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1.
In 2001 Carijoa riisei, an octocoral native to the tropical Western Atlantic, was discovered overgrowing black corals in the Au’au Channel in Hawaii.
In this paper data from a 2001 survey are reanalyzed and combined with new data from 2003 and 2004 to assess the ecological
impact in greater detail. C. riisei differentially affected reproductively mature black coral colonies with maximum impact between 80 and 105 m. The pattern
of C. riisei overgrowth on black corals and C. riisei on the substrata appears to be bounded by high irradiance in shallow water and cold temperature in deep water. Evidence suggests
that the C. riisei settlement on black corals is facilitated by other epifauna. Once established, C. riisei spreads vegetatively and smothers the coral. The success of the C. riisei invasion appears to be unaided by anthropogenic disturbance and is at least partially attributable to Hawaii’s depauperate
shallow-water (<100 m) octocoral fauna.
相似文献
Richard W. GriggEmail: |
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The impact of a disturbance is normally measured in terms of its effects on adult mortality, whilst the less obvious impact
on reproductive biology is generally ignored. Although previous studies have contributed to understanding the effects of a
mass mortality of gorgonians in 1999 at NW Mediterranean Sea, none of them have considered its impact on reproduction. The
goal of this study was to determine the impact of mass mortality events on the reproduction of the gorgonian Paramuricea clavata, and examine the effect of the damage 1 year (June 2000) and 2 years (June 2001) after the event. The reproductive parameters
of female colonies were more affected than those of males. In female colonies that were moderately or severely damaged, the
proportion of fertile polyps decreased by about 22–35%, whilst in the worst affected males there was only a 12% decrease.
Female colonies showed a progressive decrease in gonadal biomass with increasing damage to a maximum reduction of 73–75% of
oocyte production observed in colonies with >33% injury. In contrast, in males, the gonadal biomass decreased rapidly for
colonies with 5% of injured surface, with a reduction in spermary production of 49–64%. The same pattern of decrease in gonadal
output compared to the extent of the injury was observed in 2001, two years after the mass mortality event. This indicated
that the observed pattern was a response to the extent of the injury rather than a direct effect of the event. These severe
effects on the reproduction of the red gorgonian species have implications for the recovery of affected populations in the
long-term. This study demonstrated that an evaluation of the impact over different demographic parameters is needed to understand
all the consequences of these disturbances. 相似文献
4.
Moutassem Billah Masmoudi Lamya Chaoui Nur Eda Topçu Pachka Hammami Mohamed Hichem Kara Didier Aurelle 《Ecology and evolution》2016,6(24):8665-8678
Understanding the factors explaining the observed patterns of genetic diversity is an important question in evolutionary biology. We provide the first data on the genetic structure of a Mediterranean octocoral, the yellow gorgonian Eunicella cavolini, along with insights into the demographic history of this species. We sampled populations in four areas of the Mediterranean Sea: continental France, Algeria, Turkey, and the Balearic and Corsica islands. Along French coasts, three sites were sampled at two depths (20 and 40 m). We demonstrated a high genetic structure in this species (overall FST = 0.13), and most pairwise differentiation tests were significant. We did not detect any difference between depths at the same site. Clustering analyses revealed four differentiated groups corresponding to the main geographical areas. The levels of allelic richness and heterozygosity were significantly different between regions, with highest diversity in Algeria and lowest levels in Turkey. The highest levels of private allelic richness were observed in Algeria followed by Turkey. Such contrasted patterns of genetic diversity were not observed in other Mediterranean octocorals and could be the result of different evolutionary histories. We also provide new empirical evidence of contrasting results between tests and model‐based studies of demographic history. Our results have important consequences for the management of this species. 相似文献
5.
G. T. Concepcion M. W. Crepeau D. Wagner S. E. Kahng R. J. Toonen 《Coral reefs (Online)》2008,27(2):323-336
Here we report a highly variable nuclear marker that can be used for both soft and stony corals. Primers that amplify a ∼177 bp
fragment from the nuclear gene encoding the 54 kDa subunit of the signal recognition particle (SRP54) were developed for the
octocoral genus Carijoa. Cloning results from 141 individuals suggest that this hypervariable nuclear locus is a single-copy gene. Sequencing revealed
a potential cryptic species previously thought to be Carijoa riisei. Results from an Analysis of Molecular Variance (AMOVA) based on mitochondrial DNA (mtDNA) explained <10% of the variation
between Atlantic and Pacific samples of C. riisei (F
st = 0.47), whereas the same comparison with SRP54 explained >33% of the variation (F
st = 0.54). Using previously reported degenerate primers for SRP54, high levels of sequence variation were found at this locus
across both scleractinian and octocorals. For example, pairwise sequence divergence within octocorals was ∼8–13 times greater
with SRP54 than with mtDNA, and, up to 2.8% pairwise sequence divergence was found in SRP54 among individuals of Pocillopora whereas no variation at all was found in mtDNA markers. This case study with the octocoral C. riisei shows that variation in SRP54 appears sufficient to address questions of phylogeography as well as systematics of closely
related species. 相似文献
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Jimbo M Koike K Sakai R Muramoto K Kamiya H 《Biochemical and biophysical research communications》2005,330(1):157-162
In the present study, the entire amino acid sequence and cDNA structure encoding the d-galactose-binding lectin, SLL-2, isolated from the octocoral Sinularia lochmodes, were determined. SLL-2 regulates the morphology of symbiotic dinoflagellates Symbiodinium spp. through unknown mechanisms. Here, three cDNAs that encode SLL-2 were cloned and characterized. All the SLL-2 cDNAs encoded 142 amino acids with high similarity to each other. The mature subunit of SLL-2 was found to be composed of 94 amino acids and to contain one putative glycosylation site common to all three SLL-2. N-Glycopeptidase F treatment of SLL-2 resulted in a protein band shift from 16.5 to 9.5kDa in SDS-PAGE, confirming that SLL-2s are glycoproteins. Two-dimensional polyacrylamide gel electrophoresis analysis of the deglycosylated SLL-2 indicated a presence of three polypeptides as encoded in SLL-2 cDNAs. The deduced sequences of SLL-2 cDNAs had a similarity to the C-terminal region of discoidin I, the slime mold Dictyostelium discoideum lectin. 相似文献
8.
Jean-Baptiste Ledoux 《Critical reviews in biotechnology》2018,38(2):184-198
Marine natural products (NPs) represent an impressive source of novel bioactive molecules with major biotechnological applications. Nevertheless, the usual chemical and applied perspective leading most of bioprospecting projects come along with various limitations blurring our understanding of the extensive marine chemical diversity. Here, we propose several guidelines: (i) to optimize bioprospecting and (ii) to refine our knowledge on marine chemical ecology focusing on octocorals, one of the most promising sources of marine NPs. We identified a significant phylogenetic bias in the octocoral bioprospecting, which calls for the development of a concerted discovery strategy. Given the gap existing between the number of isolated NPs and the knowledge regarding their functions, we provide an ecologically centered workflow prioritizing biological function ahead of chemical identification. Furthermore, we illustrate how -omic technologies should rapidly increase our knowledge on solving different aspects of the ecology and evolution of marine NPs. 相似文献
9.
A new soft coral species of the genus Nidalia, from seamounts to the south of the Azores Archipelago is described. The main features of Nidalia aurantia n. sp. are as following: colony torch-like, a capitulum light orange in colour, not laterally flattened, dome-shaped and
not distinctly projecting beyond the stalk, an introvert with sparse sclerites transversally placed, and an anthocodial crown
with 13–17 sclerite rows. The new species is compared with its closest congeners. This is the first time that a species of
Nidalia has been located in the Mid-Atlantic Ocean. 相似文献
10.
Antisettlement and Narcotic Action of Analogues of Diterpene Marine Natural Product Antifoulants from Octocorals 总被引:2,自引:0,他引:2
Anthony S. Clare Daniel Rittschof Donald J. Gerhart Irving R. Hooper Joseph Bonaventura 《Marine biotechnology (New York, N.Y.)》1999,1(5):427-436
Prevoius studies have determined that the octocorals Renilla reniformis and Leptogorgia virgulata contain diterpenes that are potent inhibitors of barnacle settlement. These antifoulants—the renillafoulins and pukalide—are,
however, comparatively complex and thus are not amenable to commercial exploitation. The present study examined 19 analogues,
based on the functional groups of lactone and furan rings in the parent molecules, for antisettlement activity and toxicity.
The latter parameters are presented as EC50 values for inhibition of cypris settlement and naupliar swimming, respectively. Assays of a subset of the analogues indicated
that they were active in solution rather than when bound to a surface and that at relatively high concentrations they had
a narcotic action. The mechanism whereby some of the analogues were able to inhibit settlement at nontoxic concentrations
has yet to be explained but suggests that there is merit in the present approach to antifoulant development.
Received April 1, 1998; accepted February 4, 1999. 相似文献