Algal community used for assessment of water quality of Haranbaree dam and Mosam river of Maharashtra

An algal community was used to assess the quality of water of Haranbaree dam and Mosam river of Maharashtra. Pollution tolerant genera and species of 4 groups of algae from each of 3 stations of Haranbaree dam and Mosam river were recorded. By using Palmer's index of pollution for rating of water samples the total score of each station of study area was greater than 20 indicating the confirmed high organic pollution. 34 pollution tolerant genera were recorded at all stations of dam and river. Out of 34 pollution tolerant genera, 27 genera and 33 genera were observed at the dam and river sites respectively. In present study 22 pollution tolerant species are observed at dam and river sites.     

Inbreeding Depression, Environmental Stress, and Population Size Variation in Scarlet Gilia (Ipomopsis aggregata)

Despite a large body of theory, few studies have directly assessed the effects of variation in population size on fitness components in natural populations of plants. We conducted studies on 10 populations of scarlet gilia, Ipomopsis aggregata , to assess the effects of population size and year-to-year variation in size on the relative fitness of plants. We showed that seed size and germination success are significantly reduced in small populations (those 100 flowering plants) of scarlet gilia. Plants from small populations are also more susceptible to environmental stress. When plants from small and large populations were subjected to an imposed stress (combined effects of transplanting and experimental clipping, simulating ungulate herbivory) in a common garden experiment, plants from small populations suffered higher mortality and were ultimately of smaller size than plants from large populations. In addition, experimental evidence indicates that observed fitness reductions are genetic, due to the effects of genetic drift and/or inbreeding depression. When pollen was introduced from distant populations into two small populations, seed mass and percentage of germination were bolstered, while pollen transferred into a large population had no significant effect. Year-to-year variation in population size and its effects on plant fitness are also discussed. In one small population, for example, a substantial increase in size from within did not introduce sufficient new (archived) genetic material to fully overcome the effects of inbreeding depression.     

Vertical community structure and ontogenetic distribution of chaetognaths in upper pelagic waters of the Eastern Mediterranean

The vertical distribution of chaetognaths and their developmental stages were investigated in the pelagic waters (0 to 500 m) of the Eastern Mediterranean Sea. Twenty vertical hauls were taken during autumn 1991 in the Ionian, Cretan, Levantine and Rhodes Seas. The chaetognaths Sagitta bipunctata and S. enflata had the same median depth distributions, which differed from those of S. minima, S. serratodentata, S. lyra, Krohnitta subtilis, and S. decipiens, while S. hexaptera occurred only sporadically. S. bipunctata and S. enflata were mainly restricted to <50 m, and while their distributions co-occurred their stage composition differed. The remaining species took up progressively deeper positions in the water column. Ontogenetic vertical distributions, with the older stages occurring at greater depth, were only observed for the mesopelagic species S. lyra and S. decipiens. Diurnal vertical migration was not detected in any of the species nor in their developmental stages.     

马氏甲烷八叠球菌S－6的一个染色体区段的表达、序列分析和结构分析

用一组多克隆抗体对马氏甲烷八叠球菌（Ｍｅｔｈａｎｏｓａｒｃｉｎａｍａｚｅｉ）Ｓ－６菌株的基因组ＤＮＡ文库进行了筛选．仅选出ｐ６０Ａ克隆能对马氏甲烷八叠球菌中可发生细胞形态学变化菌株的抗血清发生阳性反应．对ｐ６０Ａ克隆的双链ＤＮＡ进行了序列分析．识别出一开式阅读框架（ｏｐｅｎｒｅａｄｉｎｇｆｒａｍｅＰ，ＯＲＦＰ）．表达的蛋白是ＯＲＦＰ编码的蛋白的３倍，并得到ＯＲＦＰ蛋白的三聚体，在ＳＤＳ－ＰＡＧＥ中表现出整体蛋白的迁移行为．同时，此表达蛋白抗１０％ＳＤＳ，６ｍｏｌ／Ｌ尿素及热处理．基因结构分析表明，ＯＲＦＰ具有与Ｍ．ｂａｒｋｒｉｍｃｒＡ有同源性的核糖体结合位点和一个与甲烷细菌启动子共有序列相似度达７７％的启动子序列．使用参照序列分析表明，由ＯＲＦＰ演绎的氨基酸序列，具有高密度的带电荷的氨基酸和占优势的β－层迭构型．对此表达蛋白作了Ｎｅｕｒｏｓｒｏｒａｃｒａｓｓａ的ｐｏｒｉｎ蛋白抗血清试验，以研究其可能功能．检验了Ｍ．ｍａｚｅｉＳ－６细胞的蔗糖梯度制备物，对此原细胞中的ＯＲＦＰ蛋白作了定位．结果表明，ＯＲＦＰ蛋白可能是一种古细菌Ｐｏｒｉｎ，其在Ｍ．ｍａｚｅｉＳ－６中的表达，可能象大肠杆菌那样与渗透压调节有关．     

Biodegradation of shells of the black pearl oyster,Pinctada margaritifera var. cumingii,by microborers and sponges of French Polynesia

The composition, distribution and infestation sequence of organisms that destroy the commercially valuable shells of the black oyster Pinctada margaritifera var. cumingii Jameson, 1901 were studied. Three ecologically different groups of boring (euendolithic) organisms were identified: (1) phototrophic boring microorganisms (cyanobacteria, Hyella caespitosa, Hyella sp., Mastigocoleus testarum, Plectonema terebrans, and green algae, Phaeophila dendroides, Ostreobium quekettii); (2) heterotrophic boring microorganisms (fungi, Ostracoblabe implexa); (3) filter-feeding boring organisms (sponges, Cliona margaritiferae, C. vastifica). The phototrophic endoliths dominate the external pristmatic region of the shell, whereas the valuable interior nacreous region is attacked mainly by heterotrophs. Boring patterns reflect in part the shape and behaviour of the organisms and in part the structural properties of the shell, and inflict different types of damage. Infestation starts with microbial borers, which prepare the conditions for later invasion by more damaging clionid sponges. The infestation begins always at the apex, the oldest part of the shells, from which the periostracum is often removed by natural attrition or by cleaning procedure. The rate of bioerosion in 1 yr-old hatchery shells is 36 times higher than in natural populations.     

Population structure of red drum (<Emphasis Type="Italic">Sciaenops ocellatus</Emphasis>) as determined by otolith chemistry

To examine current genetic-based paradigms pertaining to the structure and possible philopatry of red drum populations, we used solution-based inductively coupled plasma-mass spectrometry (ICP-MS) to analyze the otolith chemistry of juvenile red drum (Sciaenops ocellatus) from eight different estuaries in the Gulf of Mexico (Gulf) and the North Atlantic Ocean. One estuary (Tampa Bay, Fla.) was sampled in three different years. Analyses of variance for five elemental ratios (Mg/Ca, Mn/Ca, Zn/Ca, Sr/Ca, Ba/Ca) were all significantly different between estuaries, as was a multi-element signature (MANOVA, Pillais trace F _{50, 1020}=19.41, P<0.0001). We also found that red drum from the Gulf could be distinguished from those taken from the Atlantic Ocean with 99.5% accuracy, likely due to differences in water chemistry between these water masses. A discriminant function developed using these elemental ratios was more than 80% accurate in assigning juvenile red drum to their natal estuary, or in the case of Tampa Bay, to the correct year of spawning. We also used laser ablation ICP-MS to examine the otolith core chemistry of adult red drum collected from spawning aggregations near Tampa Bay. Using a discriminant function analysis with a calibration data set derived from juvenile signatures, we found that 75% of the adult cores matched the juvenile signal established for Tampa Bay 1982. Although preliminary, the results presented here suggest that red drum may return to their natal estuary to spawn, which has been postulated from genetic data.Communicated by P.W. Sammarco, Chauvin     

Occurrence of lysozyme in the common cockle Cerastoderma edule and the effect of the tidal cycle on lysozyme activity

In 1983 a sample of cockles [Cerastoderma edule (L.)] was removed from the mid-tide level at Booterstown Strand, County Dublin, Ireland at 2-h intervals, for a period of 24 h. The gills, mantle and visceral mass tissues contained significant levels of lysozyme, with the gills containing the highest, weight-specific levels. A tidal rhythm of lysozyme activity in the gills, mantle and visceral mass was inversely related to the tidal cycle. The data were best described by a tidal curve shifted-5 hours out of phase, with maximum and minimum levels of activity occurring one hour after low and high tides, respectively. In marine bivalves, lysozyme may be involved in the extracellular digestion and absorption of bacteria during low tide. In this context the present use of bivalves as biological indicators of bacterial pollution is discussed.Constribution No. 6282 from the Woods Hole Oceanographic Institution     

Bacterial colonization and endocytosis on the gill of a new limpet species from a hydrothermal vent

Calcification rates in different fragments along branches of the hermatypic coral Stylophora pistillata were tested in the laboratory using a new technique, the optic glassfiber method. By this method, the tested colony remains constantly in dark conditions while a narrow beam of light, transferred through the optic fiber, illuminates a small distinct point of coral tissue (on a branch tip or base). The selected illuminated portion of the branch serves as the experimental fragment, while all the other parts of the same colony serve as the dark controls. The results indicate that significantly more calcium is incorporated in the tip fragments than in the bases, both in light and in dark conditions (4.1 to 13.2 times more). Illumination of the tips or the bases did not stimulate or enhance the calcification rates of these fragments. Thus, in all colonies tested, the calcification rates of the illuminated fragments were not significantly different from the average rates of other similar, non-illuminated fragments of the same colony. It is suggested that light does not directly enhance calcification in hermatypic corals, but rather, that light enhances O₂ production, which consequently stimulates coral metabolism. Our preliminary results indicate that calcification rates recorded in aerated dark experiments are significantly higher than calcification rates of non-aerated dark controls.     

Distribution and variability in abundance ofSchistomysis spiritus (Crustacea: Mysidacea) in the Bristol Channel in relation to environmental variables,with comments on other mysids

Mysids are important components of the zooplankton biomass of estuaries and coastal regions. Twelve species were identified from the Bristol Channel and Severn Estuary (British Isles). The most abundant species wasSchistomysis spiritus (Norman), the majority of which occurred in the Channel within a salinity range of 27 to 34 S. The seasonal distribution and numerical abundance of this species are described over the period November 1973 to February 1975. The peak of abundance ofS. spiritus occurred in the Inner Channel in September (mean of 14 individuals m^-3, ca. 250 individuals m^-2 for this sub-region) when it represented 76% of the omnivore biomass (g C m^-3); for the 364 d from 4 November 1973, the species contributed 43% of the total integrated omnivore standing stock. This peak of biomass was the product of the development of the juveniles from the reproductive period in the spring. Correlation analyses were carried out betweenS. spiritus biomass and 10 physical and biotic variables for 2 mo, November 1973 and September 1974. Temperature and salinity, which are simple indices of seasonal change, exhibited significant correlations with the mysid's abundance in both months. These correlations do not necessarily imply causal relationships or mechanisms between the distribution and abundance of the species and these variables. Clearly, in such a complex environment as an estuarine ecosystem a single variable is unlikely to control the abundance of a species, it is more the result of the combined influence of a number of variables acting in concert.     

An economic assessment of air pollution damages to selected annual crops in Southern California

Agricultural production is influenced by many factors beyond the control of individual producers. In recent decades, air pollution has become one of these exogenous factors. This study uses a price-endogenous mathematical programming model to assess the economic benefits of reducing 1976 ambient oxidant exposures of 14 annual crops in southern California. A measure of the distributional consequences of these benefits across producers, consumers and locations is also provided. Results indicate that 1976 benefits of control for the fourteen included crops would have been approximately $46 million.