Role of Bacteria in the Carbon and Nitrogen Flow between Water-Column and Sediment in a Shallow Marine Bay (Bay of Piran, Northern Adriatic Sea)

Abstract. The interdependences between phytoplankton standing crop, bacterial biomass and the dissolved organic matter (DOM) pool in the water column were investigated and related to sediment parameters in a shallow marine bay (Bay of Piran, Northern Adriatic Sea) over an annual cycle. Bacterioplankton density varied between 1–10 × 10⁵ cells ml^-1, with lowest density observed in March corresponding to the low Chi a concentrations during this period. Generation times as determined by dialysis incubations ranged between 4h (June) and 82 h (March). Mean bacterial secondary production rates during summer were about 40 mg C m^-1 d^-1 and 5mg C m^-3.d^-1 during winter. With a short time lag, DOM concentrations followed the fluctuation in Chi a.
Sediment oxygen demand measurements revealed a mean mineralization rate of about 260 mg C m^-2 d^-1 during summer and 100–200 mg C m^-2 d^-1 in winter. Sediment bacterial density varied between 10⁸ - 10⁹ cells g (sediment dry wt)^-1 in the top 5 cm sediment layer or, in terms of biomass, 4.3 g C m^-l during summer and 0.6 g C m^-2 during winter. Highest concentrations of DOM in pore waters were measured in September, coinciding with high rates of sediment oxygen demand.     

红树林间隙水溶解态陆源有机质的光降解和生物降解行为分析

红树林输送的溶解态陆源有机质是海洋中陆源有机质的主要来源之一,对其光降解和生物降解过程的研究有助于进一步了解红树林生态系统输出的有机质在近岸的归宿以及对近岸水体生物地球化学过程的影响,因此于2010年4月在海南省清澜港红树林采集间隙水,并进行了光降解和生物降解培养实验。分析了光培养(光降解)和暗培养过程(生物降解)中溶解态有机碳(DOC)、细菌以及溶解态木质素等的变化。结果显示经历128 d的暗培养后,DOC由初始的2 216 μmol/L下降至718 μmol/L,表明红树林间隙水的生物可利用性约为70%左右;经历11 d的自然光照后,DOC下降至800 μmol/L。木质素在光降解过程中的移除速率(-0.132 d-1)远高于生物降解过程(-0.008 d-1)。光培养中,木质素的下降速率高于总体DOC。不同系列溶解态木质素的下降速率不同,随着培养的进行,紫丁香基酚类(S)与香草基酚类(V)的比值(S/V)呈下降趋势,而V系列的酸醛比值((Ad/Al)v)呈上升的趋势。对比光培养和暗培养过程中DOC和木质素的变化可以得出生物消耗是引起红树林间隙水DOC从水体中移除的主要因素;而光照则是陆源有机质从水体中移除的主要因素;光培养和暗培养过程中细菌变化的差异表明光照可以促进细菌对溶解态有机碳的利用。与其他地区比较发现,海南红树林间隙水的光降解速率与热带河流(刚果河)相近,高于温带密西西比河流,降解过程中各参数的变化[S/V和(Ad/Al)v]与其他区域接近。     

Seasonal variations of dissolved organic matter and nutrients in sediment pore water in the inner part of Tokyo Bay

At four stations in Tokyo Bay, pore water profiles of dissolved organic carbon (DOC), nitrogen (DON), phosphorus (DOP), and inorganic nutrients were determined at 3-month intervals over 6 years. Concentrations of dissolved organic matter (DOM) and nutrients were significantly higher in pore waters than in the overlying waters. Pore water DOC, DON, and DOP concentrations in the upper most sediment layer (0–1 cm) ranged from 246 to 888 μM, from 14.6 to 75.9 μM, and from 0.02 to 9.83 μM, respectively. Concentrations of DOM and nutrients in pore waters occasionally showed clear seasonal trends and were highest in the summer and lowest in the winter. The seasonal trends in the pore water DOM concentrations were coupled with trends in the overlying water temperature and dissolved oxygen concentration. Benthic effluxes of DON and DOP were low compared with those of inorganic nutrients, accounting for only 1.0 and 1.5 % of the total benthic effluxes of nitrogen and phosphorus, respectively; thus benthic DOM fluxes were quantitatively insignificant to the inorganic nutrient fluxes in Tokyo Bay. The DOM fluxes represented about 7, 3, and 10 % of the riverine discharge of DOC, DON, and DOP to Tokyo Bay, respectively.     

Tracing of dissolved organic matter from the Sepetiba Bay (Brazil) by PARAFAC analysis of total luminescence matrices

Fluorescent excitation-emission matrices (FEEM) of the fluorescent dissolved organic matter (FDOM) are widely used for DOM characterization and tracing. In this work, a set of FEEM from sampling campaigns in the Sepetiba Bay (Brazil) was decomposed into independent components using the parallel factor analysis (PARAFAC) algorithm. Four independent components were extracted describing the total fluorescence of the FDOM. The well described peaks A, C, M, B and T were found, and a new peak, A', linked to the C peak, was detected. Relative contribution of each of four components to the total fluorescence confirms that the coastal water has DOM of terrestrial origin, except for the 275Ex/400-500Em range (nm), which primarily occurs in marine waters.     

Subaqueous deltaic formation on the Atchafalaya Shelf,Louisiana

The Atchafalaya River in Louisiana shares the third largest drainage basin in the world with the Mississippi River. Sediment cores and seismic profiles were used to examine the development and impact on land accretion of an early-stage subaqueous delta accumulating on the shallow (<25 m water depth) continental shelf seaward of the Atchafalaya River mouths in the period (∼100 years) since the Atchafalaya has captured a significant fraction of the overall Mississippi discharge. The subaqueous clinoform is muddy (70–100% finer than 63 μm) and extends approximately 21–26 km seaward of the shell reef (to 8 m water depth) across the mouth of the Atchafalaya Bay, with a discontinuous, and, in places, mobile modern mud layer <20 cm thick covering a relict deltaic shoal area further seaward. The sigmoidal clinoform has a topset surface that steepens from east to west (1:2500 to 1:1600), a foreset with maximum slopes of about 1:550, and a limited bottomset region (<0.5 km wide). ²¹⁰Pb and ¹³⁷Cs geochronology show maximum sediment accumulation rates (>3 cm/year) correspond to the foreset and bottomset region, with rates decreasing to as low as 0.9 cm/year on the shelf topset region and its extension inside Atchafalaya Bay. Seven sedimentary facies are observed in the subaqueous delta, with differences created by degree of biological destruction of physical stratification, which is inversely related to sediment accumulation rate, and by the proximity of an area to the riverine sand source. There is a marked alongshore sediment dispersal pattern observed by the progressive winnowing of sand and coarse silt to the west. There is also a significant increase in shell content in Atchafalaya Bay relative to shelf facies. The resulting sigmoidal clinoform deposit (<3 m thick) more closely resembles strata geometries of subaqueous mud deltas associated with energetic systems (e.g., Amazon, Ganges–Brahmaputra, Fly), than it does the mature Mississippi delta 180 km to the east, albeit on a smaller scale and in shallow water.     

Physiology of Laminaria

Abstract. Sporophytes of Laminaria digitata and L. saccharina were collected from the shore at different times of year. Intact sporophytes of both species, and discs cut from L. digitata lamina tissue were maintained for several weeks in laboratory cultures under various nitrate, phosphate, temperature and daylength regimes. Substrate-saturated uptake rates of approximately 24 μgN g dry weight^-1 h^-1 from 20 μM nitrate and 8 μgP g dry weight^-1 h^-1 from 10 μM phosphate were more than sufficient to account for internal nitrogen and phosphorus accumulation. Other nitrogen sources - nitrite, ammonium and urea - were also taken up, independently of each other, and supported growth. During the late spring decline of ambient nutrient levels, when growth rates on the shore also decline markedly, enrichment with nitrate (15 μM) and phosphate (3μ) together prevented this decline and also maintained peak photosynthetic rates (net photosynthesis = 10.4 μlO₂ cm^-2 h^-1) which otherwise dropped to 4.5 μO₂ cm^-2 h^-1 over 47 days at ambient nutrient levels (0.5 μM nitrate and phosphate). Slow summer growth rates in June/July were enhanced to greater than spring peak values by combined nitrate (7.5 μM) and phosphate (1.8 μM) enrichment; neither was sufficient alone, although the individual nutrients were accumulated internally. A lesser, but significant enhancement was also achieved in September. In midwinter, nutrient enhancement itself (10.5 μM nitrate and 3.0 μM phosphate) had a small effect on growth rates only if summer water temperature (15°C) was used, but the dramatic effect of an increased photoperiod (7.5 to 17.5 h) was in excess of that expected for the increased radiant energy available. This was found to be due, at least in L. digitaia discs, to the re-establishment of a surface meristoderm in the dormant winter tissue; this was particularly active with high phosphate supply. Growth of the new lamina in January on the shore was much reduced if the old lamina was removed, although the time of initiation of new growth remained unchanged. In the laboratory, the old lamina was found to be a source of nitrogen for new lamina but not of fixed carbon or phosphorus. New lamina photosynthesis, manifest as mannitol accumulation, was directly proportional to phosphate supply up to at least 7.5 μM phosphate. Mannitol accumulation was then suppressed by a nitrate supply above 12 um, presumably by diversion of fixed carbon to other biosynthetic pathways.     

大亚湾夏季表层浮游细菌生物量分布与环境变量的关系

根据2008年夏季(7月)在大亚湾进行的现场综合调查资料,分析表层海水浮游细菌生物量的水平分布特征,探讨细菌生物量与环境变量的关系。大亚湾夏季浮游细菌生物量变化范围为14.00～118.80μg·L^-1,海区平均值为55.23±29.43μg·L^-1。大亚湾夏季细菌生物量水平分布大体上呈现南部高于北部的趋势,在北纬22°35′以北和以南的海区均各自表现为东南部高于西北部的趋势。水深、硝酸盐、铵盐、亚硝酸盐和总碱度等5个参数与浮游细菌生物量之间存在着中等水平的相关性(0.15相似文献   

Multivariate analysis of .uorescence and source identi. cation of dissolved organic matter in Jiaozhou Bay, China

Hierarchical clustering analysis and principal component analysis (PCA) methods were used to assess the similarities and dissimilarities of the entire Excitation-emission matrix spectroscopy (EEMs) data sets of samples collected from Jiaozhou Bay, China. The results demonstrate that multivariate analysis facilitates the complex data treatment and spectral sorting processes, and also enhances the probability to reveal otherwise hidden information concerning the chemical characteristics of the dissolved organic matter (DOM). The distribution of di.erent water samples as revealed by multivariate results has been used to track the movement of DOM material in the study area, and the interpretation is supported by the results obtained from the numerical simulation model of substance tracing technique, which show that the substance discharged by Haibo River can be distributed in Jiaozhou Bay.     

Water quality and phytoplankton communities in Lake Pontchartrain during and after the Bonnet Carré Spillway opening,April to October 2008, in Louisiana,USA

The Bonnet Carré Spillway, located 28 miles northwest of New Orleans, was constructed in the early 1930s as part of an integrated flood-control system for the lower Mississippi River system. From 11 April to 8 May 2008, Mississippi River water was diverted through the spillway into the 629-square-mile Lake Pontchartrain, which is hydraulically connected to the Gulf of Mexico. On 8 April, prior to the opening of the spillway, water-quality instruments were deployed and recorded hourly measurements of water temperature, dissolved oxygen, specific conductance, pH, and nitrate. Discrete water-quality and phytoplankton (algae) samples were collected in Lake Pontchartrain from 8 April to 3 October 2008 to assess the water-quality nutrient enrichment effects of the diversion on the lake. The maximum influence of river water in the southern portion of the lake was captured with continuous (hourly) monitoring of nitrate concentrations, and field measurements such as of specific conductance during the critical period in late April to early May. By late May, the deployed instruments had recorded the arrival, peak, and decline of selected constituents associated with the freshwater influx from the Mississippi River/Bonnet Carré Spillway diversion. The continuous monitoring data showed the short-term interactions of high-nitrate, low-specific conductance river water and low-nitrate, high-specific conductance lake water. The phytoplankton community composition, as an indicator of water quality, illustrated an extended response from the river water evident even after the continuous and discrete samples indicated that the lake had returned to pre-diversion conditions. The initial phytoplankton community response to nutrient increases was related to accumulations of diatoms. During periods of low nutrient concentrations, accumulations of blue-greens occurred by July and August. As blue-green algae cell densities and biovolumes increased in the summer, so did the species richness of blue-green algae, particularly the harmful algae bloom taxa. Cell densities and biovolume of the phytoplankton lake indicator taxa Skeletonema costatum, Anabaena sp., and Cylindrospermopsis raciborskii were highest and dominated the diatom and blue-green algae communities during the period of most river water influence on the lake and immediately following the freshwater inflows. The dominance and recession of these indictor taxa reflect the dramatic changes that occurred in the phytoplankton community in response to an increase in nutrient-rich freshwater from the diversion into the lake, and not normal seasonal phytoplankton compositional differences. Water-quality data indicated a gradual reversion to pre-diversion lake conditions by June to July, but shifts in the phytoplankton composition were still evident through August 2008. Observations from this study were similar to results from previous studies of Mississippi River/Bonnet Carré Spillway diversion opening in 1997.     

Plankton productivity and biomass in a tributary of the upper Chesapeake Bay. I. Importance of size-fractionated phytoplankton productivity,biomass and species composition in carbon export

Phytoplankton productivity, community composition and biomass were determined over a nine-month period in brackish waters of the lower Gunpowder River, a tributary of Chesapeake Bay. Primary productivity followed expected seasonal magnitudes for temperate estuaries with rates exceeding 142·4 mg C m^?3 h^?1 in July through September 1979 and minimum rates of 1·6 mg C m^?3 h^?1 in February 1980. Annual primary production was estimated at 45·5 gC m^?2. Cell numbers were highest in August, September and November with cyanophytes dominating the planktonic algae. Primary productivity, chlorophyll concentrations and cell densities were dominated by nanoplanktonic forms (< 10 μm) through-out the study. Phytoplankton carbon calculated from cells volumes exceeded nutritional requirements of the pelagic herbivores in all months suggesting a mean daily export (to the bay or sediments) of 1607 mg C m^?3 d^?1.     

A simple guideline to apply excitation-emission matrix spectroscopy (EEMs) for the characterization of dissolved organic matter (DOM) in anoxic marine sediments

Marine sediments represent a major carbon reservoir on Earth. Dissolved organic matter(DOM) in pore waters accumulates products and intermediates of carbon cycling in sediments. The application of excitation-emission matrix spectroscopy(EEMs) in the analysis of subseafloor DOM samples is largely unexplored due to the redoxsensitive matrix of anoxic pore water. Therefore, this study aims to investigate the interference caused by the matrix on EEMs and propose a guideline to prepare pore water sam...     

Terrestrial dissolved organic carbon consumption by heterotrophic bacterioplankton in the Huanghe River estuary during water and sediment regulation

Nearly 20%–50% of the annual terrestrial dissolved organic carbon(DOC)from the Huanghe(Yellow)River was transported to the estuary during the 5-14d of water and sediment regulation.The concentration of DOC increased sharply during the period of water and sediment regulation,which may promote the terrestrial DOC consumption by heterotrophic bacterioplankton.Water and sediment regulation provides an ideal condition for the study of terrestrial DOC consumption by heterotrophic bacterioplankton when terrestrial DOC increases sharply in rainy season,which may help to seek the fates of terrestrial DOC in the estuaries and coasts.In this study,the concentration and stable isotope of DOC,the biomass,growth,and respiration of heterotrophic bacterioplankton were determined.By the study,we found both average percent contribution of terrestrial DOC to the DOC pool and Contribution of terrestrial DOC to the carbon composition of heterotrophic bacterioplankton decreased as distance from the river mouth increased off shore,which was deceased from(39.2±4.0)%,(37.5±4.3)%to(30.3±3.9)%,(28.2±3.9)%respectively.255-484μg C/(L·d)terrestrial DOC was consumed by heterotrophic bacterioplankton.And 29%-45%terrestrial DOC consumed by heterotrophic bacterioplankton releasing as CO2 by respiration.Comparing with tropical estuary,terrestrial DOC consumed by heterotrophic bacterioplankton was lower in temperate estuary(this study).Temperature may limit the consumption of terrestrial DOC by heterotrophic bacterioplankton.     

Distribution of moon jellyfish Aurelia aurita in relation to summer hypoxia in Hiroshima Bay,Seto Inland Sea

Biological and physical surveys were conducted in order to investigate the relationship between environmental conditions and the distribution of moon jellyfish Aurelia aurita in Hiroshima Bay, western Seto Inland Sea, Japan. Moon jellyfish and ichthyoplankton were collected at 13 stations in Hiroshima Bay during monthly surveys from July to September in 2006 and 2007. Surface temperature in 2006 was significantly lower during the August and September cruises and surface salinity was lower during all cruises than in 2007. Moon jellyfish was the most dominant gelatinous plankton collected, accounting for 89.7% in wet weight. Mean moon jellyfish abundance in 2006 was higher than that in 2007 from July through September, with significant inter-year differences for July and September. Variability in precipitation and nutritional input from the Ohta River, northernmost part of Hiroshima Bay, were suggested as possible factors affecting the inter-annual variability in moon jellyfish abundance in the coastal areas of northern Hiroshima Bay. Moon jellyfish were more abundant in the coastal areas of northern Hiroshima Bay, where the dissolved oxygen (DO) concentration was lower, while low in the central part of the bay. Japanese anchovy Engraulis japonicus eggs were most dominant (58.1% in number) among the ichthyoplankton and were abundant in the central area of Hiroshima Bay. Explanatory analysis was conducted to detect possible effects of environmental conditions on the abundance of moon jellyfish and Japanese anchovy eggs during the summer months in Hiroshima Bay. Of the environmental conditions tested (temperature, salinity and DO of surface and bottom layers at each sampling station), bottom DO had the most significant effect on the moon jellyfish abundance: there was a negative correlation between the bottom DO and the moon jellyfish abundance in Hiroshima Bay during summer.     

深圳湾浮游细菌生物量的时空动态及影响因素

自2015年5月至2016年3月在深圳湾布设了3个站位,对该海域进行了每季至少1次共7个航次的浮游细菌生物量调查。结果表明:(1)深圳湾浮游细菌生物量季节均值的变化范围为(4.90~86.90)×10^-2μg·mL^-1,总均值为3.14×10^-1μg·mL^-1;(2)深圳湾浮游细菌生物量的季节变化模式为:冬季(5.98×10^-1μg·mL^-1)>秋季(3.02×10^-1μg·mL^-1)>夏季(2.79×10^-1μg·mL^-1)>春季(7.52×10^-2μg·mL^-1);(3)从空间分布来看,浮游细菌生物量湾中含量最高,湾口其次,湾顶最低;(4)深圳湾浮游细菌生物量与亚硝氮含量呈极显著的正相关(P<0.01),与氨氮含量呈显著正相关(P<0.05);(5)深圳湾水体中浮游细菌丰度季节均值变化范围为(2.45~43.50)×10⁶个·mL^-1,年均值达1.57×10⁷个·mL^-1;(6)从整体的细菌丰度及生物量来看,深圳湾海域呈现富营养化状态,湾中最严重,湾口次之,湾顶最轻。     

大鹏湾海区营养盐年际变化及富营养化研究

根据1993—2003年7月、8月和9月在大鹏湾海区3个站位的表、底层水样现场监测资料,分析了大鹏湾海区氮、磷营养盐的年际变化趋辨。分别运用水质质量标准指数法、综合指数WQI法评价了大鹏湾海区水质质量。运用营养状况综合指数法进行了营养状况评价。结果表明,大鹏湾海区夏季的氮、磷营养盐水平较低,N／P比值介于7～30之间。     

Temporal variability in the composition and abundance of terrestrially-derived dissolved organic matter in the lower Mississippi and Pearl Rivers

Here we report on temporal changes in the concentration and composition of lignin phenols in high molecular weight (< 0.2 μm, > 1 kDa) dissolved organic matter (HMW DOM) collected from the lower Mississippi and Pearl Rivers (MR and PR) (USA). Monthly water samples were collected at a station in the lower reach in each river from August 2001 to August 2003. Significantly higher concentrations of lignin and Λ₈ values (mg lignin phenols in 100 mg organic carbon) in the Pearl River than in the Mississippi River, reflected sporadic inputs of terrestrial DOM during rainstorm events from wetlands and forest soils. Larger seasonal variations in lignin concentration and composition in the Pearl River, compared to the Mississippi River, were attributed to shifts in organic matter sources from topsoil inputs during rainstorm events to groundwater inputs and in situ production during base flow in this small river. Conversely, lower Λ₈ and vanillic acid to vanillin ratios [(Ad/Al)v] in the HMW DOM of the lower Mississippi River may be a result of a lower export rate of lignin from agricultural soils due to lower carbon storage in the expansive agricultural systems of the Mississippi River watershed, as well as dilution of phytoplankton DOM inputs. Large seasonal changes in lignin concentration and Λ₈ (linked at times with river discharge), and minimal variability in the composition of lignin phenols, likely represented an integrated signal of soil-derived vascular inputs from the upstream drainage basin. If we are to better understand the controls of organic matter delivery to the coastal zone from both small and large rivers, sampling strategies need to be adjusted to account for the different scales of hydrologic response time and in situ processing associated with different residence times.     

Multivariate analysis of fluorescence and source identification of dissolved organic matter in Jiaozhou Bay, China

Hierarchical clustering analysis and principal component analysis (PCA) methods were used to assess the similarities and dissimilarities of the entire Excitation-emission matrix spectroscopy (EEMs) data sets of samples collected from Jiaozhou Bay, China. The results demonstrate that multivariate analysis facilitates the complex data treatment and spectral sorting processes, and also enhances the probability to reveal otherwise hidden information concerning the chemical characteristics of the dissolved organic matter (DOM). The distribution of different water samples as revealed by multivariate results has been used to track the movement of DOM material in the study area, and the interpretation is supported by the results obtained from the numerical simulation model of substance tracing technique, which show that the substance discharged by Haibo River can be distributed in Jiaozhou Bay.     

海州湾赤潮高发区浮游细菌与赤潮及环境因子的关系

海州湾是南黄海赤潮高发区之一。为研究浮游细菌与赤潮及环境因子的关系,于2020年11月在海州湾赤潮期间进行了现场调查,采集了8个站位的浮游细菌、浮游植物样品,获取了温度、盐度、叶绿素a以及氮、磷、硅营养盐浓度等环境因子信息,分析了赤潮原因种及浮游细菌群落结构情况。结果显示,此次赤潮原因种为三叶原甲藻(Prorocentrum triestinum)、赤潮异弯藻(Heterosigma akashiwo)及塔胞藻(Pyramimonas sp.),发生赤潮时水温、盐度较低,盐度与赤潮异弯藻的分布有一定的联系。使用16SrRNA高通量测序方法分析调查海域的浮游细菌情况,结果显示赤潮发生站位的浮游细菌多样性略低于其他非赤潮发生站位,优势细菌与其他站位有明显不同,以假单胞菌目(Pseudomonadales)、红杆菌目(Rhodobacterales)和黄杆菌目(Flavobacteriales)为主。赤潮发生站位的浮游细菌群落结构也存在一定的差异,不同站位可能处于不同的赤潮阶段,对浮游细菌群落具有不同的影响。相关性分析显示,黄杆菌目与叶绿素a显著正相关,表明黄杆菌目与赤潮发生有一定的关系。     

海南岛三亚湾浮游植物和细菌生物量时空分布特征及环境制约因素研究

根据2005年1,4,7和10月4个季度代表月份在海南岛三亚湾进行的现场综合调查资料,分析了海区浮游植物和浮游细菌生物量的空间分布及季节变异特征,探讨了它们与温度,DIN,PO₄3-,DO,BOD₅等生态环境因子的关系.结果表明,三亚湾海区2005年平均叶绿素a浓度为:(2.48±2.97)mg/m3,浮游植物生物量(C)为:(124.2±148.3)mg/m3,浮游植物生物量秋季最高,其他季节差异不大,除夏季外,浮游植物生物量(C)均表现为:表层大于底层;年平均浮游细菌丰度为(6.90±2.95)×108个/dm3,细菌生物量(C)为(13.79±5.90)mg/m3,细菌生物量夏季最高,往下依次为冬季、春季和秋季,且4个季节均为表层大于底层.4个季节表、底层浮游植物和细菌生物量的空间分布特征明显,均表现为从近岸的三亚河口往外海逐渐降低的趋势,三亚河的陆源输送和入海扩散是造成此分布特征的主要原因.无机营养盐中,DIN是调控浮游植物和细菌生物量的主导因子.位于热带的三亚湾,温度不成为影响二者季节差异的主要因子.浮游细菌生物量和浮游植物生物量的比值BB/PB为:0.06~0.15(平均为0.12),三亚湾浮游植物生物量和浮游细菌生物量间的相关性非常显著(P<0.01),初级生产是影响水域浮游细菌分布的重要因素.     

Adsorption—desorption control of phosphate in anoxic sediment of a coastal sea,Funka Bay,Japan

Sediment core samples were taken once a month from July 1980 to September 1981 at a station in Funka Bay (92-m depth) for the determination of phosphate, silicate and alkalinity in interstitial water. A remarkable seasonal variation was found for interstitial phosphate, that is, distinct maxima appeared in spring (March—April), just after a phytoplankton bloom which brought a large amount of settling particles to the bottom, and in summer (July—August) when the water was stratified and the dissolved oxygen content of the bottom water decreased due to the decomposition of organic matter. The high interstitial phosphate concentration was always accompanied by a sharp increase in alkalinity, indicating sulfate reduction. This large seasonal variation in interstitial phosphate cannot be explained by in situ decomposition of organic matter and/or the diffusive loss of interstitial phosphate. A more likely explanation is adsorption and desorption of interstitial phosphate coincident with the depth of the active sulfate reduction layer.