Further evidence for the existence of sub‐littoral populations of toheroa,Amphidesma ventricosum Gray (eulamelli‐branchiata), off the west coast of New Zealand

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.     

Oceanic circulation in the head of the Hikurangi trench,east coast,New Zealand

The geostrophic flow and direct current measurements in the inflow of the Southland Current into the Hikurangi Trench east of New Zealand confirm the geostrophic circulation pattern previously found. The northwards inflow of the Southland Current at the latitude of the Chatham Rise (44°S) is estimated at 1.7 × 10⁶ m³.s^‐1, which compares favourably with that of 1.2 × 10⁶ m³.s^‐1 calculated previously off Kaikoura.     

Oxygen consumption and apnoea in the shortfin eel,Anguilla australis schmidtii

Patterns of ventilation, oxygen consumption (VO₂), blood gas tensions (PaO₂ and PaCO₂) and pH were determined in shortfin eels (Anguilla australis schmidtii (Phillips)). At rest, shortfin eels (average weight 646.5 ± 64.5 g) had a VO₂ of 20.4 ± 1.2 ml. kg^‐1.h^‐1 (n = 13) at 17.5 ± 0.2°c, with smaller fish having the highest metabolic rates. The frequency of ventilation was inversely proportional to body weight in both A. australis schmidtii and A. dieffenbachii. In air‐saturated water 10 eels exhibited periodic apnoea (mean duration 3.59 min); periods of ventilation were more variable in duration (mean 4.92 min). After 2.62 min of apnoea, the PaO₂ of dorsal aortic blood had fallen from 9.12 to 1.91 kPa. Thus, although the blood has a high affinity for oxygen and the haemoglobins are 30% oxygen‐saturated at this low PaO₂, the eel allows its blood to be significantly depleted in oxygen during apnoeic pauses at rest. When ventilating its gills at rest, PaO₂ does not approach the PO₂ of the inspired water. It is suggested that these features of respiration in eels result in a saving of metabolic costs involved in ventilation. The results are discussed in terms of the eel's ability to withstand hypoxic conditions.     

Gomphonema novo‐zelandicum sp. nov., an epiphytic diatom with a specific host preference

Gomphonema novo‐zelandicum sp. nov., the dominant epiphytic diatom on Carpophyllum maschalocarpum and C. flexuosum, growing in the sublittoral fringe zone in northern New Zealand, is described and its taxonomic status determined. This diatom, although present on other macroalgae from the same zone, is predominantly epiphytic on these 2 species of Carpophyllum, maintaining substantial populations on them throughout the year.     

Diel changes in the abundance and size composition of invertebrate drift in five rivers in South Island,New Zealand

Drift was collected over 24‐h periods in five rivers in South Island, New Zealand, to determine whether diel periodicity was consistent across a range of river types, and whether the pattern was similar for different life stages/sizes of selected taxa. Total drift density (numbers per 100 m³ ) of aquatic invertebrates was greater at night than during the day in all rivers; peak abundance occurred shortly after sunset in clear water rivers and shortly before sunrise in a turbid, glacier‐fed river. Densities of drifting Deleatidium spp., Nesameletus spp. (both Ephemeroptera), Aoteapsyche spp., and Hydrobiosidae (both Trichoptera), were generally greater at night than during the day. However, the timing of peak abundance in the drift for other common taxa varied between rivers. Larger Deleatidium spp. larvae (> 1.00 mm head width) were more common in the drift at night than during the day in all rivers. However, this was not apparent for Aoteapsyche spp. and Hydrobiosidae, for which diel differences in the size of drifting animals were not consistent even within the same river. The propensity for some aquatic invertebrates to drift at night may influence fish feeding behaviour, particularly with respect to the timing of feeding and the species or life history stages of their prey.     

Seasonal Blooms of the HAB Dinoflagellate Alexandrium taylori Balech in a New Mediterranean Area (Vulcano, Aeolian Islands)

Abstract. High-biomass blooms of A. taylori Balech have recently been spreading over new Mediterranean areas, with evident adverse effects on the marine ecosystem. In 1999–2000, a new Mediterranean locality was affected by blooms of A. taylori: the West Bay of Vulcano (Aeolian Islands, Tyrrhenian Sea), with maximum cell densities of 1.2 × 10⁷ cells 1⁻¹ in August 1999 and 4.0 × 10⁶ cells 1⁻¹ in August 2000 observed together with yellowish water discoloration. The seawater samples contained high concentrations of nutrients as DIN (Dissolved Inorganic Nitrogen), especially NH₃-N with values of 14.4 μM and TOT-P (Total Phosphorus) with values of 3.2 μM due to the anthropic presence and discharge of untreated sewage. The climatic conditions also seem to influence the occurrence and spreading of the A. taylori blooms in the Vulcano Bay. Clonal cultures of A. taylori , established from Italian and Spanish seawater samples, were used for the sequence analyses of the 5.8S rDNA gene and ITS regions in order to study the genetic variability of different geographical populations of Alexandrium species in the Mediterranean area and to further develop the molecular markers for HAB key-species.     

海洋生境芽孢杆菌(Bacillus spp.)的培养条件及产生的胞外抗菌蛋白

测试了4株海洋芽孢杆菌的培养条件对其产生抗菌蛋白的影响;提取的粗蛋白的性质以及对6种病原指示菌的抑菌活性,结果表明,4株海洋芽孢杆菌在2216E,EMB,CM培养液;15～35℃;NaCl浓度0%～5%;pH3～9的条件下均能生长,适宜生长温度20～28℃;NaCl浓度1%～3%;pH5～8.菌株分别培养84～108h抑菌活性最强.(NH₄)₂SO₄沉淀抗菌粗蛋白的最适饱和度为50%～70%.粗蛋白对病原菌尤其对病原真菌具有强烈的抑制作用.粗蛋白性质稳定,对高温和蛋白酶不敏感.     

Reproductive characteristics of invasive gammarids in the Rhine-Main-Danube catchment, South Germany

The gammarid composition at 25 sites in the rivers Danube, Main and the southern reaches of the Rhine were studied during the years 2002–2004. Dikerogammarus villosus and Echinogammarus ischnus were the most frequent species prevailing at 17 sites. Sympatric occurrence of D. villosus and E. ischnus was observed at 12 sites. Dikerogammarus haemobaphes was recorded at 7 sites; this species prevailed in the Danube, west of the Weltenburger Enge and in the Isar mouth where it co-existed with native species (Gammarus pulex and/or G. roeseli) at 6 sites. Dikerogammarus bispinosus and E. berilloni were found at only 1 site, where they co-existed with D. villosus and E. ischnus, and with D. villosus and native species, respectively. Investigation of reproductive characteristics at 3 sites showed that females of D. villosus and D. haemobaphes produced the biggest clutches with more than 100 eggs. Females of E. ischnus produced much smaller clutches (10–35 eggs on an average), but very big eggs. Clutch sizes and egg volumes of D. bispinosus and E. berilloni resembled those of native species. Our results suggest that the most successful invaders (D. villosus, D. haemobaphes and E. ischnus) display reproductive traits that facilitate their success. Both Dikerogammarus sp. allocate energy into production of many but small eggs, thus maximizing offspring number, while E. ischnus allocates its energy into production of fewer but large eggs which could be beneficial at sites where food is scarce.     

Short-term effects of shrub control on two different plant communities in Argentina

The aim of this work was to study the effect of controlling jarilla (Larreaspp.), nonforage shrubs for livestock, on two plant communities with different forage production in the arid mid-west of Argentina. Total vegetation cover, forage species cover and carrying capacity were determined during three growing seasons, for cleared and uncleared plots. At the end of the study, significant differences were found in theLarrea cuneifoliacommunity, where average forage species cover increased by 156% over the control, and greater carrying capacity (129%) was also obtained from the cleared treatment. No significant differences were found in theLarrea divaricatacommunity. Data lead us to recommend shrub control as an improvement practice only in areas with low forage species cover and poor carrying capacity.     

The distribution of rare phenolic type compounds in wild and cultivated wheats

In 14 species of Aegilops, four species of Triticum and two species of Hordeum, a complex of rare phenolic compounds was found and showed quantitative differences between the wild and domestic species. There was a dramatic reduction in the cultivars to about 5% of the amount of these phenolic constituents. In the wild species these phenolic compounds may act as important germination regulators, such as water-dissolving germination inhibitors which may act as 'rain gauges'. This is especially important for the germination at the appropriate time in species inhabiting arid regions or deserts.