A new method for examining maritime mobility of direct crossings with contrary prevailing winds in the Mediterranean during antiquity

AbstractEffects of depth and turbidity on the in situ pumping activity of the Mediterranean sponge Chondrosia reniformis (Nardo, 1847) were characterized by measuring osculum diameter, oscular outflow velocity, osculum density per sponge and sponge surface area at different locations around the Bodrum peninsula (Turkey). Outflow velocity was measured using a new method based on video analysis of neutrally buoyant particles moving in the exhalant stream of sponge oscula, which yielded results that were in good comparison to other studies. Using the new method, it was shown that for C. reniformis, oscular outflow had a location-dependent, in most cases positive relationship with oscular size: bigger oscules process more water per cm2 of osculum surface. Turbidity and depth both affected sponge pumping in a negative way, but for the locations tested, the effect of depth was more profound than the effect of turbidity. Depth affected all parameters investigated except sponge size, whereas turbidity only affected specific pumping rates normalized to sponge surface area. Deep water sponges had clearly smaller oscula than shallow water sponges, but partially compensated for this lower pumping potential by showing a higher osculum density. Both increasing turbidity and increasing depth considerably decreased volumetric pumping rates of C. reniformis. These findings have important implications for selecting sites for mariculture of this species.

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The determination of the depths and extinction coefficients of shallow water by air photography using colour filters

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences ◽

10.1098/rsta.1947.0001 ◽

1947 ◽

Vol 240 (816) ◽

pp. 163-217 ◽

Cited By ~ 7

Keyword(s):

Shallow Water ◽

Research Unit ◽

New Method ◽

Water Research ◽

Extinction Coefficients ◽

Combined Operations ◽

Sea Bed ◽

The Mediterranean

The value of air photography for map making and for the study of land detail was appreciated before the war, but the study of under-water detail from air photographs had received little attention. The landing at Tarawa, where the danger of a submerged reef had not been accurately assessed, emphasized the need for a new method of determining depths in shallow water. Research on the interpretation of air photographs of the sea-bed was therefore started by the Army Photographic Research Unit in September 1944, under the auspices of Professor J. D. Bernal, F.R.S., Scientific Advisor to Combined Operations H.Q,., and some 10,000 photographs were taken during extensive trials in Cornwall, the Scilly Isles, Scotland, the Mediterranean and Ceylon. This work was carried out under the orders of the Air Directorate of the War Office, and as the results are of scientific and industrial value the Army Council has agreed to their publication.

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Selective Sampling and Orientation of Non-Homogeneous Tissues

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100100238 ◽

1968 ◽

Vol 26 ◽

pp. 98-99

Author(s):

C. C. Clawson ◽

L. W. Anderson ◽

R. A. Good

Keyword(s):

Electron Microscopy ◽

Electron Microscope ◽

Light Microscopy ◽

Random Sampling ◽

New Method ◽

Microscope Examination ◽

Small Areas ◽

Selective Sampling ◽

Large Numbers ◽

Specific Orientation

Investigations which require electron microscope examination of a few specific areas of non-homogeneous tissues make random sampling of small blocks an inefficient and unrewarding procedure. Therefore, several investigators have devised methods which allow obtaining sample blocks for electron microscopy from region of tissue previously identified by light microscopy of present here techniques which make possible: 1) sampling tissue for electron microscopy from selected areas previously identified by light microscopy of relatively large pieces of tissue; 2) dehydration and embedding large numbers of individually identified blocks while keeping each one separate; 3) a new method of maintaining specific orientation of blocks during embedding; 4) special light microscopic staining or fluorescent procedures and electron microscopy on immediately adjacent small areas of tissue.

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