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1.
P. A. Ryan 《新西兰海洋与淡水研究杂志》2013,47(3-4):283-287
Energy contents of several freshwater animal species collected from Lake Ellesmere, Canterbury, were determined by bomb calorimetry. Values are shown to vary seasonally and between size classes. Because of this variability the use of a single energy value of an organism in an energetics study is not recommended. 相似文献
2.
G. C. Hewitt 《新西兰海洋与淡水研究杂志》2013,47(2):173-177
This taxon is distinguished from other Ergasilidae by having only three pairs of legs, and a well‐developed hook on the penultimate joint of the second antenna abutting against the claw‐like terminal segment. A. amplexus has been reported from Anguilla australis, A. dieffenbachii, Perca fluviatilis, Carassius auratus, Retropinna retropinna, Physiculus bachus, Galaxias maculatus, Arripis trutta, Rhombosolea leporina, R. retiaria, and R. plebeia from Lake Ellesmere, near Christchurch, and from Anguilla australis from Makara River near Wellington. Both localities are euryhaline. 相似文献
3.
鄱阳湖流域淡水贝类物种多样性、分布与保护 总被引：2，自引：0，他引：2
为探究鄱阳湖流域淡水贝类物种多样性及分布, 2011～2012年对鄱阳湖及部分“五河”干流淡水贝类进行调查。结合历史资料, 共记录淡水贝类122种, 隶属于15科39属, 主要由田螺科(Viviparidae)、豆螺科(Bithyniidae)、肋蜷科(Pleuroseridae)、椎实螺科(Lymnaeidae)、扁蜷螺科(Planorbidae)、蚌科(Unionidae)和蚬科(Corbiculidae)组成。流域内以鄱阳湖的物种丰富度最高, 108种; 中国特有种丰富, 各水体特有种比例均超过50%; 优势种主要是梨形环棱螺、铜锈环棱螺和河蚬等。与历史资料相比, 鄱阳湖淡水双壳类和腹足类物种丰富度均显著减少, 人为干扰仍是淡水贝类资源衰退的主要原因, 建议加大贝类栖息地保护力度。 相似文献
4.
Intermittently closed and open lakes and lagoons (ICOLLs) are shallow barrier lakes which are intermittently connected to the sea and experience saline intrusions. Many ICOLLs are mechanically opened to prevent flooding of surrounding agricultural and urban land and to flush water of poor quality. In this study, the effects of modified opening regimes (frequency and duration of barrier openings and closures) on water quality and phytoplankton in two New Zealand ICOLLs were investigated over a number of opening/closure cycles. Water quality in Lake Ellesmere (Te Waihora) responded weakly to both opening and closing events, indicating that sea–ICOLL exchange did not markedly improve water quality. Conversely, water quality in Waituna Lagoon responded rapidly to barrier openings; water level decreased to near sea level within days of opening and subsequent seawater exchange resulted in rapid decreases in nitrate and chlorophyll a concentrations. The closure of Waituna Lagoon resulted in rapid rise in water level and a pulse of nitrate and phosphorus in the water column and phytoplankton chlorophyll a concentrations increased with increasing closed-period duration. Based on data on the underwater light climate and nutrient dynamics, phytoplankton in Lake Ellesmere was probably light-limited, whereas phytoplankton in Waituna Lagoon was rarely light-limited, and appeared to be predominately P-limited. The marked differences in responses of Lake Ellesmere and Waituna Lagoon to barrier openings and closures reflected differences in ICOLL water levels and morphological characteristics, which dictated the degree of tidal flushing when the barriers were open. The inter-ICOLL differences observed in this study indicate that unless the effects of ICOLL openings/closures on phytoplankton and nutrient dynamics are understood, changes to ICOLL opening regimes may have unintended consequences for the water quality and ecology of these systems. 相似文献
5.
Several water quality parameters, marginal vegetation, and the fish community in Lake Ellesmere, a large, shallow, turbid lake situated on the east coast of the South Island, New Zealand, were sampled along selected transects in late summer to determine species spatial patterns. Thirteen species offish were caught, with seven of them comprising major populations, although only four of these were adequately sampled by the method used—they included inanga (Galaxias maculatus), common smelt {Retropinna retropinna), shortfinned eel (Anguilla australis), and common bully (Gobiomorphus cotidianus). Inanga were almost exclusively confined to areas on the western side of the lake which has a convoluted shoreline with a variety of small embayments with scattered vegetation along the margins. Common smelt occupied both marginal and offshore areas, but they too were more abundant along the margins particularly on the western side. Both the common bully and shortfinned eel were widespread and abundant in the lake, although their abundance and biomass were higher within the vicinity of the lake outlet, major inflowing tributaries, and other marginal habitats. All three species of flounders of the genus Rhombosolea were poorly represented in our samples. However, in commercial catches they were reasonably abundant, with the sand flounder (R. plebeia) and yellowbelly (R. leporina) being more common in offshore than inshore catches, whereas the black flounder (R. retiaria) showed no difference in the catches between areas. Our overall findings are consistent with the hypothesis that bottom‐dwelling species (eels, bullies, flounders) are more widely distributed than free‐swimming forms (inanga, common smelt), which were largely confined to areas sheltered from prevailing winds. The highly turbid nature of the lake, primarily because of re‐suspension of fine bottom sediments by frequent winds, is considered an important factor in the distribution of the fish fauna. 相似文献
6.
Sampling of kōura (freshwater crayfish Paranephrops planifrons) to assess population abundance and structure in lakes is often difficult or impractical because of the absence of representative methods. The tau kôura is a traditional Maori method used to catch kôura in central North Island lakes by placing whakaweku (bundles of bracken fern Pteridium esculentum) on the lake bed that kôura then colonise. It has advantages as a monitoring tool over conventional methods, such as baited traps and dive surveys, as it samples all kôura size classes, can be used in turbid waters and at a wide range of depths, and does not require expensive equipment or specialised expertise (e.g., SCUBA). We demonstrate its use to monitor kôura populations in Lake Rotoiti (mean depth 32 m), North Island, New Zealand. Application of the method allowed differences in population size structure to be distinguished between a shallow and a moderate depth site within Lake Rotoiti and to discern seasonal breeding patterns. 相似文献
7.
P. M. Hine 《新西兰海洋与淡水研究杂志》2013,47(4):339-347
The distributions of the nematode parasites Paraquimperia sp., Spirocamallanus sp., and Cucullanus sp. in the intestines and recta of Anguilla dieffenbachii and A. australis from Lake Ellesmere and the South Branch of the Waimakariri River were studied over two years. Peak occurrence of Paraquimperia was in the anterior intestine of A. australis and mid intestine of A. dieffenbachii. Male and female Spirocamallanus sp. established in the mid intestine, but as female worms grew they attached more anteriorly and thus maintained the mid body in the mid intestine, prevented the tail end entering the rectum, and maintained the vulvae close to male worms. Cucullanus sp. was most often found in the mid intestine, but occurred throughout the intestine, possibly because of migration with food. Paraquimperia and Spirocamallanus extended their range with crowding; Cucullanus increased in density in the mid intestine. Posteriad movement, with or without subsequent evacuation, was a general feature of all species in both hosts, held live or examined after death. Chilling and freezing slowed or arrested loss from dead hosts. Larger worms (Spirocamallanus sp.) moved and were lost more rapidly than small worms (Paraquimperia sp.); worm loss was more rapid from A. dieffenbachii than from A. australis. 相似文献
8.
Grant W. Tempero Brendan J. Hicks Nicholas Ling Dai Morgan Adam J. Daniel Deniz Özkundakci 《新西兰海洋与淡水研究杂志》2019,53(3):397-415
Introduced common carp (Cyprinus carpio) are a recognised threat to New Zealand’s freshwater ecosystems. In 2011, an invasive fish removal programme was undertaken in 16.8 ha Lake Ohinewai, a Waikato riverine lake. Active fish removal using netting and boat electrofishing was supported by installation of a one-way exclusion barrier on the outflow to Lake Ohinewai. The barrier was designed to allow fish passage downstream out of the lake, while preventing adult carp from moving upstream. The estimated carp population was reduced from 8,548 fish (5,863–12,937, 95% confidence limits) in 2011–454 fish (251–889, 95% CL) in 2014. However, by 2016 the carp population had recovered to 2,063 fish (1,070–4,328, 95% CL) with increased abundance in invasive brown bullhead catfish (Ameiurus nebulosus) also observed. This research demonstrates that carp populations can be reduced to low abundances in the short to medium term, but continued removal will be required for on-going control. 相似文献
9.
The Bonnet Carré Spillway, located 28 miles northwest of New Orleans, was constructed in the early 1930s as part of an integrated
flood-control system for the lower Mississippi River system. From 11 April to 8 May 2008, Mississippi River water was diverted
through the spillway into the 629-square-mile Lake Pontchartrain, which is hydraulically connected to the Gulf of Mexico.
On 8 April, prior to the opening of the spillway, water-quality instruments were deployed and recorded hourly measurements
of water temperature, dissolved oxygen, specific conductance, pH, and nitrate. Discrete water-quality and phytoplankton (algae)
samples were collected in Lake Pontchartrain from 8 April to 3 October 2008 to assess the water-quality nutrient enrichment
effects of the diversion on the lake. The maximum influence of river water in the southern portion of the lake was captured
with continuous (hourly) monitoring of nitrate concentrations, and field measurements such as of specific conductance during
the critical period in late April to early May. By late May, the deployed instruments had recorded the arrival, peak, and
decline of selected constituents associated with the freshwater influx from the Mississippi River/Bonnet Carré Spillway diversion.
The continuous monitoring data showed the short-term interactions of high-nitrate, low-specific conductance river water and
low-nitrate, high-specific conductance lake water. The phytoplankton community composition, as an indicator of water quality,
illustrated an extended response from the river water evident even after the continuous and discrete samples indicated that
the lake had returned to pre-diversion conditions. The initial phytoplankton community response to nutrient increases was
related to accumulations of diatoms. During periods of low nutrient concentrations, accumulations of blue-greens occurred
by July and August. As blue-green algae cell densities and biovolumes increased in the summer, so did the species richness
of blue-green algae, particularly the harmful algae bloom taxa. Cell densities and biovolume of the phytoplankton lake indicator
taxa Skeletonema costatum, Anabaena sp., and Cylindrospermopsis raciborskii were highest and dominated the diatom and blue-green algae communities during the period of most river water influence on
the lake and immediately following the freshwater inflows. The dominance and recession of these indictor taxa reflect the
dramatic changes that occurred in the phytoplankton community in response to an increase in nutrient-rich freshwater from
the diversion into the lake, and not normal seasonal phytoplankton compositional differences. Water-quality data indicated
a gradual reversion to pre-diversion lake conditions by June to July, but shifts in the phytoplankton composition were still
evident through August 2008. Observations from this study were similar to results from previous studies of Mississippi River/Bonnet
Carré Spillway diversion opening in 1997. 相似文献
10.
P. M. Hine 《新西兰海洋与淡水研究杂志》2013,47(2):189-195
Myxidium zealandicum Hine, 1975 was recorded from several tissues in New Zealand freshwater eels. The gills were the most frequent site of infection, but spores also matured on the gill arch, in the skin, and occasionally in the urinary and swim bladders. Thus M. zealandicum is a histozoic species that may have evolved from a coelozoic form. Variation in spore size (8.0–11.5 jam) was found in relation to site of infection; variation in the number and arrangement of valve striations was also observed. Deposition of fibro‐blasts occurred at all sites of sporogony, except among the goblet cells of the epidermis. The small size (6.0–10.5μm) of unstriated spores occurring with normal spores in the gills of eels from Lake Otomangakau appeared to be related to the size of the cysts in which they occurred, and to the host Anguilla dieffenbachii. 相似文献
11.
Cylindrospermopsis raciborskii is a planktonic freshwater cyanobacterium that is becoming increasingly prevalent in water bodies worldwide. During a survey of toxic cyanobacteria in New Zealand, C. raciborskii was identified in a sample collected from Lake Waahi (Waikato). This is the first identification of this species in New Zealand. Liquid chromatography‐mass spectrometry and liquid chromatography‐tandem mass spectrometry were used to confirm the presence of the cyanotoxins cylindrospermopsin (CYN) and deoxy‐cylindrospermopsin (do‐CYN). Detection of CYN and do‐CYN demonstrates that C. raciborskii is a now a species of concern in recreational, stock drinking, and potable water supplies in New Zealand. 相似文献
12.
In situ data collected by Marine Hydrophysical Institute investigators have been used to reconstruct the Black Sea paleochemistry
during the period of Würmian glaciation. The geochemical behaviour of and maps for the Cu, Zn, Mo, and U steric distribution
in the New Euxinic sediments that deposited in freshwater lakes under severe climatic conditions, with salinity being virtually
zero, are reported. Similar chemical processes in the New Euxinic basin and Baikal Lake are examined.
Translated by Vladimir A. Puchkin. 相似文献
13.
《Marine Chemistry》1991,32(2-4)
The occurrence of hypoxia in October 1988 in the Krka estuary is described, with special reference to the Prokljan Lake. Hypoxia develops near the bottom in autumn in response to the temperature maximum that appears this time of the year. The decomposition rate of naturally present organic matter increases, creating higher biological oxygen demand. As the water column is stratified by salinity and temperature, mixing of seawater near the bottom with oxygen-supersaturated water which resides closer to the surface is very slow. When an extensive marine phytoplankton bloom appears below the halocline in the Prokljan Lake, then, because of the sinking and degradation of phytoplankton near the bottom, the dissolved oxygen concentration decreases further. The hypoxia becomes so severe that it causes massive mortality of benthic macrofauna. The decomposition of the macrofauna further decreases the dissolved oxygen concentration. The hypoxia may persist until an increase in the freshwater inflow occurs, which forces the arrival of colder marine water near the bottom via a compensating flow. In the absence of autumn rains, the hypoxia may be recorded throughout winter. 相似文献
14.
Ocean Science Journal - Lake Changpo (LC) is an artificial freshwater lake surrounded by wetlands and farmlands, inundated with water during the wet season, on the southwest coast of Korea. To... 相似文献
15.
Michiro Matsuyama 《Journal of Oceanography》1974,30(5):209-215
Vertical distributions of some chemical substances in the surface sediments of a typical meromictic lake, Lake Suigetsu, were measured. Metallic elements such as iron, manganese, nickel, zinc, copper and chromium showed no significant slopes in vertical direction. While, boron and total sulfur contents in the sediments decreased from the surface to the stratum 35–40 cm, and below which both substances showed no more appreciable changes. From an average sedimentation rate (about 1.1 mm/yr), estimated from the radiocarbon dating of the sediment, the sediments above the stratum 35–40 cm were thought to be deposited after the beginning of the salt water intrusion to the lake by the excavation of a canal in 1665, by which Lake Suigetsu was connected to a polyhaline lake (Lake Kugushi) directly connected to the sea. Vertical distributions of boron and total sulfur in the sediments and also of chlorinity of the interstitial waters seem to correspond to past change in the lake condition from freshwater one to a two-layered system of a deeper salt water covered by a upper freshwater. 相似文献
16.
Masumi Yamamuro Jun-Ichi Hiratsuka Yu Ishitobi Shinya Hosokawa Yoshiyuki Nakamura 《Journal of Oceanography》2006,62(4):551-558
Zostera marina L. was intensively harvested until the early 1950s in Lake Nakaumi, a eutrophic estuarine lagoon. We have estimated the amount
of nitrogen (N) and phosphorus (P) removed from the lagoon through Z. marina harvesting. Lake Nakaumi lies in Tottori and Shimane prefectures, and the annual harvest of Z. marina in the late 1940s in Tottori was recorded as at least 56,250 t wet weight. The nutrient content of 56,250 t of Z. marina was calculated to be 61.9 t of N and 12.9 t of P, which is equivalent to 5.3% and 11%, respectively, of present annual nutrient
loads to the lake. The nutrients formerly used by Z. marina were likely used by phytoplankton after the Z. marina started to decline in the mid-1950s at Lake Nakaumi. This shift in the chief primary producer, from benthic macrophytes to
phytoplankton, caused a subsequent shift in secondary producers. Benthic fish and crustacean populations decreased and the
non-commercial filter-feeding bivalve, Musculus senhausia, increased in Lake Nakaumi after the decline of seagrass beds. This affected the local economy, inducing not only eutrophication
but also the collapse of local fisheries. On the other hand, at adjacent Lake Shinji, loss of submerged aquatic vegetation
induced an increase of the commercial filter-feeding bivalve, Corbicula japonica, which doubled the fishery yield in the lake. 相似文献
17.
18.
Maryd De Wemton John S. Clayton Rohan D. S. Wells Chris C. Tanner Suzanne T. Miller 《新西兰海洋与淡水研究杂志》2013,47(2):145-151
The submerged vegetation of Lakes Sumner, Marion, Katrine, Taylor, and Sheppard was surveyed in May 1987. These high‐altitude lakes lie at c. 600 m a.s.l., within the largely unmodified upper Hurunui catchment. Submerged vegetation was diverse and included numerous short shallow‐water species, dense swards of Isoetes alpinus, low covers of taller native vascular plants, and charophyte meadows beyond the depth limit of vascular plants to a maximum of 15 m. A sparse deepwater bryophyte community was observed from 11 to 32 m depth in Lake Sumner. Displacement of native vegetation by dense growths of the adventive oxygen weed Elodea canadensis over mid‐depths of 3–6 m was noted in all lakes, except Lake Marion. 相似文献
19.
《Marine Policy》2007,31(5):599-606
The Solent region in southern England represents one of the highest concentrations of coastal lagoons and saline ponds in the UK. Four lagoon complexes within the region comprise a Special Area of Conservation (SAC), under the European Habitats Directive. The ephemeral nature of coastal lagoons presents a particular management challenge in terms of retaining designated sites in “favourable conservation status”. Consequently, in addition to sensitive management of existing sites, it is important to identify sites for habitat re-creation. A site-specific investigation of Hook Lake in Hampshire is presented. Previously, on the basis of salinity measurements alone, this site was deemed to have progressed naturally through brackish conditions to a freshwater habitat overgrown by reeds Phragmites sp. A more detailed survey, which considered salinity measurements together with an analysis of substratum heterogeneity and invertebrate fauna diversity, suggests that it is still predominantly a freshwater system with an adjacent brackish/saline ditch. Future management, linked to local biodiversity action plan targets, could proactively support the development of this site as a coastal lagoon in order to secure its integration as part of the international conservation designation. However, this is complicated by the need to then recognise and compensate for loss of freshwater habitat, the need to persuade the local community that any change would not compromise coastal defence integrity and ultimately by medium to long-term coastal defence investment decisions. 相似文献
20.
Abstract Stomach contents of Gobiomorphus cotidianus,Retropinna retropinna, Gambusia affinis, and Anguilla australis were compared between two shallow lakes in the lower Waikato River basin, to examine the relationship between turbidity and diet. Lake Waahi and the south arm of Lake Whangape had been turbid (20–40 g suspended solids (SS) m?3) and devoid of submerged macrophytes since the late 1970s and early 1980s, respectively. The main basin of Lake Whangape had been generally clearer (5 g SS m?3) with dense beds of submerged macrophytes, but at the time of sampling (1987) water clarity had deteriorated (> c. 10 g SS m3) and submerged macrophytes had declined. The mysid Tenagomysis chiltoni was an important prey for all species of fish from turbid water bodies but was less important in stomachs of fish in the main basin of Lake Whangape. Apparently, mysids were not an important prey in Lake Waahi before it became turbid. Chironomid larvae and pupae dominated the diets of small fish in the main basin of Lake Whangape. Fish and mysids were the most important prey of shortfinned eels in both lakes, with mysids most important in Lake Waahi. High mysid densities in the turbid water bodies provide an alternative food resource apparently compensating for those lost by fish when water clarity declined and submerged macrophytes collapsed. 相似文献