Survival of Filamentous Fungi in Hypersaline Dead Sea Water

A variety of filamentous fungi have recently been isolated from the Dead Sea (340 g/L total dissolved salts). To assess the extent to which such fungi can survive for prolonged periods in Dead Sea water, we examined the survival of both spores and mycelia in undiluted Dead Sea water and in Dead Sea water diluted to different degrees with distilled water. Mycelia of Aspergillus versicolor and Chaetomium globosum strains isolated from the Dead Sea remained viable for up to 8 weeks in undiluted Dead Sea water. Four Dead Sea isolates (A. versicolor, Eurotium herbariorum, Gymnascella marismortui, and C. globosum) retained their viability in Dead Sea water diluted to 80% during the 12 weeks of the experiment. Mycelia of all species survived for the full term of the experiment in Dead Sea water diluted to 50% and 10% of its original salinity. Comparison of the survival of Dead Sea species and closely related isolates obtained from other locations showed prolonged viability of the strains obtained from the Dead Sea. Spores of isolates obtained from the terrestrial shore of the Dead Sea generally proved less tolerant to suspension in undiluted Dead Sea water than spores of species isolated from the water column. Spores of the species isolated from the control sites had lost their viability in undiluted Dead Sea water within 12 weeks. However, with the exception of Emericella spores, which showed poor survival, a substantial fraction of the spores of Dead Sea fungal isolates remained viable for that period. The difference in survival rate between spores and mycelia of isolates of the same species points to the existence of adapted halotolerant and/or halophilic fungi in the Dead Sea.     

Microsatellite DNA reveals genetically different populations of Atlantic bonito Sarda sarda in the Mediterranean Basin

Microsatellites were used to investigate population genetic structure of Atlantic bonito Sarda sarda from the Black Sea, Marmara Sea, Aegean Sea, north-eastern Mediterranean Sea and Adriatic Sea. Overall average observed heterozygosity was high (0.93). Average observed heterozygosity per locus ranged from 0.79 to 0.98. Pairwise F_ST estimates for all loci between populations ranged from 0 to 0.07626, and significant F_ST values (P < 0.001) were detected between populations; the Blacks Sea and Marmara Sea samples were not significantly different from each other, but significant different from the other samples, and Aegean Sea and north-eastern Mediterranean Sea samples were also not significantly different from each other, but significantly different from all other samples. The Adriatic Sea sample was significant different from all other samples. The Mantel test revealed a significant (P < 0.001, r = 0.68) isolation-by-distance for these 11 populations. Neighbour-joining analysis clustered the Black Sea and Marmara Sea samples together while collections from Aegean Sea and north-eastern Mediterranean Sea were clustered close to each other and far from the others. On the other hand, the Adriatic Sea collection presented very distinctive relationship from the others.     

rDNA analysis of the Red Sea seagrass,Halophila, reveals vicariant evolutionary diversification

The effects of opening the Suez Canal as a connection between the Red Sea and the Mediterranean Sea were reported for a number of marine species. However, the evolutionary origin of the seagrasses in the Red Sea and the linking population genetics of seagrasses between the Arabian Sea, the Gulf of Aden, the Red Sea and the Mediterranean Sea have not yet been investigated in detail. The invasion of Halophila stipulacea Asch. from the Red Sea into the Mediterranean Sea after the opening of the Suez Canal was already recorded. We hypothesize that Halophila ovalis populations in the Red Sea developed through long-term historical processes such as vicariant evolutionary diversification. Seagrass samples were collected along the Egyptian coastline of the Red Sea and analysed by the molecular marker ITS. The sequences were compared with published ITS sequences from seagrasses collected in the whole area of interest. In this study, we reveal the linking population genetics, phylogeography and phylogenetics of two dominant seagrass species, Halophila stipulacea and Halophila ovalis, among species collected in the Red Sea and worldwide. The results indicate that the Red Sea Halophila ovalis populations do not group to Halophila ovalis worldwide, and Halophila major, Halophila ovalis collected worldwide and Halophila ovalis collected at the Red Sea are sister clades. Hence, vicariant evolutionary diversification for Halophila ovalis may occur in the Red Sea.     

Local adaptation and oceanographic connectivity patterns explain genetic differentiation of a marine diatom across the North Sea–Baltic Sea salinity gradient

Drivers of population genetic structure are still poorly understood in marine micro‐organisms. We exploited the North Sea–Baltic Sea transition for investigating the seascape genetics of a marine diatom, Skeletonema marinoi. Eight polymorphic microsatellite loci were analysed in 354 individuals from ten locations to analyse population structure of the species along a 1500‐km‐long salinity gradient ranging from 3 to 30 psu. To test for salinity adaptation, salinity reaction norms were determined for sets of strains originating from three different salinity regimes of the gradient. Modelled oceanographic connectivity was compared to directional relative migration by correlation analyses to examine oceanographic drivers. Population genetic analyses showed distinct genetic divergence of a low‐salinity Baltic Sea population and a high‐salinity North Sea population, coinciding with the most evident physical dispersal barrier in the area, the Danish Straits. Baltic Sea populations displayed reduced genetic diversity compared to North Sea populations. Growth optima of low salinity isolates were significantly lower than those of strains from higher native salinities, indicating local salinity adaptation. Although the North Sea–Baltic Sea transition was identified as a barrier to gene flow, migration between Baltic Sea and North Sea populations occurred. However, the presence of differentiated neutral markers on each side of the transition zone suggests that migrants are maladapted. It is concluded that local salinity adaptation, supported by oceanographic connectivity patterns creating an asymmetric migration pattern between the Baltic Sea and the North Sea, determines genetic differentiation patterns in the transition zone.     

Opisthobranch molluscs of the Sudanese Red Sea

Eighteen opisthobranch species are described and illustrated from the Sudanese Red Sea, including seven new species, one new subspecies and three species for which this is the first Red Sea record. Eleven bullomorphs, four pleurobranchomorphs, four sacoglossans and four phyllidiid mudibranchs are now known from the Red Sea. There appears to be a high percentage of endemic species in the Red Sea. This is what one might expect, in view of the conditions of near isolation, low temperatures and high salinity that prevailed in this sea 13000 23000 years ago. Of the groups discussed in this paper, one Red Sea species has invaded the Mediterranean Sea, and one Mediterranean species has invaded the Red Sea, since the opening of the Suez Canal in 1867. Many Red Sea species are very colourful, in comparison to Mediterranean ones. This could perhaps be because Red Sea waters are cleaner, thereby favouring the evolution of greater precision in colour markings.     

再议中国近海小黄鱼种群的划分问题

以往认为,中国近海小黄鱼可划分为3个种群.本研究从地理隔离、数量动态、形态解剖,分子遗传学和海洋水文等不同方面,重新审视了我国近海小黄鱼（Larimichthys polyactis Bleeker）种群的划分问题.研究表明：中国近海小黄鱼仅仅存在两个种群,即黄海南部和东海小黄鱼种群及渤海和黄海北部小黄鱼种群.主要证据有三：其一,分析1965年至今小黄鱼不同种群形态解剖学和分子遗传学重要文献,发现这些文献的结果仅仅支持黄海南部和东海小黄鱼是一个种群的结论;其二,依据1971-1982年我国10多个主要渔业公司小黄鱼捕捞统计资料,黄海南部和东海的小黄鱼在地理分布上几乎不存在隔离的现象.在冬季外海,黄海南部和东海小黄鱼栖息于同一个越冬场.进入春季后,它们从该越冬场分别向舟山渔场、鱼山渔场和吕泗渔场产卵洄游.同时,东海南部近海越冬场的小黄鱼向北作产卵洄游,在舟山渔场汇入外海来的小黄鱼鱼群中.从5-8月,黄海南部至东海仅存在一个小黄鱼索饵群体.而黄海北部和渤海小黄鱼群体与上述群体存在明显的地理隔离;其三,黄海南部和东海,近年来小黄鱼产量增长趋势一致,而同期的渤海和黄海北部小黄鱼资源量恢复不大.     

Opisthobranch molluscs of the Sudanese Red Sea

Eighteen opisthobranch species are described and illustrated from the Sudanese Red Sea, including seven new species, one new subspecies and three species for which this is the first Red Sea record. Eleven bullomorphs, four pleurobranchomorphs, four sacoglossans and four phyllidiid mudibranchs are now known from the Red Sea.
There appears to be a high percentage of endemic species in the Red Sea. This is what one might expect, in view of the conditions of near isolation, low temperatures and high salinity that prevailed in this sea 13000 23000 years ago.
Of the groups discussed in this paper, one Red Sea species has invaded the Mediterranean Sea, and one Mediterranean species has invaded the Red Sea, since the opening of the Suez Canal in 1867.
Many Red Sea species are very colourful, in comparison to Mediterranean ones. This could perhaps be because Red Sea waters are cleaner, thereby favouring the evolution of greater precision in colour markings.     

Variation of several erythrocyte enzymes in the Dayaks of Sarawak.

The Land and Sea Dayaks of Sarawak were surveyed for several erythrocyte enzymes. The gene frequency of 6PGDC in 132 Land Dayaks and 127 Sea Dayaks were 0.045 and 0.047, respectively. The gene frequency of PGM1-1 IN 285 Land Dayks and 240 Sea Dayaks were 0.716 and 0.779, respectively. The ADA2 gene frequency in 283 Land Dayaks and 188 Sea Dayaks were 0.154 and 0.090. ADA 5-1 was found once in the Land Dayaks and once in the Sea Dayaks. AK 2-1 was found once in 221 Sea Dayaks but not in any of 270 Land Dayaks. No PHI, LDH or CA variants were found among the Land or Sea Dayaks.     

Evidence of a hybrid-zone in Atlantic cod (Gadus morhua) in the Baltic and the Danish Belt Sea revealed by individual admixture analysis

The study of hybrid zones is central to our understanding of the genetic basis of reproductive isolation and speciation, yet very little is known about the extent and significance of hybrid zones in marine fishes. We examined the population structure of cod in the transition area between the North Sea and the Baltic Sea employing nine microsatellite loci. Genetic differentiation between the North Sea sample and the rest increased along a transect to the Baltic proper, with a large increase in level of differentiation occurring in the Western Baltic area. Our objective was to determine whether this pattern was caused purely by varying degrees of mechanical mixing of North Sea and Baltic Sea cod or by interbreeding and formation of a hybrid swarm. Simulation studies revealed that traditional Hardy-Weinberg analysis did not have sufficient power for detection of a Wahlund effect. However, using a model-based clustering method for individual admixture analysis, we were able to demonstrate the existence of intermediate genotypes in all samples from the transition area. Accordingly, our data were explained best by a model of a hybrid swarm flanked by pure nonadmixed populations in the North Sea and the Baltic Sea proper. Significant correlation of gene identities across loci (gametic phase disequilibrium) was found only in a sample from the Western Baltic, suggesting this area as the centre of the apparent hybrid zone. A hybrid zone for cod in the ecotone between the high-saline North Sea and the low-saline Baltic Sea is discussed in relation to its possible origin and maintenance, and in relation to a classical study of haemoglobin variation in cod from the Baltic Sea/Danish Belt Sea, suggesting mixing of two divergent populations without interbreeding.     

The Ecological State of the Waddensea. An Assessment

Since the present quality state of the Wadden Sea is judged more discordantly than that of the North Sea, it is examined whether the Wadden Sea is a separate ecosystem. The nutrient load into the Wadden Sea and the trend of the load are assessed. Biological indicators of the ecological state of the Wadden Sea are examined with the result that there are signs of a bad as well as of a good state. This contradiction is assigned to the fact that quality standards are absent. Self-protection mechanisms of the Wadden Sea are discussed with respect to their responsibility for the relatively good state. A qualitative model is proposed to explain the long-term behaviour of the ecosystem.     

Assessment of primary production in the White Sea

The literature and original data on the primary production of phytoplankton in the White Sea are analyzed. By this parameter, the White Sea is significantly inferior only to the Chukchi Sea; it is similar to the Barents Sea, and exceeds other Russian Arctic seas by two to three times (the Kara Sea, Laptev Sea, and East Siberian Sea).     

Multi-torsking: simultaneous measurements of cod behaviour show differences between North Sea and Irish Sea stocks*

Fish behaviour can vary considerably in response to environmental and biological conditions. We used electronic Data Storage Tags (DSTs) to investigate the behaviour of cod in different environments; 74 North Sea cod and 20 Irish Sea cod were tagged and released in late-March 1999. So far, 32 tags (>2000 days of data) have been returned from the North Sea and four (>700 days) from the Irish Sea. The maximum recorded depth of a North Sea cod was 84 m, while Irish Sea cod utilised a depth range of 154 m. Active depth changes were of greater magnitude and rate in Irish Sea cod than North Sea cod. In addition, Irish Sea cod were continually active and made proportionally more active depth changes than North Sea cod, which were very active during migration (March–June) but exhibited little vertical movement during the summer months. To our knowledge, this is the first time that the behaviour patterns of cod from different stocks have been measured simultaneously over extended periods at such a fine temporal scale. In addition to describing considerable inter-stock differences in behaviour, our results suggest that while cod in the Irish Sea remain active and highly mobile throughout the year, North Sea cod reduce their movements during the summer feeding period. Our findings will contribute to the development of more biologically realistic management models used for evaluating the efficacy of fisheries technical measures, such as closed areas.     

Length–Weight Relationship and Condition Factor of Sixteen Demersal Fish Species from the Southern part of the Marmara Sea,Turkey

Journal of Ichthyology - The Marmara Sea is an important acclimatization zone and biological transition for the biota of the Mediterranean Sea and the Black Sea. Overfishing, pollution, and changes...     

The status of coral reef ecology research in the Red Sea

The Red Sea has long been recognized as a region of high biodiversity and endemism. Despite this diversity and early history of scientific work, our understanding of the ecology of coral reefs in the Red Sea has lagged behind that of other large coral reef systems. We carried out a quantitative assessment of ISI-listed research published from the Red Sea in eight specific topics (apex predators, connectivity, coral bleaching, coral reproductive biology, herbivory, marine protected areas, non-coral invertebrates and reef-associated bacteria) and compared the amount of research conducted in the Red Sea to that from Australia’s Great Barrier Reef (GBR) and the Caribbean. On average, for these eight topics, the Red Sea had 1/6th the amount of research compared to the GBR and about 1/8th the amount of the Caribbean. Further, more than 50 % of the published research from the Red Sea originated from the Gulf of Aqaba, a small area (<2 % of the area of the Red Sea) in the far northern Red Sea. We summarize the general state of knowledge in these eight topics and highlight the areas of future research priorities for the Red Sea region. Notably, data that could inform science-based management approaches are badly lacking in most Red Sea countries. The Red Sea, as a geologically “young” sea located in one of the warmest regions of the world, has the potential to provide insight into pressing topics such as speciation processes as well as the capacity of reef systems and organisms to adapt to global climate change. As one of the world’s most biodiverse coral reef regions, the Red Sea may yet have a significant role to play in our understanding of coral reef ecology at a global scale.     

The first occurrence of the ctenophore <Emphasis Type="Italic">Mnemiopsis leidyi</Emphasis> in the North Sea

After the discovery of large densities of Mnemiopsis leidyi in the Baltic Sea near Kiel by Javidpour et al. (First record of Mnemiopsis leidyi A. Agassiz 1865 in the Baltic Sea, 2006) in October 2006, we investigated the gelatinous zooplankton in the North Sea near Helgoland and recorded Mnemiopsis leidyi for the first time in the North Sea, albeit in much lower densities than those recorded in the Baltic Sea.     

Haptoglobin, transferrin and serum albumin variants in the Dayaks of Sarawak.

The Land Dayaks and the Sea Kayaks of Sarawak were surveyed for haptoglobin, transferrin and serum albumin variants. The Hp1 gene frequency was 0.385 in 283 Land Dayaks as well as in 205 Sea Kayaks. The TfDChi gene frequency in 283 Land Dayaks was 0.030 and in 188 Sea Kayaks it was 0.040. Serum albumin Medan was found in one of the 188 Sea Kayaks.     

The Arabian scad Trachurus indicus, a new Indo-Pacific species in the Mediterranean Sea

The Arabian scad Trachurus indicus is recorded for the first time from the Mediterranean Sea (Iskenderun Bay, Turkey). The presence of this Indo-Pacific fish in the Mediterranean Sea is probably because of migration from the Red Sea via the Suez Canal.     

浙江近海后鳃类软体动物的分布及其区系

报道了浙江近海的后鳃类97种,分别隶属于7目30科44属。其中我国沿岸广温广布种14种,主要分布于东海和南海的亚热带种50种,南海的热带种18种,渤、黄海延伸到东海北部的暖温带种15种。     

Population genetic structure after 125 years of stocking in sea trout (<Emphasis Type="Italic">Salmo trutta</Emphasis> L.)

Stocking can be an effective management and conservation tool, but it also carries the danger of eroding natural population structure, introducing non-native strains and reducing genetic diversity. Sea trout, the anadromous form of the brown trout (Salmo trutta), is a highly targeted species that is often managed by stocking. Here, we assess the present-day population genetic structure of sea trout in a backdrop of 125 years of stocking in Northern Germany. The study area is characterized by short distances between the Baltic and North Sea river watersheds, historic use of fish from both watersheds for stocking, and the creation of a potential migration corridor between the Baltic and North Sea with the opening of the Kiel Canal 120 years ago. A survey of 24 river systems with 180 SNPs indicates that moderate but highly significant population genetic structure has persisted both within and between the Baltic and North Sea. This genetic structure is characterized by (i) heterogeneous patterns of admixture between the Baltic and North Sea that do not correlate with distance from the Kiel Canal and are therefore likely due to historic stocking practises, (ii) genetic isolation by distance in the Baltic Sea at a spatial scale of <?200 km that is consistent with the homing behaviour of sea trout, and (iii) at least one genetically distinct Baltic Sea river system. In light of these results, we recommend keeping fish of North Sea and Baltic Sea origin separate for stocking, and restricting Baltic Sea translocations to neighbouring river systems.     

Spawning of bluefin tuna in the black sea: historical evidence, environmental constraints and population plasticity

The lucrative and highly migratory Atlantic bluefin tuna, Thunnus thynnus (Linnaeus 1758; Scombridae), used to be distributed widely throughout the north Atlantic Ocean, Mediterranean Sea and Black Sea. Its migrations have supported sustainable fisheries and impacted local cultures since antiquity, but its biogeographic range has contracted since the 1950s. Most recently, the species disappeared from the Black Sea in the late 1980s and has not yet recovered. Reasons for the Black Sea disappearance, and the species-wide range contraction, are unclear. However bluefin tuna formerly foraged and possibly spawned in the Black Sea. Loss of a locally-reproducing population would represent a decline in population richness, and an increase in species vulnerability to perturbations such as exploitation and environmental change. Here we identify the main genetic and phenotypic adaptations that the population must have (had) in order to reproduce successfully in the specific hydrographic (estuarine) conditions of the Black Sea. By comparing hydrographic conditions in spawning areas of the three species of bluefin tunas, and applying a mechanistic model of egg buoyancy and sinking rate, we show that reproduction in the Black Sea must have required specific adaptations of egg buoyancy, fertilisation and development for reproductive success. Such adaptations by local populations of marine fish species spawning in estuarine areas are common as is evident from a meta-analysis of egg buoyancy data from 16 species of fish. We conclude that these adaptations would have been necessary for successful local reproduction by bluefin tuna in the Black Sea, and that a locally-adapted reproducing population may have disappeared. Recovery of bluefin tuna in the Black Sea, either for spawning or foraging, will occur fastest if any remaining locally adapted individuals are allowed to survive, and by conservation and recovery of depleted Mediterranean populations which could through time re-establish local Black Sea spawning and foraging.