The Morphology of Cysts and Motile Cells of Gyrodinium instriatum (Dinophyta), a Species New to the Seas of Russia

The germination of dinoflagellate cysts isolated from the surface sediment from Peter the Great Bay (Sea of Japan) provided motile cells of Gyrodinium instriatum. This is the first report on this species for the seas of Russia. The morphology of both collected and germinated cysts and motile cells is described, and data on the ecology and distribution of the species are provided.     

Morphological peculiarities of <Emphasis Type="Italic">Fragilidium mexicanum</Emphasis> Balech, 1988 (Dinophyta) from the Far-Eastern Seas of Russia

The vegetative cells of Fragilidium mexicanum Balech are recorded from the Far Eastern seas of Russia (Sea of Japan and Sea of Okhotsk) for the first time. Morphological study of both cultured and wild cells of F. mexicanum showed that the shape of the cell and the first (1″) and second (2″) precingular plates, the direction of the slot in plate 1″, and the shape of the anterior sulcul plate (S.a.) vary greatly. These features bear similarity to those of F. mexicanum, as well as a closely related species, F. subglobosum. The most conservative characters distinguishing the two species are the shape and size of the first and seventh postcingular plates and the shape of the posterior sulcal plate.     

Seasonal Dynamics of the Diatoms of the Genus Chaetoceros Ehrenberg in Amursky Bay (Sea of Japan)

The qualitative and quantitative composition of the Chaetoceros Ehr. species was studied in Amursky Bay (Sea of Japan) from January 1996 until May 1998. In all, 30 species, 1 variety, and 1 form of this genus were registered. The species Chaetoceros occurred in plankton throughout the year at a water temperature of –1.8–25°C and a salinity of 11–35. The numbers of Chaetoceros species varied between 100 and 1071000 cells/l, and the biomass varied between 0.9 × 10^–3 and 3.3 g/m³. The numbers were maximum in summer and minimum in the beginning of spring. The Chaetoceros species comprised 45–70 and 5–18% (winter), 68–98 and 65–95% (spring), 50% (summer), and 20% (autumn) of the total phytoplankton numbers and biomass. Six dominant species and 1 variety of Chaetoceros were found. Seasonal complexes formed by the Chaetoceros species were identified and described.     

Toxin profiles of natural populations and cultures ofAlexandrium minutum Halim from Galician (Spain) coastal waters

The toxin profiles of three isolates and natural populations of the PSP agentAlexandrium minutum from several Galician rías (NW Spain) was obtained by HPLC. The toxin content of cultures ofA. minutum is dominated by GTX4 (80–90%) and GTX4 (10–15%) with small amounts of GTX3 and GTX2 (less than 3% of each); similar results were obtained for natural populations ofAlexandrium from three different Galician rías, where a mixture ofA. lusitanicum Balech andA. minutum can occur. Important quantitative differences were found between the three isolates, one being highly and two weakly toxic. The results obtained from these isolates and natural populations ofAlexandrium were very similar to those obtained from HPLC analyses of mussels intoxicated during a PSP outbreak in Ría de Ares (Rías Altas) in 1984, confirming thatA. minutum (previously identified asGonyaulax tamarensis Lebour andAlexandrium lusitanicum) was the PSP agent during the toxic outbreak in May 1984. Toxin profiles obtained from natural populations during different PSP outbreaks in different rías and from cultures are fairly consistent and suggest that at least from the toxin point of view,A. lusitanicum andA. minutum are identical, and that the toxin profile ofA. minutum from Galicia can be used as a biochemical marker.     

First Records of Dinoflagellates Alexandrium margalefi Balech, 1994 and A. tamutum Montresor, Beran et John, 2004 in the Seas of the Russian Far East

New records of two Alexandrium species are reported for the Russian seas. A. margalefi Balech was found in Peter the Great Bay (Sea of Japan), and A. tamutum Montresor, Beran et John was found in Aniva and Sakhalinskii bays (Sea of Okhotsk). Both species were observed in summer in small numbers at water temperatures of 22– 24°C and 8.6–11°C, respectively. Data on the morphology and distribution of the species is provided.Original Russian Text Copyright © 2005 by Biologiya Morya, Selina, Morozova.     

Species composition, comparative size and abundance of the genus Littoraria (Gastropoda: Littorinidae) from different mangrove strata along the East African coast

Variation in the abundance, distribution and size of four species of mangrove littorinid gastropods (genus Littoraria) was investigated using a nested sampling design at different spatial scales along the East African coast, from Tanzania to South Africa. Littorinid abundance and diversity decreased abruptly south of Inhaca Island at the southern end of the study area. All species presented a large-scale spatial variation in abundance, with L. subvittata showing the greatest abundance while L. intermedia was rare. Littoraria scabra and L. intermedia were found mainly at the seaward edge of the forests. Littoraria subvittata increased in abundance in the middle of the forest and towards the landward side. Littoraria pallescens occurred mainly at the seaward edge and in the middle areas in the Rhizophora zone. These small-scale variations show contrasting specific distribution patterns within the mangrove, likely reflecting different tolerances to physical factors and biological interactions. All species appeared decreased in shell height from north to south. Littoraria scabra was always significantly larger than other species at all mangrove study sites. Handling editor: P. Viaroli     

贵州楼梯草属(荨麻科)植物种类组成及分布格局

荨麻科(Urticaceae)楼梯草属(Elatostema)植物种类繁多、形态相似、关系密切,是植物分类学界公认的疑难分类群之一。贵州省地理位置特殊,水热条件较好,喀斯特地貌复杂多变,是我国楼梯草属植物的重要分布区,但一直以来种类不清,分类不明。为进一步理清资源本底及分布特征,该文通过近年调查和查阅资料形成贵州楼梯草属植物名录,分析其物种组成,并基于分布地及海拔数据分析空间分布特征,以期为贵州植物多样性保护以及区系研究提供进一步的基础资料。结果表明:全省赤车类群植物有1组1系7种,楼梯草类群有5组20系69种,分别占全国种类的17.94%、20.78%。楼梯草属植物共76种,其中13种为贵州楼梯草属特有种。在地理分布上,赤车类群主要见于黔北-黔东-黔南部分地区,沿赤水、桐梓、习水、正安-江口、印江-剑河-都匀、荔波-望谟一线,总体分布反呈“C”状; 楼梯草类群植物主要分布在黔北-黔东-黔南-黔西南大部分地区,沿赤水、正安、江口-七星关、开阳、施秉、黄平-兴义、兴仁、安龙、贞丰、望谟、独山、荔波一带分布较多,总体分布呈“三”字状; 楼梯草属特有植物总体呈点状、不均匀分布。该属植物主要分布在海拔600～1 000 m的范围内。     

Morphogenetic diversity and biotoxin composition of Alexandrium (Dinophyceae) in Irish coastal waters

The diversity of Alexandrium spp. in Irish coastal waters was investigated through the morphological examination of resting cysts and vegetative cells, the determination of PSP toxin and spirolide profiles and the sequence analysis of rDNA genes. Six morphospecies were characterised: A. tamarense, A. minutum, A. ostenfeldii, A. peruvianum, A. tamutum and A. andersoni. Both PSP toxin producing and non-toxic strains of A. tamarense and A. minutum were observed. The average toxicities of toxic strains for both cultured species were respectively 11.3 (8.6 S.D.) and 2.3 (0.5 S.D.) pg STX equiv. cell⁻¹. Alexandrium ostenfeldii and A. peruvianum did not synthesise PSP toxins but HPLC–MS analysis of two strains showed distinct spirolide profiles. A cyst-derived culture of A. peruvianum from Lough Swilly mainly produced spirolides 13 desmethyl-C and 13 desmethyl-D whereas one of A. ostenfeldii, from Bantry Bay, produced spirolides C and D. Species identification was confirmed through the analyses of SSU, ITS1-5.8S-ITS2 and LSU rDNA genes. Some nucleotide variability was observed among clones of toxic strains of A. tamarense, which all clustered within the North American clade. However, rDNA sequencing did not allow discrimination between the toxic and non-toxic forms of A. minutum. Phylogenetic analysis also permitted the differentiation of A. ostenfeldii from A. peruvianum. Resting cysts of PSP toxin producing Alexandrium species were found in Cork Harbour and Belfast Lough, locations where shellfish contamination events have occurred in the past, highlighting the potential for the initiation of harmful blooms from cyst beds. The finding of supposedly non-toxic and biotoxin-producing Alexandrium species near aquaculture production sites will necessitate the use of reliable discriminative methods in phytoplankton monitoring.     

Species composition,distribution and seasonal dynamics of Rotifera in a Rift Valley lake in Ethiopia (Lake Awasa)

The species composition of rotifers in Lake Awasa was studied and 40 species recorded. Seven species appeared in large numbers in the plankton seasonally. Brachionus and Keratella species made up more than 50% of the rotifer community by numbers during the observation period (1983–1987). The standing stock numbers of rotifer species are low with a maximum of 50 individuals L^–1, and some possible reasons for this observation are discussed. Most rotifer species are distributed randomly in the lake and show 3-fold fluctuations between consecutive days.The seasonal dynamics of most rotifer species are correlated with mixing periods in the lake, and the amplitude of seasonal fluctuation may be as high as 50-fold. Clear-cut seasonal succession of rotifer species was observed during the study period, but no consistent seasonal pattern for individual species was obvious. Also, observations indicate that rotifer biomass is partly sustained by availability of carbon through the bacterial pathway and that competitive exclusion for food by nauplii and ciliates probably keeps rotifer abundance low.     

Autotomy and regeneration of limbs in the male blue king crabParalithodes platypus from the Bering Sea and the Sea of Okhotsk

Limb loss and the frequency of regeneration was investigated in the male blue king crabParalithodes platypus collected in the Sea of Okhotsk and the Bering Sea. TheP. platypus population in the Bering Sea is characterized by an anomalously high proportion of crabs with missing limbs, which is largely due to the intensive fishing. The present approach to the exploitation of the Bering Sea population, in which large intact crabs are removed and injured crabs are left to recover to the normal state, may result in a decline in the reproductive potential of this population as early as this coming year.     

Distribution and Seasonal Dynamics of the Abundance of Centropages abdominalis Sato and C. tenuiremis Thompson et Scott (Copepoda) in Amursky Bay, Sea of Japan

The distribution and seasonal dynamics of Centropages abdominalis and C. tenuiremis (Copepoda) in Amursky Bay (Sea of Japan) were studied from May through November 1991. C. abdominalis occurred in plankton from May through August and in November, with a peak density of more than 40000 specimens/m³ in June, at a temperature of 15–18°C. C. tenuiremis occurred from late June through November, with a maximum total density of 6900 specimens/m³ in August, at 23°C. During the observation period, the distribution of species in the bay was irregular due to the hydrological regime and sanitary conditions of water.     

Distribution of the Eelpout Lycodes soldatovi(Pisces: Zoarcidae) over the Continental Slope of the Sea of Okhotsk

The eelpout Lycodes soldatovi was found at depths of 153 to 1005 m in the Sea of Okhotsk; however, it usually inhabits the depth range of 400 to 800. The mean and maximum abundance and the biomass of this species were 198.5 and 1037 individuals per km² and 173.7 and 1275 kg/km², respectively. In view of the data on the distribution of young fish (up to 30 cm in total body length) and the reports on the absence of Lycodes larvae, a hypothesis was developed that this species spawns predominantly in the waters off western Kamchatka and eastern Sakhalin at the depth range of 700 to 900 m. Large individuals (>50 cm) exhibit higher migratory activity and are more tolerant of environmental conditions. That is why they are encountered throughout the distribution area of this species, even in subzero temperature areas. Lycodes soldatovi seems to be a typical inhabitant of the Sea of Okhotsk, except for the waters off the South and Central Kuril Islands and the Pacific waters off the North Kuril Islands.