Plakina trilopha. The present work demonstrates that integrative taxonomy should be used in order to revise the entire Plakinidae family and especially the non‐monophyletic genus Plakina.  相似文献   
8.
For 3 years aspects of the population dynamics, growth, and bioactivity (measure of biologically active metabolite biosynthesis) of the Demospongiae Latrunculia sp. nov. and Polymastia croceus (Kelly‐Borges & Bergquist) were examined on a subtidal reef on the Wellington south coast, New Zealand. For both species, survival of adult sponges was high in all seasons, whereas juvenile sponges had poor survival. Recruitment of Latrunculia sp. nov. occurred in all seasons indicating that this species is reproductively active throughout the year. P. croceus recruited mostly in autumn, supporting previous work that found the sponge to be reproductively active in summer and early autumn only. For both sponge species, growth rates varied greatly between individuals and were unaffected by initial sponge size within the range examined. Sponges generally grew during winter and spring as the water temperature rose, and shrank during summer and autumn as the water temperature fell. This growth pattern may relate to seasonal variation in food abundance, and for P. croceus it may result also from seasonal differences in reproductive investment. After 2 years, Latrunculia sp. nov. and P. croceus had on average, halved and doubled in size, respectively. Latrunculia sp. nov. showed a seasonal pattern of bioactivity, being most active in spring possibly to prevent the surface overgrowth of fouling organisms. P. croceus had no seasonal pattern of bioactivity, but individuals were either very active or inactive. The bioactive metabolites in both species possibly aid in competitive interactions and prevent predation and biofouling.  相似文献   
9.
舟山虾塘纹藤壶种群结构研究   总被引:1,自引:0,他引:1  
应用挂板试验,研究了挂板浸水时间、挂板角度和对虾养殖塘内外环境差异等因素对附着于挂板上纹藤壶种群结构的影响.  相似文献   
10.
Perceived changes in the culture of sponge science and sponge conferences served as motivation for an evaluation of the sponge science community and research, over time and at present. Observed changes included a decrease in proceedings publications on sponge fossils and freshwater sponges, sponges from temperate environments, review papers and data syntheses, frequency of aquarium studies, and number of species investigated per publication. Publications on recent sponges, hexactinellids, calcareans, marine, Indo‐Pacific and warm‐water sponges increased, as well as the number of authors per publication and the proportion of field studies. Studies at the level of specimens and ultrastructure were gradually replaced by molecular approaches, but studies at the community level remained stable. The five sub‐disciplines morphology/taxonomy, phylogeny/evolution, physiology, ecology and faunistics also retained about equal proportions over time. Conference publications related to taxonomy, phylogeny and biodiversity prevailed, whereas those on management and conservation were rare, possibly because studies on sponge recovery, survival and mortality were also scarce. The community of sponge scientists has grown and become more diverse over time, presently representing 72 nations. The gender distribution evened out since the first sponge conference and presently favours women at early and men at late career stages. Although stated research interests are generally dominated by physiology and ecology, taxonomy and evolution are favoured after retirement. Sponge science has become more dynamic, but maybe also more competitive and less inclusive. We now face the dual challenge of safeguarding against the loss of some sub‐disciplines, and fostering the collaborative, helpful culture characteristic of sponge science.  相似文献   
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