Impacts of fisheries on plankton community structure   总被引：3，自引：2，他引：3  

Reid  P. C.; Battle  E. J. V.; Batten  S. D.; Brander  K. M. 《ICES Journal of Marine Science》2000,57(3):495-502

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Gene flow within and between regions: The population genetic structure of the phantom midge Chaoborus crystallinus (Diptera: Chaoboridae)     

Thomas Berendonk  Ken Spitze 《Limnologica》2006,36(3):147-154

To determine the gene flow of Chaoborus crystallinus, populations throughout Europe were sampled. To test if the gene flow is higher within regions than between regions and to investigate if regional populations may act as metapopulations, four regions with several populations each were examined. For a detailed analysis of the regional gene flow, subregions within one region were analysed. Allozymes and mitochondrial restriction fragment length polymorphism (RFLP) were used to estimate the relative amounts of gene flow. On the European scale gene flow between populations within regions is higher than between regions. On the regional scale, gene flow between subregions is higher than between populations within subregions. Generally, the genetic differentiation between populations within regions is higher for the mitochondrial RFLP data than for the allozyme data. These results suggest that most of the dispersal is female dominated and mostly takes place between populations within regions. Due to this extensive regional gene flow, local adaptation may be influenced by regional processes. This might have interesting implications for the coevolution of the predator C. crystallinus and its plankton prey.  相似文献   

Monitoring pelagic ecosystems using plankton indicators   总被引：2，自引：0，他引：2  

Beaugrand  Gregory 《ICES Journal of Marine Science》2005,62(3):333-338

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Interdecadal variability in the Gulf of Maine zooplankton community, with potential impacts on fish recruitment   总被引：4，自引：1，他引：4  

Pershing  Andrew J.; Greene  Charles H.; Jossi  Jack W.; O'Brien  Loretta; Brodziak  Jon K.T.; Bailey  Barbara A. 《ICES Journal of Marine Science》2005,62(7):1511-1523

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Spatial demography of Calanus finmarchicus in the Irminger Sea     

M.R. Heath  J. Rasmussen  J. Allen  A.S. Brierley  A. Bunker  R. Davidson  W.S.C. Gurney  S. Hay  A.G. Hirst  A. Ingvarsdottir  P. Lindeque  D. Montagnes  R. Pollard  R.A. Saunders  G. Smerdon  P. Walsham  L. Webster 《Progress in Oceanography》2008,76(1):39-88

Continuous Plankton Recorder data suggest that the Irminger Sea supports a major proportion of the surface-living population of the copepod Calanus finmarchicus in the northern North Atlantic, but there have been few studies of its population dynamics in the region. In this paper, we document the seasonal changes in the demographic structure of C. finmarchicus in the Irminger Sea from a field programme during 2001/2002, and the associations between its developmental stages and various apparent bio-physical zones. Overwintering stages were found widely at depth (>500 m) across the Irminger Sea, and surviving females were widely distributed in the surface waters the following spring. However, recruitment of the subsequent generation was concentrated around the fringes of the Irminger Sea basin, along the edges of the Irminger and East Greenland Currents, and not in the central basin. In late summer animals were found descending back to overwintering depths in the Central Irminger Sea. The key factors dictating this pattern of recruitment appear to be (a) the general circulation regime, (b) predation on eggs in the spring, possibly by the surviving G0 stock, and (c) mortality of first feeding naupliar stages in the central basin where food concentrations appear to be low throughout the year.We compared the demographic patterns in 2001/2002 with observations from the only previous major survey in 1963 and with data from the Continuous Plankton Recorder (CPR) surveys. In both previous data sets, the basic structure of G0 ascent from the central basin and G1 recruitment around the fringes was a robust feature, suggesting that it is a recurrent phenomenon. The Irminger Sea is a complex mixing zone between polar and Atlantic water masses, and it has also been identified as a site of sporadic deep convection. The physical oceanographic characteristics of the region are therefore potentially sensitive to climate fluctuations. Despite this, the abundance of C. finmarchicus in the region, as measured by the CPR surveys, appears not to have responded to climate factors linked to the North Atlantic Oscillation Index, in contrast with the stocks in eastern Atlantic areas. We speculate that this may because biological factors (production and mortality), rather than transport processes are the key factors affecting the population dynamics in the Irminger Sea.  相似文献   

Application of food waste based diets in polyculture of low trophic level fish: Effects on fish growth,water quality and plankton density     

Wing Yin Mo  Zhang Cheng  Wai Ming Choi  Yu Bon Man  Yihui Liu  Ming Hung Wong 《Marine pollution bulletin》2014

Food waste was collected from local hotels and fish feed pellets were produced for a 6 months long field feeding trial. Three types of fish feed pellets (control diet: Jinfeng® 613 formulated feed, contains mainly fish meal, plant product and fish oil; Diet A: food waste based diet without meat and 53% cereal; Diet B: food waste based diet with 25% meat and 28% cereal) were used in polyculture fish ponds to investigate the growth of fish (grass carp, bighead and mud carp), changes in water quality and plankton density. No significant differences in the levels of nitrogen and phosphorous compounds of water body were observed between 3 fish ponds after the half-year feeding trial, while pond receiving Diet A had the highest density of plankton. The food waste combination of Diet B seems to be a better formulation in terms of the overall performance on fish growth.  相似文献   

Assessing impacts of invasive phytoplankton: The Baltic Sea case     

Irina Olenina  Norbert Wasmund  Iveta Jurgensone  Janina Kownacka  Diana Vaiciūt? 《Marine pollution bulletin》2010,60(10):1691-1700

There is an increasing understanding and requirement to take into account the effects of invasive alien species (IAS) in environmental quality assessments. While IAS are listed amongst the most important factors threatening marine biodiversity, information on their impacts remains unquantified, especially for phytoplankton species. This study attempts to assess the impacts of invasive alien phytoplankton in the Baltic Sea during 1980-2008. A bioinvasion impact assessment method (BPL - biopollution level index) was applied to phytoplankton monitoring data collected from eleven sub-regions of the Baltic Sea. BPL takes into account abundance and distribution range of an alien species and the magnitude of the impact on native communities, habitats and ecosystem functioning. Of the 12 alien/cryptogenic phytoplankton species recorded in the Baltic Sea only one (the dinoflagellate Prorocentrum minimum) was categorized as an IAS, causing a recognizable environmental effect.  相似文献   

Lake morphometry and wind exposure may shape the plankton community structure in acidic mining lakes     

Guntram Weithoff  Michael Moser  Ursula Gaedke 《Limnologica》2010,40(2):161-166

Acidic mining lakes (pH <3) are specific habitats exhibiting particular chemical and biological characteristics. The species richness is low and mixotrophy and omnivory are common features of the plankton food web in such lakes. The plankton community structure of mining lakes of different morphometry and mixing type but similar chemical characteristics (Lake 130, Germany and Lake Langau, Austria) was investigated. The focus was laid on the species composition, the trophic relationship between the phago-mixotrophic flagellate Ochromonas sp. and bacteria and the formation of a deep chlorophyll maximum along a vertical pH-gradient. The shallow wind-exposed Lake 130 exhibited a higher species richness than Lake Langau. This increase in species richness was made up mainly by mero-planktic species, suggesting a strong benthic/littoral - pelagic coupling. Based on the field data from both lakes, a nonlinear, negative relation between bacteria and Ochromonas biomass was found, suggesting that at an Ochromonas biomass below 50 μg C L⁻¹, the grazing pressure on bacteria is low and with increasing Ochromonas biomass bacteria decline. Furthermore, in Lake Langau, a prominent deep chlorophyll maximum was found with chlorophyll concentrations ca. 50 times higher than in the epilimnion which was build up by the euglenophyte Lepocinclis sp. We conclude that lake morphometry, and specific abiotic characteristics such as mixing behaviour influence the community structure in these mining lakes.  相似文献   

Oceanographical patterns during a summer upwelling–downwelling event in the Northern Galician Rias: Comparison with the whole Ria system (NW of Iberian Peninsula)     

N. Ospina-Alvarez  R. Prego  I. Álvarez  M. deCastro  M.T. Álvarez-Ossorio  Y. Pazos  M.J. Campos  P. Bernárdez  C. Garcia-Soto  M. Gómez-Gesteira  M. Varela 《Continental Shelf Research》2010

Summer upwelling and downwelling processes were characterized in the Northern Galician Rias during July and August 2008 by means of sampling carried out onboard R/V Mytilus (CSIC) and R/V Lura (IEO). Thermohaline variables, dissolved oxygen, nutrients, chlorophyll, phytoplankton, ciliates and zooplankton abundances were measured at sections located in the Rias of Viveiro, Barqueiro and Ortigueira and their adjacent shelves. Ekman transport was calculated from QuikSCAT satellite, upwelling intensity estimated with upwelling index from the average daily geostrophic winds, and SST maps obtained from NASA GHRSST satellite. Ekman transport and SST behaviour showed two different patterns: (i) offshore and upwelling favourable conditions on 13–22nd of July; (ii) onshore and downwelling favourable conditions from 23rd July to 19th August. During upwelling, TS diagram showed an intrusion of Eastern North Atlantic Central Water affecting the continental shelf but not the rias. Nutrient salt concentrations increased with depth, reaching their maximum values near the mouth of Ortigueira Ria. During downwelling, coastal water increased its temperature (18.5–19.8 °C) and was retained inside rias; nutrients were nearly depleted, except for the innermost ria (estuarine zone) due to fluvial nutrient inputs. In this inner area, the maximum of chlorophyll-a (Barqueiro Ria) was observed. Low phytoplankton abundances were measured in both cases, even though a short increase in the plankton biomass was observed inside rias during upwelling, while under downwelling a small red tide of Lingulodinium polyedrum was detected. During the upwelling period Northern Rias tend to be mesotrophic systems as revealed by nutrient concentrations, chlorophyll levels and plankton abundances. On the contrary, in similar situations, the Western Rias behaves as eutrophics.  相似文献   

观音山水库水化学和浮游生物调查及其利用的初步研究     

方春林  何珍娣  吴宣胜  应为民  黄能武 《广东海洋大学学报》1995,(1)

对观音山水库水化学、浮游生物及利用进行了调查研究。（１）库水属Ｓ、中营养型，含盐量很低；营养元素Ｎ／Ｐ平均９５．６，磷是限制性因子。２）浮游生物量平均４．５２４７ｍｇ／Ｌ，其中浮游植物量平均３．０６０６ｍｇ／Ｌ，以硅藻、裸藻和甲藻占优势；浮游动物量平均１．４６４１ｍｇ／Ｌ，以枝角类和桡足类占优势，分别占６９．２％和３０．２％。（３）鱼产力为１１２８ｋｇ／ｈｍ２，鲢、鳙、鲤每公顷放养尾数分别为９２２、６４５和４７０（都在１３．３ｃｍ或１３．３ｃｍ以上）。（４）提出渔业利用意见。  相似文献