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1.
Sea level oscillations in Wellington Harbour 总被引：1，自引：1，他引：0
R. A. Heath 《新西兰海洋与淡水研究杂志》2013,47(2):403-414
Periods of oscillations of sea level in Wellington Harbour, New Zealand (41° 17'S, 174° 52’ E), are calculated by spectral analysis of the residual elevations observed in tide gauge records. These periods are compared with those computed by numerically integrating a one‐dimensional linear momentum equation and the continuity equation. The two main oscillations are the first harmonics along and across the harbour with periods of about 27 and 22 min respectively — the second harmonics were also observed. The quarter wavelength oscillation with forcing at the mouth which was excited by the 1960 Chilean Tsunami has a period of about 160 min. 相似文献
2.
J. D. Booth 《新西兰海洋与淡水研究杂志》2013,47(3):333-354
Observations were made on several hydrological features of Wellington Harbour, New Zealand (41° 16’ S, 174° 51’ E) during 1970 to 1972. These suggest that the harbour is topographically partially isolated from oceanic influences, and that waters within the harbour undergo efficient mixing. Monthly mean sea‐surface temperatures ranged seasonally between 10.5°c and 18.5°c, and some stratification was observed during summer and winter. Salinities usually ranged from 33.5‰ to 34.5‰, and water transparency by Secchi disc from 3 m to 6 m. Dissolved oxygen content ranged from 96% to 127% saturation, usually exceeding 100% saturation in surface waters. Under normal discharge conditions during winter, the Hutt River was observed to markedly affect surface temperatures and salinities as far south as Somes Island to a depth of about 5 m. 相似文献
3.
Barbara Spurr 《新西兰海洋与淡水研究杂志》2013,47(4):547-562
The physical, chemical and biological properties of Bird Pond, Cape Bird, Ross Island, Antarctica (77° 13’ 10” S, 166° 28’ 30” E), were investigated at weekly intervals for 2 months in the summer of 1970–71. The above properties were also investigated over a 24‐h period. Salinity and temperature tolerance of the rotifer Philodina gregaria were investigated in the laboratory at Cape Bird. Bird Pond is characterised by a high conductivity and chloride ion concentration, and an alkaline pH. It has a water temperature as high as 15°c in mid summer, with the bottom water temperature often 3°c higher than the surface temperature. Diurnal measurements suggest a vertical movement of phytoplankton during a 24‐h period. P. gregaria survives ionic concentrations up to 250 000 g.m‐3 Na+ + Cl‐, and water temperatures up to 32°c. 相似文献
4.
W. de L. Main 《新西兰海洋与淡水研究杂志》2013,47(1):15-38
The distributions of two swimming crabs endemic to the New Zealand region are described, mostly from material obtained at 118 of 2544 New Zealand Oceanographic Institute benthic stations sampled. Nectocarcinus antarcticus (Jacquinot) was found within the geographic limits 34°S‐51°S and 166° E‐176° W, with concentrations around Cook Strait, the Chatham Rise, Foveaux Strait, and the Auckland Is. N. bennetti (Takeda & Miyake) occurred between 44° S and 53° S, and 165° E and 180°, most frequently in the south and west, on the ‘highs’ of the Campbell Plateau. Although the distributions overlap between 44° S and 51° S, and this overlap zone produced most of the available material, only one joint occurrence of the two species was noted. This apparent separation was not satisfactorily explained by any of the ecological factors recorded. The depth ranges of both species were broadly similar (0–550 m for TV. antarcticus, 20–474 m for JV. bennetti); both were most frequently obtained at depths less than 200 m. Both occurred primarily on the coarser sediment grades, though N. antarcticus occupied a broader range of grades than N. bennetti. The size ranges of the two species were similar; carapace lengths were 8.0–62.0 mm for N. antarcticus and 5.8–68.0 mm for N. bennetti. The larger specimens of both species were found towards the southern limits of distribution. Larger specimens of N. antarcticus were absent from depths greater than 120 m; smaller N. antarcticus and all N. bennetti occurred throughout their respective depth ranges. Ovigerous N. antarcticus (smallest, 8.8 mm carapace length) were obtained at depths of 17–263 m from May to October; ovigerous N. bennetti (smallest 36.1 mm) were from depths of 150–183 m in May only. 相似文献
5.
The limnology of Lake Rerewhakaaitu (36°18'S, 176° 30'E) was studied at various intervals between 1971 and 1974; comparisons were made between the main lake (area 6.32 km2, mean depth 7 m, maximum depth 15 m), and the smaller (0.15 km2) and deeper (mean depth 15 m, maximum 31 m) crater which are connected by a narrow, 1 m deep channel. The main lake was usually homothermal, although temporary stratification periodically occurred, and the oxygen content of the deeper water could be as low as 2 g.m‐3. The crater showed strong thermal and chemical stratification persisting well into the winter. Its heat budget and other factors related to lake stability are compared with those of some other New Zealand lakes. The failure of the crater to become fully re‐oxygenated during its brief period of homothermy is believed to be related to its morphometry, since the amount of phytoplankton did not appear to be great enough to explain the low levels of dissolved oxygen in the hypolimnion. The hypolimnetic oxygen deficit in 1973–74 was 0.038 mg. cm‐2.day‐1. Qualitatively the phytoplankton, usually dominated by desmids, was characteristic of oligotrophic waters, but quantitatively the main lake could be rated as mesotrophic. Differences were also found in the abundance of zooplankton between the crater and the main lake: there were usually more Bosmina but considerably fewer Ceriodaphnia in the main lake which had greater numbers of Piona. Adult Calamoecia were generally more abundant in the crater. 相似文献
6.
A small‐scale experiment was done to test the feasibility of thermally marking hatchery‐reared rainbow trout (Oncorhynchus mykiss Walbaum) fry that are released into rivers and impoundments in New South Wales (NSW), Australia. Fry of rainbow trout were exposed to two different 48‐h thermal cycles each of a cold and warm water period. One thermal regime consisted of a cold water period during which the temperature was reduced from 14 to 8°C for 18 h followed by a return to 14°C for 30 h. For the second thermal treatment, water temperature was reduced to 4°C for 10 h followed by a period of 38 h at 14°C. Thermal cycles were repeated 4 and 8 times for each thermal regime, respectively. Following a growth period after treatment, obvious marks were visible on all treated otoliths as distinct from control otoliths. The 10°C differential treatment created the most visible patterns and growth of these fish was not significantly different from control fish. This marking method could be applied to normal hatchery practices to evaluate the effectiveness of large‐scale rainbow trout stockings in NSW. 相似文献
7.
J. D. Booth 《新西兰海洋与淡水研究杂志》2013,47(4):671-689
Observations were made on several hydrological features of Bay of Islands during 1970 to 1971. The topography of Bay of Islands allows for a gradual change from estuarine to oceanic conditions within the harbour.Monthly means of sea surface temperatures ranged between 15°c and 23°c, and some sea stratification was observed during summer. Salinities in the main basin were about 35.5‰; water transparency ranged from 2 m to 6 m by Secchi disc in the estuaries, to more than 15m in outer basin areas. Dissolved oxygen content was high, usually exceeding 100% saturation in surface waters. Water circulation within the bay appears to consist of an anti‐clockwise movement of at least the surface water, induced by a north‐west moving current, possibly derived from the East Auckland Current.The observations suggest that, except; for the estuarine areas, Bay of Islands is hydrologically a fairly homogeneous, well‐mixed body of water. 相似文献
8.
A detailed gravimetric geoid around Japan has been computed on the basis of 30’ × 30’ block mean free‐air gravity anomalies and GSFC GEM‐8 geopotential coefficient set. The 30’ × 30’ block means were read from various gravity maps around Japan, and the block means have been compiled into the JHDGF‐1 gravity file. Since the gravity file is restricted around Japan (see Figure 1), additional gravity data are needed to perform the Stokes’ integration in the cap with radius ψ0 = 20°. The 1° × 1° block gravity means have been used outside the JHDGF‐1 region. The remarkable features of the gravimetric geoid occur over the trench areas. The geoidal dents over the trenches amount to ‐20~ ‐25 m in comparison with the geoidal heights in the land areas of Japan. The mean error of the 30’ × 30’ detailed gravimetric geoid obtained is estimated to be around 1.4 m, and the relative undulation of the geoid between the distance of a few hundred kilometers may be more accurate. 相似文献
9.
Landlocked sockeye salmon (Oncorhynchus nerka), ranging in fork length (FL) from 105 to 313 mm, were captured in fine‐mesh gill nets set in the limnetic zone of the Waitaki hydro lakes (44° 30′ S, 170° 10’ E) in the South Island, New Zealand. A total of 443 stomachs was examined and the frequency of occurrence, volume and weight of prey items calculated. In the Ahuriri Arm of Lake Benmore the principal food (54% by weight) was zooplankton (Boeckella dilatata) whereas in the Haldon Arm of Lake Benmore it was larval and juvenile common bullies (Gobiomorphus cotidi‐anus) (73% by volume). In Lake Waitaki in winter, salmon had eaten insects (43% by volume) with smaller amounts of snails (Potamopyrgus antipo‐darum, 23%) and bullies (24%). In Lake Ohau adult insects may be an important food. There were also variations in diet with season and fish size. The stomachs of 147 brown trout (Salmo trutta) and 181 rainbow trout (S. gairdnerii) caught in the same gill nets were also examined. In contrast to sockeye salmon stomachs they contained negligible amounts of zooplankton (< 1% by weight) and large amounts of aquatic insects (50–58% by weight in the Ahuriri Arm of Lake Benmore). Comparisons with juvenile sockeye salmon and kokanee in North American lakes are made. The impact of introductions of sockeye salmon into other New Zealand lakes is discussed. 相似文献
10.
D. J. Jellyman 《新西兰海洋与淡水研究杂志》2013,47(2):193-209
Recruitment of glass‐eels into freshwater is in two distinct phases characterised by behavioural differences: an initial invasion from the sea, and an upstream migration. Catches made at night in the Makara Stream, Wellington (41° 13'S, 174° 43’ E) indicate that the invasion by both New Zealand species commences in July, with that of the long‐finned eel Anguilla dieffenbachii Gray finishing by November, and that of the short‐finned eel A. ausiralis schmidlii Phillipps by December. The length of post‐metamorphic sea‐life influences both morphology and behaviour of the glass‐eels. Differences in this period of sea‐life between early and late season glass‐eels explain the initial avoidance but later attraction of fresh water to the glass‐eels. Responses to fresh water also explain the preference for early season glass‐eels to invade on the flood tide and late season glass‐eels on the ebb tide. Neither the lunar cycle nor rainfall appear to be significant influences on invasion periodicity. 相似文献
11.
《Coastal Engineering》2001,42(1):17-34
The linear mild-slope equation (MSE) is examined in the limit of very shallow water. This is done by means of a series comparison with the more ‘exact’ linear classical theory (E) valid over arbitrary uniform slopes and known to have a “minimum norm” solution basis pair, respectively, regular and logarithmically singular at the shore line. It is shown that the agreement between E and MSE is exact for the first three terms for the regular wave and the first two for the singular wave. It is further demonstrated, by application of this example, that the MSE represents a better approximation than does the classical linearised shallow water equation (SWE) in the case of extremely small depth. In particular, if solutions to each are tuned to the same finite wave height at the shoreline, then MSE predicts the correct curvature of wave height there whereas SWE does not.The work of Booij (Booij, N.A., 1983. A note on the accuracy of the Mild-Slope Equation. Coastal Engineering 7, 191–203.) is supported and varied to allow performance on very steep beds to be tested against exact values rather than those of numerical simulation. Those tests are carried out both as Boundary Value Problems, BVP (Scheme A) and Initial Value Problems, IVP (Scheme B) with matching results on global error. Methods are found of specifying phase and group velocity, which are consistent with linear wave beach theory and lead to improvements in solving the MSE over steep flat beaches. The improvements are found generally superior, in the case considered, to those of some recently developed ‘modified’ and ‘extended’ MSEs. Finally, it is demonstrated, and confirmed by both asymptotic theory and calculation, that the addition of evanescent modes constitutes improvement only in intermediate depths and is not recommended in depths of the order of only a wavelength on a steep (e.g. 45°) beach. 相似文献
12.
13.
Based on the mineralogy and composition of sediment cores from three locations along the East Pacific Rise, sediments from 12°58’ N are shown to contain about 34% metalliferous sediment (on a carbonate‐ and salt‐free basis) whereas those from 23°50’ S and 27°24’ S each contain about 73% metalliferous sediment. The latter two cores are situated near the West Rift of the Easter Microplate. The metalliferous contents of the sediments at 23°50’ S and 27°24’ S are among the highest recorded on the East Pacific Rise. The distribution of elements with depth in these cores indicates that the hydrothermal activity has lasted more than 100,000 years. These data suggest that the West Rift of the Easter Microplate is a highly prospective site for submarine hydrothermal minerals. This is in accord with the high rate of ocean spreading (15–16 cm/yr) and the complex processes of plate extension and rotation there. 相似文献
14.
The sedimentary structures, composition, and texture of sediments from the barrier coast complex (Matarangi Beach—Omaro Spit—Whangapoua Harbour) at Whangapoua, Coromandel Peninsula, are described. Sediments are mainly fine sands, rarely muddy or silty, and most are plagioclase feldsarenites, reflecting derivation from a predominantly Tertiary volcanic hinterland. Sediments from each of the modern environments, namely nearshore, foreshore, back‐shore, frontal dunes, tidal flats, and tidal channels, are characterised by a particular combination of sedimentary structures and subtle textural parameters. Dune ridge and barrier flat paleoenvironments on Omaro Spit were successfully identified by comparing their lithologic properties with the modern sediments. ‘Surficial’ sediments of the well‐preserved dune ridge system developed immediately inland from Matarangi Beach closely resemble those in the modern frontal dunes, and the ‘in depth’ dune ridge sediments are more analogous to the present foreshore sands. The barrier flat deposits separating the dune ridge system from Whangapoua Harbour have similar characteristics to the modern tidal flat sediments in the harbour. Omaro Spit probably began as an offshore bar across the mouth of Whangapoua Harbour, an embayment formed by the post‐glacial drowning of a Late Tertiary dislocated fault‐block. Tidal flat sedimentation within the harbour formed the ancient barrier flat deposits which rise to at least 2 m above the modern harbour flats, suggesting local sea level at the time was higher than at present. During a subsequent cyclic fall in sea level, supratidal aeolian deposition led to a succession of 15 to 18 parallel dune ridges developed on high‐tide berms. Linear regression analyses of dune ridge and swale heights and the height distribution of positive (aeolian) and negative (beach foreshore) skewness values and of contrasting sedimentary structures in dune ridgL paleosediments, together with the stages in dune soil development across the barrier, suggest initial sedimentation occurred from 4000–5000 years ago when local sea level was 2–3 m above present mean high water level. Barrier progradation was interrupted by an important period of coastal erosion during a temporary rise in sea level immediately before deposition in the dune ridge system of a layer of 2000‐year‐old sea‐rafted Leigh Pumice. Sea level probably reached its modern position at Whangapoua about 1000 years ago, since when some evidence suggests the barrier spit may have experienced minor uplift. 相似文献
15.
The shear strength and dilatancy of typical uncemented calcareous sand from the South China Sea are investigated by soil lab tests. According to drained triaxial tests at various relative densities and confining stresses, it is found that the constant volume friction angle is approximated as 39° and the traditional Bolton’s equations can be modified to estimate the peak friction angle and dilation angle. The reliability of the equation proposed for the peak friction angle is verified in terms of calcareous sands from more onshore and offshore sites worldwide, while the errors of the predicted dilation angles scatter in a relatively large range. Totally, the dilation angles of sands in the South China Sea are estimated by the equation presented with an error of ±30%. The peak friction angle measured by the undrained is similar to that by the drained tests as the relative density smaller than 60%, while the former is slightly lower for denser samples.
相似文献16.
G. J. Macchi M. Pájaro O.C. Wöhler M. J. Acevedo R. L. Centurión D. G. Urteaga 《新西兰海洋与淡水研究杂志》2013,47(5):993-1000
The reproductive biology of southern blue whiting (Micromesistius australis) inhabiting waters of the southwest Atlantic Ocean (52°‐53°S and 57°‐62°W) was studied through histological analysis of the ovaries. During 2003, the spawning peak occurred at the beginning of September south of the Malvinas Islands. Batch fecundity of this species ranged from 35 000 (41 cm total length, TL) to 245 000 (62 cm TL) oocytes and relative batch fecundity was 122 ± 43 (Mean ± SD, n = 24) oocytes per gram somatic weight. The average proportion of mature females with stage‐0 post‐ovulatory follicles was 0.25 for September 2003, which indicated a spawning frequency of 4 days during the peak of the season. Large females produced more egg batches than small spawners during the same period, but no significant relationship was found between oocyte dry weight and female size of southern blue whiting. 相似文献
17.
J. B. Jillett 《新西兰海洋与淡水研究杂志》2013,47(4):543-557
Distinctly different water masses are to be found near the sea surface within 40 km of the coast off Otago Peninsula, south‐eastern New Zealand (45° 50’ S, 170° 45’ E). Although the hydrological regime is complex in this area, the three water masses have a stable relationship to one another: neritic water close to shore, then modified Subtropical Water, and Subantarctic Water off shore. Quantitative zooplankton samples from the upper 150 m were taken from a four‐station, 50‐km latitudinal transect at monthly intervals over 15 months, October 1966‐December 1967. Data were analysed by group‐average sorting methods into a hierarchical classification of 37 components, identified to species where practicable. Each species group was clearly associated with particular stations and from this hydrological affinities were deduced. The classification recognised a primary division between “neritic” and “oceanic” groups of zooplankton, each of which contained further subdivisions. “Neritic” zooplankton contained “coastal” and “shelf” subgroups; “oceanic” plankton contained “transitional” and “subantarctic” subgroups. Zooplankton from Otago waters had hydrological affinities which were consistent with their wider distributions. Presence of subtropical zooplankton in Otago waters helps to resolve confusing differences between various interpretations of surface circulation in the southern Tasman Sea. 相似文献
18.
R. A. Heath 《新西兰海洋与淡水研究杂志》2013,47(4):331-367
Results are presented from direct measurements of subsurface currents at ten coastal positions around the southern half of New Zealand, and from geomagnetic electrokinetograph measurements of surface currents between these positions. Currents on the continental shelf were predominantly tidal. Strongest mean flows were found on the continental slope adjacent to areas where the continental shelf is narrowest. The flow on the west coast of the South Island was southwards south of 44° S, with a maximum mean speed at a depth of 100 m of 0.64 m.s‐1. On the east coast of the South Island the flow was generally towards the north, with a maximum speed at a depth of 100 m of 0.21 m.s‐1 near latitude 42° 30’ S. 相似文献
19.
Alex E. Gilmour 《新西兰海洋与淡水研究杂志》2013,47(2):353-357
Results from a preliminary spectral analysis of inertial currents at a site with co‐ordinates 42° 1.73’ S, 168°41.1 l'E and a depth of 1505 m are described. Rotary spectral analysis indicates that inertial currents form a significant constituent of the observed oscillatory currents recorded. 相似文献
20.
The protozoan populations of microhabitats in Blue Lake, Raoul Island, Kermadec Group, 28° 30’ S 178° 00’ W are described qualitatively and semi‐quantitatively. The in situ and in vitro pH values of the four micro‐habitats examined were recorded. After two days in vitro there was a marked drop in the pH of the mud zones, a slight drop in pH of the water zone and no decrease in the pH at the surface. The nature of the protozoan populations is discussed in relation to the pH values and the changes which took place in these values. 相似文献