Hypo-Osmotic Urine in Nereis Diversicolor

1970 ◽  
Vol 53 (1) ◽  
pp. 101-108
Author(s):  
RALPH I. SMITH
Keyword(s):  
Baltic Sea ◽  
Sea Water ◽  
Coelomic Fluid ◽  
Osmotic Concentration ◽  
Nereis Diversicolor ◽  
Low Salinity

1. Nereis diversicolor, when regulating in water of low salinity, produces urine of lower osmotic concentration than the coelomic fluid. 2. The urine is significantly hypo-osmotic in 0.9-5.3 % sea water (Cl = 5-30 mM/l), and slightly hypo-osmotic in natural Baltic Sea water (17 % sea water; Cl = 95 mM/l). 3. The urine is probably iso-osmotic in 28 % sea water (Cl = 157 mM/l) and higher salinities.

The Regulation of Calcium and Magnesium in the Brackish Water Polychaete Nereis Diversicolor O.F.M

1970 ◽  
Vol 53 (2) ◽  
pp. 425-443
Author(s):  
C. R. FLETCHER
Keyword(s):  
Brackish Water ◽  
Calcium Concentration ◽  
Sea Water ◽  
Calcium Influx ◽  
Coelomic Fluid ◽  
Nereis Diversicolor ◽  
Active Uptake ◽  
Calcium And Magnesium ◽  
Electrochemical Potentials

1. Nereis diversicolor tolerates changes in the concentration of calcium and magnesium in its coelomic fluid proportional to the concentrations in the medium between chlorosities of 100-1000 mM/kg of water. 2. In lower salinities both ions are maintained relatively constant providing that the ratios of these ions to chloride in the medium are similar to the ratios in sea water. 3. The ratio of the concentration of calcium in the coelomic fluid to the concentration in the medium is a function of the salinity of the medium but not of the calcium concentration. 4. Both calcium and magnesium are at lower electrochemical potentials in the coelomic fluid than in the medium, indicating that it is not necessary to invoke active uptake. 5. The rate of calcium influx is substantial. 6. In salinities below to mM of chloride/kg of water the urine must contain less calcium than the coelomic fluid. 7. The significance of these results is discussed.

scholarly journals Student cruise: Observing techniques for Physical Oceanographers Cruise No. AL529

2020 ◽  
Author(s):  
Johannes Karstensen ◽  
Alexandra Andrae ◽  
Ludwig Bitzan ◽  
Jakob Deutloff ◽  
Christiane Lösel ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Sea Water ◽  
Measurement Data ◽  
Opportunity To Learn ◽  
Layer System ◽  
Low Salinity ◽  
Zonal Section ◽  
Short Time ◽  
Observational Techniques ◽  
The Impact

Oct. 07 2019 – Oct. 10, 2019 Kiel (Germany) – Kiel (Germany) MNF-Pher-110The main purpose of the ALKOR cruise AL529 was the training of students in observational techniques applied by physical oceanographers. The students who participated in the trip attend the module "Measurement Methods of Oceanography" which is offered in the Bachelor program "Physics of the Earth System" at CAU Kiel. During the AL529 the students were instructed in instrument calibration and in the interpretation of measurement data at sea. In addition, the students had the opportunity to learn about working and living at sea and to explore and study the impact of physical processes in the western Baltic Sea, the sea at their doorstep. The observations show a quasi-synoptic picture of the hydrography and currents in the western Baltic Sea. Twice-repeated hydrographic and current sections across the Fehmarn Belt show well the short time scales where significant changes occur. A zonal section along the deepest topography, from about 10°40'E to 014°21'E, shows very nicely the two-layer system of outflowing low salinity and inflowing North Sea water. A bottom shield anchorage shows the currents in the water column and the near-bottom temperature and salinity variations in the Fehmarnbelt area.

Solute Secretion By The Tube Foot Epithelium In The Starfish Asterias Forbesi

1977 ◽  
Vol 68 (1) ◽  
pp. 35-43
Author(s):  
ROBERT D. PRUSCH
Keyword(s):  
Driving Force ◽  
Sea Water ◽  
Vascular System ◽  
External Environment ◽  
Coelomic Fluid ◽  
Active Secretion ◽  
Osmotic Concentration ◽  
Asterias Forbesi ◽  
K Secretion ◽  
Tube Feet

1. The K+ and Cl- levels and osmotic concentration of the tube feet fluid in intact starfish (Asterias forbesi) are higher than that in the external sea water or perivisceral (coelomic) fluid. 2. The increase in K+ in the fluid in the tube feet lumen is brought about by the active secretion of K+ by the tube feet epithelium. 3. No exchange of material from the external environment with the more distal portions of the water vascular system across the madreporite was observed in this study. 4. It is suggested that the fluid volume in the tube feet is maintained by active K+ secretion, by the tube feet epithelium, which creates an osmotic driving force for water into the lumen of the tube feet.

scholarly journals Relation of ice growth rate to salt segregation during freezing of low-salinity sea water (Bothnian Bay, Baltic Sea)

2006 ◽  
Vol 44 ◽  
pp. 134-138 ◽  
Author(s):  
Mats A. Granskog ◽  
Jari Uusikivi ◽  
Alberto Blanco Sequeiros ◽  
Eloni Sonninen
Keyword(s):  
Growth Rate ◽  
Sea Ice ◽  
Baltic Sea ◽  
Growth Rates ◽  
Sea Water ◽  
Isotopic Fractionation ◽  
Ice Growth ◽  
Low Salinity ◽  
Wide Range ◽  
The Baltic

AbstractSalt segregation and isotopic fractionation during sea-ice formation can be parameterized as a function of the ice growth rate. We performed a study to investigate if the salt segregation models derived for saline sea-ice studies are pertinent during the growth of Baltic Sea ice in brackish water. We used a time series of ice-salinity profiles and modeled growth rates to examine the relationship between effective salt segregation and growth rate. The results show that models derived for saline sea water are not directly applicable for use in the brackish waters of the Baltic Sea. We derived a simple model for the effective salt segregation in relation to ice growth rate, for a wide range of growth rates, pertinent for use in low-salinity Baltic Sea conditions and in the future development of a Baltic Sea ice salinity model.

scholarly journals DNA Markers Reveal Genetic Associations among 11,000-Year-Old Scots Pine (Pinus sylvestris L.) Found in the Baltic Sea with the Present-Day Gene Pools in Lithuania

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 317
Author(s):  
Darius Danusevičius ◽  
Jurata Buchovska ◽  
Vladas Žulkus ◽  
Linas Daugnora ◽  
Algirdas Girininkas
Keyword(s):  
Baltic Sea ◽  
Scots Pine ◽  
Sea Water ◽  
Pcr Amplification ◽  
Balkan Peninsula ◽  
Gene Pools ◽  
Genetic Associations ◽  
The Baltic Sea ◽  
Assignment Probability ◽  
The Baltic

We aimed to extract DNA and amplify PCR fragments at the mitochondrial DNA Nad7.1 locus and 11 nuclear microsatellite loci in nine circa 11,000-year-old individuals of Scots pine found at the bottom of the Baltic sea and test the genetic associations with the present-day gene pool of Scots pine in Lithuania. We followed a strict anticontamination protocol in the lab and, simultaneously with the aDNA specimens, tested DNA-free controls. The DNA was extracted by an ATMAB protocol from the ancient wood specimens sampled underwater from Scots pine stumps located circa 20–30 m deep and circa 12 km ashore in western Lithuania. As the references, we used 30 present-day Lithuanian populations of Scots pine with 25–50 individuals each. The aDNA yield was 11–41 ng/μL. The PCR amplification for the mtDNA Nad7.1 locus and the nDNA loci yielded reliable aDNA fragments for three and seven out of nine ancient pines, respectively. The electrophoresis profiles of all the PCR tested DNA-free controls contained the sizing standard only, indicating low likelihood for contamination. At the mtDNA Nad7.1 locus, all three ancient Scots pine individuals had the type A (300 bp) allele, indicating postglacial migration from the refugia in Balkan peninsula. The GENECLASS Bayesian assignment tests revealed relatively stringer and consistent genetic associations between the ancient Scots pine trees and the present-day southern Lithuanian populations (assignment probability 0.37–0.55) and several wetlands in Lithuania. Our study shows that salty sea water efficiently preserves ancient DNA in wood at the quality levels suitable for genetic testing of trees dated back as far as 11,000 years before present.

Modeling Transit Flow Through Port Gates and Connecting Channel in Baltic Sea—Liepaja Port—Liepaja Lake System

2021 ◽  
Vol 8 ◽  
Author(s):  
Vilnis Frishfelds ◽  
Juris Sennikovs ◽  
Uldis Bethers ◽  
Jens Murawski ◽  
Andrejs Timuhins
Keyword(s):  
Baltic Sea ◽  
Sea Level ◽  
Sea Water ◽  
Lake System ◽  
The North ◽  
Transit Flow ◽  
Trade Channel ◽  
Calm Weather ◽  
Set Up ◽  
The Baltic

This study investigates a water transport features by extending Copernicus Marine Environment Service (CMEMS) to the Liepaja coast-port-channel-lake system with a two-way nested model. The Liepaja lake and Liepaja port are connected by Trade channel. The Liepaja port has three gates—the openings in wave breakers connecting the port aquatory with the Baltic sea. Each of gates has a corresponding dredged channel for securing the navigation. A hydrodynamic model is set up to study the flow and water level in this system. The area of the port gates, port and Trade channel are resolved by 33 m grid. The model results are verified against currents and sea level observations inside/outside port, Trade channel and Liepaja lake. Results and observations show that strong currents occur in the Trade channel in case of rapid sea level change in Baltic sea despite the Trade channel is rather shallow at the connection with Liepaja lake. The northern part of the Liepaja lake gets filled with brackish water during storm surge events. The channel has notable alternating current also during a relatively calm weather due to the port seiches. Long and narrow shape of the channel implies the Helmholtz type oscillations between the lake and the port with a period in approximately semidiurnal range. Hydrodynamic simulations describe well these oscillations but the phase of hourly scale oscillations in the port may differ in case of weak external forcing. Water exchange is significantly increased by the transit (gate to gate) sea currents. This transit flow usually occurs between South or Central gate and the North gate carrying sea water into the port. Northward flow of the surface layer is more characteristic in the port aquatory due the prevailing south-western winds. There are intense morphological processes at the coastline and underwater slope near the Liepaja port due to a sandy western coastline of Latvia, long fetch of the waves and strong currents at the port gates. Liepaja port is one of the Latvian ports in HywasPort operational service of hydrodynamics, waves and siltation.

The effect of external salinity on drinking rate and rectal secretion in the larvae of the saline-water mosquito Aedes taeniorhynchus

1977 ◽  
Vol 66 (1) ◽  
pp. 97-110
Author(s):  
T. J. Bradley ◽  
J. E. Phillips
Keyword(s):  
Sea Water ◽  
External Medium ◽  
Narrow Range ◽  
Saline Water ◽  
Fluid Secretion ◽  
Osmotic Concentration ◽  
Drinking Rate ◽  
Aedes Taeniorhynchus ◽  
External Salinity ◽  
Kinetics Of

1. The drinking rate of the saline-water mosquito larva Aedes taeniorhyncus (100 nl.mg-1.h-1) is unaffected by the salinity of the external medium, but is directly proportional to the surface area of the animal. 2. Haemolymph Na+, Mg2+, K+, Cl-, SO42- and osmotic concentrations were measured in larvae adapted to 10%, 100% and 200% seawater and were found to be regulated within a narrow range. 3. With the exception of potassium, ionic concentrations in rectal secretion were found to increase with increasing concentrations of the sea water in which larvae were reared. 4. The osmotic concentration of rectal secretion was unaffected by changes in haemolymph osmotic concentration but did rise when sodium or chloride concentrations of the haemolymph were increased. High levels of these ions also stimulated the rate of fluid secretion. 5. Transport of chloride and sodium by the rectum exhibits the kinetics of allosteric rather than classical enzymes.

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