浙江中南部近岸海域游泳动物功能群特征与多样性

为探明浙江中南部近岸海域游泳动物的群落结构和多样性, 作者于2016年春季进行了2个航次的底拖网调查, 应用生物多样性指数、冗余分析对游泳动物功能群组成进行了研究。结果表明, 该海域166种游泳动物依据摄食习性可分为6个功能群, 平均丰度百分比最高的为浮游动物/游泳动物食性功能群, 最低的为底栖动物食性功能群; 平均生物量百分比最高的为浮游动物食性功能群, 最低的为碎屑食性功能群。相似性分析结果显示, 该海域游泳动物的功能群结构在不同月份之间差异极显著。4月和5月的功能群多样性均值分别为1.30和1.23, 功能群多样性指数与大个体种类(体质量 > 50 g)的总生物量呈极显著正相关, 功能群多样性与物种多样性呈正相关关系。冗余分析显示该海域游泳动物食性功能群受温度变化影响较大; 底栖动物食性功能群受水深变化影响较大。上述结果表明, 浙江中南部海域游泳动物群落结构相对较稳定。     

浙江苍南南部沿岸海域主要游泳动物生态位及种间联结性

根据2014年苍南南部沿岸海域春季(5月)和秋季(11月)的渔业资源调查资料,采用生态位测度、方差比率法、基于2×2列联表的χ²检验和联结系数(AC)等方法分析群落物种间的相互关系.结果表明： 该海域主要游泳动物按生态位宽度值可划分为广生态位种、中生态位种和窄生态位种3大类,其中广生态位种包括龙头鱼、三疣梭子蟹、口虾蛄等5种,中生态位种包括棘头梅童鱼、哈氏仿对虾和细巧仿对虾等8种,窄生态位种包括日本蟳、六丝钝尾鰕虎鱼和葛氏长臂虾等10种;种对间生态位重叠值差异较大,最大值和最小值分别为0.93和0, 部分游泳动物间可能存在资源利用性竞争.方差比率法分析表明,主要游泳动物总体呈显著正关联,其中有78个种对间的联结性达到显著水平(χ²≥3.841),联结系数(AC)中正显著联结的种对多于负显著联结.     

河口缺氧生物效应研究进展

世界许多河口都存在季节性缺氧的现象,并且低氧出现的频率、范围、持续时间、强度都有明显上升的趋势,因此河口缺氧引起的生态效应受到人们越来越多的关注.河口生物种类繁多,根据它们的运动能力和栖息环境的不同可分为浮游生物、游泳生物和底栖生物.河口缺氧不仅影响河口生物的分布与生存,而且还会改变群落结构、影响生态系统的结构与功能.从分子、群落和生态系统等不同层次综述了河口缺氧生物效应的研究进展,并提出了展望与建议.     

Features of species composition and abundance of the nekton community in the upper epipelagic layer of the Northwest Pacific in early summer

The composition and structure of nekton in the upper epipelagic zone is considered based on the data of trawl surveys conducted in the Northwestern Pacific Ocean and adjacent waters in 2004–2009. Alterations in the nekton community during the early summer period, as well as peculiarities of its species composition and quantitative distribution that depend on changes in background conditions are described. In total, as many as 66 species of fish and 22 species of cephalopods were recorded in catches for the studied period. The lowest biodiversity was found in the near-shore waters (areas nos. 5, 7, and 9) and the highest one was in open oceanic waters (area no. 13). In 2004–2009, nekton biomass was formed mainly by mesopelagic species and their share amounted to 40–60% of the entire nekton community. Pacific salmon varied within 17–37% the total nekton biomass in various years. In general, for the period of studies, the mean biomass of nekton community was 2 431 000 tons, and in 2009, the total biomass approached this value.     

An evaluation of isotope dilution effect from conventional data sets of 15N uptake experiments

A practical calculation procedure to correct the underestimatecaused by isotope dilution in ¹⁵N uptake experiments is described.The estimate is based on the experimental observation of ¹⁵Nincorporation into particuUtc organic matter but not on directmeasurement of isotope enrichment in the substrate. Conventionaldata sets of ¹⁵N uptake and an estimate of the ratio of theflux of regeneration and uptake can provide the informationneeded to correct for isotope dilution. Application of thismethod to ¹⁵NH₄⁺ uptake data in the literature showed that theunderestimate is small in open ocean waters but sometimes substantialin coastal or estuarine waters.     

Abundance and productivity of heterotrophic nanoplankton in Georgia coastal waters

The population abundances and rates of biomass production ofheterotrophic nanoplankton (HNAN) in Georgia coastal waterswere evaluated by epifluorescence microscopy. HNAN populations(mostly non-pigmented microflagellates <10 µm in diameter)ranged from 0.3 x 10³ cells ml^–1 in shelf waters 15 kmoffshore to 6.3 x 10³ cells ml^–1 in waters 0.25 km fromthe coast. There was a strong correlation (r = 0.83) betweenHNAN and free bacterioplankton population abundances, but noapparent relation (r = 0.38) between HNAN and phototrophic nanopLankton(PNAN) abundances. HNAN biomass production in estuarine andnearshore shelf waters, as estimated from increases in HNANpopulations during laboratory incubations of natural water samples,ranged from 0.10 to 0.79 mg C m^–3 h^–3, with populationgeneration times of 9.7 to 26.5 h. There was a significant linearrelation (r = 0.95) between HNAN biomass and HNAN productivity.We calculated that HNAN may graze at least 30% to 50% of dailybacterioplankton production in Georgia coastal waters.     

The Effects of Road Culverts on Nekton in New England Salt Marshes: Implications for Tidal Restoration

In recent years, salt marsh restoration projects have focused upon restoring hydrology through culvert enlargement to return functional values lost due to reduced tidal flow. To evaluate culvert effects on upstream nekton assemblages, fyke nets were set upstream of tidally restricted creeks, creeks recently restored with larger culverts, and paired reference creeks in New Hampshire and Maine, U.S.A. Subtidal habitats created or enlarged by scour were found immediately upstream of undersized culverts. All marshes supported similar assemblages and densities of fish, suggesting that marshes upstream of moderately restrictive culverts provide suitable habitat to support fish communities. However, densities of Crangon septemspinosa (sand shrimp) were significantly reduced upstream of culverts. A mark–recapture study was conducted in tidally restricted, restored, and reference marsh creeks to evaluate culvert effects on the movement of Fundulus heteroclitus (mummichog), the numerically dominant fish species in New England salt marshes. Recapture data indicated that small culvert size and consequently increased water velocity significantly decreased fish passage rates. We infer that upstream subtidal habitats and greater water velocities due to undersized culverts decreased nekton movements between upstream and downstream areas, resulting in segregated nekton populations. Restoration of salt marsh hydrology by the installation of adequately sized culverts will support increased fish access to marsh habitats and nekton‐mediated export of marsh‐derived production to coastal waters.     

On the biology of Blepsias cirrhosus (Hemitripteridae) from coastal waters of northern Primorye

Data on the distribution, size-age composition, dates, and conditions of spawning, fecundity, and feeding of Blepsias cirrhosus from the coastal waters of northern Primorye are presented. It is demonstrated that individuals in this region reach a length of 19.5 cm, weight of 87.0 g, and age of 6 years. Spawning occurs in the first half of July in coastal reefs at a water temperature of 10–15°C, at depths down to 8 m. The nuptual color of females is described. In connection with a clearly pronounced care for progeny, fecundity is low, 234–404 eggs. B. cirrhosus feeds mainly on nekton and benthic crustaceans.     

Chlorophyll standing crop and phytoplankton production in the western Irish Sea during 1992 and 1993

Chlorophyll standing crop and phytoplankton production werestudied in the western Irish Sea over a 21 month period during1992 and 1993. For both years, the start of the production seasonwas first observed in Dundalk Bay and occurred progressivelylater in more northerly coastal and offshore waters. Standingcrop and production exhibited marked spatial heterogeneity with12.5- to 19-fold differences in crop observed over distancesof 20–30 km. Distinct regional differences in the lengthof the production season were apparent. The longest season,6–7 months with a production of 194 g C m^–2, occurredin Dundalk Bay. The season lasted 3–4 months in the summerstratified region with a production of 140 g C m^–2. Northerly,offshore mixed waters and coastal waters of Northern Irelandsupported a short (2–3 months) season and production of194 and 140 g C m^–2, respectively. The similarity in seasonalproduction between Dundalk Bay and coastal waters of NorthernIreland, and between the summer stratified and northern mixedregions, is attributed to the intensity of production duringthe summer. Between 59 and 79% of seasonal production in thenorthern mixed region and coastal waters of Northern Irelandtook place during June and July, compared to 29–40% inDundalk Bay and the summer stratified region. Lower summer productionin the latter two may be due to nutrient limitation and thishas implications for the sensitivity of these two regions toanthropogenic nutrient enrichment.     

Temporal variability of particulate organic carbon,nitrogen and phosphorus in the Northern Adriatic Sea

The particulate organic carbon (POC), nitrogen (PN) and phosphorus (PP) vertical distribution along the water column and temporal variability in coastal and offshore waters of the Northern Adriatic Sea were related to the hydrodynamic conditions and biological processes. Fresh water inputs from the Po and Adige rivers enhance primary production, resulting in high POC, PN and PP concentrations at the surface. In offshore waters, POC and PN concentrations were about 3–4 times less than in the coastal waters, while PP were up to 10 times lower, highlighting a marked phosphorus depletion. In the bottom layer, the POC content decreases due to the strong density gradients which separate bottom waters with prevailing degradation processes. Short term 48 h-variability of POC, PN and PP in the coastal waters was determined to a great extent by variations in the spreading of river plumes at the surface and by nepheloid layers and resuspension processes in the bottom waters. The particulate matter in the Adriatic offshore waters is extremely depleted as regards particulate phosphorus and is characterised by C_org:P and N:P ratios higher than the Redfield ratio.     

Interannual Recruitment Dynamics for Resident and Transient Marsh Species: Evidence for a Lack of Impact by the Macondo Oil Spill

The emulsification of oil at the Deepwater Horizon (DWH) well head relegated a large proportion of resultant hydrocarbon plumes to the deep sea, facilitated the incorporation of oil droplets into microbial and planktonic food web, and limited the severity of direct, wetland oiling to coastal Louisiana. Nevertheless, many transient fish and invertebrate species rely on offshore surface waters for egg and larval transport before settling in coastal habitats, thereby potentially impacting the recruitment of transient species to coastal nursery habitats quite distant from the well site. We compared the utilization of salt-marsh habitats by transient and resident nekton before and after the DWH accident using data obtained from an oyster reef restoration project in coastal Alabama. Our sampling activities began in the summer preceding the DWH spill and continued almost two years following the accident. Overall, we did not find significant differences in the recruitment of marsh-associated resident and transient nekton in coastal Alabama following the DWH accident. Our results, therefore, provide little evidence for severe acute or persistent oil-induced impacts on organisms that complete their life cycle within the estuary and those that spent portions of their life history in potentially contaminated offshore surface waters prior to their recruitment to nearshore habitats. Our negative findings are consistent with other assessments of nekton in coastal vegetated habitats and bolster the notion that, despite the presence of localized hydrocarbon enrichments in coastal habitats outside of Louisiana the most severe oil impacts were relegated to coastal Louisiana and the deep sea. Analyzing all the information learned from this accident will undoubtedly provide a synthesis of what has or has not been affected in the Northern Gulf of Mexico, which when put in context with oil spill studies elsewhere should improve our ability to avert and manage the negative consequences of such accidents.     

Meroplankton distribution in the central Barents Sea in relation to local oceanographic patterns

Abundance and spatio-temporal distribution of meroplankton (larvae of invertebrate benthos) in the central Barents Sea and their dependence on abiotic factors were investigated. Samples were taken in different depth intervals on a south-north transect in the marginal ice zone in May 1997. At several locations sampling was repeated in June 1997. In May, total meroplankton abundances varied between 0.1 ind. m^-3 and 32.0 ind. m^-3, but mainly fluctuated around 10-15 ind. m^-3. They were strongly affected by the mass occurrence of single species. At the northern, heavily ice-covered stations numbers decreased significantly. Larvae of 27 types were found. Polychaetes represented the most diverse group (13 species), followed by echinoderms (8 species). Larvae of only one bivalve species were found (Mya truncata), but with very high abundances (86 ind. m^-3). Other taxa were represented only by single specimens. In June, total abundances were similar. The same species were present but the distribution patterns were less distinct, diversity values were higher and most larvae were further developed than in May. Distribution patterns of the larvae were to a large extent determined by physical processes in the area of the Polar Front, which acted as a distinct barrier in surface waters. In May, four meroplankton assemblages were distinguished, each associated with a different water mass. Most of the larvae have also been found in other investigated Arctic areas and belong to species with an Atlantic-Boreal-Arctic or Boreal-Arctic distribution. The relatively high numbers of larval types found in this study indicate that indirect development with pelagic larval stages plays a role in benthic recruitment in this sub-Arctic region. The relevance of these observations for the so-called Thorson rule is discussed.     

Environmental conditions and compositions of plankton and nekton in the epipelagic zone of the northwestern Pacific Ocean in summer 2009, the year of the largest spawning migration of pink and Chum Salmon

The distribution of temperature, salinity, phytoplankton, zooplankton, and nekton, including Pink Salmon and Chum Salmon, is analyzed based on the data from a complex survey conducted in the upper epipelagic zone of the northwestern Pacific Ocean in June–July 2009. An estimate of water transfer, plankton biomass (by size fractions and taxonomic groups), and biomass and abundance of nekton is made. The water circulation pattern was notable for the “compressed” state of the Western Subarctic Gyre. Copepods predominated in zooplankton (60.8% biomass), and Pacific Salmon dominated in the nekton. The ratio of the plankton biomass to the nekton biomass in various biostatistical areas varied from 23.9 to 195.1 (mean 46.7). It was found that the nekton biomass in the area of the spreading subarctic waters reaches its maximum in the summer months and that in the area of subtropical waters reaches its maximum in the fall. In the upper 30-meter layer, the biomass of fish and squid rose during the night to 2.92 million tons, or 1.6 times as much, due to mesopelagic migrants. The nekton communities of the upper epipelagic of the northwestern Pacific Ocean functioned normally, providing a high level of biological and fish productivity.     

Seasonal variability of phytoplankton populations in the middle Adriatic sub-basin

The seasonal variability of phytoplankton assemblages in themiddle Adriatic sub-basin is described. The investigated areacrossed the middle Adriatic from the Italian to the Croatiancoasts. Hydrographic data, chlorophyll (Chl) a and phytoplanktonwere collected on a seasonal basis from May 1995 to February1996. Highest phytoplankton densities (up to 6 x 10⁶ cells dm^–3)were observed in spring and autumn in the western side, withinthe diluted waters. The vertical distribution of Chl a exhibiteda pronounced subsurface maximum associated, in coastal waters,with micro-planktonic diatoms. Phytoplankton assemblages weredominated by phytoflagellates in all the periods investigated.Diatom maxima were observed in spring and autumn: their verticaldistribution generally reflected the Chl a pattern and in thewestern coastal area peaks are due to large diatom species (Pseudo-nitzschiaspp.). In offshore waters, dinoflagellates strongly prevailover diatoms and provide a relevant contribution to the totalbiomass, especially in highly stratified conditions. Coccolithophoridswere mostly encountered in surface layers and their highestcontribution to the total biomass was observed in the LevantineIntermediate Water.     

The Polychaete Polydora limicola in Benthic Communities of the Black Sea

Many papers dealing with nonindigenous species in the Black Sea do not mention the polychaete Polydora limicola Annenkova, a new invader in the Pontic-Azov Basin. In this connection, we will analyze here the taxonomic status of this species and discuss the history of its introduction and distribution in the northwestern Black Sea and related coastal lagoons. It is shown that P. limicola is now one of the most common species of the benthos in the Black Sea, especially in estuarine areas and coastal lagoons. The naturalization of this species resulted in changes in the structure of some bottom biocenoses of this region.     

First record of a brackish radiolarian (Polycystina): Lophophaena rioplatensis n. sp. in the Rio de la Plata estuary

Vertically stratified bottle plankton samples collected in theRío de La Plata estuary (Atlantic coast of South Americaat 35°S) and in coastal waters off Mar del Plata (38°S)in December 1999 and November 2001 yielded up to 394 live cellsl^-1 of a single new nassellarian species: Lophophaena rioplatensisn. sp. (family Plagoniidae). In estuarine waters, the specieswas recorded at salinities as low as 15.4 p.s.u.; densitiesin excess of 100 cells l^-1 were found at salinities rangingfrom 16.9 p.s.u. These extremely high concentrations (the highestever reported in the literature), as well as the fact that >90%of the individuals recorded contain cytoplasm, indicate thatthese are self-sustaining populations which thrive in the estuary(and in nearshore coastal waters), probably due to plentifuldissolved silica and an abundant food supply. Lophophaena rioplatensisis the first polycystine brackish-water species described. Thisfinding shows that radiolarian fossils are not unequivocallyassociated with open-ocean conditions, but may also be usefulindicators of coastal and brackish estuarine paleoenvironments.     

Distribution patterns of Baltic herring larvae, Clupea harengus L., in the coastal waters off Helsinki, Finland

Changes in the spatial distribution of Baltic herring larvaethrough time were investigated in the waters off Helsinki, thenorthern Baltic Sea. The average larval densities were comparableto the relatively low levels (mean around 2 larvae m^–2)found in other studies in the Gulf of Finland. In shallow baysvirtually no herring larvae were found in early June. In lateJune and early July the densities of larvae longer than 10 mmincreased to 1–4 larvae m^–2 in shallow areas (depth<2 m), i.e. to levels higher than those recorded in deeperwaters. In combination with data on the size distributions ofthe larvae, these observations suggest that a significant proportionof the herring larvae are found in shallow water after the yolksac stage. We conclude that shallow coastal waters are potentiallyimportant nursery areas for herring larvae and that this featureof herring larval biology should be taken into account in planningsampling programs for larval herring.     

Contrasting effects of substrate and grazer manipulations on picoplankton in oceanic and coastal waters off Brazil

In two contrasting regions off the coast of Brazil, picoplankton(<1 µm) responses to removal of larger grazers andto the additions of glucose and amino acids were determined.Effects of glucose and amino acid additions (1 µM) onparticulate nitrogen and chlorophyll a concentrations, and onrates of NH₄⁺ uptake and regeneration, were observed after 5h pre-incubation. In the oceanic waters, removal of the >1µm fraction had no significant effect on the chlorophylla of the picoplankton after 5 h. However, the addition of glucosestimulated both uptake and regeneration by a mean of 27%, andthe addition of arginine led to significant decreases in therates of NH₄⁺ uptake and regeneration. In contrast, in the coastalwaters, significant increases in chlorophyll and particulatenitrogen concentrations were found after 5 h incubation in boththe amended samples and in the controls, and mean rates of NH₄⁺uptake and regeneration were affected to a lesser degree bythe additions of either glucose or amino acids than in the oceanicwaters. The oceanic responses were suggestive of carbon limitationof heterotrophic bacteria. In the coastal region, on the otherhand, the supply of organic carbon and nitrogen was likely tohave been sufficient to meet the nutritional requirements ofthe heterotrophic bacteria and cyanobacteria. Grazing by largerorganisms on the picoplankton appeared to play a more significantrole in the nitrogen cycle in the coastal waters than in theoceanic waters.     

Hydrologic and Vegetative Removal of Cryptosporidium parvum,Giardia lamblia,and Toxoplasma gondii Surrogate Microspheres in Coastal Wetlands

Constructed wetland systems are used to reduce pollutants and pathogens in wastewater effluent, but comparatively little is known about pathogen transport through natural wetland habitats. Fecal protozoans, including Cryptosporidium parvum, Giardia lamblia, and Toxoplasma gondii, are waterborne pathogens of humans and animals, which are carried by surface waters from land-based sources into coastal waters. This study evaluated key factors of coastal wetlands for the reduction of protozoal parasites in surface waters using settling column and recirculating mesocosm tank experiments. Settling column experiments evaluated the effects of salinity, temperature, and water type (“pure” versus “environmental”) on the vertical settling velocities of C. parvum, G. lamblia, and T. gondii surrogates, with salinity and water type found to significantly affect settling of the parasites. The mesocosm tank experiments evaluated the effects of salinity, flow rate, and vegetation parameters on parasite and surrogate counts, with increased salinity and the presence of vegetation found to be significant factors for removal of parasites in a unidirectional transport wetland system. Overall, this study highlights the importance of water type, salinity, and vegetation parameters for pathogen transport within wetland systems, with implications for wetland management, restoration efforts, and coastal water quality.     

典型气候事件对浙江近海底层鱼类时空分布的影响

气候变化对海洋生态系统产生多方面的影响,作为海洋生物中的主体,鱼类对气候变化的响应机制研究是探索典型气候事件对海洋生态系统影响的关键。根据2013-2022年浙江近海底拖网渔业资源调查数据,结合尼诺指数(Ocean Nino Index, ONI)、海表温度 (Sea Surface Temperature, SST)、海表温度距平 (Sea Surface Temperature Anomaly, SSTA)、叶绿素a浓度(Chlorophyll a, Chl-a)等海洋环境数据,采用小波函数、相关性分析等探究典型气候事件厄尔尼诺、拉尼娜对浙江近海底层鱼类生物量及其时空分布的影响。结果表明,浙江近海底层鱼类生物量与SST及Chl-a呈极显著正相关(P ＜ 0.01)。厄尔尼诺与拉尼娜发生时期春、秋季生物量均小于正常年份,正常年份及拉尼娜事件期间春季生物量具有显著性差异(P ＜ 0.05);正常年份及厄尔尼诺事件期间秋季生物量具有极显著性差异(P ＜ 0.01)。对ONI与海洋环境因子指数进行交叉小波发现,浙江近海SST、Chl-a对于典型气候事件均存在不同的频域同步及相关性:ONI与SST在时间局部存在2-3.9个月频域同步,SST滞后ONI3个月;ONI与 Chl-a存在1.7-3个月频域同步,Chl-a与ONI呈正相关;ONI与生物量存在3-3.6个月频域同步,生物量滞后于ONI3个月;ONI与SSTA在研究期间不存在明显的频域同步。春季,相较于正常年份,厄尔尼诺期间鱼类整体分布偏北;秋季厄尔尼诺发生期间鱼类整体向南移动,拉尼娜期间则向北移动。厄尔尼诺及拉尼娜事件不仅对鱼类群落在纬度上的分布产生影响,还会对鱼类向近岸洄游的快慢产生影响。两种典型气候事件通过影响浙江近海SST等环境进而对浙江近海底层鱼类时空分布产生影响。