Biogeographical structure of the microphytoplankton assemblages in the region of the Subtropical Convergence and across a warm-core eddy during austral winter

The distribution of rnicrophytoplankton in the region of theSubtropical Convergence (STC) and across a warm-core eddy shedfrom the Aguihas Return Current was investigated along two transectsin late austra] winter (June-July) 1993, during the South AfricanAntarctic Marine Eco system Study (SAAMES) III cruise. Samplingwas undertaken for the analysis of nutrients, and for the enumerationand identification of microphytoplankton species. Along bothtransects, chlorophyll con centrations were highest at stationsat the southern boundary of the STC and at the periphery ofthe warm-core eddy. Of the variance associated with chlorophyllconcentration, temperature accounted for 65% of the total. Alongboth transects, a decrease in species richness from north tosouth was observed. The spatial distribution of the numericallydominant diatom species was similar in both tran sects. Themicrophytoplankton assemblage was dominated by the subtropicaldiatom species Chaetoceros constnctus north of the STC, andby Pseudoeunotia doliolus within the eddy and south of the STC.Using cluster and ordination analyses, three significantly differentgroupings of stations were identified along the combined transects.These coincided with stations located north and south of theSTC and with the warm-core eddy proper, confirming that theSTC represents a strong biogeograph ical boundary. The predominanceof the warm-water species P.doliolus and Planktoniella sol inand around the warm-core eddy south of the STC suggests thateddies are important in the transfer of microphytoplankton acrossthis strong biogeographical boundary.     

SPERM WHALE DISTRIBUTIONS AND COMMUNITY ECOLOGY ASSOCIATED WITH A WARM-CORE RING OFF GEORGES BANK

Sperm whale (Physeter macrocephalus) sighting rate in the vicinity of a thermal front on the eastern boundary of a Gulf Stream warm-core ring was five times greater than the pooled rate in the remainder of the study area. No sperm whales were sighted within the ring away from frontal boundaries. Sperm whale distribution patterns associated with the ring were examined using hydrographic and zooplankton data. Hydrographic structure and zooplankton densities and community composition differed between the high-use region and the remainder of the study area, suggesting that mesoscale patterns in the biological and physical environments regulate sperm whale habitat usage. Satellite thermal images indicated cool water associated with the eastern front was shelf or slope water entrained from the Scotian Shelf to the north. Interaction of the warm-core ring with the shelf or slope water is probably indirectly responsible for greater sperm whale presence on the eastern boundary of the ring, providing suitable habitat for their squid prey. Entrainment of shelf water by warm-core rings occurs frequently, providing potential sperm whale habitat in the vicinity of rings. Surveys of warm-core rings and other Gulf Stream features are needed to improve accuracy of sperm whale population estimates.     

Validation of age readings from otoliths of juvenile roundnose grenadier, Coryphaenoides rupestris, a deep-water macrourid fish

Validation of the ageing of deep-water fish is difficult and there are only a few instances where the rings on the otoliths have been shown to be laid down annually. Roundnose grenadier have been fished commercially in the North Atlantic since the 1960s and the adult fish have frequently been aged by counting the rings in otoliths or scales. All the ageing was done on the assumption that the rings in the otoliths or scales were annual. Between 1975 and 1992, the Scottish Association for Marine Science carried out seasonal trawling surveys in the Rockall Trough using a fine-meshed trawl, and collected otoliths from a wide size range of roundnose grenadier. An examination of the growing edge of otoliths from juvenile fish from these collections suggests that the rings in the otoliths are laid down annually. The broader, opaque zones which represent the growth phase were dominant between September and March. The thinner, hyaline zones were dominant between April and July. The apparent delay in the growth phase compared with most shallow-water species is discussed in relation to the availability of mesopelagic prey.     

The effects of fluctuations in North Sea flows on zooplankton abundance

Time series of annual mean zooplankton abundance observed bythe Continuous Plankton Recorder Survey in the North Sea duringthe last three decades are compared with transports from a depth-averagedstorm-surge model by means of multiple regression analysis.In the northern areas, more than half the variance of Calanusfinmarchicus can be accounted for by the winter flows. Thereare no statistically significant relationships in other NorthSea areas or by using the flows from other seasons. This isconsistent with the accepted view that this copepod overwintersin the North Atlantic and enters the North Sea in the earlyspring. The model flows are strongly related to the strengthof the North Atlantic Oscillation (NAO). which may explain therecently reported association of C.finmarchicus with the NAO.Other species do not exhibit statistically significant relationshipswith any of the model flows.     

Seasonal variation and life history of the pelagic chaetognatha, Sagitta elegans Verrill, in Toyama Bay, southern Japan Sea

The seasonal variation and life history of the pelagic chaetognatha,Sagitta elegans Verrill, in Toyama Bay, southern Japan Sea,were investigated using a time series of 0–500 m verticalhauls with a Norpac net from 1 February 1990 to 30 January 1991.Nine species of one genus occurred in Toyama Bay throughoutthe year, including the cold-water species S.elegans. Therewas no remarkable variation in abundance throughout the year,although many individuals were collected in August. Juvenilesoccurred mostly in spring and summer, from late March to August.Adults (Stage 3) occurred in all seasons, except summer. Thebody length of adults ranged from 26 to 30 mm. There were twoprincipal spawning periods. One was in March-May and the otherwas in August. Life spans of both cohorts were 10–12 months.Copepods were major prey of S.elegans inhabiting Toyama Bay.The annual mean food-containing ratio (FRC) was 6.1%, but values>10% occurred in February, April, May, July and September.     

The distribution of hyperiid amphipods (Crustacea:Peracarida) in relation to warm-core eddy J in the Tasman Sea

Hyperiid amphipods were sampled in and around warm-core eddyJ in the Tasman Sea off eastern Australia in August, Septemberand October 1979. Samples were taken at night to a depth of400 m with a midwater trawl (RMT-8). In all, 22 798 hyperiidsrepresenting 38 species and 10 families were collected. Sevenspecies, individually found in numbers >4% of the total amphipodpopulation, together contributed 87.1% to the total. Of these,Scina crassicornis, Phronima sedensataria, P.atlantica, Phrosinasemilunata, Primno johnsoni and Brachyscelus crusculum wereusually found in highest numbers outside the eddy. Streetsiachallengeri was the only abundant species with significantlyhigher numbers inside the eddy. Outside the eddy, samples werecharacterized by large numbers of few species, whereas abundanceswere more evenly distributed between species inside the eddy.The size distributions of two abundant species (B.crusculumand S.challengeri) were not significantly different betweenthe inside and outside of eddy J. Hyperiid faunal patterns wereassociated with depth and temperature (August), position withrespect to the eddy (September, October) and the presence ofgelatinous zooplankton (September, October).     

莱州湾大型砂壳纤毛虫群落季节变化

为揭示莱州湾砂壳纤毛虫群落季节变化规律, 在莱州湾设置8个站位, 于2011年5-11月及2012年3-4月进行了9个航次的调查, 用浅海III型浮游生物网由底至表垂直拖网采集砂壳纤毛虫。结果表明, 莱州湾3-11月砂壳纤毛虫物种丰富度的变化范围为5-19, 周年变化呈现一峰两谷的趋势。丰度的范围为0-318 ind./L, 丰度较大(> 50 ind./L)的种类有运动类铃虫(Codonellopsis mobilis)和清兰拟铃虫(Tintinnopsis chinglanensis)。各月平均丰度随时间的变化趋势为双峰型, 最大值出现在7月(63 ind./L), 次峰值出现在5月(48 ind./L), 最小值出现在3月(2 ind./L)。黏着壳种类在3-11月均有出现, 透明壳种类仅在温度较高(> 15°C)的6-9月出现。各月的优势种数目为1种(5月)到8种(8月), 其中运动类铃虫在所有月中都是优势种, 对砂壳纤毛虫丰度周年的变化规律产生较大影响。使用各月所有种类的平均丰度对各月砂壳纤毛虫群落进行聚类分析, 得到两个群落(相似度30%): 群落I(7-9月)和群落II(3-6月、10-11月), 说明砂壳纤毛虫群落发生了明显的季节变化。砂壳纤毛虫的物种丰富度、丰度与环境因子(温度、盐度)均没有明显的相关性。     

Gulf Stream warm core rings: phytoplankton in two fall rings of different ages

Warm core ring (WCR) 82-H was sampled in September–October(1982) as a Gulf Stream meander pinched off and became a ring.It is compared with the 3-month-old WCR 81-D, visited September–October(1981). Although the rings have different histories, their phytoplanktonassemblages share some characteristics. Using cluster analysesbased on quantitative group counts, a station from one ringoccasionally clusters most closely with a station from the otherring, showing a similar balance of organisms. The younger ringat the time of sampling, WCR 82-H, had lower diversity, fewershelf species, and greater consistency between stations, exceptfor a high level of Oscillatoria in the meander before the ringpinched off. Interaction with slope water was seen principallyat the ring margin. WCR 81-D, on the other hand, showed a greatdeal of structure, and immediate dilutions with slope waterand the Gulf Stream were apparent, with higher diversity beforeand a week after such interactions. The upper water column ofwarm core rings, although showing evidence of physical mixing,can exhibit stratification of species, even after a storm.     

鼎湖山马尾松径向生长动态与气候因子的关系

Dendroclimatology method was used to study the relationship between ring index of Pinus massoniana and three climate factors in Dinghushan,South China.The ring indices were negatively correlated with the average tem-perature in June,August and September,and positively correlated with the average temperature of March,whereas no statistically significant correlation was found with monthly precipitation,showing that high summer temperature could limit the radial growth of the species,Meanwhile,tree ring indices showed a strong positive correlation with the relative humidity of April June,August,September,October and November,and also with the average humidity of the whole year,indicating that atmospheric moisture could not fully satisfy the growth of Pinus massoniana despite of abundant rainfall,The possible impact of climate change on the growth of Pinus massoniana was discussed accordingly.     

Avoidance of nets by Euphausia pacifica in Dabob Bay

Avoidance of nets by Euphausia pacifica was investigated inDabob Bay, WA. Differential catches were found to be a resultof the vibrational signal of the tow cable ahead of the net.Daylight was not a proximal factor but rather exerted an indirecteffect by changing the depth distribution of the euphausiids.Net avoidance varied as a function of animal size and couldbias size distribution estimates as well as abundance estimates.Plummet nets with minimum turbulence and vibration in, and aheadof, the mouth are recommended for sampling euphausiids untilbetter technology becomes available. Some size and species distributionsof euphausiids in Dabob Bay are reported.     

Revision of the Genus Goodallia (Bivalvia: Astartidae) with the Description of Two New Species

A revision of the Recent species of the genus Goodallia (Astartidae)is presented. Adult shell and prodissoconch morphology of allthe species are described and figured. In total, five speciesare recognized: G. triangularis (Montagu, 1803), G. pusilla(Forbes, 1844), G. macandrewi (Smith, 1881), G. micalii new species,and G. gofasi new species. G. triangularis and G. pusilla are widespreaddistributed in the Atlantic coasts of Europe and North Africa,and in the Mediterranean. G. macandrewi is restricted to thetype locality in the Canary Islands, while what has been calledG. macandrewi from the Mediterranean corresponds to an undescribedspecies here named G. micalii, distributed in the Central andEastern Mediterranean. A second undescribed species from offthe Atlantic Moroccan coast is named G. gofasi, and is knownonly from the type material of station B33 of the expedition CINECA CHARCOT III. The named forms, variability and distributionof G. triangularis are discussed. (Received 30 January 1998; accepted 27 August 1998)     

Seasonal changes in zooplankton composition in the Barents Sea, with special attention to Calanus spp. (Copepoda)

The Barents Sea is an important area with respect to fisheriesresources (i.e. capelin and cod). In May, June and August 1981zooplankton biomass was measured along a transect at 30°E,from the ice border southwards. A maximum was recorded in Atlanticwater by the end of June (>100 g wet weight m^–2 InAugust the biomass values were relatively low south of the Polarfront and increased northwards into Arctic water (–50g m^–2 The species composition was influenced by the distributionof cold Arctic water and warmer Atlantic water. The zooplanktonwas dominated by the copepods Calanus finmarchicus and C. glacialis;the former is regarded as an Atlantic species and C. glacialisas an Arctic species.     

长江口沿岸碎波带仔稚鱼的种类组成及其多样性特征

为了进一步探明长江口沿岸碎波带仔稚鱼的种类组成和多样性特征,2006年7月-2007年6月的每月大潮期间,在长江口沿岸碎波带13个站位点的水深0.5-1.5m处,两人沿海岸平行方向步行拖曳小型拖网(1m×4m,网目1mm)采集仔稚鱼样本。周年共拖网397网次,采集到仔稚鱼49045尾。仔稚鱼隶属于31科,共84种,其中海洋性鱼类16种,河口性鱼类30种,洄游性鱼类4种,淡水性鱼类34种。洄游性鱼类刀鲚占总个体数的82.63%,为最优势种。仔稚鱼的物种数、个体数和丰度在冬季较低,以3月份最低,夏季最高。Margalef丰富度指数2006年11月—2007年4月相对较低,2006年10月最高。Shannon-Wiener多样性指数在10月最高,7月最低。Pielou均匀度指数全年较恒定,2006年7月和2007年6月相对较低。     

The consumption of euphausiids by the pelagic fish community off southwestern Vancouver Island, British Columbia

The consumption of adult euphausiids was estimated for the sevenmost abundant fish species found on the continental shelf offsouthwestern Vancouver Island, British Columbia, Canada. Empiricaldata on fish feeding rates, diets and biomass were used to estimateeuphausiid consumption in August for each year from 1985 to1997. The fish community in August was estimated to consumean average 297 kt of euphausiids (124 t km^–2). Pacifichake (Merluccius productus) and Pacific herring (Clupea harengus)accounted for 60% and 30%, respectively, of the total euphausiidsconsumed by fish. The total estimated consumption of euphausiidsper tonne of fish averaged 0.93, and there was no significanttrend in the time series. In addition, there was no significantrelationship between the total fish community consumption oreuphausiids consumed per tonne of fish and euphausiid biomass,and there was no change in the fraction of euphausiids in thediet of small or large Pacific hake. Thus, it appears that predationpressure from the pelagic fish community was relatively constantand not responsible for the apparent fivefold decline in adulteuphausiid biomass observed in the 1990s.     

红鳍原鲌鳃部寄生单殖吸虫的种群研究

单殖吸虫的感染率和丰盛度表现出明显的季节变化.三种指环虫的丰盛度高峰依次出现在4、6、8月.单殖吸虫对寄生部位的选择性与种群数量有关,时间生态位的分离,正是种间竞争的结果.       

Nectar and pollen sources for honeybees in Kafrelsheikh province of northern Egypt

This study was conducted at the apiary of the Beekeeping Research Section at the Sakha Agricultural Research Station, ARC, Kafrelsheikh, and other apiaries in Kafrelsheikh province, during two successive years 2015 and 2016. The study aimed to survey nectar and pollen floral resources in Kafrelsheikh province. Ninty seven plant species belonging to 33 families were recorded as nectar sources, and 82 plant species belonging to 36 families were recorded as pollen sources during the whole year. The largest amount of monthly trapped pollen was obtained during May followed by August. It can be concluded that, beekeepers in Kafrelsheikh province can harvest good honey yield at the end of blooming seasons of citrus (Citrus spp.) during March and April, Egyptian clover (Trifolium alexandrinum L.) during May and June, loofah (Luffa aegyptiaca Mill.) during June to October, cotton (Gossypium spp.) during July and August, and banana (Musa spp.) during August and September. They also, could be trapping pollen loads collected from faba bean (Vicia faba L.) and flax (Linum usitatissimum L.) during January to March, date palm (Phoenix dactylifera L.) during March and April, Egyptian clover during May and June, summer seed watermelon (Citrullus lanatus var. colothynthoides L.) during June and July, loofah and maize (Zea mays L.) during June to November.     

Differential Use of Nursery Areas Within the Tagus Estuary by Sympatric Soles, Solea solea and Solea senegalensis

The spatio-temporal pattern of estuarine use by both Solea solea and Solea senegalensis was investigated between April 1995 and November 1996 by beam trawl surveys. Spatial and seasonal distribution and abundance were different for each species. The highest densities of S. solea were recorded in deeper, warmer, low salinity areas and where the sediment consisted of a high proportion of fine sand and presented a high abundance of amphipods. The 0-group individuals of this species first occurred on the nursery ground in April. Numbers peaked in June and July, and from October to April abundance was low. S. senegalensis had a wider distribution and its abundance was related to food availability. The 0-group individuals of this species occurred in the nursery areas later than S. solea, from June to August.     

Ecological investigations on the zooplankton community of Balsfjorden, northern Norway: population dynamics of the euphausiids Thysanoessa inermis (Kroyer), Thysanoessa raschii (M.Sars) and Meganyctiphanes norvegica (M.Sars) in 1976 and 1977

The population dynamics of the euphausiids Thysanoessa inermis(Kröyer), T. raschii (M.Sars), and Meganyctiphanes norvegica(M.Sars) have been followed in Balsfjorden in 1976 and 1977.Seasonal variations in length-frequency distributions, growthin carapace length, sex-ratio, and spermatophore productionand attachment are presented and discussed in relation to changesin hydrography and phytoplanlcton standing-crop. An annual generationof T. inermis and T. raschii was spawned in April and May. Eggsand larvae of M. norvegica were not found in Balsfjorden, indicatingthat recruitment occurs from outside the fjord. T. inermis andT. raschii reached maximum carapace lengths of 7–8 mmand 6–7 mm respectively and had life-spans of c. 2 years3 months. M. norvegica had a life-span of c. 2 years 6 monthsand reached a maximum carapace length of c. 12.5 mm. In bothT. inermis and T. raschii 0-group underwent the greatest lengthincreases from May to October, I-group from March to Augustand II-group from April to June. The population structure, growthpatterns and growth periods of M. norvegica were difficult todiscern. The phytoplanlcton cycle appears to be the dominantfactor regulating both growth and spawning of the Thysanoessaspp in Balsfjorden, while temperature has no obvious influence.     

Stratification analysis of the Óhalász Ox-bow of the River Tisza (Kisköre Reservoir,Hungary)

The present study was carried out in Palaeochori Bay, south eastern coast of Milos, where outflow of hot gas bubbles and hydrothermal water seepage was observed. The study tests hypotheses about relationships between seawater temperature and species with warm-water affinities in areas close to shallow-water vents. We predicted that if temperature plays a major role in influencing abundance of species with warm-water affinities, then there should be more thermophilous species in areas with higher seawater temperature. Time series of seawater temperature were recorded in Palaeochori Bay and Pollonia Bay where hot emission was not observed. Temperature, water pressure and conductivity were measured every 30 min from 19 June 1996 to 16 June 1997. Fourteen qualitative samples of benthic flora were collected by SCUBA diving in six rocky sites. Photosamples of benthic assemblages were collected using an UW camera equipped with a wide-angle lens (15 mm) and an electronic flash unit. A constant area of 0.7 m² was sampled. Quantitative estimates of abundance of algal species were performed as percent cover. This paper shows that patterns of fluctuation in seawater temperature in Palaeochori were different from the control where no venting was found. In Palaeochori, algal assemblages were dominated by species with warm-water affinities that were not found elsewhere. These results are consistent with the hypothesis that temperature plays a major role in influencing abundance of species with warm-water affinities. According to our results, hydrothermal vents are potential oases that experience biological-physical coupling not yet clearly understood. They are important in affecting migration of alloctonous thermophilous species suggesting a possible role of vent areas as stepping stones for species migration.     

Structure and distribution of pelagic ostracods (Ostracoda: Myodocopa) in the Arctic Ocean

The study of the pelagic ostracod fauna of the Arctic Ocean based on materials collected by numerous Russian expeditions (1929–1993) and data from the literature showed the extreme poorness of the Arctic pelagic ostracod fauna, its mainly North Atlantic genesis and complete isolation from the Pacific fauna. Maximum ostracod abundance was observed in the epipelagic zone, and the greatest species diversity occurred in the relatively warm deep Atlantic layer throughout the year. To the north, east, and west of Franz Josef Land and Spitsbergen, the number of species and abundance indices of pelagic ostracods were decreased. In superficial water layers of the Central Arctic, maximum ostracod density and biomass were recorded in June and September. The best bioindicator of warm Atlantic water in the Arctic basin is Obtusoecia obtusata; and of cold polar water in the North Atlantic, Boroecia maxima.