Nutrients and biomass distribution in the Gulf of Aqaba (Elat), Red Sea

The distribution of phosphate, nitrate and silicate values obtained from 300 samples and of biomass determined by displacement volume in about 1,900 vertical plankton hauls (65, 200 and 330 m) collected from 8 oceanographic station during 1974–1975 in the Gulf of Aqaba (Elat) are summarized and illustrated by crosssections. Generally, the Gulf is poor in nutrients and the data indicate that it is filled with upper (150 m) Red Sea waters, flowing in over the sill of Tiran. Nutrient content of the upper and deep waters immediately outside the sill are well within the known range of those in the northern Red Sea. Biomass values are relatively low in the Gulf are generally similar to those reported from the northern Red Sea. Both nutrients and biomass values display seasonal and bathymetric variations in the Gulf and outside the sill.     

Possible strategy for the survival of marine bacteria under starvation conditions

A population of a psychrophilic marine vibrio (Ant-300) suspended at a low cell density in natural seawater (SW) or artificial seawater (ASW) showed an initial 200-fold increase in cell numbers. Ant-300 suspended in ASW at various densities showed a magnified initial increase in numbers as well as increased longevity as the population density decreased. The magnitude of the initial increase and the viability of the cells after 7 weeks continued incubation were the same whether the cells were suspended in SW, ASW amended with amino acids, or organic-free ASW. Continued incubation (long-term starvation) of a culture of Ant-300 at low cell densities in ASW showed that after 70 weeks over 15 times the orginal number of cells were still viable. When compared to the starvation survival of other bacceria, Ant-300 exceeds the longest reported starvation survival by at least 2.5 times. Our data indicate that Ant-300 is especially adapted for survival at low nutrient concentrations and low population densities due to a sustained increase in cell numbers that may represent a species survival mechanism for marine bacteria.Technical Paper No. 4493, Oregon Agricultural Experiment Station.     

Development of a new antifouling method for a marine cooling water system

Variations in meristic characters occur within and between samples of milkfish Chanos chanos (Forsskal) collected on June 1977 from five localities in Philippine waters. The unbranched anal and ventral fin rays are the most plastic, and vertebral number is the most stable of nine meristic characters examined. The number of ventral fin rays is the only meristic feature which differed consistently enough to suggest distinct population groups: South China Sea, comprising samples from Ilocos and Panay Island; Pacific Ocean from Bicol; and Celebes Sea, from Zamboanga and Davao. A discriminant analysis which incorporated generalized distance (Mahanalobis D²) and percent overlap of a reduced set of characters indicated several morphometric subgroups of milkfish in Philippine waters, although geographic subgroups were not clearly demonstrated.SEAFDEC Contribution No. 218     

Population genetic structures of the fissiparous seastar Coscinasterias acutispina in the Sea of Japan

The morphological characteristics and the population genetic structures of the fissiparous seastar Coscinasterias acutispina were investigated for eight sites in the Sea of Japan in order to clarify the presence of sexual and asexual reproduction. Morphological observation based on arm length showed that fission was common at all eight sites examined, indicating the likely production of clonal individuals. A random amplified polymorphic DNA (RAPD) marker was used to detect clones arising by fission and to assess gene flow among sites. A simulation approach using RAPD data revealed the presence of clonal individuals at almost all sites, suggesting the existence of asexual reproduction. The result of phylogenetic analysis according to RAPD genotype showed no relationship between genetic and geographic distances. Considering the limited movement ability of seastar species during the adult phase, these observations suggest the existence of marked gene flow among sites, due to dispersal of planktonic larvae produced by sexual reproduction. These observations suggest that multi-locus genotypic compositions depend on the relative amounts of recruitment from sexual and asexual reproduction in each population.     

A simple approach to modeling microbial biomass in the rhizosphere

Microorganisms make an important contribution to the degradation of contaminants in bioremediation as well as in phytoremediation. An accurate estimation of microbial concentrations in the soil would be valuable in predicting contaminant dissipation during various bioremediation processes. A simple modeling approach to quantify the microbial biomass in the rhizosphere was developed in this study. Experiments were conducted using field column lysimeters planted with Eastern gamagrass. The microbial biomass concentrations from the rhizosphere soil, bulk soil, and unplanted soil were monitored for six months using an incubation–fumigation method. The proposed model was applied to the field microbial biomass data and good correlation between simulated and experimental data was achieved. The results indicate that plants increase microbial concentrations in the soil by providing root exudates as growth substrates for microorganisms. Since plant roots are initially small and do not produce large quantities of exudates when first seeded, the addition of exogenous substrates may be needed to increase initial microbial concentrations at the start of phytoremediation projects.     

交联壳聚糖冠醚的合成及其对金属离子的吸附性能

本文合成了交联壳聚糖苯并－１５－冠－５醚和交联壳聚糖苯并－１８－冠－６醚,研究了它们对Ａｇ（Ⅰ）Ｐｄ（Ⅱ）,Ｐｂ（Ⅱ）,Ｃｄ（Ⅱ）,Ｃｒ（Ⅲ）等金属离子的吸附性能和选择性,实验结果表明：无论是在单一金属离子体系还是在二元或三元金属离子体系中,ＣＣＴＳ－ＢＸ和ＣＣＴＳ－ＢＹ对Ａｇ（Ⅰ）和Ｐｄ（Ⅱ）者有较高的吸附选择性。     

GUS基因在诸葛菜子叶原生质体中的瞬间表达

本文以诸葛菜无菌苗子叶组织为材料，采用原生质体培养获得成功，建立了原生质体培养高频再生体系，植板率３％，植株再生频率１００％。在此基础上，本文首次研究了ＰＥＧ介导转化诸葛菜原生质体的影响因素，系统地试验了ＰＥＧ法转化子叶原生质体的过程，发现：最适质粒量为２５－３０μｇ；ＰＥＧ终浓度为１５％，ｐＨ８．０；另外，表达效率还与质粒的大小有关，较小的质粒具有相对较高的转化效率；而ＣＴ－ＤＮＡ以及热击处理未     

Cadmium bioaccumulation in organs of the scallopMizuhopecten yessoensis

Cadmium and Zinc content was determined in organs of the Japanese scallopMizuhopecten yessoensis, collected in 1984 from the Sea of Japan and aged between 1 and 8 yr. Under conditions of background Cd, Cd concentration in hepatopancreas and kidney increased linearly with age from 39 to 400µg g^?1 dry wt in hepatopancreas, and from 100 to 640µg g^?1 dry wt in kidney. Such a pattern was not determined for Zn. Cd concentration in muscle, mantle and gill did not exceed 6µg g^?1 dry wt in the oldest scallops. In subcellular fractions of the hepatopancreas, cytosolic Cd accounted for 71.7% in 1-yr-old scallops and 98.8% in 8-yr-olds. A similar ratio was established for gills, although gill Cd content was an order of magnitude lower. Analysis of Cd distribution in cytoplasmic proteins (of different molecular weight) in the hepatopancreas, showed that the amount of Cd bound to metallothionein-like proteins increases with scallop growth. A considerable amount of Cd also was detected in high molecular weight proteins. Thus, Cd accumulation, with age, in organs of the Japanese scallop is due to metal binding by cytoplasmic proteins.     

Bioaccumulation and elimination of copper in the rock oyster Crassostrea cucullata

The kinetics of copper bioaccumulation in the rock oyster Crassostrea cucullata Born showed that the initial rate of uptake was directly related to metal concentration in the medium. As the accumulation in the tissues increased, the oysters remained closed and the uptake rate fell. At the end of 7 weeks, the average copper concentrations in the tissue were 60.42 g g^-1 and 63.97 g g^-1 wet weight in the 0.01 and 0.05 ppm experimental groups, respectively. The net rate of uptake ranged from 1.76 to 1.97 g g^-1 week^-1 and the rate of copper loss, measured after transferring the oysters into natural sea water, was dependent on the original cooper concentration in the soft parts. The concentration of copper in the tissues declined by 37.38 and 36.56% in the 0.01 and 0.05 ppm experimental groups, respectively. Even after a 7 week period of depuration (self-purification) there was some residual copper left in the tissue. This indicates that accumulation occurs in the tissue more rapidly than cleansing can eliminate it.     

围栏禁牧对川西北亚高山高寒草甸群落结构的影响

围栏禁牧4a后,与放牧草地相比较:1)围栏草地物种数量有所下降,群落内出现物种27种,而长期放牧草地为33种.2)围栏草地物种平均高度较高,为20.23cm,群落分层现象明显;放牧草地物种平均高度仅为8.14cm,群落无分层现象.3)围栏草地内,杂草类的盖度(98%)大于禾草类的盖度(14%);放牧草地上,杂草类的盖度(53%)小于禾草类的盖度(56%)。4)围栏草地以禾草为主的优良牧草的生产能力(35.24g/m2)低于放牧草地的生产能力(75.47g/m2).5)围栏草地的地上生物量(272.64g/m2)和地下0～30cm生物量(801.61g/m3)都高于放牧草地的地上生物量(184.84g/m2)和地下0～30cm生物量(683.82g/m3).研究结果表明,围栏草地具有比放牧草地更复杂的群落结构,但其物种组成和优良牧草的生产能力,都低于放牧草地.