Tsuchida, Kohei; Lützen, Jørgen; Nishida, Mutsumi
Parasitization by sacculinids (Cirripedia: Rhizocephala: Sacculinidae) induces severe modifications in morphology, behavior, and reproduction of their host crabs. To understand the mechanisms involved, it is important to have comprehensive information on their association. However, such information...
substratum and initiate metamorphosis. In the presumed sister group to Rhizocephala, the true barnacles or Thoracica, metamorphosis leads to a juvenile filter-feeding version of the adult organism. In Rhizocephala the female cyprid settles on the integument of a crustacean and undergoes metamorphosis into a...
Glenner, Henrik; Hebsgaard, Martin Bay
resolve the phylogenetic relationship of the order Rhizocephala and elucidate the evolution of the different life history strategies found within the Rhizocephala, we have performed the first comprehensive phylogenetic analysis of the group. Our results indicate that Rhizocephala is monophyletic with a...... filter-feeding barnacle-like ancestor. The host-infective stage, the kentrogon larva, inserted in the lifecycle of the rhizocephalan suborder, Kentrogonida, is shown to be ancestral and most likely a homologue of the juvenile stage of a conventional thoracican barnacle. The mode of host inoculation found...... in the suborder Akentrogonida, where the last pelagic larval stage directly injects the parasitic material into the heamolymph of the host is derived, and has evolved only once within the Rhizocephala. Lastly, our results show that the ancestral host for extant rhizocephalans appears to be the...
Sacculina nectocarcini, a new species of rhizocephalan, a new species of rhizocephalan(Cirripedia: Rhizocephala) parasitising the red rock crabNectocarcinus integrifrons (Decapoda: Brachyura: Portunidae)(Decapoda: Brachyura: Portunidae)
Gurney, Robert H.; Rybakov, Alexey V.; Høeg, Jens Thorvald;
The parasitic barnacles, Rhizocephala, are a little known group within Australia with only seven described species from a coastline stretching approximately 59763 km. This study describes a new species of Rhizocephala, Sacculina nectocarcini. The description is based on a unique combination of...
Glenner, Henrik; Lytzen, Jørgen Gjerom
Alle biologiske, ultrastrukturelle og molekylære data understøtter konlusionen at subordernerne Cirripedia, Rhizocephala og Thoracica er nært beslægtede. Williamsons spekulationer, nemlig at den såkaldte hybridogenesis kan forklare hvo ledes Rhizocepahlerne har udviklet sig, hviler på et selektiv...
Høeg, Jens Thorvald; Møller, Ole Sten; Rybakov, Alexey V.
Nauplii of the rhizocephalan families Peltogastridae and Lernaeodiscidae carry a torus-shaped collar around the body. It consists of an exceedingly thin cuticle connected to the general body cuticle along a continuous narrow ridge. In nauplii of some species, the collar is very large and its surf...
Lützen, Jørgen; Jespersen, Åse
Interna development within the intertidal tropical crab, Leptodius exaratus, requires up to 4.5 months; the roots become distributed from the CNS along the major nerves and, when the crab moults, results in emergence of numerous externae located symmetrically on the abdomen and bases of the thora...
Høeg, Jens T; Achituv, Yair; Chan, Benny K K; Chan, Karen; Jensen, Peter Gram; Pérez-Losada, Marcos
there are no specific apomorphies with either the Acrothoracica, the Rhizocephala or any particular subgroup within the Thoracica. This is in agreement with recent molecular evidence that Ibla (Ibliformes) is the sister taxon to all other Thoracica and the ibliforms therefore become the outgroup of...
Cypris Larvae in Polysaccus Mediterraneus and Mycetomorpha Vancouverensis: Their Importance in Analyzing the Phylogeny and Sexual Evolution of Parasitic Barnacles (Crustacea: Cirripedia: Rhizocephala)
Høeg, Jens Thorvald; Rybakov, AV
modes of metamorphosis, and this is reflected in specializations of their cyprids. The larval morphologies of P. mediterraneus and M. vancouverensis suggest that these two species have a sexual system and life cycle much closer to that seen in the Kentrogonida. Our results show that adult and larval...
On 30 November 1941 a sunfish Mola mola (L.) was found on the beach near Schoorl (Province of Noord-Holland). The fish was parasitized by a specimen of Pennella filosa (L.) (Crustacea, Copepoda) on which a specimen of Conchoderma virgatum (Crustacea: Cirripedia) had attached itself. This is the firs
Khandeparker, L.; Anil, A.C.; Raghukumar, S.
present in the adults is thought to be responsible for this behavior (Knight-Jones, 1953; Knight-Jones and Crisp, 3 1953; Crisp and Meadows, 1963). Clare et al. (1995) reported the involvement of cyclic AMP in the pheromonal modulation of barnacle... of the fourth antennular segment of Balanus amphitrite amphitrite (Crustacea: Cirripedia). J Mar. Biol. Ass. U. K. 74, 967-970. Clare, A.S., Thomas, R.F., Rittschof, D., 1995. Evidence for the involvement of cyclic AMP in the pheromonal modulation...
Desai, D.V.; Anil, A.C.
Comparison of nutritional status of field and laboratory reared Balanus amphitrite Darwin (Cirripedia: Thoracica) larvae and implication of starvation Dattesh V. Desai, A.C. Anil * Marine Corrosion and Materials Research Division, National Institute... (Thorson, 1950; Crisp, 1976; Olson and Olson, 1989; Anil et al., 1995). Starvation will lead to nutritional stress, which can kill the larvae directly or may increase or decrease the duration of larval developmental stages (Knowlton, 1974; Sandifer...
Magni, Paola A; Venn, Cynthia; Aquila, Isabella; Pepe, Francesca; Ricci, Pietrantonio; Di Nunzio, Ciro; Ausania, Francesco; Dadour, Ian R
Human activities involving water may result in a crime scene. Typically, death may be due to natural causes, homicide, or mass disasters. Decomposition in water is a complex process where many factors may interplay. Human remains in water are subject to many potential interactions, depending upon the remains themselves, the type of water and the characteristics of the water. A number of studies are focused on the decomposition process of the corpse in water, on the identification of the post mortem submersion interval (PMSI) and on the diagnosis of drowning, but very few studies consider the fate of floating remains in any aquatic environment. The following case describes a corpse found on a shore of the Tyrrhenian Sea (South West of Italy, Calabria Region). The corpse and the soles of his shoes were colonized by the barnacle Lepas anatifera L. (Crustacea: Cirripedia: Pedunculata). The analyses of the barnacles present on the corpse aided in the evaluation of the floating time of the corpse which assisted in estimating the minimum time since death. PMID:25538026
Linse, Katrin; Jackson, Jennifer A.; Fitzcharles, Elaine; Sands, Chester J.; Buckeridge, John S.
The phylogenetic relationships of seven Antarctic barnacle species, one verrucomorph and six scalpelliforms from the Scotia, Weddell and Ross seas were investigated using DNA sequences from two nuclear genes (18 S and 28 S) and one mitochondrial gene (COI), with a combined total length of 3,151 base pairs. Analyses of these new sequences, together with those of previously published ibliform, lepadiform, scalpelliform, balanomorph and verrucomorph species, confirm that the Scalpelliformes are not monophyletic. Bayesian and maximum likelihood analyses consistently recovered a monophyletic group which comprised Ornatoscalpellum stroemii (Sars) and the Southern Ocean scalpellomorphs; Arcoscalpellum sp. from the Weddell Sea, Arcoscalpellum africanum from Elephant Island, A. bouveti from Bouvet Island, the circum-Antarctic Litoscalpellum discoveryi, Litoscalpellum sp. from Shag Rocks and Scalpellum sp. from the Falkland Trough. We also used multiple fossil constraints in a relaxed clock Bayesian framework to estimate divergence times for the 18 S+28 S phylogeny. Our results indicate a mid Cretaceous divergence for the Weddell Sea Arcoscalpellum sp, followed by a late Cretaceous divergence from the North Atlantic O. stroemii. Subsequent to this, the Antarctic scalpellomorphs began to radiate at the Cretaceous-Tertiary boundary. Monophyly within the scalpellid genera Arcoscalpellum, Litoscalpellum and Scalpellum was strongly rejected by all loci. Our results show incongruence between taxonomy and molecular systematics and highlight the need for more species to be sequenced as well as taxonomic revisions to resolve uncertainties in the phylogenetic relationships of the stalked barnacles.
Ross, Arnold; Newman, William A.
The coral-eating barnacle Hoekia monticulariae (Gray, 1831), the only internal parasite among the Thoracica described to this day, is characterized by an irregularly-shaped shell nestled cryptically between the polyps of the hermatypic coral Hydnophora Fischer, 1807, which occurs throughout most of
The year round breeding capability of Balanus amphitrite indicates a potential for continuous recruitment. The recruitment pattern however indicated a lull during monsoon. The study site experiences increased land run off lowering the salinity...
On a New Species of Parasitic Barnacle (Crustacea: Rhizocephala), Sacculina shiinoi sp. nov., Parasitizing Japanese Mud Shrimps Upogebia spp. (Decapoda: Thalassinidea: Upogebiidae), Including a Description of a Novel Morphological Structure in the Rhizocephala.
Lützen, Jørgen; Itani, Gyo; Jespersen, Åse; Hong, Jae-Sang; Rees, David; Glenner, Henrik
The rhizocephalan Sacculina shiinoi sp. nov. parasitizes three species of Upogebia in Japan. It is described morphologically and compared with another Upogebia parasite, Sacculina upogebiae Shiino, 1943 from Japan and Korea. These two species are the only sacculinids that parasitize mud shrimps. DNA analyses clearly show the two species to be separate and not closely related. The cuticle differs in being provided with close-set, branched, and spiny excrescences in S. shiinoi, while it lacks excrescences, but forms small scales in S. upogebiae. In S. upogebiae, the bulbous sperm-producing part and the narrow receptacle duct are separated by a compartmentalized mid portion, which is missing in S. shiinoi. A ridge, having a thickened, fluffy cuticle with a U-shaped course, passes across the visceral mass between the two receptacle openings in S. shiinoi. Such a structure has never been described in other rhizocephalans, and its function is uncertain. PMID:27032686
Pérez-Losada, Marcos; Høeg, Jens Thorvald; Crandall, K. A.
calibration point, Cirripedia, divergence times, DNA sequences, fossils, genetic algorithms, mixed models, phylogeny......calibration point, Cirripedia, divergence times, DNA sequences, fossils, genetic algorithms, mixed models, phylogeny...
Desai, D.V.; Anil, A.C.; Venkat, K.
Biol Ecol 19:227-232 Barnes H, Crisp DJ (1956) Evidence of self-fertilization in certain species of barnacles. J Mar Biol Ass U K 35:631-639 Charnov EL (1987) Sexuality and hermaphroditism in barnacles: a natural selection approach. In: Southward...
Hayashi, Ryota; Chan, Benny K K; Simon-Blecher, Noa; Watanabe, Hiromi; Guy-Haim, Tamar; Yonezawa, Takahiro; Levy, Yaniv; Shuto, Takuho; Achituv, Yair
Barnacles of the superfamily Coronuloidea are obligate epibionts of various marine mammals, marine reptiles and large crustaceans. We used five molecular markers: 12S rDNA, 16S rDNA, 18S rDNA, 28S rDNA and Histone 3 to infer phylogenetic relationships among sixteen coronuloids, representing most of the recent genera of barnacles of this superfamily. Our analyses confirm the monophyly of Coronuloidea and that this superfamily and Tetraclitoidea are sister groups. The six-plated Austrobalanus clusters with these two superfamilies. Based on BEAST and ML trees, Austrobalanus is basal and sister to the Coronuloidea, but the NJ tree places Austrobalanus within the Tetraclitoidae, and in the MP tree it is sister to both Coronuloidea and Tetraclitoidae. Hence the position of Austrobalanus remains unresolved. Within the Coronuloidea we identified four clades. Chelonibia occupies a basal position within the Coronuloidea which is in agreement with previous studies. The grouping of the other clades does not conform to previous studies. Divergence time analyses show that some of the time estimates are congruent with the fossil record while some others are older, suggesting the possibility of gaps in the fossil record. PMID:23306306
Full Text Available Descripción morfológica de las estructuras reproductivas de Austromegabalanus psittacus en dos periodos de maduración sexual. Se determinó que es un organismo hermafrodita que transfiere sus espermatozoides mediante un órgano intromitente o pene. El aparato reproductor masculino consta de testículos organizados en acinos que se distribuyen arboriformemente, dos conductos deferentes que se unen en la base del pene para formar el conducto eyaculador. El aparato reproductor femenino consiste principalmente en un ovario sacular que rodea al resto del cuerpo y se encuentra adherido a través de musculatura a la base de las placas operculares. Se organiza internamente en sacos acinares elongados que contienen ovogonias y ovocitos previtelogénicos adheridos a su pared y vitelogénicos y maduros libres dentro del lumen. Se observaron diferencias notorias en los ovarios entre los organismos recolectados en septiembre y octubre. En septiembre presentaron coloración amarillenta y en su interior se encontraron dos estructuras compactas denominadas lamelas ovígeras en cuyo interior se observaron ovocitos fecundados, embriones en diferentes estados de desarrollo y nauplius libres en la cavidad corporal; en octubre los ovarios son gruesos, blanquecinos y con gran cantidad de fluido lechoso en su interior.
-filtered (0.22 ?m), UV- irradiated seawater. 2.2.4 Visualization of footprints The sugar-treated, as well as non-treated cyprids, were siphoned out and introduced individually into six-well plates (Corning- 430343) coated with 50 ?g ml-1 AE and to non... introduced into wells of 24-well plates coated with AE and to non-coated multiwells (Corning-430262) along with 2 ml of autoclaved, filtered seawater at 35? (Maki et al. 1990). The above treatments were repeated employing a single cyprid (single cyprid...
Khandeparker, L.; KrishnaKumar, S.
The role of biofilm proteins in modulating cyprid metamorphosis is not well understood. In the present investigation this possibility was explored by disrupting biofilm proteins using commercially available protease. The influence of natural biofilm...
Desai, D.V.; Anil, A.C.
of starvation factor in recruitment ecology8. Among barnacles, Balanus amphitrite has gained prominence in studies relevant to larval metamorphosis, influence of different chemical cues and mechanism of their perception. Selection of this species... for his support and encouragement, Dr. A. B. Wagh for his interest in initiating this investigation. We are thankful to Dr. N. B. Bhosle, Head, MCMRD as well as other colleagues. We acknowledge the assistance extended by Mr. S Naik, Mr. N Prabhu and Mr. P...
Desai, D.V.; Prakash, S.
-mediated toxicity (Halliwell 1978, Halliwell & Gutteridge 1986, Pryor & Godber 1991, Winston & Di Giulio 1991, Ahmad 1995). B. amphitrite is regularly exposed in the intertidal area of the study region to tidal fluctuations from 0.25 to 2.5m. Being an intertidal... #................... 17 REFERENCES Ahmad S (1995) Antioxidant mechanism of enzymes and proteins. In: S. Ahmad (ed) Oxidative stress and Antioxidant defenses in Biology, Chapman and Hall, New York, p 238-272 Anger K, Dawirs RR (1981) Influence of starvation...
Cristiane Maria Rocha Farrapeira
Full Text Available This study aimed to describe the epibiosis of barnacles Amphibalanus improvisus on eight adult Macrobrachium acanthurus males from the Mundaú Lagoon, state of Alagoas, Brazil. The number of epibiont barnacles varied from 247 to 1,544 specimens per prawn; these were distributed predominantly on the cephalothorax and pereiopods, but also on the abdomen and other appendices. Although some were already reproducing, most barnacles had been recruited recently or were still sexually immature; this suggests recent host arrival in that estuarine environment. Despite the fact that other barnacles occur in this region, A. improvisus is the only species reported as an epibiont on Macrobrachium acanthurus; this was also the first record of epibiosis on this host. The occurrence of innumerable specimens in the pereiopods' articulations and the almost complete covering of the carapace of some prawns (which also increased their weight suggest that A. improvisus is adapted to fixate this kind of biogenic substrate and that the relationship between the two species biologically damages the basibiont.O objetivo deste trabalho foi relatar a epibiose de cirrípedes Amphibalanus improvisus em oito camarões machos adultos da espécie Macrobrachium acanthurus provenientes da Laguna Mundaú, Alagoas, Brasil. O número de cirrípedes epibiontes variou desde 247 até 1.544 espécimes por camarão, distribuídos predominantemente no cefalotórax e pereiópodos, mas presentes também no abdome e demais apêndices. A grande maioria dos cirrípedes era recém-recrutada ou ainda estava sexualmente imatura, embora de alguns estivessem já em reprodução, sugerindo a chegada recente de seu hospedeiro no ambiente estuarino. Apesar de ocorrem outros cirrípedes na região, A. improvisus foi à única espécie relatada como epibionte em Macrobrachium acanthurus e isto se constituiu o primeiro registro de epibiose de Amphibalanus improvisus A ocorrência de inúmeros espécimes nas articulações dos pereiópodos e o recobrimento quase total da carapaça de alguns camarões (incrementando peso aos mesmos indicam que a espécie epibionte está adaptada à fixação neste substrato biogênico e que a relação entre estas duas espécies traz prejuízos biológicos ao basibionte.
Benny K K Chan
Full Text Available The biogeography and ecology of the species of Chthamalus present on the west coast of America are described, using data from 51 localities from Alaska to Panama, together with their zonation on the shore with respect to that of other barnacles. The species present were C. dalli, Pilsbry 1916, C. fissus, Darwin, 1854, C. anisopoma Pilsbry 1916 and four species in the C. panamensis complex. The latter are C. panamensis Pilsbry, 1916, C. hedgecocki, Pitombo & Burton, 2007, C. alani nom. nov. (formerly C. southwardorum Pitombo & Burton, 2007 and C. newmani sp. nov.. These four species were initially separated by enzyme electrophoresis. They could only be partially separated by DNA bar coding but may be separated using morphological characters.
Pérez-Losada, Marcos; Høeg, Jens Thorvald; Crandall, Keith A.;
Chthamaloidea has been debated since Darwin's seminal monographs. Theories of morphological and ontogenetic evolution suggest that the group could have evolved multiple times from pedunculated relatives and that shell plate number diminished gradually (8¿6¿4) from an ancestral state with eight wall plates...
Lagersson, Niklas; Garm, Anders Lydik; Høeg, Jens Thorvald
This study presents electron microscopy (SEM, TEM) observations on the putative settlement receptors of the fourth antennulary segments. The TEM data from all nine setae are from the outer dendritic segment. Eight of them have morphological characteristics, indicating bimodal sensory properties...
Anil, A.C.; Desai, D.V.; Khandeparker, L.
incorporated during the earlier planktotrophic naupliar development. Nucleic acids play a major role in growth and development. It has been shown that Ž. the RNArDNA ratio is an indicator of nutritional condition Clemmesen, 1996 , and has been routinely used... for estimating growth rates or nutritional condition of larval fish in the field. Only a few studies have applied this technique to crustaceans and their larvae Ž Dagg and Littlepage, 1972; Sulkin et al., 1975; Anger and Hirche, 1990; Wagner et al., . 1998...
Desai, D.V.; Anil, A.C.
that with development the utility of food types changes. The differences in the carbon gain can be attributed to differences in grazing rate due to variations in the size of the diatom cells, larval intersetular distance, diatom sinking rate and the photo-taxic behavior...
Blomsterberg, Mikkel; Høeg, Jens T; Jeffries, William B;
attachment site within the branchial chamber of swimming crabs and, in particular, no similarities with cyprids of rhizocephalan barnacles, many of which also attach in the gill chamber. The synapomorphies between cyprids of the lepadid species may be adaptations to their life in the neuston....
Anil, A.C.; Khandeparker, R.
The influence of bacterial exopolymers and conspecific adult extract of Balanus amphitrite on metamorphosis of cyprid larvae at different salinities has been evaluated through laboratory assay. The bacterial exopolymers (epm) extracted from...
Baragi, L.V.; Anil, A.C.
of the suitable food type (Barnes and Barnes, 1958). The growth rate of an organism is also influenced by the food quality and quantity (Moyse, 1963). Several studies have reported that the rising pCO2/reduced pH change the nutritional quality (Burkhardt et al... on the nutritional quality of the diatom (Chaetoceros calcitrans) which is used as feed for the rearing of barnacle larvae. In this experiment the growth of this diatom was measured in terms of cell numbers; and the nutritional quality was measured in terms...
Southern hemisphere deep-water stylasterid corals including a new species, Errina labrosa sp. n. (Cnidaria, Hydrozoa, Stylasteridae, with notes on some symbiotic scalpellids (Cirripedia, Thoracica, Scalpellidae
Full Text Available A number of stylasterid corals are known to act as host species and create refuges for a variety of mobile and sessile organisms, which enhances their habitat complexity. These include annelids, anthozoans, cirripeds, copepods, cyanobacteria, echinoderms, gastropods, hydroids and sponges. Here we report the first evidence of a diverse association between stylasterids and scalpellid pedunculate barnacles and describe a new stylasterid species, Errina labrosa, from the Tristan da Cunha Archipelago. Overall, five stylasterid species are found to host eight scalpellid barnacles from several biogeographic regions in the southern hemisphere (Southern Ocean, temperate South America and the southern Indo-Pacific realms. There is an apparent lack of specificity in this kind of association and different grades of reaction to the symbiosis have been observed in the coral. These records suggest that the association between pedunculate barnacles and hard stylasterid corals has a wide distribution among different biogeographic realms and that it is relatively rare and confined largely to deep water.
Full Text Available We have implemented a simple program to solve three of the problems related to 3D reconstruction (3D-Rec of soft tissues: alignment of sections, distortions, and estimation of the spatial position of elements of interest inside the tissues. As a model, we chose the distribution of FMRFamide-like immunopositive neurons in the ventral ganglion of the barnacle Balanus amphitrite collected during different seasonal periods. Images of immunostained sections were acquired by means of a CCDcamera- equipped microscope and a PC and the reference points were taken inside the sections. The FMRFamide-like immunopositive neurons detected in the barnacle ventral ganglion were grouped into four different classes according to size, shape and staining intensity. More numerous FMRFamide- like immunopositive neurons were detected in the autumn-collected barnacle than in the summer counterpart. The two 3D reconstructions obtained from transverse and longitudinal ventral ganglion sections were efficaciously compared after 90° rotation of one of them. Comparison of these two 3D-Rec suggests the presence of at least two groups of FMRFamide-like immunopositive neurons that are seasonally-related and probably involved in reproduction.
Pérez-Losada, Marcos; Høeg, Jens Thorvald; Crandall, Keith A
metamorphosis found in the Facetotecta and Rhizocephala suggests a common evolutionary origin, but until now no comprehensive study has looked at the basic evolution of these thecostracan groups. Results To this end, we collected DNA sequences from three nuclear genes [18S rRNA (2,305), 28S rRNA (2......)))). Conclusion Our analyses indicate a convergent evolution of the very similar and highly reduced slug-shaped stages found during metamorphosis of both the Rhizocephala and the Facetotecta. This provides a remarkable case of convergent evolution and implies that the advanced endoparasitic mode of life known...
Høeg, Jens Thorvald; Maruzzo, Diego; Okano, Keiju;
Cypris metamorphosis was followed using video microscopy in four species of cirripeds representing the suspension-feeding pedunculated and sessile Thoracica and the parasitic Rhizocephala. Cirripede metamorphosis involves one or more highly complex molts that mark the change from a free cypris...
Glenner, Henrik; Høeg, Jens Thorvald; Stenderup, Jesper;
We use sequences from the nuclear ribosomal genes, 18S and 28S to analyze the phylogeny of the Rhizocephala Akentrogonida including two species, Clistosaccus paguri and Chthamalophilus delagei, that are critical for understanding rhizocephalan evolution but have not previously been part of a mole...
JUAN CARLOS CASTILLA
This bibliographic review revisits circumstances in which the wharf, shell burrowing barnacle, Cryptophialus minutus, was first collected by Charles Darwin in southern Chile, in 1836. Further, explores how its collection marked Darwin's taxonomical interest in Cirripedia. A short review analyzes the initial number of extant species of Cirripedia, as described by Darwin and the present situation, with emphasis on recent collections of C. minutus in the southern tip of South America.Esta revisi...
Larval development of the pedunculate barnacles Octolasmis angulata Aurivillius 1894 and Octolasmis cor Aurivillius 1892 (Cirripedia: Thoracica: Poecilasmatidae) from the gills of the mud crab, Scylla tranquebarica Fabricius, 1798.
Yap, F C; Wong, W L; Maule, A G; Brennan, G P; Lim, L H S
Detailed studies of larval development of Octolasmis angulata and Octolasmis cor are pivotal in understanding the larval morphological evolution as well as enhancing the functional ecology. Six planktotrophic naupliar stages and one non-feeding cyprid stage are documented in details for the first time for the two species of Octolasmis. Morphologically, the larvae of O. angulata and O. cor are similar in body size, setation patterns on the naupliar appendages, labrum, dorsal setae-pores, frontal horns, cyprid carapace, fronto-lateral gland pores, and lattice organs. Numbers of peculiarities were observed on the gnathobases of the antennae and mandible throughout the naupliar life-cycle. The setation pattern on the naupliar appendages are classified based on the segmentation on the naupliar appendages. The nauplius VI of both species undergoes a conspicuous change before metamorphosis into cyprid stage. The cyprid structures begin to form and modify beneath the naupliar body towards the end of stage VI. This study emphasises the importance of the pedunculate barnacle larval developmental studies not only to comprehend the larval morphological evolution but also to fill in the gaps in understanding the modification of the naupliar structures to adapt into the cyprid life-style. PMID:25770075
Høeg, Jens Thorvald; Perez-Losada, M; Glenner, H; Kolbasov, GA; Crandall, KA
the advanced metamorphosis and endoparasitism known from the Rhizocephala and strongly indicated for the Facetotecta are the result of convergent evolution. We also discuss reproductive systems, which range from separate sexes, over hermaphrodites combined with a separate male sex (androdioecy), to...... pure hermaphroditism. It is concluded, as envisaged by Darwin, that the Thecostraca provide excellent opportunities for studying the evolution of a wide range of complex life history traits which can now be better analyzed and understood in a robust phylogenetic framework....
Høeg, Jens Thorvald; Møller, Ole Sten
the larvae hatch as cyprids. The cypris larvae are very similar among the ingroups of the Cirripedia, but interesting variations occur in structures used for substrate location and attachment. The cyprid is specialized to both swim through the water and actively explore the substratum by walking on...... the antennules and using an array of sensory organs in search for a suitable site to attach. This unique morphology and behavior of the cyprid have enabled the Cirripedia to colonize widely different habitats ranging from hard rock to soft animal tissue. Yet, the cyprid can metamorphose into juveniles...
Pérez-Losada, Marcos; Høeg, Jens Thorvald; Crandall, Keith A.
The thecostracans include the Facetotecta, Ascothoracida, and Cirripedia and show great diversity in both morphology and biology. This makes them ideal models for studying evolutionary adaptations of the larval and adult body-plan, lifestyle, and reproduction. Surprisingly, despite all the work p...
JUAN CARLOS CASTILLA
Full Text Available This bibliographic review revisits circumstances in which the wharf, shell burrowing barnacle, Cryptophialus minutus, was first collected by Charles Darwin in southern Chile, in 1836. Further, explores how its collection marked Darwin's taxonomical interest in Cirripedia. A short review analyzes the initial number of extant species of Cirripedia, as described by Darwin and the present situation, with emphasis on recent collections of C. minutus in the southern tip of South America.Esta revisión bibliográfica describe las circunstancias en el que el cirrípedo enano, Crypophialus minutus, perforador de conchas, fue recolectado por Charles Darwin en el sur de Chile, en 1836. Además, cómo esta recolección marcó el interés taxonómico de Darwin en Cirripedia. Se presenta una revisión resumida sobre el número inicial de especies vivas de Cirripedia, como fueron descritas por Darwin, y la situación actual, con énfasis en recolecciones recientes de C. minutus en el cono sur de Suramérica.
Anil, A.C.; Kurian, J.
Influence of food concentration (0.5, 1 and 2 x 10 sup(5) cell ml sup(-1) of Skeletonema costatum), temperature (20 and 30 degrees C) and salinity (15, 25 and 35 ppt) on the larval development of Balanus amphitrite (Cirripedia: Thoracica...
Reproduction and larval development in three scalpellid barnacles, Scalpellum scalpellum (Linnaeus 1767), Ornatoscalpellum stroemii (M. Sars 1859) and Arcoscalpellum michelottianum (Seguenza 1876), Crustacea: Cirripedia: Thoracica): implications for reproduction and dispersal in the deep sea
Buhl-Mortensen, Lene; Høeg, Jens Thorvald
the female/hermaphrodite, type of larval development and the number and size of eggs were recorded. All three species have a pair of pocket-like receptacles, each of which can host only a single male in O. stroemii, up to five males in S. scalpellum and up to 12 males in A. michelottianum. Eggs and...
Comparação da tolerância fisiológica (temperatura e salinidade) entre as cracas (crustacea, Cirripedia) Fistulobalanus Citerosum Henry, 1974 (espécie nativa) e Amphibalanus reticulatus Utinomi, 1967 (espécie invasora)
Veiga, Marcos Paulo Trindade da
Resumo: A introdução de espécies é um dos fatores que mais causa prejuízo a ecossistemas, ocasionando a perda de biodiversidade em ambientes terrestres e aquáticos, tanto marinhos quanto dulcícolas. Regiões portuárias são muito suscetíveis a este processo, e a Baía de Paranaguá é o exemplo mais próximo. Muitos organismos são frequentemente transportados entre áreas portuárias, incrustados nas embarcações ou suspensos em águas de lastro, e podem se estabelecer em locais nos quais não chegariam...
Kristensen, Tommy; Nielsen, Anders Isberg; Stig-Jørgensen, Anders Isak;
Male crabs infected by parasitic barnacles (Rhizocephala) are known to be morphologically feminized. Here, we investigate morphological chances in green crabs, Carcinus maenas, induced by the parasitic barnacle Sacculina carcini. Infected males acquire a broader, longer and segmented abdomen......, fringed with marginal setae. Copulatory appendages and pereopods are reduced in length, and the chelae become smaller. The feminization show great individual variation. Males with scars from lost externae, the parasites reproductive organ situated under the abdomen, are less modified than males carrying...... an externa, and the feminization is more pronounced in smaller than in larger males. No super-feminization is evident in female crabs that remain morphologically unaffected by infection. The protective value of a parasitically induced enlargement of the male abdomen may constitute an adaptation that...
External morphology of the two cypridiform ascothoracid-larva instars of Dendrogaster: The evolutionary significance of the two-step metamorphosis and comparison of lattice organs between larvae and adult males (Crustacea, Thecostraca, Ascothoracida)
Kolbasov, G.A.; Grygier, M.J.; Høeg, Jens Thorvald;
stage between the naupliar stages and the dispersive and fully functional second ascothoracid-larva that accomplishes settlement. The presence of two instars of ascothoracid-larvae (a-cyprids) in members of the order Dendrogastrida differs from the single cypridiform instar found in the Cirripedia...... (cyprid) and Facetotecta (y-cyprid), and we discuss the evolutionary significance of these ontogenies. We found lattice organs in both the second ascothoracid-larvae and in adult males of Dendrogaster. We could not observe both ascothoracid-larvae and males in any single species, but our data suggests...
Ortiz, M.; Alvarez-Alemán, A.; Angulo-Valdés, J.
Se presentan dos especies de crustáceos asociados a la piel del manatí Trichechus manatus, en una localidad de la costa noroccidental cubana. Un cirripedio del género Chelonibia (Cirripedia, Sessillia) y un tanaidáceo del género Sinelobus (Crustacea, Peracarida) son registrados por primera vez para las aguas cubanas. También la aparición de un tanaidáceo asociado a la piel de un manatí constituye el primer registro, en Cuba. De ambas especies se presentan, además, algunos d...
Full Text Available The diet composition of the American freshwater goby, Ctenogobius shufeldti, was investigated in an estuarine area and two of its tributaries. 397 individuals, total length from 21 to 70mm, were sampled over a period of 12 months and their stomach contents were analysed by the Frequency of Occurrence and Number of Points methods. According to the Alimentary Index, diet was constituted mainly by Ostracoda (IA=50.51 and Tanaidacea (IA=40.85, and secondarily by Gastropoda (IA=1.21, Amphipoda (IA=0.10, Isopoda (IA=0.01, Cirripedia (IA=0.01, Decapoda larvae (IA=0.01, Insecta (IA=0.01, Chlorophyta (IA=2.15 and Rodophyta (IA=0.15 filamentous algae, and plants (IA=4.99. Diversity of diet was higher in rivers than in the Bay. Except for Decapoda larvae, items found in the two rivers were the same. In the Bay, Amphipoda and Cirripedia were not found. Previous to this research, the filamentous algae Chlorophyta and Rodophyta had not been noted in the diet of this species in estuaries close to Guaratuba. In view of this, and regarding the possible roles played by cryptobenthic fish species in aquatic communities (Depczynski and Bellwood, 2003, it is concluded that C. shufeldti takes part in trophic dynamics feeding on benthic organisms as well as on algae, a behaviour that can result from both marine and continental influences existing in the region.
Full Text Available The present paper deals with data on zooplankton collected from the estuary of Potengi, Natal, Rio Grande do Norte, Brazil covering a period of one year from October 1992 to October 1993. Three fixed stations within the estuary located at varying distances from the mouth of the river were sampled. Sampling was done monthly when the tide was lowest. Analysis of the samples has shown clear pattern of seasonal variations in abundance of the dominant zooplankton components which are composed of Copepoda, Appendicularia, larvae of Brachyura, larvae of Cirripedia and Chaetognalha. A detailed study of the larvae of Brachyura was also attempted which showed that seven species can be identified in the samples, of which those of Aratus pisonii (H. Milne Edwards and Cardisoma guanhumi Latreille have already been described. Other five species are designated here numerically and description of various stages present in the samples are given.
Mazé, Raquel A.; Domínguez, Josefa; Pérez-Cardenal, David
Between February and December 1988, a total of 261 specimens of Lipophrys pholis were caught in eleven intertidal pools on the western coast of Asturias. This blenniid species mainly feeds on different groups of invertebrates, although algal remains also appear. Mollusca is the most highly represented taxon with the largest number of prey being Gastropoda, followed by Bivalvia and, to a lesser degree, Polyplacophora. Crustacea is well represented by Cirripedia. Isopoda also stands out and Amphipoda, Tanaidacea and Decapoda appear sporadically. Temporal diet analysis throughout the year shows no great differences. Likewise, a great similarity was observed among the feeding of L. pholis specimens collected in pools at a different tidal level, of variable size and with different algal cover. Changes in diet are appreciable as size increases, especially from a length of 6 cm on.
Full Text Available The European Common Barnacle Balanus perforatus Brugiére (Crustacea, Cirripedia has been introduced into the east coast of Korea, presumably via the ballast water of ships. The species has since been spreading along both the northern and southern coast to the east, most likely due to alongshore currents. We predicted the potential range expansion of Balanus perforatus in Korean waters using Genetic Algorithm for Rule-set Prediction (GARP, an environmental niche modeling technique. The results show that much of the southern coastal waters of Korea could be colonized by the spread of the nonindigenous species, but that the west coast is unlikely to be invaded. More sampling on the west coast would enhance the predictability of the model. To our knowledge, this is the first report of its kind for predicting marine nonindigenous species in Korean waters using GARP modeling.
Bruno Pereira Masi
Full Text Available Abstract The present study describes the successional trajectory of the fouling community in the upwelling region of Cabo Frio in southeastern Rio de Janeiro, Brazil. For 12 months, five PVC panels were sampled monthly by underwater photography to record the percent cover of fouling organisms, which allowed for the evaluation of the successional process through functional groups. The variability in the composition of the fouling community increased throughout the successional trajectory, creating a mosaic pattern. The identification of two associations after a year of observation, with one characterized by filamentous algae, Hydrozoa and Cirripedia and another mainly by articulated calcareous algae, shows that divergent trajectories can be observed even under the same environmental conditions. As an important seasonal factor of the local oceanographic characteristics, the upwelling events allowed for an environmental heterogeneity, and rejecting the classic orderly and directional succession model.
Luciano Felício Fernandes
Full Text Available The epizoic diatoms Pseudohimantidium pacificum and Falcula hyalina, which live on copepods, were investigated using light and electron microscopes, based on material gathered from different marine environments along the Brazilian coast. Pseudohimantidium pacificum is reported for the first time for the Southwestern Atlantic Ocean, significantly enlarging its range of geographic distribution. This species usually covers the entire body surface of the copepods Corycaeus amazonicus and Euterpina acutifrons, and of cypris larvae of Cirripedia. Falcula hyalina uses a higher number of copepod hosts, particularly Oithona oswaldocruzii, Pseudodiaptomus richardii and Acartia spp. The valve morphology and biometrical data of both diatoms were within the range limits recorded in the literature, including the original publications. Both species occurred in all the sampling stations along the Brazilian coastline stretching from 12°S down to 28°S. Falcula hyalina had already been found as far as latitude 31°S in the Southwestern Atlantic Ocean.As diatomáceas epizóicas em copépodos Pseudohimantidium pacificum e Falcula hyalina foram investigadas em microscopias óptica e eletrônica de varredura, com base em amostras coletadas em diferentes ambientes marinhos da costa brasileira. Pseudohimantidium pacificum é reportada pela primeira vez no Oceano Atlântico Sul Ocidental, ampliando significativamente sua faixa de distribuição geográfica. A espécie ocorreu sobre os copépodos Corycaeus amazonicus e Euterpina acutifrons, e em larvas cypris de Cirripedia. Falcula hyalina utilizou um número maior de hospedeiros, particularmente os copépodos Oithona oswaldocruzii, Pseudodiaptomus richardii e Acartia spp. A morfologia e dados biométricos das valvas de ambas as diatomáceas estiveram dentro dos limites registrados na literatura, incluindo as publicações originais. As duas espécies ocorreram em todas as estações de coleta ao longo da regi
Rees, David John; Noever, Christoph; Høeg, Jens Thorvald; Ommundsen, Anders; Glenner, Henrik
In his monograph on Cirripedia from 1851, Darwin pointed to a highly unusual, plateless, and most likely parasitic barnacle of uncertain phylogenetic affinity. Darwin's barnacle was Anelasma squalicola, found on deep-water sharks of the family Etmopteridae, or lantern sharks. The barnacle is uncommon and is therefore rarely studied. Recent observations by us have shown that they occur at an unusually high prevalence on the velvet belly lantern shark, Etmopterus spinax, in restricted fjord areas of western Norway. A phylogenetic analysis based on ribosomal DNA data (16S, 18S, and 28S) from 99 selected barnacle species, including all available pedunculate barnacle sequences from GenBank, shows that A. squalicola is most closely related (sister taxon) to the pedunculate barnacle Capitulum mitella. Both C. mitella and species of Pollicipes, situated one node higher in the tree, are conventional suspension feeders from the rocky intertidal. Our phylogenetic analysis now makes it possible to establish morphological homologies between A. squalicola and its sister taxon and provides the evolutionary framework to explain the unprecedented transition from a filter-feeding barnacle to a parasitic mode of life. PMID:24909326
Liu, Yan; Xue, Junzeng; Lin, Junda; Wu, Huixian
Invasive species generally possess unique characteristics that allow them to survive the invasion process in order to establish and spread in new habitats. Successful invaders must resist both physical and physiological stresses associated with the changing environment. A common littoral barnacle, Chthamalus challengeri Hoek, 1883 (Crustacea, Cirripedia), which is native to Japan, South Korea and northern China, has become established in the high-littoral zone adjacent to Yangshan Port, Shanghai, China. A comparison of the morphology of Chthamlus species from Zhoushan archipelago with previous description indicates the occurrence of C. challengeri. The new immigrant becomes a dominant species in certain high-intertidal habitats of the adjacent area to of Yangshan Port. C. challengeri was found in part of sampling sites in Zhoushan in 2010; however, it dispersed to all the eleven sampling sites in 2012. Densities of C.challengeri had increased over 10 times in the last 2 years, with the highest mean value reaching 39533 ± 6243 ind. m-2 in the new habitat. The specific ratios of both operculum area ( Sa) to base area ( SA) and average height of parietal plates ( H) to length of base ( L) revealed that C. challengeri displays morphological changes to resist stronger currents in the new habitats for invasion.
John A. Fornshell
Full Text Available The scope of this key is restricted to the larvae of marine arthropods. The key is based solely on their morphology, patterns of body segmentation, numbers of appendages, and mode of locomotion. An effort has been made to treat all traditionally named larval forms, both planktonic and benthic. It is intended that this key be useful for a researcher working with archived museum specimens and therefore, does not include habitat information as a identifying trait, even though this information is usually available in the archived records. Within the phylum Arthropoda there are two sub-phyla and eleven classes having larval stages in the marineenvironment. Where feasible the original names of the various larval types have been used. Because this nomenclature is less commonly used today compared to the past, the more recent taxonomic affinities are included in parentheses after the original larval name. The key includes the following thirty-four larvae: Branchhiopoda nauplii; Cephalocarida nauplii; Mystacocarida nauplii; trilobite larva; protonymphon; hexapod larvae; Remipedia nauplii; nauplius - Y larvae; Cirripedia nauplii; Ascothoracida nauplii; Ostracoda nauplii; Euphausiacea nauplii; Penaeidea nauplii; Cyclopoida nauplii; Calanoida nauplii; Harpacticoida nauplii;Polyarthra nauplii; cypris larva; eryonecius larva; cypris-Y larva; elapthocaris larvae; mysis larvae; lucifer zoea; acetes zoea; acanthosoma larva; phyllosoma; antizoea larva; anomuran zoea; brachyuran zoea; calyptopis larvae; furcilia larva; crytopia larva; puerulus larva; alima larva.
Vanessa C. Winter
Full Text Available Um estudo de distribuição dos macroepizóicos foi realizado numa população do caranguejo-aranha Libinia ferreirae Brito Capello, 1871 proveniente do litoral dos estados do Paraná e de Santa Catarina. O material biológico foi obtido junto aos pescadores, e faz parte do rejeito de pesca. Os caranguejos foram mensurados e os macroepizóicos identificados e contados. Os seguintes macroepizóicos sésseis foram registrados: Calliactis tricolor (Lesueur, 1817 (Cnidaria; Actiniaria (Cnidaria; Arca sp. (Mollusca; Ostreidae (Mollusca; Acanthodesia tenuis (Desor, 1848 (Bryozoa; Cirripedia e duas espécies tubícolas de Gammaridea (Crustacea. Além destes organismos ocorreram dois tubos desabitados e quatro animais vágeis. A anêmona C. tricolor foi a espécie mais abundante e freqüente, sendo, provavelmente, utilizada como mecanismo de camuflagem pelo caranguejo. O macroepizoísmo em L. ferreirae está relacionado com a idade ou tamanho do caranguejo, tendo maior incidência naqueles mais velhos ou de maior porte. Entretanto, a densidade dos macroepizóicos por caranguejo se mantém em torno de três. Não há relação entre o macroepizoísmo e o sexo do hospedeiro; somente fêmeas ovígeras utilizam desse recurso mais freqüentemente do que as não-ovígeras. Devido à maior área de fixação, os macroepizóicos colonizam principalmente a carapaça do caranguejo, enquanto nos pereiópodos há predominância de Bryozoa.A study of the distribution of the macroepizoites was carried out on a population of the spider crab Libinia ferreirae Brito Capello, 1871 from the Southern Brazilian coast. Crabs were obtained from shrimps and fishes by-catch. They were measured, and their macroepizoites were identified and counted. The following sessile macroepizoites were registered: Calliactis tricolor (Lesueur, 1817 (Cnidaria; Actiniaria (Cnidaria; Arca sp. (Mollusca; Ostreidae (Mollusca; Acanthodesia tenuis (Desor, 1848 (Bryozoa; Cirripedia and two species
Cristiane Maria Rocha Farrapeira
Full Text Available Ports of big coastal cities are exposed to exotic species as a consequence of shipping traffic. As the Port of Recife receives an annual average of 491 ships from other regions of Brazil and from all over the world, this work was aimed at knowing which marine animals were passively transported on such vessels hulls, in order to map and monitor new bioinvasions in the area. Thus, 32 vessels of several origins were investigated between November 2005 and March 2006, samples were taken and the macrofauna identified. Sixty species of associated animals were identified, consisting of 28 sessile species, particularly the Cirripedia Balanomorpha and Lepadomorpha as dominants, 8 sedentary animals, namely Mytillidae and Dreissenidae and 23 free-living species, particularly, Caprellidae, Gammaridae, Tanaidacea, Turbellaria, Nemertea and Polychaeta. The first occurrence of Conchoderma virgatum was recorded with exact location for the Brazilian littoral, and Conchoderma auritum, Amphibalanus subalbidus and Haliplanella lineata were recorded for the first time at the littoral of Pernambuco State. The invasion pathway was confirmed for Amphibalanus reticulatus and Mytilopsis leucophaeta, invader species of the estuarine area of Recife's city. Megabalanus coccopoma was considered as a risk invader species for the region.Regiões portuárias das grandes cidades litorâneas estão sujeitas à recepção de espécies exóticas como conseqüência da movimentação dos navios. Como o Porto do Recife recebe uma média anual de 491 atracações de navios, provenientes de várias regiões do Brasil e do mundo, objetivou-se conhecer quais animais marinhos eram transportados passivamente nos cascos das embarcações para mapear e monitorar novas invasões biológicas na área. Assim, foram investigados 32 barcos de diversas origens, nos meses de novembro de 2005 a março de 2006, tendo a macrofauna sido amostrada e identificada. Foram encontradas 60 espécies de animais
Full Text Available Increased tourist activity in coastal regions demands management strategies to reduce impacts on rocky shores. The highly populated coastal areas in southeastern Brazil are an example of degradation caused by development of industry and tourism. Among different shore impacts, trampling has been intensively studied, and may represent a significant source of stress for intertidal fauna. A randomised blocks design was applied to experimentally study the effects of two different trampling intensities on richness, diversity, density and biomass of the rocky shore fauna of Obuseiro beach, Guarujá, southeastern Brazil. Blocks were distributed in two portions of the intertidal zone, dominated respectively by Chthamalus bisinuatus (Cirripedia and Isognomon bicolor (Bivalvia. Blocks were trampled over three months, simulating the vacation period in Brazil and were monitored for the following nine months. Results indicate that Chthamalus bisinuatus is vulnerable to trampling impacts. Richness, diversity and turn-over index tended to be higher in trampled plots four months after trampling ceased. In general, results agree with previous trampling studies, suggesting that even low intensities of trampling may cause some impact on intertidal communities. Management strategies should include isolation of sensitive areas, construction of boardwalks, visitor education and monitoring programmes. In Brazil, additional data obtained from experimental studies are necessary in order to achieve a better understanding of trampling impacts on rocky shore communities.O aumento da atividade turística em áreas costeiras nas últimas décadas faz necessária a adoção de estratégias de manejo para reduzir os impactos gerados às comunidades de costões rochosos. A região costeira do sudeste brasileiro possui bons exemplos de degradação causada pelo turismo e desenvolvimento industrial. Dentre os diferentes distúrbios causados pela visitação, o pisoteio têm sido
Full Text Available The increasing CO2 concentration in the atmosphere caused by burning fossil fuels leads to increasing pCO2 and decreasing pH in the world oceans. These changes may have severe consequences for marine biota, especially in cold-water ecosystems due to higher solubility of CO2. However, studies on the response of mesozooplankton communities to elevated pCO2 are yet lacking. In order to test whether abundance and taxonomic composition change with pCO2, we have sampled nine mesocosms, which were deployed in Kongsfjorden, an Arctic fjord at Svalbard, and were adjusted to eight CO2 concentrations, initially ranging from 185 μatm to 1420 μatm. Samples were taken weekly over a six-week period with an Apstein net (55 μm mesh size in all mesocosms and the surrounding fjord. In addition, sediment trap samples, taken every second day in the mesocosms, were analyzed to account for losses due to vertical migration and mortality. The taxonomic analysis revealed that meroplanktonic larvae (cirripeds, polychaetes, bivalves, gastropod, and decapods dominated in the mesocosms while copepods (Calanus spp., Oithona similis, Acartia longiremis and Microsetella norvegica were found in lower abundances. In the fjord copepods prevailed for most of our study. With time, abundance and taxonomic composition developed similarly in all mesocosms; the pCO2 had no significant effect on the overall community structure. However, single taxa responded to elevated CO2 concentrations. The ratio of cirripedia nauplii to cypris larvae, the next developmental stage, in the sediment traps averaged over the entire experiment increased with pCO2 and this suggests that increased pCO2 may have delayed their development. Also, the number of bivalves, averaged over the experimental period, decreased significantly with increasing pCO2. The nature of the CO2 effect, either direct or indirect, remains open and needs to be addressed in future.
Full Text Available The increasing CO2 concentration in the atmosphere caused by burning fossil fuels leads to increasing pCO2 and decreasing pH in the world ocean. These changes may have severe consequences for marine biota, especially in cold-water ecosystems due to higher solubility of CO2. However, studies on the response of mesozooplankton communities to elevated CO2 are still lacking. In order to test whether abundance and taxonomic composition change with pCO2, we have sampled nine mesocosms, which were deployed in Kongsfjorden, an Arctic fjord at Svalbard, and were adjusted to eight CO2 concentrations, initially ranging from 185 μatm to 1420 μatm. Vertical net hauls were taken weekly over about one month with an Apstein net (55 μm mesh size in all mesocosms and the surrounding fjord. In addition, sediment trap samples, taken every second day in the mesocosms, were analysed to account for losses due to vertical migration and mortality. The taxonomic analysis revealed that meroplanktonic larvae (Cirripedia, Polychaeta, Bivalvia, Gastropoda, and Decapoda dominated in the mesocosms while copepods (Calanus spp., Oithona similis, Acartia longiremis and Microsetella norvegica were found in lower abundances. In the fjord copepods prevailed for most of our study. With time, abundance and taxonomic composition developed similarly in all mesocosms and the pCO2 had no significant effect on the overall community structure. Also, we did not find significant relationships between the pCO2 level and the abundance of single taxa. Changes in heterogeneous communities are, however, difficult to detect, and the exposure to elevated pCO2 was relatively short. We therefore suggest that future mesocosm experiments should be run for longer periods.
Howaida Yehia ZAKARIA
Full Text Available Lake Manzalah is the largest of the four Nile Delta lakes in Egypt. It provides more than 50% of the total inland fisheries of the country. During the last two decades the Lake has been exposed to multiple changes mainly due to local human activities. Monthly zooplankton samples were collected during an integrated environmental monitoring program within the MELMARINA Project that extended from July 2003 to September 2004 to study the distribution and occurrence of zooplankton community in Lake Manzalah. Results showed that, the average zooplankton standing crop was 1277 x 103 individuals m-3 . Spring was the most productive season (2127 x 103 individuals m-3 representing 41.65% to the total zooplankton counts. Five groups dominated zooplankton community; Rotifera, Copepoda, Ostracoda, Protozoa and Cladocera. The meroplanktonic larvae of Polychaeta, Cirripedia, Mysidacea and Gastropoda as well as free living nematods were rarely recorded. Rotifera contributed 81.89% to the total zooplankton community. They were represented by 38 species belonging to 19 genera dominated by genus Brachionus (86.65% of the total Rotifera followed by genus Keratella (8.68%. Keratella species has been indicated as an indicator of pollution. Copepoda (including their larval stages was the second group in order of abundance forming about 14.28% of the total zooplankton counts and represented by seven species. Acanthocyclops americanus was the dominant species. The productivity of Lake Manzalah decreased from 1979 to become highly eutrophic lake during the present study, but with higher production than the other Egyptian lakes. Management is needed to stabilize the Manzalah lake ecosystem in a way that promotes the sustainability of the system.
Blachowiak-Samolyk, Katarzyna; Kwasniewski, Slawek; Dmoch, Katarzyna; Hop, Haakon; Falk-Petersen, Stig
The trophic structure of zooplankton was investigated in Fram Strait (north western Svalbard) in spring and autumn of 2003. Depth-stratified zooplankton samples were collected at 12 stations on the shelf (˜200 m), across the shelf-slope (˜500 m) and over deep water (>750 m), using a Multiple Plankton Sampler equipped with 0.180-mm mesh size nets. Higher zooplankton abundance and estimated biomass were found in the shelf area. Abundance and biomass were two times higher in August, when sea-surface temperature was higher than in May. Herbivores dominated numerically in May, and omnivores in August, suggesting a seasonal sequence of domination by different trophic groups. Cirripedia nauplii and Fritillaria borealis prevailed in spring, whereas copepod nauplii and Calanus finmarchicus were numerically the most important herbivores in autumn. Small copepods, Oithona similis and Triconia borealis, were the most numerous omnivorous species in both seasons, but their abundances increased in autumn. Chaetognatha (mainly Eukrohnia hamata) accounted for the highest abundance and biomass among predatory taxa at all deep-water stations and during both seasons. Regarding vertical distribution, herbivores dominated numerically in the surface layer (0-20 m), and omnivores were concentrated somewhat deeper (20-50 m) during both seasons. Maximum abundance of predators was found in the surface layer (0-20 m) in spring, and generally in the 20-50 m layer in autumn. This paper presents the first comprehensive summary of the zooplankton trophic structure in the Fram Strait area. Our goals are to improve understanding of energy transfer through this ecosystem, and of potential climate-induced changes in Arctic marine food webs.
Experimental manipulations of invertebrate prey and predators on rocky shores have been done by many authors. In the northern Atlantic the predators involved are usually the green crab Carcinus maenas and/or the dogwhelk Nucella lapillus, and the prey species studied are acorn barnacles (balanid Cirripedia), mussels ( Mytilus spp.) and winkles ( Littorina spp.). Usually the predators are found to have a regulating "top-down" effect on the prey species. In Iceland the acorn barnacle Semibalanus balanoides, the blue mussel Mytilus edulis and the flat periwinkle Littorina obtusata (including to some extent Littorina mariae) are found on rocky shores all around Iceland in what would seem to be near-optimal physical conditions. The predators Carcinus maenas and Nucella lapillus, on the other hand, are relatively southern species that do not thrive on the colder coasts of Iceland. Thus general surveys of different coasts of Iceland would seem to offer opportunities to see whether the results of local experiments can be discerned on a geographical scale (hundreds of km). The roughly 4900 km of the rocky coastline in Iceland was in this study subdivided into four regions, I-IV, according to the commonness or presence of the two predators. With the hope of reducing compounding factors the surveys were confined to sheltered or semi-sheltered fucoid shores, which were further divided into Ascophyllum (more sheltered) and Fucus vesiculosus (less sheltered) shores. Estuaries or other low-salinity environments were avoided. The study was based on 761 stations distributed around the rocky coastline on these two types of shores. The results for barnacles and mussels, being generally more abundant in regions were predators were scarce or absent, and being less common in Ascophyllum than F. vesiculosus shores in contrast to the predatory dogwelks, were in large measure in accord with predictions from experiments indicating "top-down" regulation. The results for the periwinkles
Estrada, Rafael; Harvey, Michel; Gosselin, Michel; Starr, Michel; Galbraith, Peter S.; Straneo, Fiammetta
Zooplankton communities were examined for the first time in three different hydrographic regions of the Hudson Bay system (HBS) in early August to early September from 2003 to 2006. Sampling was conducted at 50 stations distributed along different transects located in Hudson Bay (HB), Hudson Strait (HS), and Foxe Basin (FB). Variations in zooplankton biomass, abundance, taxonomic composition, and diversity in relation to environmental variables were studied using multivariate techniques. During all sampling years, the total zooplankton biomass was on average four times lower in HB than in HS and FB. Clustering samples by their relative species compositions revealed no interannual variation in zooplankton community but showed a marked interregional variability between the three regions. Water column stratification explained the greatest proportion (25%) of this spatial variability. According to redundancy analysis (RDA), the zooplankton taxa that contribute most to the separation of the three regions are Microcalanus spp., Oithona similis, Oncaea borealis, Aeginopsis laurentii, Sagitta elegans, Fritillaria sp., and larvae of cnidaria, chaetognatha, and pteropoda in HB; hyperiid amphipods in FB; and Pseudocalanus spp. CI-CV, Calanus glacialis CI-CVI, Calanus finmarchicus CI-CVI, Calanus hyperboreus CV-CVI, Acartia longiremis CI-CV, Metridia longa N3-N6 CI-CIII CVIf, Eukrohnia hamata, larvae of echinodermata, mollusca, cirripedia, appendicularia, and polychaeta in the northwestern and southeastern HS transects. For the HB transect, the RDA analyzed allowed us to distinguish three regions (HB west, central, and east) with different environmental gradients and zooplankton assemblages, in particular higher concentration of Pseudocalanus spp. nauplii and CI-CVI, as well as benthic macrozooplankton and meroplankton larvae in western HB. In HS, Calanoid species (mainly C. finmarchicus and C. glacialis) were mostly observed at the north shore stations associated with the
Lejeune P. H. de Oliveira
Full Text Available Côr das águas de Sepetiba; as pròpriamente marítimas, pela Escala de Forel e as outras côres aparentes totais feitas por comparação com escalas de SÉGUY e com o Dicionário de Côres de MAERZ & PAUL, 1950. Côr Forel nº6 mostrava no litoral cirrípedes como a Tetraclita squamosa, nas rochas; Águas com a cianofícea planctônica Trichodesmium erythraeum tinham côr de "fôlha de bananeira" ou alpine green. O verde esmeralda mais intenso no local 7, com plancto maciço da diatomácea Coscinodiscus; a parte central da Baía com 150 [quilometros quadrados], cheia de larvas de camarão Penaeus schmidti, águas de cõr de ferrugem nas superfícies das águas; os estuários côr caramelo, isabellinus e bistre. Êste levantamento preliminar serve para comparações futuras, pois a Baía de Sepetiba ainda não é poluída. Futuramente haverá um pôrto de minérios com 3.000.000 de toneladas anuais, cais do pôrto, siderúrgicas e outras indústrias que a poluirão. Várias cõres de águas poluídas da Baía de Guanabara, como águas negras, águas côr de asfalto e outras escurecidas não foram encontradas em Sepetiba. Também não foram encntradas "águas vermelhas" com plancto predominante de dinoflagelados do que já vimos na Baía de Guanabara seguidos de mortandadas de peixes. A fig. 3 mostra as curvas de transparência, e a relação entre côr e transparência é dada para as côres totais aparentes. Foi marcado o coeficiente de extinção da luz K, pelo cálculo a partir do Disco de Secchi. Havendo poluições todos êsses dados que apresentamos deverão ser alterados.The apparent total color of sea by comparison with samples tested by "MAERZ & PAUL: A Dictionary of Colors, 1950". We find green colors of Forel Scale: Forel n. 5 in waters with Pheophyceae, Sargassum, and Rhodophyceae; Forel n. 6 waters in stones with the Cirripedia, the barnacle Tetraclita squamosa; the alpine green in waters with Trichodesmium exuthraeum. Emerald