The characteristics of distribution and change of the seawater temperature and salinity of Cai river estuary and Northern Part of Nha Trang bay in the dry and rainy season

In this paper, some results of analyzing the hydrographic characteristics of the seawater temperature and salinity are presented. The received results showed that: in dry season, the influence of the Cai river water has is limited in Cai river estuary with the approximate transferable distance from the river mouth to the open sea of about 1 km. The isohaline 32%o could be defined as the separate boundary of the Cai river water; In rainy season, due to the river water discharges are high, the influence of Cai river water could be transferred to the open sea and island areas. The immerge of the Cai river water in the open sea areas in rainy season has changed the vertical structure of salinity and temperature in the northern part of Nhatrang bay. In both seasons, the Cai river water have influenced in the surface water layers 0 - 2m and the water layers deeper than 2m are influenced by the sea waters with the salinity of higher than 32%o.

The effect of spirulina (fresh and dry) on some biological factors in Penaeus semisulcatus larvae

Spirulina is a filamentous cyanobacteria with many applications in food and drug industries, as a food in human, aquaculture, vet and poultry industries… . Semi and mass culture of Spirulina carries out in different countries. This study was carried out in five phases in order to produce this microalga in Iran. The first phase, Spirulina pure stock was imported from Indonesia. After identification of species, it was cultured in laboratory until we took 20 liters of biomass. The semi-mass culture was carried out in green house. Cell concentration and size of Spirulina were recorded during culture daily and their growth rates were calculated. After two weeks, when the size of Spirulina was suitable, biomass of Spirulina was harvested then accumulated Spirulina weighted and dried in 24 hours in laboratory. In order to microbiological study, the samples of Spirulina (dry and fresh) were cultured on blood agar medium and coliforms were counted. The chemical composition of produced Spirulina was measured by standard methods. Fatty acid and amino acid profiles were acquired by GC and HPLC instruments, respectively. The amount of chlorophyll in Spirulina was determined by spectroscopy method. Also astaxanthin pigment as an important carotenoid was measured by HPLC in Spirulina and Penaeus semisulcatus larvae fed on Spirulina. At final phase of this project, larva fed on produced Spirulina (biomass and dry powder) was compared to Z plus, microencapsulated Spirulina (M.C.F) and Chaetoceros algae as control. This experiment was carried from zoa to early post larvae stage then survival and growth rate of larvae were recorded. The growth rate of larvae was evaluated with ANOVA test and survival rate of treatments was assessed by Log Rank (Mantel –Cox) test. Also during larvae stage, two parameters of water such as nitrate and nitrite were measured in zoa, mysis and post larvae stages. The results of this study were shown that colifom counts were 1.85×106 and 92.3×105 coliform per ml in fresh and dry spirulina, respectively. Protein percent of dry spirulina was 50.93 % (dry weight) and the amount of astaxanthin in spirulina and larvae fed on spirulina were 0.21 and 0.01 mg/kg, respectively. The most survival rate of larvae were observed in zoa III (88.8%) with Z plus supplement treatment, in mysis III (76.5%) combination of Z plus and dry spirulina in comparative between treatments. Larvae growth (4.5mm) of control in early post larvae was the best.

Plant nutrients and major ions in the Little Sea, Studland, Dorset

This short paper records some measurements made on the Little Sea, a shallow, coastal, acidic lake on Studland Heath, Dorset. The lake, formed about 100 years ago by dunes cutting off a sea inlet, has not received any input of agricultural fertilizers or other waste products for at least the last 30 years. It is a Site of Special Scientific Interest (SSSI). Samples of surface water were taken from the northern and southern ends of the lake at 3-monthly intervals, from July 1995 to April 1996. The first samples in July 1995 were taken during a period of drought; rain, sometimes very heavy, came in late September. With the exception of silicate, potassium and phosphate, there were no large changes in plant nutrient concentrations during the year. The concentration of nitrate-nitrogen was very low (close to the limits of analytical detection), but total phosphorus at ca. 30 mu g per litre was similar to concentrations found in some of the Cumbrian eutrophic lakes. The large number of algal species at low cell/colony concentrations suggested that the lake is mesotrophic. Sodium, chloride and magnesium in the lake water were close to the same proportions as those found in sea water. Dry and wet deposition of sea-salts on the lake surface and its catchment area probably is the major source of sodium, magnesium and chloride ions in the lake, and also accounts for about half of the mean potassium and sulphate concentrations.

Patterns of orographic uplift in the Sierra Nevada and their relationship to upper-level atmospheric circulation

We examine monthly and seasonal patterns of precipitation across various elevations of the eastern Central Valley of California and the Sierra Nevada. A measure of the strength of the orographic effect called the “precipitation ratio” is calculated, and we separate months into four groups based on being wet or dry and having low or high precipitation ratios. Using monthly maps of mean 700-mb height anomalies, we describe the northern hemisphere mid-tropospheric circulation patterns associated with each of the four groups. Wet months are associated with negative height anomalies over the eastern Pacific, as expected. However, the orientation of the trough is different for years with high and low precipitation ratios. Wet months with high ratios typically have circulation patterns factoring a west-southwest to east-northeast storm track from around the Hawaiian Islands to the Pacific Northwest of the United States. Wet months with low precipitation ratios are associated with a trough centered near the Aleutians and a northwest to southeast storm track. Dry months are marked by anticyclones in the Pacific, but this feature is more localized to the eastern Pacific for months with low precipitation ratios than for those with high ratios. Using precipitation gauge and snow course data from the American River and Truckee-Tahoe basins, we determined that the strength of the orographic effect on a seasonal basis is spatially coherent at low and high elevations and on opposite sides of the Sierra Nevada crestline.

Physical, chemical, and biological characterization of water year types in the San Francisco Bay estuary [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Twenty-three years of physical, chemical, and biological data were used to characterize conditions associated with wet, normal, dry, and critical water year types in the upper San Francisco Bay estuary.

Challenges to effective fishing and preferred fishing gear in a hydrodynamic freshwater system

Challenges to fishing and preferred gear of multiple used Lake, whose water depth is controlled by opening of its dam gate were investigated. Geographic survey, interview and focused group discussion of fishermen were used to assess factors influencing effectiveness of fishing and the preferred gear of Asejire Lake. Water usage (s) such as frequency of Complete and Partial Opening of Dams Gate (CODG and PODG) were investigated as indices for hydrodynamic condition. Response during focused group discussion with about 33% of fishermen of the Lake were obtained on sources of disturbance to effective fishing (SDEF), most effective gear (MEG)- least environmentally perturbed gear, comparability of catch structure of preferred gear to conventional gear and sustainability of superiority of preferred gears in situations outside hydrodynamic condition (SSPPG). The PODG occurred 1-7times/Month-dry season, 15-18times/Month-wet season; CODG occurred 1-2times/Month in both season; Interval of CODG was 3-17 and 5-12days (dry and wet season). It affected set-net and catch. The SDEF were gear availability, weather condition, dam’s gate opening, religion activities and Health of fisher-folks. 50% respondents accepted opening of dams gate as most important disturbance while religion was least (5% respondents accepted). 60% respondents accepted traps as MEG being the least affected while 75% respondents accepted Gura cage trap as the MEG among traps.90% respondents accepted that among traps, its catch structure was closest (comparable) to conventional gear. However, 75% respondents rejected SSPPG. Opening of dams’ gate creates hydrodynamic condition and it affects fishing. Gura trap was preferred for fishing hydrodynamic condition.

Biomonitoring of polycyclic aromatic hydrocarbons (PAH) and heavy metals Ni, V in sediments and anodonts of the Anzali Lagoon and applicability of netural red retention assay (NRR) as biomarkers of these pollutants

Biochemical ecotoxicology and biomarkers using are a new sciences that are used for biomonitoring in aquatic environment. Biomonitoring plays a vital role in strategies to identify, assess, and control contaminants. On the other hands in recent year's attention to polycyclic Aromatic Hydrocarbons (PAHs) and heavy metals increased in aquatic environments because of their carcinogenic and mutagenic properties combined with their nearly ubiquitous distribution in depositional environments by oil pollution or industrial waste waters. The present research aimed to assess PAHs and Ni, V levels in surface sediments and bivalves (Anodonta cygnea)and the effects of PAHs and heavy metals (Ni,V) on the hemocyte of the Anodonta cygnea were investigated in 2 stations (Mahrozeh, Selke in Anzali Lagoon, North of Iran). Samples were collected during at 2 different periods of the year, Dry and rain seasons, (June & September) and to confirm our first observations, Cage station is added. The bivalves hemocytes were monitored for membrane injury by NRR methods (neutral red retention assay). Heavy metal (Ni, V) concentrations were determined by Atomic Absorption in Anodonta cygnea and the sediments in Anzali Lagoon. The vanadium concentration in bivalves and sediments was ND(not detect )-0.4231 μg/g and 1.4381-306.9603 μg/g dry weight respectively. Nickel concentration in bivalves and sediments was 0.0231-1.3351, 0.4024-19.3561 μg/g dry weight respectively. PAHs concentrations were determined by GC-Mass in Anodonta cygnea and the sediments. Average concentration of PAHs is 115-373.788 ng/g dry weight in bivalves and average concentration of PAHs is 34.85-1339.839 ng/g dry weight in sediments. Bioaccumulation sediments factor(BASF) is high about PAHs (>1) and BASF is low for Ni, V (<1) . Internal Damage mechanisms of bivalves hemocytes (cell mortality, dye leakage, decreased membrane stability, are observed (Lowe Methods). Statistical analysis was used to explore the relationship between altered cellular and above contaminants. There are power and negative correlations between PAHs and NRR method for hemocytes in Anodonta cygnea (P<0.0005), but good correlation is not observed between Ni, V and NRR method for hemocytes in every time. This research indicates that the NRR assay is a useful screening technique able to discriminate polluted sites and at first we announce that Anodonta cygnea hemocytes are efficient biomarker for PAHs pollutants in fresh water.

Oceanographic atlas of habitats of larval tunas in the Pacific Ocean off the Azuero Peninsula, Panama

This report presents maps and statistics of summaries by season (dry and wet) of temperature, salinity, density, oxygen concentration, and oxygen saturation at six depths (0, 3, 10, 30, 50, and 100 m) in the Pacific Ocean off the Azuero Peninsula, Panama. Profiles made with a conductivity-temperature-pressure (CTD) probe on a 14-station grid from July 1989 through August 1991 provide the basis for these products. (PDF contains 37 pages.)

Seasonal variation of some trace metal concentrations in some fish species on stretch of River Kubanni, Zaria

In a semi-urbanized stretch of river Kubanni, Zaria, seasonal variations of some tree metals (copper, zinc and lead) in fish species (Clarias sp., Tilapia sp and Alestes sp) were investigated over a period of eight months. Water and fish were sampled monthly, pooled separately and seasonal analysis of each trace determined using atomic absorption method. The concentration of each of the elements in water higher in the dry season than during the rainy season. The dry and rainy season concentrations of copper, zinc and lead were 6.85~c10.66 mu gg super(-1)&1.45~c1.10 mu gg super(-1); 2.13~c1.68 mu gg super(-1)&0.1 5~c0.05 mu gg super(-1); and 0.52~c0.50 mu gg super(-1) & 0.31~c0.14 mu gg super(-1) respectively. Similarly, all the three accumulated more zinc and lead in the dry season than during the rainy season. Tilapia species and to some extent, Alestes species being pelagic had a higher concentration of trace metals than Clarias species which is a bottom dwelling fish Tilapia species may therefore be a better indicator species than Clarias species for monitoring trace metals in water bodies. Reasons for the observed variations in the trace metals were discussed

Has the California drought returned?

In 1993, enough rain and snow fell to end the 1987-1992 drought in California, at least in most areas. The 1994 season has again been dry and has given rise to questions about whether the drought has returned. But carryover reservoir storage from 1993 has been good and will be meeting a portion of the state's water needs this year. Concern about 1995 has placed California in a "drought watch" mode for 1994, a stage indicating caution but not yet a full drought.

Studies on the transportation of live clams

Live clams (Villorita cyprinoides) collected from their natural beds were packed in different ways like dry pack, tray pack, in oxygenated water (wet pack) and depurated samples in wet pack. It was found that the packaging in l kg lots in 200 gauge polythene bags with oxygen at a temperature of 20°C could keep them live for 4 days. In tray pack without oxygen and water they can be kept alive for 3 days at 20°C. Temperature seems to be the critical factor in the transportation of live clams. At room temperature both dry and wet pack can be kept for 24 h only. Depuration technique does not appear to be useful in prolonging the storage life of clams in live condition as percentage mortality is more at 48 h both at 20°C and room temperature compared to the non-depurated samples.

Rapapport's broth, a better enrichment medium in the identification of Salmonella from processed frog legs

Live clams (Villorita cyprinoides) collected from their natural beds were packed in different ways like dry pack, tray pack, in oxygenated water (wet pack) and depurated samples in wet pack. It was found that the packaging in l kg lots in 200 gauge polythene bags with oxygen at a temperature of 20°C could keep them live for 4 days. In tray pack without oxygen and water they can be kept alive for 3 days at 20°C. Temperature seems to be the critical factor in the transportation of live clams. At room temperature both dry and wet pack can be kept for 24 h only. Depuration technique does not appear to be useful in prolonging the storage life of clams in live condition as percentage mortality is more at 48 h both at 20°C and room temperature compared to the non-depurated samples.