Paleoenvironmental significance of a new species of freshwater sponge from the Late Miocene Quillagua Formation (N Chile)

This paper reports the first fossil (Tertiary) occurrence of freshwater sponges of the genus Ephydatia in the southern hemisphere. The sponges appear in diatomite lacustrine sediments of Late Miocene Quillagua Formation (Chile, Atacama region). The investigated specimens represent a new species, Ephydatia chileana sp. nov., which is close to the Recent cosmopolitan E. fluviatilis. On the basis of sedimentological and diatom assemblage data, sponge-bearing diatomites have been interpreted as deposited in open offshore shallow lacustrine conditions with slightly alkaline waters. The sponges show malformations, similar to some diatoms and probably caused by high heavy metal concentrations in a lake water. These concentrations are related to hydrothermal activity, which favored the leaching of volcanic rocks that outcrop extensively in the catchment.     

High-resolution seabed imagery as a tool for biodiversity conservation planning on continental margins

Submarine canyons increase seascape diversity on continental margins and harbour diverse and abundant biota vulnerable to fishing. Because many canyons are fished, there is an increasing emphasis on including them in conservation areas on continental margins. Here we report on sponge diversity and bottom cover in three canyons of South-eastern Australia, test the performance of biological and abiotic surrogates, and evaluate how biological data from detailed seabed surveys can be used in conservation planning in these habitats. The biological data on sponge assemblage structure and species richness were obtained from 576 seafloor images taken between 148 and 472 m depth, yielding 65 morphospecies. Seafloor characteristics were similar within and between canyons, being almost exclusively composed of sediments with very few rocky substrates of higher relief. This environmental homogeneity did not, however, translate into biological uniformity of the megabenthos, and environmental factors were consequently poor predictors of biological features. By contrast, total bottom cover of sponges was highly correlated with species richness and served as a good proxy for species-level data in this situation. Design strategies that employ information on cover or richness of sponges provided a large dividend in conservation effort by dramatically reducing the number of spatial units required to achieve a specified conservation target of 50–90% of species to be included in reserves. This demonstrates that image-derived data are useful for the design of reserves in the deep sea, particularly where extractive sampling is not warranted. Using biological data on the sponge megabenthos to identify conservation units can also minimise socio-economic costs to fisheries because of a smaller geographic and bathymetric ambit of conservation areas.     

黄海繁茂膜海绵细胞培养中抗生素的使用

以黄海海域的繁茂膜海绵(Hymeniacidon perleve)为研究对象,考察了海绵细胞培养中细胞团的形成过程。细胞在培养24h后贴壁聚集,有类似胶原物质分泌。培养第5天形成的细胞团,中心致密,边缘有平滑的表皮结构。为控制培养中的微生物污染,比较了6种抗生素的使用效果,其中庆大霉素有较好的抑菌效果且不影响细胞成团,而两性霉素B对细胞的贴壁和成团有不利影响。     

Defense by association: Sponge‐eating fishes alter the small‐scale distribution of Caribbean reef sponges

Recent studies have demonstrated that sponge‐eating fishes alter the community of sponges on coral reefs across the Caribbean. Sponge species that lack chemical defenses but grow or reproduce faster than defended species are more abundant on reefs where sponge‐eating fishes have been removed by overfishing. Does predator‐removal have an effect on the distribution of sponges at smaller spatial scales? We conducted transect surveys of sponge species that are palatable to sponge predators in proximity to refuge organisms that are chemically or physically defended (fire coral, gorgonians, hard corals) on the heavily overfished reefs of Bocas del Toro, Panama, and a reef in the Florida Keys where sponge‐eating fishes are abundant. In Panama, palatable sponge species were not distributed in close association with refuge organisms, while in the Florida Keys, palatable sponge species were strongly associated with refuge organisms. The presence of fish predators alters the meter‐scale pattern of sponge distribution, and defense by association enhances biodiversity by allowing palatable sponges to persist on reefs where sponge‐eating fishes are abundant.     

Comparative Morphology, Ecology, and Fatty Acid Composition of West Indian Spheciospongia (Demospongea)

Abstract. The morphological variability of the common West Indian loggerhead sponge, Spheciospongia vesparium, is examined in light of the latest morphological and ecological information and new biochemical criteria, that is, composition and concentration of fatty acids. A typical and a yellow ecophenotypical form are distinguished. Comparing this species with its next relatives in the same zoogeographical region it is found that S. othella, first described from Bermuda, cannot be maintained as a separate species. S. cuspidifera, previously misinterpreted as "Xestospongia tier-neyi", is confirmed as a distinct species of Spheciospongia, whereas "Prianos" tierneyi is considered a morphological variant of S. vesparium.     

Stochastic Events and Dynamics of a Mangrove Root Epifaunal Community

Abstract. Submerged roots of red mangroves ( Rhizophora mangle ) in the Florida Keys were photographed at 1– or 2-month intervals for 38 months to measure population dynamics of the epifaunal invertebrate species. Photographs were analysed for species composition and abundance and information on life spans, persistence, mortality, and seasonality. Larval recruitment to artificial surfaces was used to assess reproductive seasonality. As a measure of stability, populations were tested for narrow stochastic boundedness.
In contrast to reports for a tropical mangrove root community, the Florida Keys root community showed enormous variability despite being dominated by long-lived species with low, largely non-seasonal recruitment. Species composition on individual roots changed dramatically on short time scales. Populations of the major species were not narrowly bounded on most roots and there was little evidence for a closely regulated community.
Variability of this community related to the frequency and intensity of stochastic perturbations. Physical disturbance due to strong tidal Rows appeared to be the most important structuring process. Species-specific predation and fragmentation of sponges were also important. These features contribute to the instability of the community by producing dramatic fluctuations in species abundances and preventing competitive processes from producing a more stable, equilibrium community. Temporal measurement scale was an additional important consideration in this habitat. Structuring processes occurred on very short time scales (1–2 months) and analysis on longer time scales gave inaccurate impressions of community dynamics.     

New species of Spongia (Porifera: Demospongiae: Dictyoceratida) from New Zealand,and a proposed subgeneric structure

This paper is the fifth in a series revising the taxonomy of New Zealand dictyoceratid sponges (phylum Porifera, subclass Ceractinomorpha, order Dictyoceratida). Six new species of the genus Spongia are added to New Zealand's known fauna. The use of subgenera within the genus Spongia is discussed, and two new subgenera are proposed. The genus Hippospongia is revised, and an emended generic diagnosis is proposed.     

Methods to quantify components of the excavating sponge Cliona orientalis Thiele, 1900

This study applied the loss after combustion (LAC) method and the acid decalcification (ADC) method to quantify different components of an excavating sponge. Samples of dried coral skeleton of Favia sp. invaded by the Indo‐Pacific excavating sponge Cliona orientalis Thiele, 1900 were used. The sponge tissue penetrated the 12‐mm‐thick samples to approximately 10 mm. The average proportional weight of organic matter, siliceous spicules, calcareous substrate and salts in the entire samples was found to be respectively 2.5%, 4.4%, 90.5% and 2.5% of dry weight applying the LAC method, and 2.9%, 5.9%, 89.0% and 2.3% of dry weight applying the ADC method. Respective volumetric proportions of the organic matter, spicules, substrate and salts were then calculated to be 6.4%, 5.5%, 85.2% and 3.0% of volume with the LAC method, and 7.4%, 7.2%, 82.7% and 2.7% of volume with the ADC method. The LAC method showed low variability of data and is simple and fast and therefore is recommended. The ADC method generated very similar results to the LAC method. However, due to the handling involved in the ADC method, more than half of the spicules may be lost and the method is therefore not recommended unless careful data corrections are considered. In addition, the buoyant weight method was used to quantify actual substrate weight in the fresh sponge‐substrate samples. This method was found to be at least 97% effective, revealing that buoyant weights can potentially be used to quantify bioerosion rates of excavating sponges. To our knowledge, this is the first study to systemically quantify organic and inorganic components of an excavating sponge and its calcareous substrate, providing improved standard methods for future studies.     

Sexual reproduction of Hippospongia communis (Lamarck, 1814) (Dictyoceratida,Demospongiae): comparison of two populations living under contrasting environmental conditions

The study of the reproductive processes of benthic invertebrates is essential to the understanding of their population dynamics and is also important in formulating conservation plans, especially for exploited species. The sexual reproduction of Hippospongia communis, the ‘honeycomb’ bath sponge, was studied at two locations in the Mediterranean Sea: the Kerkennah Islands (Tunisia, South Mediterranean), where the mean annual seawater temperature is 19 °C, and Marseille (France, Northwestern Mediterranean Sea), where the mean annual water temperature is 16 °C. The aim of this comparative study was to determine whether different environmental conditions could affect reproduction patterns. At both locations, H. communis was found to contain sexual reproductive elements year‐round. Oogenesis and embryogenesis occurred throughout the year, whereas spermatogenesis occurred during shorter periods between October and November, in both populations. While gametogenesis seemed to be synchronized, indicating that fertilization could occur at the same time at both locations, spawning was observed in late summer in Marseille, whereas it started in late spring for the Kerkennah population. Larval development of H. communis seems to take longer for sponges living at cooler locations such as Marseille. Reproductive effort calculated for both sexes showed significantly higher values for specimens from Kerkennah Islands. By comparing sexual reproductive patterns of populations living in two contrasted environments, we suggest that a change of thermal regime can affect H. communis phenology.     

Differential effects of thermal and chemical stressors on tissue balls from scleractinian corals

Coral cell aggregates (tissue balls) from four species (Acropora muricata, Fungia repanda, Pavona cactus and Pocillopora damicornis) were used as an indicator to investigate the effects on the corals of thermal stress and of chemical extracts from three sponges (Adocia sp., Haliclona sp. and Lissodendoryx sp.) and one ascidian (Didemnum molle). The formation and disintegration of tissue balls were studied through exposure to a temperature range of 23–30 °C at time intervals of 0–90 min, and to sponge and ascidian crude extracts at concentrations of 50–200 µg ml^?1 at temperatures of 23 and 30 °C and at time intervals of 10, 60 and 120 min. The negative effect of temperature on overall tissue ball density (number per cm² of coral surface) was greatest at higher temperatures (28 and 30 °C) but varied among coral species. Tissue balls of P. damicornis were the most robust whereas those of A. muricata were the most sensitive. High concentrations of extracts of Adocia sp., Haliclona sp. and Lissodendoryx sp. generally inhibited the formation of tissue balls or caused their disintegration, or both, most markedly at 30 °C. Adocia sp. induced the least negative effects and Haliclona sp. the most. No tissue balls were formed in the presence of D. molle extracts (50 and 100 µg ml^?1), indicating a high level of interference with tissue ball formation. The differential susceptibility to thermal and chemical stressors exhibited by the corals under study have possible implications for the interactions of the corals with other sedentary reef organisms under climate change-driven ocean warming.