环境DNA分析大亚湾夜光藻藻华对真核浮游生物群落的影响*     

陈靖夫  钟瑜  王磊  郭雨沛  邱大俊 《热带海洋学报》2022,41(5):121-132

夜光藻是全球广泛分布的藻华种之一, 其摄食作用对浮游生物的群落结构有着重要影响。利用环境DNA技术和Spearman相关性分析, 文章研究了2021年1月中旬大亚湾夜光藻高丰度站位浮游生物的群落结构与生物相关性。结果显示, 夜光藻高丰度站位的海水温盐条件为温度 14.4~18.3℃、盐度 32.52‰~33.14‰。夜光藻丰度较高的站位中, 卡顿藻科、海链藻科等浮游植物类群的相对丰度均值为2.41%和2.23%, 明显高于其他站位的0.75%和0.62%; 同时拟哲水蚤科与长腹剑水蚤科等类群的相对丰度均值为8.22%和4.46%, 明显低于其他站位的64.13%和11.12%。结合Spearman相关性分析表明, 夜光藻丰度增加可能导致其对拟哲水蚤科等类群摄食压力增加, 拟哲水蚤科类群丰度减少降低了卡顿藻科、海链藻科、原甲藻科、隐芽藻科等浮游植物类群的摄食压力, 使其生物丰度增加; 同时夜光藻摄食压力增加使得裸甲藻科、圆筛藻科等浮游植物丰度下降。因此, 夜光藻丰度增加影响了水域中真核浮游生物群落结构。综上结果表明, 环境DNA技术有助于认识夜光藻在浮游生物群落中的生态地位, 可用于浮游生物各类群之间的关系分析。  相似文献   

A winter upwelling event in the Northern Galician Rias: Frequency and oceanographic implications     

I. Alvarez  N. Ospina-Alvarez  Y. Pazos  M. deCastro  P. Bernardez  M.J. Campos  J.L. Gomez-Gesteira  M.T. Alvarez-Ossorio  M. Varela  M. Gomez-Gesteira  R. Prego   《Estuarine, Coastal and Shelf Science》2009,82(4):1362

A winter shelf-water upwelling evidence (February 2008) is described by first time in the Northern Galician Rias (NW Iberian Peninsula). On February 20, after 9 consecutive days of upwelling favorable conditions, inside the O Barqueiro Ria was observed the presence of seawater below 10 m depth which replaced the less saline water previously observed in January. This situation was in agreement with the analyzed Ekman transport close to the northern Galician coast. Salinity and temperature distribution revealed that the upwelled water inside the rias corresponds to shelf bottom seawater which is not associated with Eastern North Atlantic Central Water or the Iberian Poleward Current. In addition, TS diagram indicated a higher influence of upwelling eastward (Viveiro–Barqueiro–Ortigueira). Nutrient salts' concentrations also suggested the presence of seawater from subsurface origin with a small variation with regard to the winter mixing in this marine area. Plankton showed the existence of spring conditions related to solar radiation increase associated to upwelling favorable winds. Some species also corroborated the intrusion of shelf-water inside the ria. Results from the analysis of Ekman transport data from 1967 to 2007 revealed that this event cannot be considered an isolated episode. In fact, the number of days per month under upwelling favorable conditions in winter (January–March) was not negligible (8–10 days) showing that upwelling events along the northern Galician coast are also possible during winter.  相似文献   

Seasonal dynamics of trophic relationships among co-occurring suspension-feeders in two shellfish culture dominated ecosystems     

Sébastien Lefebvre  Julio César Marín Leal  Stanislas Dubois  Francis Orvain  Jean-Louis Blin  Marie-Paule Bataillé  Alain Ourry  Robert Galois 《Estuarine, Coastal and Shelf Science》2009

The temporal dynamics of carbon and nitrogen isotope values of co-occurring suspension-feeders in two shellfish culture areas (Normandy, France) were investigated over two years to evaluate the inter-specific trophic partitioning and relative contributions of organic matter sources to benthic suspension-feeders' diet. Oysters (Crassostrea gigas), mussels (Mytilus edulis), cockles (Cerastoderma edule), slipper limpets (Crepidula fornicata), and sand-mason worms (Lanice conchilega) were sampled in an estuarine environment (Baie des Veys, east Cotentin, Normandy), while oysters, mussels, slipper limpets, and honeycomb worms (Sabellaria alveolata) were sampled in an open-marine environment (Lingreville-sur-mer, west Cotentin, Normandy). Whatever the sampling period, the bivalves, C. gigas and M. edulis, exhibited the lowest values of δ¹³C and δ¹⁵N compared with the other species. Feeding relationships among suspension-feeders in both C. gigas culture areas exhibited temporal variations due to the marine/estuarine influence and seasonal changes in food supply. In the open-marine ecosystem, the contribution of phytoplankton remained the most important for all species except S. alveolata, while in the estuarine ecosystem, microphytobenthos and/or macroalgae detritus contributed a larger extent to the organisms' diets. During phytoplankton bloom periods (e.g. May and July) suspension-feeders, except for S. alveolata, relied strongly on phytoplankton; however, the majority of suspension-feeders exhibited different opportunistic behaviour in winter when phytoplankton biomass might be a limiting factor. We hypothesized that differences in particle capture and selection by the suspension-feeders influenced their isotopic values. Feeding ecology of suspension-feeders partly explained why competition was limited and why ecosystems can often support unexpectedly large numbers of suspension-feeders. We also showed that understanding ecosystem characteristics of the organic matter sources is of primary importance to determine the extent to which members of the suspension-feeding guild potentially compete for food.  相似文献   

Feeding of Aurelia sp. (Scyphozoa) and links to the microbial food web     

Valentina Turk  Davor Lučić  Vesna Flander‐Putrle  Alenka Malej 《Marine Ecology》2008,29(4):495-505

The impact of the scyphomedusa Aurelia sp. on planktonic assemblages was experimentally studied in enclosures incubated in situ in the sea lake of Mljet Island (Big Lake, Southern Adriatic), where jellyfish are present throughout the year. In situ feeding experiments using plankton at natural densities indicated a reduction in abundance for small calanoid and cyclopoid copepods, copepodites, nauplii and ciliates in the presence of Aurelia sp. In addition to direct predatory pressure, Aurelia sp. exerted an indirect cascading effect on autotrophic and heterotrophic microbial plankton. Phytoplankton biomass increases of up to 0.5 μg C·l^?1·h^?1 were mainly related to 19′‐hexanoyloxyfucoxanthin‐ and 19′‐butanoyloxyfucoxanthin‐containing phytoplankton. Bacterial production was about twice as high in the presence of Aurelia sp. and biomass was also consistently higher. It appears that the top‐down effect of predation along with material release by Aurelia sp. results in increases in microbial biomass and production.  相似文献   

The summertime plankton community at South Georgia (Southern Ocean): Comparing the historical (1926/1927) and modern (post 1995) records     

Peter Ward  Michael P. Meredith  Peter Rothery 《Progress in Oceanography》2008,78(3):241-256

The earliest comprehensive plankton sampling programme in the Southern Ocean was undertaken during the early part of last century by Discovery Investigations to gain a greater scientific understanding of whale stocks and their summer feeding grounds. An initial survey was carried out around South Georgia during December 1926 and January 1927 to describe the distribution of plankton during the summer, and to serve as a baseline against which to compare future surveys. We have reanalysed phytoplankton and zooplankton data from this survey and elucidated patterns of community distribution and compared them with our recent understanding of the ecosystem based on contemporary data. Analysis of Discovery data identified five groups of stations with characteristic phytoplankton communities which were almost entirely consistent with the original analysis conducted by [Hardy A.C., Gunther, E.R., 1935. The plankton of the South Georgia whaling grounds and adjacent waters 1926-1927. Discovery Report 11, 1-456]. Major groupings were located at the western end of the island and over the northern shelf where Corethron spp. were dominant, and to the south and east where a more diverse flora included high abundances of Nitzschia seriata. Major zooplankton-station groupings were located over the inner shelf which was characterised by a high abundance of Drepanopus forcipatus and in oceanic water >500 m deep that were dominated by Foraminifera, Oithona spp., Ctenocalanus vanus, and Calanoides acutus. Stations along the middle and outer shelf regions to the north and west, were characterised by low overall abundance. There was some evidence that groupings of stations to the north of the island originated in different water masses on either side of the Southern Antarctic Circumpolar Current Front, the major frontal system in the deep ocean close to South Georgia. However, transect lines during 1926/1927 did not extend far enough offshore to sample this frontal region adequately. Interannual variability of zooplankton abundance was assessed from stations which were sampled repeatedly during seven recent British Antarctic Survey cruises (1995-2005) to the region and following taxonomic harmonization and numerical standardization (ind. m⁻³), a subset of 45 taxonomic categories of zooplankton (species and higher taxa) from 1926/1927, were compared with similar data obtained during the BAS cruises using a linear model. Initially comparisons were restricted to BAS stations that lay within 40 km of Discovery stations although a comparison was also made using all available data. Despite low abundance values in 1926/1927, in neither comparison did Discovery data differ significantly from BAS data. Calculation of the percentage similarity index across cruises did not reveal any systematic differences in species composition between 1926 and 1927 and the present. In the light of ocean warming trends, the existence of more subtle changes in species composition is not ruled out, but an absence of finely resolved time-series data make this impossible to determine.  相似文献   

Environmental control of short-term variation in the plankton community of inner Tokyo Bay, Japan   总被引：1，自引：0，他引：1  

Toru Nakane  Kisaburo Nakaka  Heather Bouman  Trevor Platt 《Estuarine, Coastal and Shelf Science》2008,78(4):796-810

Water temperature, salinity, nutrient concentrations and the composition of the plankton community were recorded at three stations in inner Tokyo Bay over a period of 328 days (from June 8, 1995 to April 30, 1996) with a nominal sampling frequency of once per day. Inspection of the results revealed that the data could be divided into two blocs as an aid to analysis: the period from June to October was characterized by the development of stratification of temperature and salinity (stratification period), and November to March was characterized by uniform temperature and salinity in the water column due to vertical mixing (mixing period). Oxygen-depleted water forms in the bottom layer during the stratification period, but vertical mixing of the water column, due to changing wind and rainfall conditions caused by passing weather fronts, results in the breakdown of the oxygen-depleted water mass. Nutrient loads are high in the surface water due to the freshwater supply, but occasional pulses of primary production cause a depletion of phosphate in the surface water, suggesting that the phosphorus becomes a limiting nutrient for phytoplankton growth in this period. Several short-term peaks of plankton abundance (blooms) occurred as responses to temporal changes in water quality from June to November, with consequent species succession. Significant fluctuations in the densities of the diatom Skeletonema costatum and several species of ciliates corresponded to the daily changes in the physical and chemical characteristics of the coastal environment. During the mixing period, when water temperature and solar radiation decreased, there were no short-term variations in water quality and although nutrient concentrations gradually increased from November to February, primary production remained low. This study shows that the short-term dynamics of the phytoplankton community are closely coupled to fluctuations in environmental forcing, and that the degree of coupling is stronger during periods when solar radiation is greater. The results provide a novel typological understanding of seasonal plankton dynamics in a shallow, eutrophicated marine embayment, and suggest how such systems may be treated in simulation modeling.  相似文献   

Comparison of biomass and size spectra derived from optical plankton counter data and net samples: application to the assessment of mesoplankton distribution along the Northwest and North Iberian Shelf   总被引：1，自引：0，他引：1  

Nogueira  Enrique; Gonzalez-Nuevo  Gonzalo; Bode  Antonio; Varela  Manuel; Moran  Xose Anxelu G; Valdes  Luis 《ICES Journal of Marine Science》2004,61(4):508-517

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Temporal and spatial variability in phytoplankton ammonium and nitrate uptake in the Delaware Estuary     

Jonathan R. Pennock 《Estuarine, Coastal and Shelf Science》1987,24(6)

Phytoplankton NH₄⁺ and NO₃⁻ uptake was examined along the longitudinal salinity gradient of the Delaware Estuary over several seasonal cycles using ¹⁵N-tracer techniques. Saturated nitrogen uptake rates increased directly with water temperature and reached a maximum of 380 nmol Nl⁻¹h⁻¹ during summer. This temperature dependence was related primarily to changes in the rate of maximum chlorophyll specific uptake, which varied exponentially between 2 and 70 nmol N [μg Chl h]⁻¹ over a temperature range of 2–28°C. Despite these high uptake rates, balanced growth (C:N7:1) could be maintained over the diel light cycle only by highly efficient nitrogen uptake at low light intensities and dark uptake below the photic zone and at night (dark UPTAKE=25% maximum uptake).Ammonium fulfilled 82% of the annual phytoplankton nitrogen demand in the estuary despite dominance of NO₃⁻ in the ambient dissolved inorganic nitrogen pool. The predominance of NH₄⁺ uptake occurred because of the general suppression of NO₃⁻ assimilation at NH₄⁺ concentrations in excess of 2 μ . This suppression, however, was not as universal as has been reported for other systems, and it is suggested that the extremely high NO₃⁻ concentrations found in the estuary contribute to this pattern. Nitrate was a significant source of nitrogen only during periods of high phytoplankton production in summer, and when NH₄⁺ concentrations were low towards the end of the spring bloom.  相似文献   

Zooplankton trends: US north-east shelf ecosystem and adjacent regions differ from north-east Atlantic and North Sea     

Jossi  J. W.; Goulet  J. R.  Jr 《ICES Journal of Marine Science》1993,50(3):303-313

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Laboratory study of nitrogen and phosphorus remineralization during the decomposition of coastal plankton and seston   总被引：1，自引：0，他引：1  

Jonathan H. Garber 《Estuarine, Coastal and Shelf Science》1984,18(6):685-702

The decomposition of cultured marine phytoplankton (Skeletonema costatum) and natural estuarine seston from Narragansett Bay, RI, was studied at two temperatures (8°C and 18°C) in bottles containing sterile bay-water (30‰) and in bay-water with micro-organisms small enough to pass through a glass fibre filter (nominally < 1μ). About 50% of the particulate organic nitrogen (PON) and particulate phosphorus (PP) was immediately released to the water in dissolved organic forms from both types of organic matter. Comparison of changes in the dissolved organic nitrogen (DON) fraction in the sterile and non-sterile systems indicated that nearly all of the DON initially released was subsequently remineralized. Ammonification proceeded only in non-sterile bay-water. 20–25% of the PP was converted to dissolved inorganic-P (DIP) fraction after only 7 h in both sterile and non-sterile bay-water. Following autolytic releases of DON, DOP and DIP the initial rates of N and P remineralization were temperature dependent: Q₁₀ values for PON and PP decay during first phase of microbially mediated decomposition ranged from 1·3 to 6·4. Rates of remineralization then slowed so that about equal amounts of nutrients were remineralized (45–50% of the N and 57–60% of the P in the phytoplankton and 60–63% of the N and 36–60% of the P in the natural seston) after 30 days storage at either temperature. During 30 days of decomposition in non-sterile seawater the N/P ratios in the dissolved inorganic fractions converged on the ratios of total-N/total-P initially present in the bottles. Kinetic analysis of the decay of total organic-N (TON) and total organic-P (TOP) in the non-sterile systems and analysis of similar sets found in the literature showed that the initial stages of the decomposition of N and P from planktonic POM in vitro could be modelled as the sequential decay, at first-order rates, of two particulate fractions. The first, more labile, fraction comprised about 60% of the particulate N and P. First-order rate constants (−k, base e) for decomposition during the 1st and 2nd phases were 0·02 to 0·2 day⁻¹ and 0·003 to 0·02 day⁻¹, respectively. The decay rates are far too slow to account for the ‘rapid in situ recycling’ of nutrients needed to support phytoplankton production when other means of nutrient resupply (by advection, fixation, rainfall, etc.) are very low.  相似文献