South Channel Research Articles

The text of Thucydides iv 8.6 and the South Channel at Pylos

Scholars have long praised the overall topographic accuracy of Thucydides' account of the campaign at Pylos (iv 3–6, 8–23, 26–41); and among the numerous details mentioned, only two apparent inaccuracies have been identified, both involving measurements. One, an inaccurate estimate of the length of Sphakteria, has been previously explained as nothing more than a simple numeral corruption and is, in any case, irrelevant for understanding the military narrative. But the other, the underestimated width of the southern harbour entrance, remains a serious error which implies a fundamental misconception of relevant local geography and has made the account of Spartan strategy incomprehensible. Furthermore, its impact on the question of Thucydides' investigative methodology has been considerable, since most commentators, thinking the information reliably transmitted, have concluded that Thucydides never visited Pylos and somehow accepted misinformation on this crucial point. However, close study of the passage suggests that a textual corruption, not Thucydides, is responsible for the present inaccuracy.

DISTRIBUTION OF RECENT SEDIMENTS IN SALDANHA BAY AND LANGEBAAN LAGOON

Summary Sediment distribution in Saldanha Bay is wave controlled and can be related to the energy levels created by the refraction pattern. Four energy zones are distinguished in the inner bay: a centrally exposed zone, two marginal semi-exposed zones, a sheltered zone in the north and a bay/lagoon transitional zone in the south. Sediment is supplied on the abrasion platform of the exposed zone and along the rocky shoreline of the North Channel. These areas display the coarsest sediments. In North Bay medium sands dominate, whereas the South Channel is characterized by very fine sands. Both semi-exposed zones as well as the sheltered zone consist of very fine sand. The bay/lagoon transitional zone is constructed of a tidal delta made of fine sand. Sediment distribution seems to be in equilibrium with the prevailing hydrodynamic regime. In contrast, Langebaan Lagoon is a current controlled regime. Four physiographic units can be separated: tidal channels, subtidal flats and sandbanks, intertidal flats, and salt marshes. These units reflect the major energy levels of the tidal system. Texturally the lagoon divides into two major zones separated roughly by the central channel. East of the channel fine sands dominate, whereas west of the channel medium sands are more frequent. Coarse sediments occur as lag deposits in the northern outflow channels. In contrast to the dominating presence of very fine sand in Saldanha Bay this size fraction is surprisingly deficient in Langebaan Lagoon. There is evidence for a Holocene high stand of the sea between 6 000 and 2 000 y B.P. The modern sediment distribution is the result of the subsequent regression and stabilization of the sea-level about 1 800 y B.P., and is therefore essentially a relict feature.

Hydrography of South Pass, Mississippi River

In the lower South Pass channel, a combination of salt-water intrusion and tide dominate circulation and mixing. Seaward discharge and vertical mixing in the channel are greatest during ebbing tide, when the hydrostatic gradient is at a maximum. Direction of flow within the salt-water wedge is largely a function of tidal phase, upstream currents prevailing during flooding tide, and downstream currents characterizing ebbing tide. Bed load transport in the lower channel, particularly at low and normal river stage, is, therefore, considered to be tide dependent.

Glaciation on the Continental Margin off New England

The Pleistocene glacial limit in the marine environment off New England can be traced by plotting the seaward limit of abundant sandy gravel and the position of shoals. Maximum limit of the last glaciation was probably along an irregular line extending through Nantucket Shoals, across Great South Channel, northern Georges Bank, and at least to the edge of the Scotian Shelf. If, as we assume, glaciers lowered sea level approximately 130 m, the ice margin was probably a subaerial one on Nantucket Shoals and Georges Bank, and it was bordered by outwash and meltwater channels leading away from the ice front. On the Scotian Shelf, the margin may have bordered directly on the ocean, to judge by the lack of shoals and the widespread dispersion of gravel out to the shelf edge. The glaciofluvial nature of the original deposits and marine reworking during the eustatic rise in sea level have made it difficult to recognize ice-contact deposits near the limit of maximum glacial advance. The gravel on shallow banks and ledges is in a bimodal mixture with sand. Association of coarse gravel and sand suggests postdepositional reworking of till by marine processes and removal of silt and clay. Gravel in the Gulf of Maine is mixed with sand, silt, and clay, a mixture characteristic of till.

A study of the vertical distribution of larval haddock : Miller, D. J., J. B. Colton Jr. and R. R. Marak, 1963. J. Cons. Int. Exp. Mer., 28 (1): 37–49

In late May 1992, cod and haddock eggs and larvae were sampled at discrete depths using MOCNESS on the southern flank of Georges Bank when seasonal stratification of the water column was developing. A deeper, stratified site (80-m bottom) was sampled over 7 days in relation to the temporal evolution of vertical structure and compared to a nearby shoal, mixed site (50 m). Sampling also was conducted to the west along two transects in the Great South Channel. Larval biochemical composition was measured and nutritional condition inferred from RNA:DNA ratios.During the period 22–24 May 1992, surface warming resulted in a temperature gradient from 6 to 10°C (0.6 δt units) in the upper 20 m at the stratified site. Gadid eggs (93% haddock) were most abundant (6–14 per 100 m3, on average) in the surface 20 m, with maximum density just above the base of the thermocline at 20-10 m. The few recently-hatched larvae (5–6 mm) caught were broadly distributed in the water column, with maximum average densities (1–3 per 100 m3) deeper at 10–40 m. The naupliar and copepodite stages of Pseudocalanus spp. were principal prey of these larvae, and also were more abundant (3–7 prey 1−1) in the surface 20 m, with a maximum density at 20-10 m. A moderate storm on 25 May mixed the upper part of the water column to 5–6°C. The day after the storm, gadid eggs and copepods had highest densities in the surface 10 m.At the shoal (mixed site) egg densities were low (1–3 per 100 m3) and distributed evenly through the water column. Cod and haddock larvae were larger (7–8 mm modal length) and more abundant than at the stratified site. At night, they were evenly distributed at 4–6 per 100 m3 on average, but by day, maximum density increased to 6–16 per 100 m3 in the deepest strata sampled (40–30 m). The larger larvae at this site preyed predominantly on copepodite stages of Pseudocalanus spp., which were uniformly distributed in the water column.Of all the larvae sampled for biochemical analysis, 10% of haddock and 1.5% of cod had ratios below 4.1. Based on laboratory studies, fish larvae with RNA:DNA ratios below 4.1 are considered to have been in poor condition. There were no larvae in poor condition at the Great South Channel Transect, where their mean size was greatest; no larvae were collected at the stratified site for comparison. At the mixed site, cod larvae sampled before and after the storm had identical ratios, while haddock larvae had significantly higher ratios after the storm. Larvae from different sampling depths had significantly different ratios, inferring that they remained together long enough to acquire a unique signature.

Calorific values of Microcrustacea : Comita, G. W. and D. W. Schindler, 1963. Science, 140 (3574): 1394–1395

On 3 June 1989, during SCOPEX'89, two right whales were observed to be feeding close to the surface at separate sites in the Great South Channel of the Gulf of Maine. The R.V. Marlin deployed and monitored a radio tag on one whale, and underway measurements were made near each whale from the R.V. Endeavor to investigate the small-scale spatial structure of water properties and zooplankton abundance in the upper water column near the whales. These measurements included two CTD tow-yos, zooplankton sampling with a MOCNESS, continuous vertical profiling of currents with a 150-kHz ADCP, and continuous vertical profiling of zooplankton concentration with a towed acoustic profiler operating at 120 and 200 kHz.The whales were feeding on a relatively homogeneous mixture of primarily two stages (copepodite IV and V) of a single copepod species (Calanus finmarchicus), which was most abundant in the upper 10–20 m of the water column above the seasonal pycnocline. Descriptions of the spatial structure of copepod abundance in patches traversed by the whales were developed based on MOCNESS samples, acoustic backscatter, and light transmission. In particular, a high correlation was found between MOCNESS biomass measurements and certain 200-kHz acoustic biomass estimates, which enabled the acoustic data to be interpreted solely in terms of copepod abundance. Acoustic measurements made in a copepod patch while closely following one whale indicated mean and peak copepod biomasses of 6.0 and 28.4 g m−3 (corresponding to mean and peak concentrations of 8.7 × 103 and 4.1 × 104) copepods m−3 in the 4–10 m depth band, where the whale was probably feeding. With a mean energy content of 10−3 kcal copepod−1, that whale's mean energy intake rate was 3.8 × 104 kcal h−1. The whale was observed to reverse course and turn back into the patch when it swam into a region of lower copepod abundance, with biomass less than roughly 1–3 g m−3 or 1.5–4.5 × 103 copepods m−3. This concentration is consistent with independent estimates of the minimum prey concentration required for a right whale to regain the energy it expends when it feeds.The next morning, one of the whales was found to be skim-feeding on a Calanus finmarchicus patch in which a bucket sample gave a copepod biomass of 256 g m−3 or 3.3 × 105 copepods m−3. If this one sample approximated the mean abundance of the patch, then the whale had a mean energy intake of 1.4 × 105 kcal h−1. At this rate, it could consume its daily basal metabolic energy requirement in roughly 9 min, and its annual requirement in roughly two days (assuming continuous feeding at a mean speed of 1.2 m s−1 as determined from the ADCP measurements). Although physical advection on regional and smaller scales appears to be an important element in the processes that cause such dense patches to form in this region during late spring, the lack of a clear linkage between the small-scale physical and biological data reported here suggest that some nonphysical, species-specific animal behavior like swarming must be partially responsible for creating the very densest copepod patches observed during SCOPEX'89.

Rotational water movements in western Lake Erie

SummaryPrevious studies of the currents in western Lake Erie have been based on one method of investigation, drift bottles or drift cards. The studies revealed a gyral around Pelee Island. However, later evidence indicated that a much larger area was involved. The hypothesis of a net rotary movement of water in the western basin was confirmed. The force which is believed to produce the rotation is the primary longitudinal seiche which becomes a derived wave in the western basin. The island region acts as a spill-way for the overflowing seiche. The present study employed five different simple techniques to establish the pattern of water movements. 1. Lake level records at three strategic locations in western Lake Erie showed a rise and fall of water level, progressing in a clockwise direction around the basin.2. Wind generated surface currents move to the northeast under the prevailing southwest winds. This was shown by the movement of drift cards. The prevailing southwest winds contribute to the rotation of water in the western basin.3. Isotherms are distorted by the seiche action and the distortion showed a definite movement of water westward through the South Channels, and a northward movement through the island region. Net outflow occurred only through the Pelee Passage.4. Light transmission data, used as a measure of turbidity, showed the deflection of turbid water toward the north and an ingress of clear water from the east. Extremely turbid water was shown to enter the western basin from the Maumee River. The pattern of turbidity in western Lake Erie corresponds closely to the current pattern indicated by the distortion of isotherms.5. The net flow of water into and out of the western basin has been determined using direct current measurements. The net inflow through the South Channels was 57,600 cfs. The inflow plus the average river discharge into the western basin of 184,000 cfs was moved out of the western basin through the Pelee Passage. The net outflow through the Pelee Passage was 209,300 cfs.

Naval Operations in the South Channel of Corcyra 435–433 B.C.

Such attention as the battle of Sybota has received has resulted rather in criticism of Thucydides than in clarification of the battle; yet, as the greatest naval battle between Greek and Greek before the Peloponnesian War, it is of some interest to the naval historian. My attempt to reconstruct the battle is based on the belief that Thucydides' account is accurate, though cursory in some respects, and contains enough topographical clues for my purpose. In interpreting these clues I have drawn upon the results of travels in Epirus, which I hope to publish elsewhere; the relevant data are adduced here in brief. The paper falls into two parts, a topographical introduction and the study of Thucydides' narrative.The South Channel of Corfu is contained between the almost parallel coasts of Corfu and Epirus. The Corfu coast between Cape Lefkimo and Cape Bianco is low-lying with sandy beach and shallow water inshore; but south of St. Theodoro Point sunken rocks make approach dangerous, especially off Cape Bianco, where the Bianco Shoal stretches both south and east into the Channel. Thus in modern times the only area suitable for beaching is between Cape Lefkimo and St. Theodoro Point. There is no evidence of any general change since antiquity in the coastline or sea-level; and as this coast is sheltered from heavy seas the extent of the Bianco Shoal and the sunken rocks is likely to have been more or less constant. The stretch of coast between Cape Lefkimo and St. Theodoro Point is alluvial and may therefore have encroached slightly on the sea since antiquity. The Cape Leukimme of Thucydides should be identified with Cape Lefkimo; apart from the persistence of the ancient name, it alone affords the beaching facilities required for a naval base.

THE DISTRIBUTION OF AMMONIA IN THE WATERS OF THE GULF OF MAINE

1. In the deeper basins of the Gulf of Maine in May ammonia occurred in minimal concentrations at the surface and at all depths below sixty meters; maximal concentrations varying up to 45 mg. N per cubic meter occurred in a definite stratum between 30 and 60 meters.2. In September the concentration of ammonia was rather uniform at all depths and increased as the distance from the open sea increased, concentrations exceeding 50 mg. N per cubic meter occurring in the western basin.3. In the tideways of the North and South Channels, ammonia is distributed uniformly with depth in both May and September.4. In shallow waters its occurrence showed no regularity.5. The occurrence of ammonia may be correlated in part with the distribution of organic phosphorus compounds, of nitrite, and of zooplankton, so as to support the view that its distribution marks the place and the intensity of organic decomposition.

A Three-Eyed Haddock, with Notes on Other Three-Eyed Fishes

Is York Herald-Tribunie for October 9, 1927, was an announcement of capture by a fisherman on fishing schooner Marjorie Parker of a three-eyed haddock in south channel of Boston Harbor. Here it was stated that the third eye is midway between normal ones. In rotogravure section of York Times for following Sunday (October 16) was a picture with following caption: oddest fish in sea . . . a haddock caught off Boston, which was found to have three perfect eyes, third in middle of head. I then set to work to find original of photograph published in Ti;eMees. Presently I got in touch with Air. J. V. Dumas, sales manager of New York Times Wide World Photos, who courteously sent me a copy of figure referred to above and what is more to purpose of this article lie also sent a photograph showing head in closer view than is seen in figure in Times. This third eye is placed on back of head in mnedian line and looks like a perfectly good eye. Both these figures are herein reproduced as Nos. 1 and 2. The first photograph is in original 8 by 10 inches in size and shows a m-nan holding fish in his hand. This has been cut down so as here to show in Fig. 1 fish, hand holding it and part of man's coat. From second photograph (which is of same size) head of fish has been cut out and is reproduced as Fig. 2. The first figure shows that head (when compared to size of hand holding it) is evidently that of an adult fish. This does not show eye clearly. 559

Report of experiments made on the tides in the Irish Sea; on the similarity of the tidal phenomena of the Irish and English Chan­nels; and on the importance of extending the experiments round the land’s-end and up the English Channel. Embodied in a letter to the hydrographer, by Captain F. W. Beechey, R. N., F. R. S.. Communicated by G.

The author commences by stating, that the set of the tides in the Irish Sea had always been misunderstood, owing to the disposition to associate the turn of the stream with the rise and fall of the water on the shore. This misapprehension, in a channel varying so much in its times of high water, could not fail to produce much mischief; and to this cause may be ascribed, in all probability, a large proportion of the wrecks in Caernarvon Bay. The present inquiry has dispelled these errors, and has furnished science with some new and interesting facts. It has shown that, notwithstanding the variety of times of high water, the turn of the stream throughout the north and south Channels occurs at the same hour, and that this time happens to coincide with the times of high and low water at Moricombe Bay, a place remarkable as being the spot where the streams coming round the opposite extremities of Ireland finally unite. These experiments, taken in connexion with those of the Ordnance made at the suggestion of Professor Airy, show that there are two spots in the Irish Sea, in one of which the stream runs with considerable rapidity, without there being any rise or fall of the water, and in the other the water rises and falls without having any perceptible stream; that the same stream makes high and low water in different parts of the channel at the same time; and that during certain portions of the tide, the stream, opposing the wave, runs up an ascent of one foot in three miles, with a velocity of three miles an hour.