scholarly journals Seasonal Changes in The Phytoplankton During the Year 1951–52 As Indicated by Spectrophotometric Chlorophyll Estimations

1953 ◽  
Vol 31 (3) ◽  
pp. 495-508 ◽  
Author(s):  
W. R. G. Atkins ◽  
Pamela G. Jenkins
Keyword(s):  
Seasonal Changes ◽  
Sea Water ◽  
Diffuse Light ◽  
Botanical Composition ◽  
Spectral Absorption ◽  
Colour Intensity ◽  
Surface Samples ◽  
Winter Sample ◽  
Pure Cultures ◽  
Wet Weight

Chlorophyll from the phytoplankton at station Ei was examined from September 1951 till August 1952, from o to 50 m. The minimum was in June, i-8 mg./m.3, and the maximum 342 in March, both surface samples. The maximum 50 m. sample contained 18-4 mg./m.3 in April. The winter minima were 4-6 and 43, surface and bottom, in November. Converted to water column (70 m.) values, over iog./m.2 is obtained for the wet weight of phytoplankton for September and March, the April maximum and the June minimum being 132 and 015 g./m.2. A comparison with the production obtained from phosphate analyses suggests that the phytoplankton crop each month is rapidly devoured.Exact proportionality was found between concentration and absorption in a chlorophyll band up to 40 mg./l. and a moderate error up to 80 mg./l. The spectral absorption curves have been given for pure cultures of phytoplankton and for cells filtered out of sea water. The chlorophyll in such extracts, made with 80% acetone, is stable when kept in total darkness.The collodion disks containing suspended clay arid the algal cells may show a surprising variation in their colour intensity, from dark grey to a very faint tint, even though obtained from sea water about 20 miles from land and over 70 m. in depth. The surface may be far darker than 5, 10 or 15 m. samples.The botanical composition of the water was studied by allowing the algae to multiply in diffuse light after enriching the water chemically. Eight species of Chlorophyceae, and one species each of the Chrysophyceae and Dinophyceae were recorded. Of the Cryptophyceae one winter sample from 50 m. gave a nearly pure growth of Hemiselmis rufescens Parke. The diatoms Melostra borreri, Nitzschia closterium and Navicula sp. occurred commonly.

scholarly journals Aedes Aegypti: Energetics of Osmoregulation

1982 ◽  
Vol 101 (1) ◽  
pp. 135-141 ◽  
Author(s):  
H.A. EDWARDS
Keyword(s):  
Oxygen Consumption ◽  
Energy Cost ◽  
Sea Water ◽  
External Medium ◽  
Minimum Energy ◽  
Body Volume ◽  
Wet Weight ◽  
Minimum Energy Cost ◽  
Anal Papillae ◽  
Theoretical Minimum

1. Oxygen consumption of A. aegypti larvae, about 210 mul l g−1 tissue wet weight h−1, does not change when the salinity of the environment is changed. The number of mitochondria in the anal papillae, a salt-absorbing epithelium, increases as the external medium is diluted. There is no difference in oxygen consumption between isolated anal papillae in 0, 2 and 20% sea water. The papillae represent about 5% of body volume and their oxygen consumption is about 2% of the animal's total. The theoretical minimum energy cost of osmoregulation is four orders of magnitude smaller than the measured figure for the anal papillae alone. Osmoregulatory phenomena which would explain the recorded observations are discussed.

Marine Biosurfactants, III. Toxicity Testing with Marine Microorganisms and Comparison with Synthetic Surfactants

1991 ◽  
Vol 46 (3-4) ◽  
pp. 210-216 ◽  
Author(s):  
Knut Poremba ◽  
Wilfried Gunkel ◽  
Siegmund Lang ◽  
Fritz Wagner
Keyword(s):  
Marine Bacterium ◽  
Sea Water ◽  
Toxicity Testing ◽  
Test System ◽  
Marine Microorganisms ◽  
Oil Dispersants ◽  
Test Organisms ◽  
Pure Cultures ◽  
Microtox Test ◽  
Synthetic Surfactants

Eight synthetic and nine biogenetic surfactants were tested on their toxicity. Because of their possible application as oil dispersants against oil slicks on sea. the test organisms used were marine microorganisms (mixed and pure cultures of bacteria, microalgae, and protozoa). Bacterial growth was hardly effected or stimulated, whilst that of algae and flagellates was reduced. All substances tested were biodegradaded in sea water. The bioluminescence of Photobacter phosphoreum (Microtox test) was the most sensitive test system used. A ranking shows that most biogenetic surfactants were less toxic than synthetic surfactants. No toxicity could be detected with the glucose-lipid GL. produced by the marine bacterium Alcaligenes sp. MM 1.

The Respiratory Metabolism of Dendrostomum cymodoceae Edmonds (Sipunculoidea)

1957 ◽  
Vol 8 (1) ◽  
pp. 55 ◽  
Author(s):  
SJ Edmonds
Keyword(s):  
Carbon Dioxide ◽  
Lactic Acid ◽  
Dissolved Oxygen ◽  
Blood Volume ◽  
Sea Water ◽  
Respiratory Metabolism ◽  
Anaerobic Conditions ◽  
Paraffin Oil ◽  
End Products ◽  
Wet Weight

The consumption of oxygen of Dendrostomum cymodoceae at 22'C in aerated sea-water varied from 4-5-5.5 μl/g (wet weight)/hr for adults to 20-31 μ/g/hr for juveniles. The production of carbon dioxide was 13-17 μ/g/hr (juveniles) and the R.Q. varied from 0.55 to 0.67 (juveniles). The rate of consunlption of oxygen decreased as the tension of the dissolved oxygen decreased. The oxygen combined with the pigment of the blood was 2.1 vols. of oxygen per 100 vols. of blood and the ratio of blood volume (ml) to total weight (g) of the animal was 0.47. D. cymodoceae was able to live under anaerobic conditions in sea-water for as long as 5 days and in paraffin oil for 4 days. The haemerythrin in the blood of animals kept under oil was found to be reduced after about 6 hr. Lactic acid was identified as one of the end-products of anaerobiosis. The concentration of lactic acid in the blood of animals living under anaerobic conditions increased after 60 hr from 7-12 to 46-61 μg/ml of blood. The ability to revert to anaerobiosis may have survival value for the species.

KAJIAN KEMAMPUAN RUMPAI LAUT ULVA INTESTINALIS SEBAGAI PENAPIS AIR LAUT SEMULA JADI BAGI PENGKULTURAN SECARA INTENSIF ROTIFER BRACHIONUS PLICATILIS

2015 ◽  
Vol 76 (1) ◽  
Author(s):  
Abdull Razak Abd Rahman ◽  
Zaidi Che Cob ◽  
Zainoddin Jamari ◽  
Abdul Majid Mohamed ◽  
Tatsuki Toda ◽  
...  
Keyword(s):  
Water Quality ◽  
Intertidal Zone ◽  
Quality Index ◽  
Sea Water ◽  
Brachionus Plicatilis ◽  
Day Treatment ◽  
Intensive Culture ◽  
Rotifer Brachionus Plicatilis ◽  
Ulva Intestinalis ◽  
Wet Weight

The ability of Ulva intestinalis as a biofilter in the intensive culture of rotifer Brachionus plicatilis was evaluated. 20 g wet weight of U. intestinalis was added into a 40 liters beaker containing 10 liters sea water of the cultured rotifer with quality index 0.36 ± 0.28 mg/L of NH3–N, 0.069 ± 0.025 mg/L of NO2––N, 0.90 ± 0.77 mg/L of NO3––N and 0.993 ± 0.0058 mg/L of PO43– and the alkalinity reading 114 ± 0.1 mg/L, pH 7.23 ± 0.08, temperature 26.3 ± 0.1OC and salinity was 30 ± 0.1 psu. The result of the following day of treatment with U. intestinalis, the water quality index changed to 0.001 mg/L of NH3–N, 0.090 ± 0.014 mg/L of NO2––N, 0.70 ± 0.60 mg/L of NO3––N and 0.89 ± 0.03 mg/L of PO43– while the alkalinity was 114 ± 0.1 mg/L, pH 7.45 ± 0.05, temperature 26.0 ± 0.10OC and the salinity was 30.0 ± 0.1 psu. The biofiltration capacity of U. intestinalis was confirmed by significantly reduced concentration of the NH3–N and 10% of PO43–  compared to control only 2% over one day treatment. However from day two onwards the readings were conflicting from the first day readings. These findings were probably because U. intestinalis live in intertidal zone and flushing area therefore the use of U. intestinalis as a biofilter by continuous immersion in cultured water is unnatural. Therefore using U. intestinalis as a biofilter should be used not more than 24 hours.

scholarly journals The Hydrogen Ion Concentration of Sea Water in its Relation to Photosynthetic Changes. Part II

1923 ◽  
Vol 13 (1) ◽  
pp. 93-118 ◽  
Author(s):  
W. R. G. Atkins
Keyword(s):  
Seasonal Changes ◽  
Sea Water ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Equal Degree

In the first publication under the above general title the seasonal changes in sea water were studied, but as explained previously it was not possible to regard all the data as of an equal degree of accuracy. For this and other reasons the seasonal changes were further traced in the hydrographical cruises up to October, 1922, when the approach of the winter equilibrium made it profitless for some months to continue. Since, however, at times from April to September the changes are relatively rapid it may be advisable to follow up the matter during the period mentioned at shorter intervals.

The roles of filters in the photophores of oceanic animals and their relation to vision in the oceanic environment

1985 ◽  
Vol 225 (1238) ◽  
pp. 63-97 ◽  
Keyword(s):  
Sea Water ◽  
External Surface ◽  
Red Light ◽  
Visible Spectrum ◽  
Transmission Band ◽  
Spectral Absorption ◽  
Good Match ◽  
Mesopelagic Zone ◽  
Light Filters ◽  
Colour Match

In many of the photophores found in deep-sea fishes and invertebrates, light filters containing pigments lie between the tissues that generate light and the sea. The loss of light within such filters has been measured throughout the visible spectrum for a variety of animals. These filters differ greatly in their spectral absorption characteristics and do not all contain the same pigments. All those from ventral photophores have a transmission band in the blue corresponding to the daylight that penetrates best into oceanic waters. For two fishes it is shown that the light generated inside their photophores is a relatively poor spectral match for the ambient submarine daylight while the light emitted into the sea, after passing through the filters, is a good match. For a third fish a similar improvement in ‘colour match’ is brought about not by passing the light through a filter containing pigments but by reflecting the light into the sea by a blue mirror. All these observations support the hypothesis that the ventral photophores are used for camouflage. Malacosteus niger Ayres 1848 is an oceanic fish which emits red light from a large suborbital photophore. The red light generated inside the photophore is largely absorbed by a coloured filter over its external surface which transmits only a band of light of wavelengths around 700 nm. This is a waveband which is heavily absorbed by oceanic sea water. It is shown, however, that animals that can emit and are sensitive to such far-red light will have very great advantages in being able to see without being seen. The ranges over which such red light can be useful for vision are, however, relatively small. The nature of the pigments found in these various photophores is discussed. It is also calculated that the intensities of penetrating daylight are such that visual acuity could be fairly good down to considerable depths in the mesopelagic zone.

THE SPECTRAL ABSORPTION OF LIGHT BY PURE WATER AND BAY OF FUNDY WATER

1932 ◽  
Vol 7 (1) ◽  
pp. 73-89 ◽  
Author(s):  
WILLIAM REGINALD SAWYER
Keyword(s):  
Natural Waters ◽  
Sea Water ◽  
Pure Water ◽  
Ultra Violet ◽  
Bay Of Fundy ◽  
Distilled Water ◽  
The Sun ◽  
Spectral Absorption ◽  
Absorption Of Light ◽  
Quartz Spectrograph

The spectral absorption of light (350–650 mμ) by pure water and bay of Fundy water was determined by means of a quartz spectrograph, Nicol prisms, and tubes of water of varying lengths up to 5 metres. The sun at noon on clear days was used as the source of radiation, its constancy being checked by means of a pyrheliometer. The tubes and spectrograph were placed in an equatorial mounting and the radiation from the sun controlled by a heliostat mirror. The results in the visible for distilled water agree with those of other workers. There appears to be a surprising difference in the absorption of ultra-violet between distilled water and natural waters. Less than 0.5 per cent of the near ultra-violet was transmitted by 1 metre of one of the samples of sea-water. A number of applications of the above method have been suggested.

Spectral Absorption of Turbid Systems Using Diffuse Light

Science ◽  
1955 ◽  
Vol 121 (3143) ◽  
pp. 441-442
Author(s):  
J. B. Bateman ◽  
G. W. Monk
Keyword(s):  
Diffuse Light ◽  
Spectral Absorption
Sign in / Sign up

Export Citation Format

Share Document