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1.
M. A. Barker 《新西兰海洋与淡水研究杂志》2013,47(4):406-430
Summary Lake Pupuke, situated in the North Island of New Zealand near Auckland (Latitude 36° 53'S, Longitude 174° 52'E), is a small, circular body of water (maximum width 1.2 km, maximum depth 55 m). From November 1966 to November 1967 observations on its physico‐chemical factors were made twice monthly. The range of temperatures in the year was 12.0–24.2°c at the surface and 11.3–14.5°c at 40 m. A thermocline farmed between early October and early January, when it became strongly developed at about 17 m and persisted until late April. Between early May and late June the stratification was breaking down and between mid July and mid September the lake was isothermal. The values for light transmitted per metre through the water were high from mid August to mid December (53–76% per metre), very low from mid December until mid February (23–49% per metre), high in March (75% per metre) and relatively constant over the winter months (53–64% per metre). The amount of light transmitted depended closely on the density of phytoplankton. Changes in the depth at which a Secchi disc disappeared paralleled the light transmission values, and the mean Secchi depth was 2.2 m, range 1.0–5.2 m. Oxygen concentrations down to 30 m were highest at all depths from mid November to early January (112–134% saturation). From early January to late April oxygen was strongly stratified (epilimnion 55–100% saturation, hypolimnion 24–77% saturation). During winter oxygen values gradually increased at all depths. The range of pH was 7.8–9.5 units at the surface and 7.8–8.6 units at 30 m. From early January to late April pH values were strongly stratified but from mid July to mid August they were nearly uniform. The range of alkalinity (mainly HCO3 ? ions) was 76.0–80.8 ppm CaCO3 and values showed stratification in summer. Carbonate ion was present from early October to mid June, but free carbon dioxide was only found in trace amounts. The range of nitrate ion concentrations was 0.05–0.31 ppm; nitrate became obviously depleted in summer. Only one nitrite value was significant, 0.25 ppm. other nitrite values never exceeded 0.10 ppm. The concentration of ammoniacal nitrogen built up to a summer maximum of 0.95 ppm in the hypolimnion (annual range 0–0.95 ppm); values for albuminoid ammonia (0.016–1.03 ppm of nitrogen) varied with the quantity of living matter present. The annual mean for total ion concentration (3.30 meq./1) was high and the order of ions was Na+>Mg2+>Ca2+>K+ and HCO3 ?>CI?>SO4 2?. Such dissolved salts may have arrived as airborne particles, dissolved in rain, or as sea spray. 相似文献
2.
Tide gauges distributed all over the world provide valuable information for monitoring mean sea level changes. The statistical models used in estimating sea level change from the tide gauge data assume implicitly that the random model components are stationary in variance. We show that for a large number of global tide gauge data this is not the case for the seasonal part using a variate-differencing algorithm. This finding is important for assessing the reliability of the present estimates of mean sea level changes because nonstationarity of the data may have marked impact on the sea level rate estimates, especially, for the data from short records. 相似文献
3.
K. R. Grange 《新西兰海洋与淡水研究杂志》2013,47(3):315-329
A survey of the macrobenthos at 42 stations in the channels and subtidal sandflats in Manukau Harbour, Auckland, revealed four biotic associations; although referred to as communities, they are not equivalent to Peterson‐type communities since they are not particularly discrete and there is some overlap in species composition. The similarity in species between stations was measured by percentage similarity coefficients using Jaccard's coefficient for presence‐absence data and Czekanowski's coefficient for log‐transformed quantitative data. Stations were grouped in dendrograms by group‐average sorting which allowed re‐arrangement of the similarity matrices into trellis diagrams. Dominant species in each of the four groups of stations were ranked by calculating a ‘community score’ for each, based on its abundance, fidelity, and bioindex value within the group. Each of the four groups was found to support a unique group of species and these are considered as representing four communities. Two indicator species in each community were identified from the highest community scores: Group 1, the Microcosmus/Nolomithrax community — associated with a coarse sediment of dead bivalve shells and small rocks in shallow water. It has high species diversity indices; Group 2, the Halicarcinus/Bugula community— associated with a relatively coarse sediment of dead shells, grit, and little sand in deep water in the main channels; Group 3, the Amalda/Myadora community—associated with fine sand with mud or shell grit in shallow parts of the channels; and Group 4, the Fellaster/Pagurus community — associated with ironsand in shallow water in the outer harbour. It has low species diversity indices. 相似文献
4.
J. D. Green 《新西兰海洋与淡水研究杂志》2013,47(2):199-222
Lake Ototoa is a warm monomictic lake at 36° 31’ S, 174° 14'E. During a year's study (March 1969‐March 1970), the lake became thermally stratified in November, the metalimnion being between depths of 12 m and 16 m. Surface temperatures ranged between 10.2°c (in August) and 25.2°c (in late January), and bottom temperatures between 9.7°c and 17.5°c. The annual heat budget was calculated to be 642 354 KJ.m‐2 (15 500 cal.cm‐2) and the work of the wind in distributing the heat income 1.730 KJ.m‐2 (1766 g.cm.cm‐2). Secchi disc transparencies ranged between 5 m and 9.2 m (mean 7.07 m) and were greatest in the summer. Light transmission per metre was also high, ranging between 61% and 87%. Surface waters were normally supersaturated with oxygen, but during summer stratification oxygen concentrations in the bottom waters dropped to a minimum of 2.3 mg.litre‐2 and a positive heterograde distribution of oxygen with depth was found. The oxygen deficit was 0.015 mg.cm‐2.day‐1 and showed the lake to be oligotrophic. Mean surface pH was 7.82, and the ionic composition of the waters was similar to that of other small New Zealand and Australian lakes located near the sea. Compared with other New Zealand lakes PO4‐P concentrations (range 1.00–10.20 μg.litre‐1) were low and NO3—N concentrations (range 0.12–0.60 mg.litre‐1) high. 相似文献
5.
Abstract The use of marine high‐resolution geophysical profiling data, seafloor soil samples, and accepted land‐based methods of analysis have provided a means of assessing the regional geotechnical conditions and relative slope stability of the portion of the Gulf of Alaska Continental Margin known as the Kodiak Shelf. Eight distinct types of soils were recognized in the study; the seafloor distribution of these indicates a complex geotechnical setting. Each soil unit was interpreted as having a distinct suite of geotechnical properties and potential foundation engineering problems. Seven categories of relative slope stability were defined and mapped. These categories range from “highest stability”; to “lowest stability,”; and are based on the degree of slope of the seafloor, type of soil underlying the slope, and evidence of mass movement. The results of the analysis indicate that the highest potential for soil failure exists on (1) the slopes forming boundaries between the submarine banks and the broad sea valleys, and (2) the upper portion of the continental slope, where evidence of past slope failure is common. Also of concern are gently sloping areas near the edges of submarine banks where evidence of possible tension cracks and slow downhill creep was found. 相似文献
6.
Survival and reproductive rates in fish are often a function of body size. Consequently, spatial‐ and sex‐specific variation in somatic growth rates can have important consequences for population growth and resilience. We used otolith‐based approaches to estimate geographic‐ and sex‐specific growth rates of yellow‐eyed mullet (Aldrichetta forsteri) collected from 14 estuaries and harbours around New Zealand. Aldrichetta forsteri is an abundant and dominant component of New Zealand's estuarine fish fauna. We extracted otoliths from 511 fish, validated daily and annual increments, and prepared transverse thin sections of otoliths to determine age. “Size‐at‐age” relationships were estimated using both linear‐ and non‐linear (von Bertalanffy) growth models, and model performance was evaluated using Akaike's Information Criterion. Because growth rates of sampled fish were best approximated by linear functions, we used ANCOVA to test the null hypothesis that growth rates of A. forsteri were homogeneous between sexes and among geographic locations around New Zealand. Our analyses suggest heterogeneous growth rates between sexes and among locations. Interestingly, relative growth rates between sexes appeared to vary across separate latitudinal gradients for North Island and South Island. Within each island (but not across islands), female A. forsteri generally grew faster than males at the lowest latitudes; relative growth rates of females declined progressively below males with increasing latitude. 相似文献
7.
Gary C. B. Poore 《新西兰海洋与淡水研究杂志》2013,47(4):577-590
A 31/2‐year succession of wharf‐pile fauna is described from communities of different known ages on piles at Lyttelton, New Zealand. Intertidal regions of the piles were initially colonised by the barnacle Elminius modestus; these populations developed to form a subclimax community which was subsequently replaced by a climax community of the mussel Modiolus neozelanicus after 21/2 years. The stability of this climax is discussed. In the infratidal region initial settlement of the tubicolous amphipod Corophium acherusicum and an erect bryozoan Bugula sp. was followed after 5 months by colonisation by solitary tunicates. These tunicates became dominant only after H years and provided numerous niches for superficial foulers, crevice dwellers, and motile organisms. This succession is compared and contrasted with a terrestrial succession of plants. Four vertical zones were recognised: supralittoral zone, midlittoral zone, in‐fralittoral fringe, and infralittoral zone. Species additional to those recorded by Skerman (1958) are appended. 相似文献
8.
Sean J. Handley 《新西兰海洋与淡水研究杂志》2013,47(4):681-687
Larvae of Boccardia knoxi (Rainer) were reared in the laboratory after dissection from brood capsules extracted from the outer shell and perio‐stracum of Cookia sulcata and Haliotis iris collected from Tasman Bay, New Zealand. All the eggs within each brood capsule developed into embryos. The dissected larvae had provisional setae and fed on phytoplankton. Larval development is described through to metamorphosis. 相似文献
9.
L. W. Sinton 《新西兰海洋与淡水研究杂志》2013,47(3-4):317-326
A baseline groundwater quality survey of 120 household wells in an unsewered area at Yaldhurst, near Christchurch, was carried out between September and December, 1976. Ammonia‐N levels were below the detection limit (0.02 g m‐3) in all samples. Nitrate‐N, conductivity, and chloride levels tended to vary according to well depth and location, being lower in the deeper wells and in wells located in an area of shallow, stony soils. Approximately 33% of the wells contained coliform bacteria, faecal coliform bacteria or faecal streptococci. A subset of 25 wells was sampled fortnightly from January to August 1977. From January to June, mean nitrate‐N and conductivity levels remained stable at approximately 1.5 g m‐3 and 11.2 mS m‐1 respectively. An increase in these levels to 3.3 g m‐3 and 15.8 mS m‐1 in July‐August corresponded with a rise in the water table. Leaching losses from soils probably accounted for most of the nitrate entering the Yaldhurst aquifers, the contribution by septic tank systems being estimated at 20–30%. No direct evidence of contamination of the wells by septic tank effluent was found, although 23 of the 25 wells exhibited intermittent contamination by indicator bacteria throughout the 8 month sampling programme. Although a localised health hazard may exist, septic tank systems in the area were not considered likely to constitute a health threat to the confined aquifers underlying Christchurch city. 相似文献
10.
A. A. Fincham 《新西兰海洋与淡水研究杂志》2013,47(4):677-696
Abstract Substrate and infauna samples were taken at four tidal levels (mean high water springs, high mid beach, low mid beach, and mean low water neaps) with a 0.0625 m2 quadrat at 14 North Island beaches in New Zealand. The distributions of Peracarida (Crustacea) were correlated with sediment type, tidal height, and degree of exposure; sampling began in March 1972 and was completed in November 1973. Substrate samples were sieved and median diameter of the particles ranged from very coarse sand of — 0.60? to very fine sand of + 3.259?. Substrates were variously sorted: ? quartile deviation ranged from 0.14? to 0.66?, skewness from ‐ 0.08? to + 0.07?. Peracarid fauna was moderately abundant; the maximum value was 720 animals per square metre on a fully exposed beach. Highest average abundance (303 per square metre) for the 14 beaches was recorded from the mean low water neap station. Amphipoda was the dominant group (54% of all Peracarida recorded), followed by Isopoda (33%) and Cumacea (13%). Frequency of occurrence at the 56 stations was headed by Amphipoda (64%), followed by Isopoda (46%), and Cumacea (20%). The results are compared with data from Stewart Island beaches, and the biogeographical distributions of recorded Peracarida are discussed. An unexpectedly high degree of endemism exists for a warm‐temperate region, caused by the isolation of New Zealand, which has no direct shallow water contact with tropical or cold temperate regions. 相似文献
11.
Short‐finned wild eels fed an artificial diet containing either a low (5%) or a high (20%) oil content were found to increase their mass by an average of more than 30% after a 34‐day feeding period; the lipid content of the eels’ muscle was also increased from about 10% to around 20%. 相似文献
12.
State‐of‐the‐art technology is presently being used for the acquisition of water level and meteorological data in the Intra‐Americas Sea to support the Global Sea Level Observing System (GLOSS) network of sea‐level monitoring stations. GLOSS stations provide data for the investigation of regional relative sea level change in areas of complex tectonic motion, national geodetic vertical datums, near real‐time data for input to climatic diagnostic numerical models, calibration of satellite altimeter and scatterometer data, and the evaluation of the feasibility of producing synoptic mean sea level charts for the prediction of climatic trends, long‐range weather forecasts, and ocean processes. 相似文献
13.
Michael J. Dunnington Richard A. Wahle Michael C. Bell Nathan R. Geraldi 《新西兰海洋与淡水研究杂志》2013,47(6):1253-1276
Seabed mapping, spatially referenced trapping, and mark‐recapture methods have all been useful tools in ecological studies of lobsters and other benthic animals. Here we integrate the three methods to evaluate local population dynamics and movements of American lobsters, Homarus americanus, in coastal fishing grounds in Maine, United States. The study was conducted on five study areas of different size, and used two different sampling protocols. At one site (1 km2 in area) we used a monthly mark‐recapture sampling interval over a 6‐month period, only tagging a subsample of the catch. At four smaller sites (0.3 km2) we used a shorter‐term approach, sampling at 3–4‐day intervals for a 2‐week duration, tagging the entire catch. Tagging data were analysed with a modified Jolly‐Seber model adapted for continuous sampling to estimate population abundance, gains (immigration), and losses (emigration and mortality). Side‐scan sonar surveys of the seabed combined with diver‐based population surveys, stratified by substrate type, provided an independent comparison to mark‐recapture‐based estimates of abundance over the same areas. Spatial referencing of trap catch also allowed us to relate catch rates and lobster movements directly to seabed features. The longer‐term tagging data on the larger study area provided abundance estimates that were more consistent with the diver observations, and estimates of gains and losses statistically more robust, than those derived from the shorter‐term effort on the smaller sites. The flux of lobsters followed the well known seasonal movements on these fishing grounds, with gains and losses from the larger study area ranging over 1000 individuals per day, and an estimated mid‐summer peak density of >65 000 lobsters per km2 (individuals >50 mm carapace length). This approach may lend itself to broader application with the American lobster. 相似文献
14.
Infaunal bivalve molluscs on the flood tidal delta of Tauranga Harbour, north‐eastern New Zealand, were surveyed twice over a 6‐month period, with the aim of assessing shellfish resources, assessing the magnitudes of temporal and spatial variability in abundances, and identifying potentially important processes. The surveys identified a total of 31 bivalve taxa from 27 sites. Species richness per site ranged between 0 and 9, and varied greatly in space and time, as did two other measures of diversity. Extremely high densities of bivalves (>20 000 m‐2) were encountered at several sites. Densities of several abundant species varied greatly in time, as a result of recruitment pulses. The abundances of the three species that dominated the fauna (Paphies australis, Tawera spissa, and Ruditapes largillierti) had characteristic spatial scales on the order of 200 m. Comparisons of size frequency distributions for individual sites suggested that mortality or emigration in the first year of benthic life was high. Substantial populations of bivalves occur on Centre Bank, and the most abundant of these are greatly influenced by events early in their lives. 相似文献
15.
P. E. Roberts 《新西兰海洋与淡水研究杂志》2013,47(3):455-472
During two trolling surveys in February 1972, albacore, Thunnus alalunga (Bonnaterre), were located between Cape Reinga and Cape Egmont, but were more abundant between Kaipara Harbour and Albatross Point. Fish catches and associated hydrological data are presented. Albacore were caught only in areas where the sea surface temperatures were between 18.5°c and 21.3°c, and usually in areas where the water was blue and the bottom depth between 45 m and 80 m. The albacore were mainly of the 2‐ and 3‐year age‐groups. Of the 665 fish landed, 449 were tagged and released, but no recoveries have been made. Commercial vessels located albacore within 20 km of New Plymouth during the summers of 1970 and 1971 when sea surface temperatures were 1.5–2.5°c higher than in February 1972, probably because of a more southward extension of the West Auckland Current in 1970 and 1971. 相似文献
16.
B. P. Penlington 《新西兰海洋与淡水研究杂志》2013,47(4):349-355
The presence of suitable gravel size alone can stimulate female rainbow trout (Salmo gairdneri) to excavate nests for spawning on the shores of Lake Rotoma. Emergent fry result from lake‐shore spawning, and could contribute significantly to the trout fishery in Lake Rotoma. Lake‐shore spawning could be enhanced by the use of stable artificial spawning beds that have adequate depth and appropriate sizes of gravel. 相似文献
17.
Photo‐identification has been established as a helpful tool in cetacean research. However, no study to date has attempted to apply this method to short‐beaked common dolphins (Delphinus delphis L.). We present here the results of two studies that were conducted concurrently in Mercury Bay and the Hauraki Gulf on the north‐east coast of New Zealand's North Island. Methods for distinguishing between individual dolphins are discussed. Sighting records of recognisable individuals indicate that some common dolphins move between Mercury Bay and the Hauraki Gulf (100 km distance), as well as between Mercury Bay and Whakatane (200 km distance). Common dolphin abundance and site fidelity appeared to be greater in the Hauraki Gulf than in Mercury Bay. A selection of photographs of distinct individuals is presented to allow future studies to compare their sighting records to ours, which may help establish the extent of home ranges, site fidelity, and possibly even longevity for common dolphins. 相似文献
18.
The finding of shells of toheroa (Amphidesma ventricosum Gray) which had been drilled by gastropods absent from the littoral zone, is presented as evidence for the existence of sub‐littoral populations of toheroa. 相似文献
19.
Behavioural deficiencies in 4th and 5th stage hatchery‐reared lobsters were examined using time budget analysis and predator trials. Hatchery‐reared 4th stage lobsters were found to behave differently than wild‐caught lobsters and differences existed between hatchery‐reared lobsters from different sources. Local hatchery‐reared 4th stage lobsters spent less time on shelter and suffered higher predator rates in laboratory trials than both wild‐caught 4th stage and lobsters reared in a hatchery in Maine. Fifth stage hatchery‐reared lobsters spent significantly more time in shelter than their wild‐caught counterparts. These differences may be attributable to the lack of development of proper predator‐avoidance behaviour and need to be understood and corrected to maximise the effect of enhancement projects. 相似文献
20.
Abstract The tsunami travel‐time charts that are presently in use by the Tsunami Warning Center were constructed originally in 1948 based on the hydrographic data available in the mid 1940s. Even the revised charts of 1971 made use of essentially the same data. It is shown here that the travel times deduced by these charts could be in error by as much as two hours in some cases. Even worse, the compiled travel times as deduced from these charts are generally greater than the observed travel times, which is a dangerous situation from a tsunami warning point of view. 相似文献