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1.
The Subtropical Convergence east of New Zealand   总被引：1，自引：1，他引：0  
Hydrographic data from the region of the Subtropical Convergence east of New Zealand between 177°E and 179°E show that in spring the convergence occurs near the Chatham Rise. North of the Chatham Rise the structure is fairly regular with isolines of temperature and salinity sloping upwards towards the south. To the south of the Chatham Rise the structure is more complex with an apparent intrusion of Subtropical Water into the Sub‐antarctic Water below depths of about 150 m.  相似文献   

2.
Meristic and genetic methods were used to determine the stock relationships of black Allocytus niger (James, Inada & Nakamura, 1988) and smooth oreo Pseudocyttus maculatus (Gilchrist, 1906) in the New Zealand Exclusive Economic Zone (EEZ). Samples were collected from four management areas—OEO 1 (south‐west), OEO 3A (Chatham Rise west), OEO 4 (Chatham Rise east), and OEO 6 (subantarctic) during the 1998 October‐December spawning period. Lateral line scale counts and pyloric caeca counts revealed differences between black oreo samples from OEO 6 and the other three OEO management areas. Lateral line scale counts in smooth oreo showed no significant differences between areas. Genetic analyses of four non‐coding regions of nuclear DNA and mitochondrial (mt) DNA haplotypes in black oreo showed no significant differentiation among the four management areas. Likewise for smooth oreo, genetic analyses of five non‐coding regions of nuclear DNA and mtDNA haplotypes showed no overall regional differentiation, although there was weak evidence at one locus for a difference between OEO 3A and OEO 6. The data do not reject the null hypothesis of a single genetic stock in New Zealand waters, and are typical of marine species with long pelagic juvenile stages.  相似文献   

3.
Plankton samples from the Chatham Rise, Pukaki Rise, and Campbell Plateau provided information on the young stages of a number of poorly known New Zealand fish species, and on the presence of a large spawning area of barracouta, Thyrsites atun, over the Mernoo Bank, The Chatham Rise was more important as a spawning area than the areas further south.  相似文献   

4.
The steep Antipodes Scarp, along the eastern boundary of the Campbell Plateau south‐east of New Zealand, is attributed to dextral tear‐faulting within a NE‐SW belt, the Antipodes Fracture Zone, which also truncates the eastern end of the Chatham Rise. A complementary zone of sinistral movement, the Waipounamu Fracture, separates the Campbell Plateau and Chatham Rise from mainland New Zealand.

The origin of these fracture zones is linked with that of the parallel Alpine Fault of South Island, and is related to a phase of NE‐SW crustal compression that dominated the New Zealand region during the Mesozoic era. It is suggested that this compression resulted from the north‐eastward “drift” of the Australian craton and the simultaneous elevation of the Darwin Rise in the central Pacific.  相似文献   

5.
A calculation of the area of the New Zealand 200 nautical mile Exclusive Economic Zone is presented with definitions, cartographic methods, and calculations based on areas of quadrilaterals of the earth's surface of 1° extent in latitude and longitude. An area of 1 181 487 square international nautical miles (4 053 049 km2), ± 0.377%, includes enclaves adjacent to the Chatham Rise and the Pukaki Rise retained for assessments related to fisheries research programmes.  相似文献   

6.
Two species of spiny lobsters (marine crayfish) inhabit New Zealand waters: Jasus edwardsii (Hutton, 1875), and J verreauxi (H. Milne Edwards, 1851). J edwardsii, the more common species, is present along most rocky coastlines in New Zealand, but is more abundant in the south‐west of the South Island and at the Chatham Islands. The species apparently reaches its northern limit of distribution at the Three Kings Islands (34°S) and its southern limit at the Auckland Islands (51°S).

J. verreauxi, the less common species, is almost solely restricted in New Zealand waters to the north‐east coast of the North Island. It is uncommon in the west and the south of the North Island, and is rare in the South Island. J. verreauxi apparently reaches its northern limit of distribution at the Kermadec Islands (31°S), and its southern limit near Bluff (47°S) in the South Island.  相似文献   

7.
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8.
Measurements of total dissolved arsenic (As(III+V)) and antimony (Sb(III+V) and their simple methylated species are presented for samples collected from three vertical profiles and along three surface transects in the Chatham Rise region, east of New Zealand. As(III+V) concentrations showed a slight increase with depth (16–17 nM at 25 m to 20 nM at 100 m) whereas Sb(III+V) concentrations were conservative with depth (1.02–1.12 nM). Along the three surface water transects, As(III+V) and Sb(III+V) concentrations showed little variation, with average concentrations of 18±2 and 0.99±0.05 nM, respectively. Inorganic arsenic was not correlated with orthophosphate (r2=0.01). Monomethyl- and dimethyl-arsenic (MMAs, DMAs) concentrations (0.04–0.01 and 0.65–0.07 nM, respectively) decreased with depth, suggesting surface water production by biota and degradation at depth. Along the Chatham Rise transect, DMAs concentrations increased on the Rise (0.65 nM maximum) compared to waters north and south of the Rise (∼0.22 nM). Fluctuation in MMAs concentrations were also seen for water samples collected on the Chatham Rise. Monomethyl-, dimethyl- and trimethyl-antimony (MMSb, DMSb, TMSb) species were detected in water samples collected along all the three surface water transects suggesting surface water production by biota. Concentrations of MMSb, DMSb and TMSb in water samples were fairly constant along all the three surface transects (0.06–0.07, 0.015–0.025 and 0.005–0.015 nM, respectively), showing no significant enrichment on the Chatham Rise. These arsenic and antimony results support the current global view that inorganic As and Sb are conservative and the methyl species are of biological origin.  相似文献   

9.
Projections of potential submerged area due to sea level rise are helpful for improving understanding of the influence of ongoing global warming on coastal areas. The Ensemble Empirical Mode Decomposition method is used to adaptively decompose the sea level time series in order to extract the secular trend component. Then the linear relationship between the global mean sea level(GMSL) change and the Zhujiang(Pearl) River Delta(PRD)sea level change is calculated: an increase of 1.0 m in the GMSL corresponds to a 1.3 m(uncertainty interval from1.25 to 1.46 m) increase in the PRD. Based on this relationship and the GMSL rise projected by the Coupled Model Intercomparison Project Phase 5 under three greenhouse gas emission scenarios(representative concentration pathways, or RCPs, from low to high emission scenarios RCP2.6, RCP4.5, and RCP8.5), the PRD sea level is calculated and projected for the period 2006–2100. By around the year 2050, the PRD sea level will rise 0.29(0.21 to 0.40) m under RCP2.6, 0.31(0.22 to 0.42) m under RCP4.5, and 0.34(0.25 to 0.46) m under RCP8.5, respectively.By 2100, it will rise 0.59(0.36 to 0.88) m, 0.71(0.47 to 1.02) m, and 1.0(0.68 to 1.41) m, respectively. In addition,considering the extreme value of relative sea level due to land subsidence(i.e., 0.20 m) and that obtained from intermonthly variability(i.e., 0.33 m), the PRD sea level will rise 1.94 m by the year 2100 under the RCP8.5scenario with the upper uncertainty level(i.e., 1.41 m). Accordingly, the potential submerged area is 8.57×103 km2 for the PRD, about 1.3 times its present area.  相似文献   

10.
龚彩霞  陈新军  高峰  余为 《海洋学报》2022,44(7):95-102
根据影响西北太平洋柔鱼栖息地分布的主导环境因子—海表面温度,基于最大熵模型,利用1996-2005年气候历史数据和两种不同情景（RCP4.5和RCP8.5）下的气候预估数据,分析了1996-2005年、2021-2030年、2051-2060年、2090-2100年主要捕捞月份（7-10月）柔鱼潜在栖息地变化。结果表明,柔鱼渔场纬度方向空间分布呈季节性南北移动;随着未来气候变化,在RCP4.5和RCP8.5两种情景下,2021-2030年、 2051-2060年、 2090-2100年7-10月柔鱼潜在栖息地分布较1996-2005年7-10月均呈现向北极移动趋势,适宜面积增加。推测柔鱼渔场季节性南北移动可能受各月适宜海表面温度范围变化的影响,在RCP4.5情景下,到21世纪末,各月柔鱼潜在最适宜生境向北移动1°～2°,适宜面积增加3%～13%;在RCP8.5情景下,到21世纪末,各月柔鱼潜在最适宜生境向北移动3°～5°,适宜面积增加42%～80%。  相似文献   

11.
Records of four species of Delphinidae, Delphinus delphis, Lissodelphis peroni, Lagenorhynchus obscurus, and Lagenorhynchus cruciger in waters to the east and south‐east of New Zealand are discussed in relation to surface temperatures.

In this region D. delphis appears to be largely confined north of the Subtropical Convergence and a minimum surface temperature of about 14°c, and near New Zealand from Hawke Bay southward in the warm water of the East Cape Current; L. peroni to the Subtropical Convergence and the subantarctic water to the south of it, between surface temperatures of 9°c and 16°c; L. obscurus to the immediate vicinity of the Subtropical Convergence and surface temperatures in summer of about 14° to 15°c, and L. cruciger across the Antarctic Convergence region, in a surface temperature range of 2° to 9°c.  相似文献   

12.
ABSTRACT

We test the paradigm that in a future warmer ocean, shallower winter mixing will lead to less net primary production (NPP), by investigating whether warming between 2002 and 2018 led to changes in NPP in the Tasman Sea/New Zealand region. The 2002–18 trend in sea surface temperature (SST) was positive over most of the region, and was driven by increasingly warmer summers and marine heat waves (MHWs) rather than year-round warming. In contrast, the trends in sea surface chlorophyll (SSC) and NPP were generally positive over the Subtropical Front (STF) and in a subtropical band north-east of New Zealand, but negative elsewhere. Regressions between SSC and SST, and between spring SSC and the coldest SST during the preceding winter, show similar spatial patterns to the SSC trend. We suggest these findings reflect different ecosystem functioning in the subtropical and subantarctic biomes that are separated by the STF. We conclude that any future warming is likely to lead to less production in the Tasman Sea, but more production over the STF. Three recent MHWs had different impacts on production, but generally led to less surface biomass north of the STF and more biomass south of the front.  相似文献   

13.
气候变化背景下海平面上升、强台风和风暴潮对我国东南沿海地区的洪涝灾害影响日益严重,为应对气候变化的影响,本文以位于我国东南沿海的厦门地区为例,应用多种海洋大气观测资料和数理统计及模拟方法,分析了历史上9914号和1614号两次台风对厦门海域极端海面高度(极值水位)的影响,预估了未来海平面上升情景下厦门海域极值水位的变化...  相似文献   

14.
New Zealand seamounts support major fisheries for several deepwater fish species, including orange roughy (Hoplostethus atlanticus) and smooth oreo (Pseudocyttus maculatus). Although a high proportion of features in the depth range 500–1000 m have been fished, very little is known about the ecological impacts of bottom trawling on seamounts. The potential impact is likely to be influenced by the spatial extent and frequency of fishing. A new index is presented to assess the relative intensity of trawling on New Zealand seamounts. The fishing effects index (FEI) incorporates information on the density of fishing on the seamount as a proportion of the seabed area and also on tow direction. Detailed fisheries data from more than 250 000 tows were examined to calculate FEI for New Zealand seamounts. The most intensively fished seamounts were on the south Chatham Rise, an area characterised by a large number of relatively small features which were fished serially for orange roughy in the 1980s and 1990s. Other seamounts with high FEI were on the north Chatham Rise, Challenger Plateau, and off the east coast of the North Island. A range of sensitivity analyses indicated that the general rankings of seamounts were relatively robust to the choice of arbitrary thresholds used to assign tows to seamounts.  相似文献   

15.
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   

16.
Recent cruises to the Chatham Rise and to the Challenger Plateau have provided new material of 3 species of xenophyophores: Reticulam‐mina labyrinthica Tendal, 1972; Syringammina fragillissima Brady, 1883; and S. tasmanensis Lewis, 1966. These records confirm the occurrence of S. fragillissima in New Zealand waters, indicate a wide distribution of S. tasmanensis, and amend our knowledge of species variation and depth range of the New Zealand xenophyophores.  相似文献   

17.
A global ocean carbon cycle model based on the ocean general circulation model POP and the improved biogeochemical model OCMIP-2 is employed to simulate carbon cycle processes under the historically observed atmospheric CO 2 concentration and different future scenarios (called Rep- resentative Concentration Pathways, or RCPs). The RCPs in this paper follow the design of Inter- governmental Panel on Climate Change (IPCC) for the Fifth Assessment Report (AR5). The model results show that the ocean absorbs CO 2 from atmosphere and the absorbability will continue in the 21st century under the four RCPs. The net air-sea CO 2 flux increased during the historical time and reached 1.87 Pg/a (calculated by carbon) in 2005; however, it would reach peak and then decrease in the 21st century. The ocean absorbs CO 2 mainly in the mid latitude, and releases CO 2 in the equator area. However, in the Antarctic Circumpolar Current (ACC) area the ocean would change from source to sink under the rising CO 2 concentration, including RCP4.5, RCP6.0, and RCP8.5. In 2100, the anthropogenic carbon would be transported to the 40 S in the Atlantic Ocean by the North Atlantic Deep Water (NADW), and also be transported to the north by the Antarctic Bottom Water (AABW) along the Antarctic continent in the Atlantic and Pacific oceans. The ocean pH value is also simulated by the model. The pH decreased by 0.1 after the industrial revolution, and would continue to decrease in the 21st century. For the highest concentration sce- nario of RCP8.5, the global averaged pH would decrease by 0.43 to reach 7.73 due to the absorption of CO 2 from atmosphere.  相似文献   

18.
Future potential sea level change in the South China Sea(SCS) is estimated by using 24 CMIP5 models under different representative concentration pathway(RCP) scenarios. By the end of the 21 st century(2081–2100 relative to 1986–2005), the multimodel ensemble mean dynamic sea level(DSL) is projected to rise 0.9, 1.6, and 1.1 cm under RCP2.6, RCP4.5, and RCP8.5 scenarios, respectively, resulting in a total sea level rise(SLR) of 40.9, 48.6, and 64.1 cm in the SCS. It indicates that the SCS will experience a substantial SLR over the 21 st century, and the rise is only marginal larger than the global mean SLR. During the same period, the steric sea level(SSL) rise is estimated to be 6.7, 10.0, and 15.3 cm under the three scenarios, respectively, which accounts only for 16%, 21% and 24% of the total SLR in this region. The changes of the SSL in the SCS are almost out of phase with those of the DSL for the three scenarios. The central deep basin has a slightly weak DSL rise, but a strong SSL rise during the 21 st century, compared with the north and southwest shelves.  相似文献   

19.
The diet of hoki was determined from examination of stomach contents of 1992 fish of 26–112 cm total length (TL) sampled at depths of 209–904m on Chatham Rise, New Zealand, from summer research trawl surveys and seasonal commercial fishing trawls, during 2004–2008. Prey was predominantly euphausiids, mesopelagic fishes and natant decapods. Multivariate analyses using distance-based linear models, non-parametric multi-dimensional scaling and similarity percentages indicated that the best predictors of diet variability were the position of the fish in relation to the subtropical front (STF), fish size and longitude. Pasiphaeids were more important to the north of the STF, and sternoptychid fishes and euphausiids more important in the STF convergence area. Euphausiids and sternoptychid fishes were important for smaller hoki (26–55 cm TL), myctophid fishes and natant decapods for larger hoki, and macrourids for the largest hoki (>84 cm TL). The longitudinal effect was characterised by pasiphaeids, euphausiids and sternoptychids to the west, and myctophids in the centre of Chatham Rise. Feeding activity was analysed using generalised additive models, and was found to vary with time of day, sample source (research or commercial), longitude, hoki size and depth. The variability in diet suggested hoki forage opportunistically within their preferred habitat and biological limits.  相似文献   

20.
The distribution and movements of sperm whales, Physeter catodon Linn., in the western South Pacific (latitudes 30–70° S, longitudes 150E‐150°W) are examined. An undetermined number of catches by nineteenth century American whaleships, 9,720 catches by pelagic fleets in 1961–70, and 427 sightings in 1967 are analysed and correlated with oceanographic data from Australian and New Zealand surveys.

The proportion of females decreases southwards, abruptly at about latitude 44° S in the Tasman Sea, and at about 46–47° S east of New Zealand. Virtually no females occur south of 50° S. The male population density also decreases southwards: the density between 50–70° S appears to be less than 25% of that between 30–50° S. Sperm whales also appear to be less abundant in the eastern part of the region away from the New Zealand plateau, but more data are required.

The pattern of distribution and its seasonal changes probably correlate with vertical temperature gradients of about 5°c in the upper 100 m of water, i.e., optimal conditions for squid schooling. Catch per unit effort in autumn is lower than in spring. A northward population shift in autumn is inferred, based on reduction of available food species and probable temperature tolerances of calves, most of which are born in February and March, towards the end of the southern summer. Some males overwinter in areas where suitable gradients persist, e.g., around the Chatham Islands.

Possibly the summer surface temperature maxima south of the South Island are low enough to inhibit the passage of breeding schools with calves from one side of the New Zealand archipelago to the other. Sperm whales do not pass through Cook Strait normally. Thus, unless considerable mixing of stocks occurs north of New Zealand in winter, there may be two “unit stocks”, one oscillating seasonally between the central Tasman Sea and the Fiji‐Tonga region, and another (probably smaller) between the east coast of the South Island and the region just north of the Chatham Islands.  相似文献   

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