Dynamics of pigment degradation by the copepodite stage of <Emphasis Type="Italic">Pseudodiaptomus</Emphasis><Emphasis Type="Italic">euryhalinus</Emphasis> feeding on <Emphasis Type="Italic">Tetraselmis</Emphasis><Emphasis Type="Italic">suecica</Emphasis>

Short-term (3 h) changes in concentration of chlorophylls and their derivatives in stage V Pseudodiaptomus euryhalinus and their fecal material were followed by HPLC during a 24 h experiment. Copepodites were fed with the prasinophyte Tetraselmis suecica. Intact chlorophyll a and b were found in animals and fecal material and had similar dynamics of accumulation over time. The extent of transformation of chlorophyll a and b to colorless compounds was different with chlorophyll a being more extensively degraded. Additionally, several chlorophyll derivatives (pheophytin and pyropheophytin-like pigments) were found. Pyropheophytin a was the most abundant followed by pheophytin b, pheophytin a, and pheophorbide a. Relative amounts of pheopigments were different in copepodites and fecal material, and pheophytin a, pheophorbide a, and pheophytin b concentrations were low and variable. The amount of ingested chlorophyll recovered as chlorophyll a and its derivatives in fecal and copepodite pools was generally low (<5%), with one exception occurring after 9 h, when it accounted for >70%. These data suggest individual pheopigments are produced at different rates and that chemical or enzymatic mechanisms in the gut of copepodites act on the two chlorophylls in different ways.     

Localization of granulatimide alkaloids in the tissues of the ascidian <Emphasis Type="Italic">Didemnum</Emphasis><Emphasis Type="Italic">granulatum</Emphasis>

Ascidians are a notable source of nitrogen-bearing secondary metabolites with a wide range of biological activities. Although many biologically active compounds have been isolated from ascidians, it is often unclear whether the animal or associated microbial symbionts such as bacteria or fungi are the true biosynthetic source of the metabolites. We have addressed the question of the biosynthetic source of the alkaloids granulatimide and isogranulatimides by localizing these compounds within the ascidian. In this work, we demonstrate that granulatimide is stored in Didemnum granulatum tunic bladder cells. Analysis by confocal fluorescence microscopy at the granulatimide emission range indicated the presence of fluorescent cells as highly vacuolated cells found dispersed in the ascidian tunic. Since this is the most exposed ascidian tissue, it is possible that these alkaloids may have a protective role, either as sunscreens and/or as feeding deterrents.     

Evidence of a spawning area of <Emphasis Type="Italic">Anguilla</Emphasis><Emphasis Type="Italic">marmorata</Emphasis> in the western North Pacific

Leptocephali of the tropical eel Anguilla marmorata have been consistently collected in the same area of the North Equatorial Current (NEC) in the western North Pacific during three consecutive cruises in June and July of 1991 (N=28) and 1994 (N=20), and July and September of 1995 (N=27), indicating that this is a spawning area of this species. These leptocephali were collected from 130°E to 142°E and 12°N to 20°N, to the west of the Mariana Islands, in 20 tows in 1991, in 13 tows in 1994 and in 17 tows in 1995, indicating a widespread presence, but a relatively low abundance. Six of these specimens (16.3-36.0 mm total length) from the 1995 cruise, which were of the typical size range of these leptocephali, were genetically confirmed to be A. marmorata in a previous study. The consistent presence of recently spawned A. marmorata leptocephali (9-20 mm) in all 3 years, suggests that the western region of the NEC is the spawning area of the northern population of A. marmorata that was identified in a recent population genetics study. These leptocephali would thus be transported westward by the NEC and then transported north into the Kuroshio Current and toward Taiwan and Japan, or south toward the southern Philippines and into the Celebes Sea by the Mindanao Current. Available evidence indicates that A. marmorata may have potentially year-round spawning, and the presence of a spawning area of this species in the same region as that of Anguilla japonica suggests that the northern population of A. marmorata has evolved a spawning migration from East Asia, the Philippines and the Celebes Sea region to the NEC area, but differs from A. japonica by having some individuals that recruit to more southern areas.     

Small effective number of parents (<Emphasis Type="Italic">N</Emphasis><Subscript><Emphasis Type="Italic">b</Emphasis></Subscript>) inferred for a naturally spawned cohort of juvenile European flat oysters <Emphasis Type="Italic">Ostrea edulis</Emphasis>

The great fecundity and very high larval mortality of most marine invertebrates and fish make possible substantial variance in the number of offspring contributed by adults to subsequent generations. The reproductive success of such organisms may thus resemble a sweepstakes lottery, in which a minority of progenitors succeeds in replacing an entire population, while the majority fails to procreate. One specific prediction of this hypothesis, that genetic diversity of newly settled cohorts should be less than that of the adult population, is tested in the present study. Microsatellite DNA markers were examined in naturally spawned juvenile European flat oysters Ostrea edulis (L.), collected over a 12-day period in 1993 from the western Mediterranean Sea, near Sète, France (43°32′N, 3°56′E) and grown out for a period of up to 10 months. Variation in these juveniles was compared to that in a pooled sample of adults collected in 1994 from two locations (Thau Lagoon and Port St. Louis) that had statistically homogeneous allelic frequencies. Though nearly twice as large as the pooled adult sample, the juvenile sample had only 60% of the adult allelic diversity. Analyses of linkage disequilibrium and kinship, as well as estimation of the effective number of parents, suggested that 10–20 adults produced this juvenile cohort. This observation supports the hypothesis of sweepstakes reproductive success and suggests that partial inbreeding may occur even in species with large populations and dispersing planktonic larvae. Electronic Supplementary Material Supplementary material is available to authorised users in the online version of this article at .     

Settlement of the wreckfish (<Emphasis Type="Italic">Polyprion</Emphasis><Emphasis Type="Italic">americanus</Emphasis>)

The wreckfish (Polyprion americanus) is a panoceanic, long-lived, deep-water demersal species, characterized by an extended pelagic juvenile phase associated with floating objects. In the present study morphometric data from 435 specimens collected from Greece (Crete), Italy (Ionian Sea) and the Atlantic coast of France from September 1999 to March 2001 were analyzed to estimate the settlement size of the species and associated changes in morphology. The fishery sample included specimens from both the pelagic and the demersal stage. Length-at-settlement (TL₅₀) and 95% confidence intervals were estimated by fitting a logistic function. Eleven morphometric characters were analyzed, and the existing inflection points, reflecting alterations in body shape, were defined: (1) iteratively, as the transition point, splitting the data set into two groups, for which the reduced major axis functions, between a character and total length, of the successive groups best fit (minimum sum of squares of residuals) the combined data set and (2) where the second derivative of the fitted third-order polynomial functions to morphometric ratios equaled zero. The main size range within which wreckfish settled was 56-65 cm, and the means of the inflection points defined by the two methods were 61 and 64 cm. These results indicate changes in functional morphology associated with settlement. The monitoring of wreckfish juveniles caught in the wild and kept individually in captivity showed changes in growth and food intake at approximately the estimated settlement length and suggested that temperature was the most likely factor triggering settlement.     

Lack of sequestration of host plant glucosinolates in <Emphasis Type="Italic">Pieris rapae</Emphasis> and <Emphasis Type="Italic">P. grarricae</Emphasis>

Summary. Sequestration of plant toxins in herbivores is often correlated with aposematic coloration and gregarious behaviour. Larvae of Pieris brassicae show these conspicuous morphological and behavioural characteristics and were thus suggested to sequester glucosinolates that are characteristic secondary metabolites of their host plants. P. rapaeare camouflaged and solitary, and are thus not expected to sequester. To test this hypothesis and to check the repeatabi-lity of a study that did report the presence of the glucosinolate sinigrin in P. brassicae, larvae were reared on three species of Brassicaceae (Sinapis alba, Brassica nigra and Barbarea stricta), and different leaf and insect samples were taken for glucosinolate analysis. The major host plant glucosinolates could only be found in traces or not at all in larval haemolymph, bled or starved larvae, faeces or pupae of both species or P. brassicae regurgitant. Haemolymph of both Pieris spp. was not rejected by the ant Myrmica rubra in dual-choice assays; the regurgitant of P. brassicae was rejected. This suggests the presence of compounds other than glucosinolates that might be sequestered in or produced by P. brassicae only. In faeces of both Pieris spp. a compound which yielded 4-hydroxybenzylcyanide (HBC) upon incubation with sulfatase was detected in high concentrations when larvae had been reared on S. alba. This compound may be derived from hydrolysis of sinalbin, the main glucosinolate of that plant. The unidentified HBC progenitor was apparently not sequestered in the two Pieris spp., and was not detected in faeces of larvae reared on B. nigra or B. stricta. Received 18 July 2002; accepted 11 September 2002.     

Gas-phase degradation of CCl<Subscript>4</Subscript>, CHCl<Subscript>3</Subscript> and CH<Subscript>2</Subscript>Cl<Subscript>2</Subscript> over metallic Fe

We studied the hydrolysis of gas-phase carbon tetrachloride (CCl₄), chloroform (CHCl₃), and dichloromethane (CH₂Cl₂) over a metallic Fe surface for its application in combination with air stripping and soil vapour extraction. The effects of chlorocarbon concentration, type and preparation of the iron-containing material, humidity, and temperature on process performance are reported. The hydrolysis of chlorinated methane derivatives is catalysed by metallic iron resulting in a noticeable decrease of the reaction temperature. The reaction kinetics were found to be consistent with the Langmuir-Hinshelwood model.     

Promotion of transition metal oxides on the NH<Subscript>3</Subscript>-SCR performance of ZrO<Subscript>2</Subscript>-CeO<Subscript>2</Subscript> catalyst

Chromium oxide and manganese oxide promoted ZrO₂-CeO₂ catalysts were prepared by a homogeneous precipitation method for the selective catalytic reduction of NO _x with NH₃. A series of characterization including X-ray diffraction (XRD), high-resolution transmission electron microscope (HR-TEM), Brunauer–Emmett–Teller (BET) surface area analysis, H₂ temperatureprogrammed reduction (H₂-TPR), and X-ray photoelectron spectroscopy (XPS) were used to evaluate the influence of the physicochemical properties on NH₃-SCR activity. Cr-Zr-Ce and Mn-Zr-Ce catalysts are much more active than ZrO₂-CeO₂ binary oxide for the low temperature NH₃-SCR, mainly because of the high specific surface area, more surface oxygen species, improved reducibility derived from synergistic effect among different elements. Mn-Zr-Ce catalyst exhibited high tolerance to SO₂ and H₂O. Cr-Zr-Ce mixed oxide exhibited>80% NO _x conversion at a wide temperature window of 100°C–300°C. In situ DRIFT studies showed that the addition of Cr is beneficial to the formation of Bronsted acid sites and prevents the formation of stable nitrate species because of the presence of Cr^{6 +}. The present mixed oxide can be a candidate for the low temperature abatement of NO _x .

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Effects of substrate type on growth and mortality of blue mussels (<Emphasis Type="Italic">Mytilus</Emphasis><Emphasis Type="Italic">edulis</Emphasis>) exposed to the predator <Emphasis Type="Italic">Carcinus</Emphasis><Emphasis Type="Italic">maenas</Emphasis>

Structure and complexity of the substrate are important habitat characteristics for benthic epifauna. The specific growth and mortality rates and inducible defence characters on medium-sized blue mussels (Mytilus edulis L.) exposed to shore crabs (Carcinus maenas L.) were examined on three different substrate types in combined field and laboratory experiments. The experiments showed that complexity of the substrate increased blue mussel survival significantly, through a decrease in predation pressure. However, increased intraspecific competition for food on the complex substrate resulted in significantly lower growth rates of the mussels. Inducible defence characters were also influenced by substrate type. Blue mussels were more affected by predators on the structurally simple substrate, where they developed thicker shells and a larger posterior adductor muscle.     

Doubly uniparental transmission of mitochondrial DNA length variants in the mussel <Emphasis Type="Italic">Mytilus</Emphasis><Emphasis Type="Italic">trossulus</Emphasis>

Doubly uniparental inheritance of mitochondrial DNA (mtDNA) is an unusual feature found in marine mussels and a few other bivalve species. In addition to a mitochondrial genome (F) inherited through the female line, heteroplasmic individuals (males) contain a second highly diverged genome (M) that is inherited through the paternal line. The Baltic mussel Mytilus trossulus is characterized by the presence of two phylogenetically close female and male genomes. We examined M. trossulus sampled from the Gulf of Gdansk, southern Baltic. Somatic tissues and gametes were surveyed for the presence of different types of mtDNA. Length variants were identified using PCR (polymerase chain reaction) amplification of the mtDNA fragment containing the major noncoding region. Seventeen length variants present in homo- and heteroplasmic individuals were found in a sample of 343 individuals analyzed. Two length variants of the major noncoding region (PCR product lengths: 1520 and 1370 bp) were the most frequent. Length heteroplasmy was found in 46.8% of males, and was mostly caused by the presence of the short length variant (PCR product length: 1370 bp) of the major noncoding region. MtDNA variants were also detected by restriction analysis of a 1.3 kb segment of coding region (ND2-COIII) amplified by PCR. This study provides evidence that the short length variant is always transmitted to sperm and has taken over the role of the M genome. The remaining length variants were present in both males and females. Longer length variants were transmitted mainly through the female line. A possibility of much higher incidence of genome role reversals in Baltic M. trossulus, in comparison with other populations of mussels is discussed.     

Seasonal variation in the degree of heterospecific association of two syntopic hyraxes (<Emphasis Type="Italic">Heterohyrax</Emphasis><Emphasis Type="Italic">brucei </Emphasis>and <Emphasis Type="Italic">Procavia capensis</Emphasis>) exhibiting synchronous parturition

Adult rock hyrax (Procavia capensis) and bush hyrax (Heterohyrax brucei) allocate much of their surface activity to being vigilant for vertebrate predators. Individuals of the two species associate for thermoregulatory basking on rock outcrops (koppies) and, in the Matobo National Park, Zimbabwe, frequently constitute heterospecific groups that produce offspring synchronously. Exposure to predators during basking is thought to put a high premium on vigilance, particularly during the presence of dependent offspring in nurseries. We predicted, therefore, an increase in the association of the two species of hyraxes when offspring were present because this would lead to larger groups, thus enhancing the ability to detect predators. Koppie aggregations of hyraxes were classified as homospecific or heterospecific according to basking group composition. Heterospecific association increased when offspring were present, and heterospecific groups were larger than homospecific ones. Fifty-one percent of nurseries were heterospecific for adults/subadults. During the pre-weaning phase (<2 months after birth), 85% of P. capensis and 65% of H. brucei juveniles were in nurseries of heterospecific basking groups. Heterospecific groups had more offspring than homospecific groups. Juvenile mortality is most evident after young are weaned and heterospecific associations break down. Heterospecific aggregation, through increased group size, may result in a higher probability of avoiding predators, thereby reducing the vulnerability of young.     

Inter-polyp genetic and physiological characterisation of <Emphasis Type="Italic">Symbiodinium</Emphasis> in an <Emphasis Type="Italic">Acropora valida</Emphasis> colony

Corals harbouring genetically mixed communities of endosymbiotic algae (Symbiodinium) often show distribution patterns in accordance with differences in light climate across an individual colony. However, the physiology of these genetically characterised communities is not well understood. Single stranded conformation polymorphism (SSCP) and real time quantitative polymerase chain reaction (qPCR) analyses were used to examine the genetic diversity of the Symbiodinium community in hospite across an individual colony of Acropora valida at the spatial scale of single polyps. The physiological characteristics of the polyps were examined prior to sampling with a combined O₂ microelectrode with a fibre-optic microprobe (combined sensor diameter 50–100 μm) enabling simultaneous measurements of O₂ concentration, gross photosynthesis rate and photosystem II (PSII) quantum yield at the coral surface as a function of increasing irradiances. Both sun- and shade-adapted polyps were found to harbour either Symbiodinium clade C types alone or clades A and C simultaneously. Polyps were grouped in two categories according to (1) their orientation towardps light, or (2) their symbiont community composition. Physiological differences were not detected between sun- and shade-adapted polyps, but O₂ concentration at 1,100 μmol photons m⁻² s⁻¹ was higher in polyps that harboured both clades A and C symbionts than in polyps that harboured clade C only. These results suggest that the acclimatisation of zooxanthellae of individual polyps of an A. valida colony to ambient light levels may not be the only determinant of the photosynthetic capacity of zooxanthellae. Here, we found that photosynthetic capacity is also likely to have a strong genetic basis and differs between genetically distinct Symbiodinium types.     

Environmental controls on shell growth rates and δ<Superscript>18</Superscript>O of the shallow-marine bivalve mollusk <Emphasis Type="Italic">Phacosoma</Emphasis><Emphasis Type="Italic">japonicum</Emphasis> in Japan

Microgrowth patterns and the oxygen isotope composition of juvenile, shallow-marine bivalve mollusk shells of Phacosoma japonicum (Reeve) in Japan were analyzed and cross-calibrated with environmental parameters. Mark-and-recovery experiments indicate that a pair of two microgrowth lines and two microgrowth increments is produced every lunar day. This finding makes it possible to assign exact calendar dates to each portion of the shell. Average daily growth rates decrease by 61% from age two to three and 55% from age three to four. The length of the growing season and the growth rate are mainly controlled by temperature: shell growth ceases below 14.2°C (age two) and 16.8°C (age four) and is most rapid between 24.6°C and 27.2°C. Based on local temperature cycles, the growing season is longest in Seto Inland Sea, central Honshu (from May to November) and shortest at Hakodate Bay, North Japan (from June to October). The annual oxygen isotope profiles of the shells reflect the temperature cycle and the varying amounts of freshwater added to the seawater by precipitation. The most negative '¹⁸O values of -3.15‰ occur during the rainy season, i.e. during the monsoon and typhoon seasons. Growth rates are only slightly affected by salinity changes. Strongly reduced growth rates during the second half of the year at Seto Inland Sea and to a lesser extent at Tokyo Bay are explained by nutrient deprivation. Our study provides the basis for the use of P. japonicum in high-resolution ecological studies and environmental reconstructions.     

Development and biology of <Emphasis Type="Italic">Periphylla</Emphasis><Emphasis Type="Italic">periphylla</Emphasis> (Scyphozoa: Coronatae) in a Norwegian fjord

The globally distributed coronate scyphomedusa Periphylla periphylla (Peron and Lesueur, 1809) occurs in permanent and extremely high abundance in some Norwegian fjords. Studies on the species in Lurefjorden, 40 km north of Bergen, have revealed a holopelagic life cycle with direct development. We distinguished 14 successive developmental stages, characterised by size and morphology. Eggs and early stages are non-mobile, neutrally buoyant, and found mainly at intermediate depths. Rearing studies indicated a development time of 2-3 months from fertilisation to stage 9, when the medusa starts feeding and becomes motile. The fjord population usually shows a strong diel vertical migration, with aggregations at shallower depths during the night. The development includes a gradual increase in pigmentation (porphyrins), starting with the stomach, and thereafter extending to tentacles and the whole exumbrella. This pigment is photodegraded by natural light. Rearing experiments in the laboratory have shown a lethal effect of light. Here, development stops at stage 5. Pigments become visible in stage 7. Older medusae are severely damaged and killed within a few days by exposure to daylight. All stages of P. periphylla are bioluminescent, with this capacity increasing with growth, probably in connection with the development of the nervous net. The light reaction starts at the point of stimulation and spreads at two different speeds corresponding to the two nerve nets of the medusae. The coronal furrow has a central function in transmission of the reaction. It is hypothesised that the bioluminescence is used mainly as a warning to some potential predators, signalling that the porphyrin-containing medusa is unpalatable. P. periphylla has the same two categories of nematocysts as other coronates, with a total of six different types. Nematocyst abundance, distribution and morphology indicate their function. The giant euryteles (capsule up to 100 µm and tubule up to 1160 µm) are the largest ones known among Scyphozoa, and are unique in that this size increases during medusa development.     

Embryo development and maternal–embryo nutritional relationships of piked spurdog (<Emphasis Type="Italic">Squalus</Emphasis><Emphasis Type="Italic"> megalops</Emphasis>)

The maternal–embryo relationship was determined for the piked spurdog (Squalus megalops). In addition, the increase in offspring size with maternal size was studied and the embryonic development was described. Wet weight of in utero eggs and offspring size was correlated with maternal size; larger females produced larger embryos which would have higher survival rate and reproductive value. All embryos present in a female were at a similar stage of development. The external yolk sac is reabsorbed late in gestation, suggesting that embryos are mostly nourished by yolk sac reserves. Embryo size-at-birth varied considerably (180–244 mm total length) as a result of the significant variability in ova size at ovulation. The amounts of water, organic and inorganic matter of embryos at different stages of development were measured to determine possible maternal contributions during embryonic development. Total wet weight from smallest and largest in utero eggs to smallest and largest term embryos changed by +46 and +58%, respectively. This pattern was due to a change in water content by +137 and +154%, and inorganic matter by +100 and +156%. Organic matter of smallest and largest in utero eggs changed by −23 and −17%, respectively. The uterus of pregnant females became specialised for water and mineral transport, not nutrient provision. These results indicate that S. megalops is a strict yolk-sac viviparous species with no maternal contribution of organic matter during development.     

Mechanisms of range expansion in the intertidal brown alga <Emphasis Type="Italic">Fucus</Emphasis><Emphasis Type="Italic">serratus</Emphasis> in northern Spain

The intertidal brown alga Fucus serratus is naturally expanding its distributional range along the north shore of Spain. Shores being colonised by F. serratus harbour saturated algal communities, with almost no free space. Processes responsible for the successful expansion were investigated in a locality where the alga was experimentally introduced. After a short period, the number of F. serratus plants increased exponentially at a monthly intrinsic rate of 0.111. At early and intermediate stages of invasion, colonisation occurred by the growth of patches of the invader around the transplant points. F. serratus is a bad disperser, with most of propagules settling in near proximity to parent plants. Colonisation of manipulated and control areas was influenced by the proximity of propagule sources. Experimental removals of canopies, irrespective of whether the turf was removed or left intact, accelerated the expansion, as this component of the community had a negative influence on recruitment of both F. serratus and F. vesiculosus. The unmanipulated algal beds were, however, invasible, as some control quadrats close (<10 m) to F. serratus patches had a 100% cover of F. serratus at the end of the study. Prior or concurrent to increases of F. serratus, a decrease in cover of F. vesiculosus and other resident macroalgae was evident. No formal competition experiment was done but results suggest that F. serratus outcompetes F. vesiculosus and Bifurcaria bifurcata at mid-tidal levels. In scraped quadrats, in which both Fucus species recruited at large densities, F. serratus grew at a higher rate than F. vesiculosus and eventually monopolised the experimental surfaces.