Oligohaline Waters Research Articles

Two new species of Pseudoniphargus (Amphipoda), in Bermudian groundwaters*

The genus Pseudoniphargus comprises a number of stygobiont Amphipoda, distributed on both sides of the Atlantic. In Bermuda, groundwaters are inhabited by two species. P. grandimanus and P. carpalis, both new. They occur throughout the entire salinity spectrum, from infrahalne to euhaline, but are most abundant in oligohaline waters. Large adults, but no ovigerous specimens. arc found at greater distance from the sea coast than juveniles, which may indicate that Pseudoniphargus needs anchihaline/marine waters for its reproduction and that juveniles migrate inland to grow up.

The Barnacle, Balanus subalbidus, as a Salinity Bioindicator in the Oligohaline Estuarine Zone

The distribution and size of the barnacle Balanus subalbidus were studies along salinity gradients in coastal Louisiana and Mississippi. It was common in gradient estuaries occurring in salinities ranging from near fresh water to 16 ppt. It was the dominant barnacle species in the oligohaline zone, but at salinities above 6 ppt its relative abundance decreased and it was replaced by B. improvicus and B. eburneus. Its low-salinity limit corresponded to the boundary between the oligohaline and fresh water estuarine salinity zones and there was a high negative correlation between size (basal rostral-carinal diameter) and salinity. Its size and distribution could be used to determine prevailing salinity at a site because of its abundance and uniform distribution in oligohaline areas.

Salt tolerance, salt preference and blood sodium regulation inGammarus roeseli Gervais, 1835 (Crustacea: Amphipoda)

1. The salt tolerance, the salt preference and the blood sodium regulation at 15°C ofGammarus roeseli from running fresh water were studied. 2. It tolerates diluted sea water of 1‰ Cl' better than habitat water. 3. It prefers the habitat water when able to choose suparnormal salinities. 4. Both the tolerance and the presence of preferential behaviour may point to a non-freshwater status. 5. G. roeseli has a hyperosmotic blood sodium regulation. Comparison of the blood sodium concentration of gammarids from fresh water and oligohaline waters shows that the environmental sodium content mostly does not give information on the blood sodium level.

北陸地方におけるプランクトンと塩分濃度との関係について

The writer has made a limnological investigation of five lakes and the rivers connecting with them in the Hokuriku district, with special reference to the relation between the salinity of the waters and the plankton species found there. The results obtained are as follows : 1. Forms of the watersA. Lakes1) Kahoku-gata…Mesohaline water2) Kita-gata…Fresh water-polyhaline water3) Imae-gata…Oligohaline water4) Kiba-gata (south-west) Shibayama-gata…Fresh waterB. Rivers a. Kakehashi-gawa1) at Sumiyoshi-bashi…α Mesohaline water2) at Shiodome-bashi at Mukaimotoori-shinbashi…Oligohaline water b. Kushi-gawa3) Muramatsu-cho…Fresh water-oligohaline water c. Shinhori-kawa4) at Genpei-bashi at Shiodome-suimon…Fresh water2. PlanktonThe plankton consist of 151 species, 20 Rotifera, 2 Cladocera, 6 Copepoda, 1 Bryozoa, 13 Protozoa, 31 Chlorophyceae, 3 Chyanophyceae and 75 Diatomaceae.The dominant and subdominant species occurring in this district are Sinocalanus tenellus, Paracyclopina nana, Pseudodiaptomus inopinus, Diaphanosoma brachyurum, Thermocyclops taihokuensis, Bosminopsis deitersi, Keratella valga, Brachionus calyciflorus var. dorcas and Ceratium hirundinella.Generally speaking, the plankton fauna in these waters, are divided into two groups according to the main representatives. One consists of Paracyclopina nana and Sinocalanus tenellus in L. Kahoku-gata and L. Kita-gata, both of which have the water of high salinity, and the other is represented by Diaphanosoma brachyurum, Bosminopsis deitersi and Thermocyclops taihokuensis in the water of low salinity, such as, L. Kiba-gata, L. Imae-gata and L. Shibayama-gata.As seen from the tables the zooplankton in the waters in question are richer in quantity than the scanty, phytoplankton, thongh the latter is rich in the number of species.Among the phytoplankton, Merismopedia sp., Anabaena sp., Pediastrum tetras, Ankistrodesmus falcatus var. mirabilis, Schroederia setigera, Scenedesmus dimorphus, S. denticulatus, S. longispina, S. maximus, Actinastrum sp., and Coelastrum sphaericum seem to adapt to brackish water.The diatoms are widely distributed in this district. The representative species found at Yoshizaki of L. Kita-gata is Melosira octogona and that at the Shiodome-bashi of the Kakehashi-gawa River is Nitzschia obtusa and N. obtusa var. scalpelliformis; that at Katayamazu by L. Shibayam-agata is Melosira varians. None of representative species is found in the other stations.

Steady-state parameters of water and chloride regulation in estuarine nereid polychaetes

1. 1. Four species of the polychaete family Nereidae, differing in the salinities of their natural habitats, have been studied: Nereis limnicola, N. succinea and N. vexillosa from the San Francisco Bay area, California, and N. succinea and Laeonereis from the Gulf coast of Florida. 2. 2. The following steady-state physiological parameters of osmoregulation have been studied: 2.1. (a) Osmotic concentration of the coelomic fluid. 2.2. (b) Chloride content of the entire animal. 2.3. (c) Water content of the entire animal. 2.4. (d) Extracellular fluid volume (as chloride space). 3. 3. In addition to varrying systematically with the concentration of the external medium, these osmotic parameters show a strong and direct correlation with the ecological distribution of the species. N. limnicola, from fresh and oligohaline waters, is the best osmoregulator; N. vexillosa, from polyhaline and marine waters, is the best osmoregulator; L. culveri, and N. succinea are intermediate. 4. 4. Low salinity is a major limiting factor in the distribution of nereids with varying osmoregulatory abilities. High salinity per se has not been proved to be limiting. 5. 5. Lack of water regulation prevents N. vexillosa from living in low salinities.

Jungquartär und End-Mesolithikum in der Provinz Kerman (Iran)

Abstract. The main masses of detritus and silts („See-Löß"), deposited in water and filling the vast plateau-valleys of Kerman-area, seem to have been formed during semi-arid conditions till in older Holocene times. North of Buhabad and in the town of Kerman, areas which are now-days arid or nearly desertic, sediments of a brackisch lake and of shallow fresh-or oligohaline waters indicate that once precipitation and humidity were higher than doday. In Kerman they contain layers of marly peat and are thought to be formed during the Last Pluvial Period. They are rich in remains of fungi, ferns, and mollusc, some of which are land gastropods depending on humid environment. These are now extinct on the Iranian Plateau but living in the damp forest areas of the Hyrcanian countries. At Kuhbanan a microlithic industry was discovered. Regarding the artifact types this industry can be called an Upper Mesolithic. Similar to the Natufian of Palestine there are already plenty sickle blades with a bright patina derived from the silica in the grain stems. This seems to testify the stage of beginning agriculture in Iran in very old times or at least a harvesting of wild grain under climatic conditions suitable for its growth.

ON THE DISTRIBUTION OF NEREIS DIVERSICOLOR IN RELATION TO SALINITY IN THE VICINITY OF TVÄRMINNE, FINLAND, AND THE ISEFJORD, DENMARK

1. A comparative field study of the distribution of Nereis diversicolor near Tvärminne, south Finland and in the Isefjord, Denmark shows that although the species penetrates into nearly fresh water in the Isefjord, its distribution near Tvärminne is limited at summer salinities of over 4°/00.2. The apparent salinity optimum of N. diversicolor on the border of the polyhaline Isefjord is lower than on the "marine-dominated" beach at Millport, Scotland, but in both instances there may be a restriction of the potential range because of interspecific competition.3. The paradoxical situation is seen near Tvärminne of N. diversicolor being among the first of the characteristic brackish-water fauna to drop out as salinity lessens, whereas in the Isefjord as well as in British estuarine situations it penetrates further toward fresh water than the rest of its associates.4. It is suggested, on the basis of hydrographic conditions in the Tvärminne area, that salinities prevailing in summer cannot be the limiting factor for N. diversicolor in the Baltic Sea, but that critically low salinities occurring in spring while temperatures are still very low may adversely affect the osmoregulation and/or reproduction of the species. Furthermore, there may be a hydrographic (as well as a purely physiological) barrier to the spread of the species into oligohaline waters, in which connection the time of breeding and the lack of a long planktonic stage in the life history may be important.

A note on the occurence of Hexarthra fennica Levander in Czechoslovakian oligohaline waters

A note on the occurence of Hexarthra fennica Levander in Czechoslovakian oligohaline waters

Distribuição geográfica da fauna e flora da Baía de Guanabara

Distribuição geográfica da fauna e flora da Baía de Guanabara