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1.
Friederike Hoffmann Hans Røy Kristina Bayer Ute Hentschel Martin Pfannkuchen Franz Brümmer Dirk de Beer 《Marine Biology》2008,153(6):1257-1264
The Mediterranean sponge Aplysina aerophoba kept in aquaria or cultivation tanks can stop pumping for several hours or even days. To investigate changes in the chemical
microenvironments, we measured oxygen profiles over the surface and into the tissue of pumping and non-pumping A. aerophoba specimens with Clark-type oxygen microelectrodes (tip diameters 18–30 μm). Total oxygen consumption rates of whole sponges
were measured in closed chambers. These rates were used to back-calculate the oxygen distribution in a finite-element model.
Combining direct measurements with calculations of diffusive flux and modeling revealed that the tissue of non-pumping sponges
turns anoxic within 15 min, with the exception of a 1 mm surface layer where oxygen intrudes due to molecular diffusion over
the sponge surface. Molecular diffusion is the only transport mechanism for oxygen into non-pumping sponges, which allows
total oxygen consumption rates of 6–12 μmol cm−3 sponge day−1. Sponges of different sizes had similar diffusional uptake rates, which is explained by their similar surface/volume ratios.
In pumping sponges, oxygen consumption rates were between 22 and 37 μmol cm−3 sponge day−1, and the entire tissue was oxygenated. Combining different approaches of direct oxygen measurement in living sponges with
a dynamic model, we can show that tissue anoxia is a direct function of the pumping behavior. The sponge-microbe system of
A. aerophoba thus has the possibility to switch actively between aerobic and anaerobic metabolism by stopping the water flow for more
than 15 min. These periods of anoxia will greatly influence physiological variety and activity of the sponge microbes. Detailed
knowledge about the varying chemical microenvironments in sponges will help to develop protocols to cultivate sponge-associated
microbial lineages and improve our understanding of the sponge-microbe-system. 相似文献
2.
Volker Gloeckner Ute Hentschel Alexander V. Ereskovsky Susanne Schmitt 《Marine Biology》2013,160(4):781-791
Homoscleromorph sponges such as Oscarella spp. are characterized by unique morphological features, and Homoscleromorpha were therefore recently proposed as the fourth class of sponges. The microbiology of these sponges was mainly studied by electron microscopy while molecular studies are scarce. The aim of this study was to characterize the bacteria in Oscarella sponges using molecular tools. Denaturing gradient gel electrophoresis revealed distinct bacterial profiles in five Oscarella species and several color morphs of Oscarella lobularis. These profiles are characteristic of low microbial abundance (LMA) sponges. This was further confirmed by analysis of a 16S rRNA clone library from O. lobularis that yielded a low phylum-level diversity with dominance of Alphaproteobacteria. Bacterial communities in O. lobularis were very similar among different individuals (collected at the same site and time), five different color morphs, and specimens from different depths and locations, indicating a species-specific association. These results allow novel insights into the microbiology of the first known LMA sponge genus within the new class Homoscleromorpha. 相似文献
3.
Jeremy B. Weisz Ute Hentschel Niels Lindquist Christopher S. Martens 《Marine Biology》2007,152(2):475-483
Many sponge species contain large and diverse communities of microorganisms. Some of these microbes are suggested to be in
a mutualistic interaction with their host sponges, but there is little evidence to support these hypotheses. Stable nitrogen
isotope ratios of sponges in the Key Largo, Florida (USA) area grouped sponges into species with relatively low δ15N ratios and species with relatively high δ15N ratios. Using samples collected in June 2002 from Three Sisters Reef and Conch Reef in the Key Largo, Florida area, transmission
electron microscopy (TEM) and denaturing gradient gel electrophoresis were performed on tissues of the sponges Ircinia felix and Aplysina cauliformis, which are in the low δ15N group, and on tissue of the sponge Niphates erecta, which is in the high δ15N group. Results showed that I. felix and A. cauliformis have large and diverse microbial communities, while N. erecta has a low biomass of one bacterial strain. As the low δ15N ratios indicated a microbial input of nitrogen, these results suggested that I. felix and A. cauliformis were receiving nitrogen from their associated microbial community, while N. erecta was obtaining nitrogen solely from external sources. Sequence analysis of the microbial communities showed a diversity of
metabolic capabilities among the microbes of the low δ15N group, which are lacking in the high δ15N group, further supporting metabolic differences between the two groups. This research provides support for hypotheses of
mutualisms between sponges and their associated microbial communities. 相似文献
4.
Marine sponges harbor dense and highly diverse bacterial communities, and some percentage of the microflora appears to be
specialized for the sponge habitat. Bacterial diversity was examined in Chondrilla nucula Schmidt to test the hypothesis that some subset of sponge symbiont communities is highly similar regardless of the species
of host or habitat requirements of the host. C. nucula was collected from a mangrove channel on Lower Matcumbe Key in the Florida Keys (25°53′N; 80°42′W) in August 1999. Domain-specific
universal bacterial primers were used to amplify the 16S rDNA gene from genomic DNA that had been extracted from sponges and
the surrounding water. An RFLP technique was used to assess diversity of sponge-associated and environmental bacterial communities.
The clone library from C. nucula contained 21 operational taxonomic units (OTUs). None of the 53 OTUs from adjacent water samples were found in the C. nucula library indicating that a distinct community was present in the sponge. Sequence analysis indicated that C. nucula harbors a microbial community as diverse as the microbes from other sponges in different habitats around the world. Phylogenetic
analysis placed several C. nucula clones in clades dominated by bacteria that appear to be sponge specialists (e.g., Acidobacteria, Bacteroidetes, and Cyanobacteria).
Proportional representation of major bacterial taxonomic groups represented in symbiont communities was compared as a function
of geographic location of sponge hosts. This study supports the hypothesis that sponges from different oceans existing in
dissimilar habitats harbor closely related bacteria that are distinct from other bacterial lineages and appear specialized
for residing within sponges. 相似文献
5.
C. R. Wilkinson 《Marine Biology》1978,49(2):169-176
Three taxonomically distant sponges Pericharax heteroraphis, Jaspis stellifera and Neofibularia irata contain phenotypically similar bacterial symbionts which differ from bacteria in the ambient water. These symbionts are predominant in the sponges and were detected after computer analysis of 526 heterotrophic bacterial strains tested for 76 characters. These facultative anaerobic symbionts metabolize a wide range of compounds and may be important in removing waste products while the sponges are not circulating water. The bacteria produce sticky-mucoid colonies and thus would contribute to sponge structural rigidity. The fourth sponge Ircinia wistarii contains a mixed aerobic population similar to that in the ambient water. The majority of the bacteria are located around the inhalant canals, facilitating the uptake of dissolved organic matter and oxygen from the incoming water. 相似文献
6.
M. S. Hill 《Marine Biology》1996,125(4):649-654
Several species of boring sponges harbor symbiotic zooxanthellae, and it is believed that the symbiont enhances boring activity of host sponges. This hypothesis was tested using manipulative field experiments to assess the effect of intracellular zooxanthella populations on boring rates of the tropical sponge Anthosigmella varians forma varians. Portions of sponge were attached to 60 calcium carbonate blocks of known weight. Three sets of 10 blocks were grown at high light levels and three sets of 10 blocks were grown at low light levels for 105 d in the Florida Keys, Florida, USA. Boring rates, growth rates (lateral growth and within-substratum tissue penetration), and zooxanthella populations were measured at the end of the experiment. Absolute rates of boring and growth of A. varians forma varians were significantly greater when zooxanthella densities were higher. Boring rate and tissue penetration related to final surface area of sponge attachment was also enhanced when zooxanthella densities were higher, suggesting that the symbiont plays a physiological role in the decalcification process. This is in contrast to the role that zooxanthellae play in coral hosts. Based on the results of this study, it appears that the presence of zooxanthellar symbionts has important ecological and life-history consequences for host sponges. Ability to laterally overgrow competitors will be correlated with the size and activity of zooxanthella populations. In addition, the fitness of host sponges will be enhanced by algal symbionts, since greater penetration within substrata will result in an increase in production of tissue that can be converted into storage, feeding and reproductive functions. 相似文献
7.
We observed a pronounced, yet reversible tissue reduction in the tropical sponge Aplysinella sp. under non-experimental conditions in its natural habitat, after transfer into seawater tanks, as well as after transplantation
from deep to shallow water in the field. Tissue reduction resulted in the formation of small “reduction bodies” tightly attached
to the sponge skeleton. Although volume loss and gain were substantial, both tissue reduction and regeneration were often
remarkably rapid, occurring within few hours. Microscopic analysis of the reduction bodies revealed morphological similarities
to previously described sponge primmorphs, with densely packed archaeocytes and spherulous cells enclosed by a thin layer
of epithelial-like cells. Denaturing gradient gel electrophoresis (DGGE) revealed pronounced changes in the sponge-associated
microbial community upon tissue reduction during laboratory and field experiments and following changes in ambient conditions
after transplantation in the field. Generally, the microbial community associated with this sponge proved less stable, less
abundant, and less diverse than those of other, previously investigated Verongid sponges. However, one single phylotype was
consistently present in DGGE profiles of Aplysinella sp. This phylotype clustered with γ-proteobacterial sequences found previously in other sponge species of different taxonomic
affiliations and geographic provenances, as well as in sponge larvae. No apparent changes in the total secondary metabolite
content (per dry weight) occurred in Aplysinella sp. upon tissue reduction; however, comparative analysis of intact and reduced tissue suggested changes in the concentrations
of two minor compounds. Besides being ecologically interesting, the tissue reduction phenomenon in Aplysinella sp. provides an experimentally manipulable system for studies on sponge/microbe symbioses. Moreover, it may prove useful
as a model system to investigate molecular mechanisms of basic Metazoan traits in vivo, complementing the in vitro sponge
primmorph system currently used in this context. 相似文献
8.
Rapid tissue reduction and recovery in the sponge <Emphasis Type="Italic">Aplysinella</Emphasis> sp.
We observed a pronounced, yet reversible tissue reduction in the tropical sponge Aplysinella sp. under non-experimental conditions in its natural habitat, after transfer into seawater tanks, as well as after transplantation
from deep to shallow water in the field. Tissue reduction resulted in the formation of small “reduction bodies” tightly attached
to the sponge skeleton. Although volume loss and gain were substantial, both tissue reduction and regeneration were often
remarkably rapid, occurring within few hours. Microscopic analysis of the reduction bodies revealed morphological similarities
to previously described sponge primmorphs, with densely packed archaeocytes and spherulous cells enclosed by a thin layer
of epithelial-like cells. Denaturing gradient gel electrophoresis (DGGE) revealed pronounced changes in the sponge-associated
microbial community upon tissue reduction during laboratory and field experiments and following changes in ambient conditions
after transplantation in the field. Generally, the microbial community associated with this sponge proved less stable, less
abundant, and less diverse than those of other, previously investigated Verongid sponges. However, one single phylotype was
consistently present in DGGE profiles of Aplysinella sp. This phylotype clustered with γ-proteobacterial sequences found previously in other sponge species of different taxonomic
affiliations and geographic provenances, as well as in sponge larvae. No apparent changes in the total secondary metabolite
content (per dry weight) occurred in Aplysinella sp. upon tissue reduction; however, comparative analysis of intact and reduced tissue suggested changes in the concentrations
of two minor compounds. Besides being ecologically interesting, the tissue reduction phenomenon in Aplysinella sp. provides an experimentally manipulable system for studies on sponge/microbe symbioses. Moreover, it may prove useful
as a model system to investigate molecular mechanisms of basic Metazoan traits in vivo, complementing the in vitro sponge
primmorph system currently used in this context. 相似文献
9.
Sediment deposition is known to affect the structure of marine rocky-bottom communities, but its specific effects on some
key organisms, such as sponges, remain poorly investigated. In a 125-day field experiment involving different treatments of
exposure to sediment deposition, we investigated survival of asexually produced recruits of the sublittoral demosponge Scopalina lophyropoda, a model organism suitable to understand similar processes in other sponges. A total of 660 explants obtained from 11 non-clonal
sponges (explant donors) were distributed on 30 experimental plates. Each donor sponge contributed two clonal explants per
plate, one settled under a roof at a silt-protected position and the other at a silt-exposed position. Plates were installed
at the rocky walls of the natural community, also at the pillars of a local harbor where the sponge does not occur naturally.
A 3-way ANOVA testing for differences in explant longevity as a function of explant donor, exposure to sediment, and habitat
detected that longevity was affected by both an undetermined genetic condition of the explant donor and exposure to silt.
Silt-protected explants lived longer than silt-exposed explants. A significant “Silt-exposure × Habitat” interaction detected
that silt-exposed explants lived shorter within the harbor than in the natural community, suggesting that harbor silt, which
was notably finer, is more deleterious. Inspection of daily mortality rates revealed that the detrimental effects of silt
were very evident during the first 20 days in treatments and irrespective of habitat. Then, mortality rates progressively
decreased, reaching negligible values in all 4 sponge groups by day 65. At this stage, an undetermined mortality factor other
than purely sediment deposition reactivated mortality in all 4 sponge groups, but it affected more intensely the sponges in
the harbor, irrespective of being protected from or exposed to sediment deposition. All together, the results of our field
experiment suggest that sediment loads are a major mortality factor among small sponge individuals in sublittoral rocky communities.
Because a significant “donor factor” suggests an unidentified “genetic component” to be involved in the ability to cope with
sediment, natural or man-driven processes increasing coastal sediment deposition are susceptible to induce changes not only
in the abundance but also the genetic structure of the sponge populations in the long term. 相似文献
10.
Several mechanisms are known to assist the survival of sponges in highly sedimented environments. This study considers the potential of sponge morphology and the positioning of exhalant water jets (through the osculum) in the adaptation of Haliclona urceolus to highly sedimented habitats. This sponge is cylindrical with an apical osculum, which is common in sedimented subtidal habitats at Lough Hyne Marine Nature Reserve, Cork, Ireland. Fifteen sponges were collected, preserved (killed with the structure and morphology maintained) and then replaced in a high sediment environment next to a living specimen (at 24 m). After 5 days, the sediment settled on both living and preserved sponges was collected and dried. No sediment was collected from living sponges, while preserved specimens had considerable amounts of settled sediment on their surfaces. The amount of sediment collected on these preserved specimens was significantly linearly correlated with sponge dry weight, maximum diameter and oscula width (R2>0.70, P<0.001, df=14). Observations of flow direction (using coloured dye) through H. urceolus showed that water is drawn into the sponge on its underside and exits via a large vertically pointing osculum. Sponge morphologies (shape) have often been considered as a means of passive adaptation to a number of different environmental parameters with oscula position enabling entrained flow through the sponge in high flow conditions. However, this study shows how the combination of sponge morphology (tubular shape) and positioning of the osculum may enable H. urceolus to survive in highly sedimented environments. Similar mechanisms may also aid the survival of some deep-water sponge species with similar morphologies.Communicated by J.P. Thorpe, Port Erin 相似文献
11.
Aline S. Turque Alexander M. Cardoso Cynthia B. Silveira Ricardo P. Vieira Flávia A. D. Freitas Rodolpho M. Albano Alessandra M. Gonzalez Rodolfo Paranhos Guilherme Muricy Orlando B. Martins 《Marine Biology》2008,155(2):135-146
In this study we performed a survey of the bacterial communities associated with the Western Atlantic demosponges Hymeniacidon heliophila and Polymastia janeirensis, based on 16S rRNA sequencing and transmission electron microscopy (TEM). We compared diversity and composition of the sponge-associated
bacteria to those of environmental bacteria, represented by free-living bacterioplankton and by bacteria attached to organic
particulate matter in superficial sediments. Partial bacterial 16S rRNA sequences from seawater, sediment, and sponges were
retrieved by PCR, cloning, and sequencing. Sequences were subjected to rarefaction analyses, phylogenetic tree construction,
and LIBSHUFF quantitative statistics to verify coverage and similarity between libraries. Community structure of the free-living
bacterioplankton was phylogenetically different from that of the sponge-associated bacterial assemblages. On the other hand,
some sediment-attached bacteria were also found in the sponge bacterial community, indicating that sponges may incorporate
bacteria together with sediment particles. Rare and few prokaryotic morphotypes were found in TEM analyses of sponge mesohyl
matrix of both species. Molecular data indicate that bacterial richness and diversity decreases from bacterioplankton, to
particulate organic sediment, and to H. heliophila and P. janeirensis. Sponges from Rio de Janeiro harbor a pool of novel and exclusive sponge-associated bacterial taxa. Sponge-associated bacterial
communities are composed of both taxons shared by many sponge groups and by species-specific bacteria. 相似文献
12.
Cyanobacterial symbionts in the sponge Diacarnus erythraenus from the Red Sea were identified in both adult sponges and their larvae by 16S rDNA sequencing. A single cyanobacterial type was found in all samples. This cyanobacterial type is closely related to other sponge cyanobacterial symbionts. The cyanobacterial rDNA, together with the morphological analysis by electron and fluorescence microscopy, provided evidence for vertical transmission of the symbionts in this sponge. In addition, we show phenotypic plasticity of the symbionts inside the sponge, probably as a result of variability in light availability inside the sponge tissue. Finally, the reproduction of Diacarnus erythraenus is also described.Matan Oren, Laura Steindler have contributed equally to the work. 相似文献
13.
The association between sponges and the crab Inachus aguiarii Brito Capello, 1876 was studied by analysing the relationships between sponge distributional patterns on the crab carapaces and several morphological and biological crab parameters. Juveniles, mature females and mature males were differentiated on the basis of sex dimorphism and terminal pubertary moult. All three groups were fouled to different degrees by sponges. Percent sponge cover was related to carapace size only in mature males whereas mature females, all but one of which were ovigerous, were extensively covered regard-less of their size. It is proposed that some behavioural patterns unique to females, such as long resting periods in sponge-rich microhabitats, are responsible for these high sponge covers in females. Sponges showed two trends in the colonization of the carapace, leading to either a monopolizing or a sharing of the available carapace surface. The sponge species found on the carapaces studied are not obligatory epibionts of crabs, but are believed to reflect the sponge population characterizing the crab home range. 相似文献
14.
L. Wulff 《Marine Biology》1995,123(2):313-325
The common Caribbean starfish Oreaster reticulatus (Linnaeus) feeds on sponges by everting its stomach onto a sponge and digesting the tissue, leaving behind the sponge skeleton. In the San Blas Islands, Republic of Panama, 54.2% of the 1549 starfish examined from February 1987 to June 1990 at eight sites were feeding, and 61.4% of these were feeding on sponges, representing 51 species. Sponges were fed on disproportionately heavily in comparison to their abundance, which was only 9.7% of available prey. In feeding choice experiments, 736 pieces of 34 species of common sponges from a variety of shallow-water habitats, and also 9 ind of a coral, were offered to starfish in individual underwater cages. Acceptance or rejection of sponge species was unambiguous for 31 of the 34 species, and there was a clear relationship between sponge acceptability and sponge habitat. Starfish ate 16 of 20 species that normally grow only on the reefs, but only 1 of 14 species that live in the seagrass meadows and rubble flats surrounding the reefs. The starfish live in the seagrass meadows and rubble flats, and avoid the reefs, and so the acceptable reef sponges are generally inaccessible until a storm fragments and transports them into starfish habitat. After Huricane Joan washed fragments of reef sponges into a seagrass meadow in October 1988, starfish consumed the edible species. When the seagrass meadow was experimentally seeded with tagged reef sponge fragments in June 1994, O. reticulatus consumed edible species and accumulated in the area seeded. Reef sponges that were living in a seagrass meadow, from which O. reticulatus had been absent for at least 4 yr (from 1978 to 1982), were eliminated when the starfish migrated into the area, and the sponges have been unable to recolonize up to June 1994. O. reticulatus feeding and habitat preferences appear to restrict distributions of many Caribbean reef sponge species to habitats without O. reticulatus and may have exerted significant selective pressure on defences of those sponges that live in O. reticulatus habitats. 相似文献
15.
The nature or structure of competition within communities has been a dynamic area of practical and theoretical research for a number of decades. Certain components of some communities have proved hard to incorporate within such studies; in marine benthic work this has included the sponges. In this study, intra- and inter-phyletic interactions involving sponges (7,817 in total) were studied on 125 rocks (ranging in surface area from 10 to 2,438 cm 2) at a site experiencing low disturbance levels at Lough Hyne Marine Nature Reserve, Co. Cork, Ireland. The outcomes of sponge-sponge (intra-phyletic) interactions were significantly different in both outcome and structure to those involving sponges and representatives of other phyla. Typically sponge-sponge competition resulted in a much higher number of tied outcomes than did inter-phyletic encounters. Sponges over-grew all groups of organisms with the exception of some cnidarians and ascidians. The morphology of any sponge species (thickness in most cases) was important in determining the outcome of intra-phyletic, but not inter-phyletic, interactions. Sponges which exhibited thick (>2 mm) crusts were, in the majority of interactions, superior competitors compared to the thin (<1 mm) crusts. However, the method used to rank species (i.e. wins:loss or wins:total ratio) made a significant difference to the ranking of sponge competitors. The transitivity of the sponge assemblage investigated was calculated using the index formulated by Tanaka and Nandakumar (1994) as 0.23, indicating the assemblage to be organised as a network rather than a hierarchical system. We suggest this network of principally tied outcomes (due to standoffs) may be maintained in part by chemical interaction. However, in the absence of disturbance, the network is more likely to be mediated through processes of growth and regression of tissues during summer and winter months respectively. 相似文献
16.
Redwood of the reef: growth and age of the giant barrel sponge Xestospongia muta in the Florida Keys 总被引:1,自引:0,他引:1
The growth of animals in most taxa has long been well described, but the phylum Porifera has remained a notable exception.
The giant barrel sponge Xestospongia muta dominates Caribbean coral reef communities, where it is an important spatial competitor, increases habitat complexity, and
filters seawater. It has been called the ‘redwood of the reef’ because of its size (often >1 m height and diameter) and presumed
long life, but very little is known about its demography. Since 1997, we have established and monitored 12 permanent 16 m
diameter circular transects on the reef slope off Key Largo, Florida, to study this important species. Over a 4.5-year interval,
we measured the volume of 104 tagged sponges using digital images to determine growth rates of X. muta. Five models were fit to the cubed root of initial and final volume estimates to determine which best described growth. Additional
measurements of 33 sponges were taken over 6-month intervals to examine the relationship between the spongocoel, or inner-osculum
space, and sponge size, and to examine short-term growth dynamics. Sponge volumes ranged from 24.05 to 80,281.67 cm3. Growth was variable, and specific growth rates decreased with increasing sponge size. The mean specific growth rate was
0.52 ± 0.65 year−1, but sponges grew as fast or slow as 404 or 2% year−1. Negative growth rates occurred over short temporal scales and growth varied seasonally, significantly faster during the
summer. No differences in specific growth rate were found between transects at three different depths (15, 20, 30 m) or at
two different reef sites. Spongocoel volume was positively allometric with increasing sponge size and scaling between the
vertical and horizontal dimensions of the sponge indicated that morphology changes from a frustum of a cone to cylindrical
as volume increases. Growth of X. muta was best described by the general von Bertalanffy and Tanaka growth curves. The largest sponge within our transects (1.23 × 0.98 m
height × diameter) was estimated to be 127 years old. Although age extrapolations for very large sponges are subject to more
error, the largest sponges on Caribbean reefs may be in excess of 2,300 years, placing X. muta among the longest-lived animals on earth. 相似文献
17.
Microbial diversity and spatial distribution of the diversity within tissue of the marine sponge Tethya californiana was analyzed based on 16S rRNA gene sequences. One candidate division and nine bacterial phyla were detected, including members of all five subdivisions of Proteobacteria. Moreover, chloroplast-derived Stramenopiles- and Rhodophyta-affiliated 16S rRNA gene sequences were found and Stramenopiles represented the most abundant clones (30%) in the clone library. On the phylum-level, the microbial fingerprint of T. californiana showed a similar pattern as its Mediterranean relative T. aurantium. An interesting difference was that Cyanobacteria that were abundantly present in T. aurantium were not found in T. californiana, but that the latter sponges harbored phototrophic Stramenopiles instead. Surprisingly, the phototrophic microorganisms were evenly distributed over the inner and outer parts of the sponge tissue, which implies that they also reside in regions without direct light exposure. The other phyla were also present in both the outer cortex and the mesohyl of the sponges. These results were confirmed by analysis on the operational taxonomic unit level. This leads to the conclusion that from a qualitative point of view, spatial distribution of microorganisms in T. californiana tissue is quite homogeneous. Thirty-two percent of the operational taxonomic units shared less than 95% similarity with any other known sequence. This indicates that marine sponges are a rich source of previously undetected microbial life. 相似文献
18.
The relationship between sponge size, habitat and shape was studied in the encrusting sponge Crambe crambe (Schmidt, 1862), which is distributed widely throughout the shallow Mediterranean littoral. Examination of sponge patches in shaded and well-illuminated habitats showed that the degree of peripheral irregularity of the edges of a patch is directly related to patch size. This relationship is valid only for sponges of >100 mm2 in area. Photophilic and sciaphilous sponges display different growth forms. The pattern of growth is interpreted in terms of competition for space. The directional growth of sciaphilous sponges may be due to the presence of dominant neighbours that are good space competitors, and the irregular growth of photophilic sponges to the absence of such neighbours. 相似文献
19.
To establish a complete understanding of reproductive variability, larval supply and ultimately population demographics of
a species it is important to determine reproduction across a broad spectrum of environmental conditions. This study quantified
sexual reproduction of the brooding, gonochoristic sponge Rhopaloeides odorabile from populations across the shelf reefs of the central Great Barrier Reef (GBR). Histological sections of reproductive sponges
collected at increasing distances from the coast were used to determine if numbers of reproductive sponges, reproductive output
(using a reproductive output index), size at sexual maturity, and sex ratios varied according to their location (distance)
from the coastline and therefore from influences of terrigenous/riverine discharge. Significantly higher proportions of reproductive
sponges occurred with increasing distance from the coast. The proportion of all reproductive sponges (both male and female)
on offshore reefs ranged from 77 to 90%, during November and December, the peak reproductive months of this sponge, compared
to 47 to 50% for sponges occurring on coastal reefs. Levels of female reproduction increased with increasing distance from
the coastline on two levels. First, oocytes from offshore sponges were significantly larger than oocytes from coastal sponges.
Second, sponges from offshore reefs showed a reproductive index (proportions of oocytes, embryos and larvae mm−2) approximately 15 times higher than coastal reef sponges. Therefore, both numbers of oocytes, embryos and larvae in conjunction
with larger oocytes contribute to a higher reproductive output index for offshore sponges. The production of spermatic cysts
in males was consistent across the GBR. Sex ratios for coastal reef sponges showed a male bias while offshore sponges showed
approximate equal sex ratios. The effect of terrigenous riverine input from coastal fluvial plains to the inner GBR is well
established and is likely to contribute to the lower levels of reproduction associated with female sponges inhabiting coastal
reefs of the central GBR. 相似文献
20.
Jeffrey Burton Marliave Kim W. Conway Donna M. Gibbs Andy Lamb Charles Gibbs 《Marine Biology》2009,156(11):2247-2254
In the Strait of Georgia and Howe Sound, British Columbia, colonies of individual cloud sponges, growing on rock (known as
sponge gardens) receive resource subsidies from the high biodiversity of epifauna on adjacent rock habitats. Bioherms are
reefs of glass sponges living on layers of dead sponges. In the same area as the sponge gardens, newly discovered bioherms
in Howe Sound, BC (49.34.67 N, 123.16.26 W) at depths of 28- to 35-m are constructed exclusively by Aphrocallistes vastus, the cloud sponge. The sponge gardens had much higher taxon richness than the bioherms. The sponge garden had 106 species from 10 phyla, whereas
the bioherm had only 15 species from 5 phyla. For recruiting juvenile rockfish (quillback, Sebastes maliger), the food subsidy of sponge gardens appears to be missing on bioherms of cloud sponge, where biodiversity is relatively
low. While adult and subadult rockfishes (S. maliger, S. ruberrimus, S. proriger, and S. elongatus) were present on bioherms, no evidence for nursery recruitment of inshore rockfishes to bioherms was observed, whereas the
sponge gardens supported high densities of newly recruited S. maliger, perhaps owing to the combination of both refuge and feeding opportunities. These results indicate that sponge gardens form
a habitat for early stages of inshore S. maliger, whereas A. vastus bioherms are associated only with older juvenile and adult rockfishes. 相似文献