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1.
太湖河蚬时空格局   总被引：14，自引：6，他引：8  
2006年12月-2007年11月对太湖河蚬种群进行了周年逐月调查.河蚬在分布区的年均密度和生物量分别为265.7ind./m2和100.9g/m2,在夏、秋季均达到高值.根据壳长频数分布的周年变化,太湖河蚬一年一代,繁殖期主要在5-7月份.河蚬主要分布在贡湖湾、马迹山以南区域、西南湖区和小梅港沿岸区域.分析表明,太湖中河蚬的空间分布表现出明显的差异性,这种差异性受到多种因素的综合影响.在北部梅梁湾和竺山湾湖区湖泊中的低溶氧量是限制河蚬生长的最重要因素;在贡湖湾、马迹山以南湖区和西南部湖区,各种生境条件和底质性质适合河蚬的生长繁殖,其密度和生物量的最高值出现在贡湖湾的中心区域(820.0ind./m2,522.9g/m2);在东太湖湖区浮游植物密度较低,底质中有机质较少,食物来源是影响河蚬分布的较重要因素.  相似文献   

2.
Acoustic Doppler current profiles and current meter data are combined with wind observations to describe the transport of water leaving Florida Bay and moving onto the inner shelf on the Atlantic side of the Florida Keys. A 275-day study in the Long Key Channel reveals strong tidal exchanges, but the average ebb tide volume leaving Florida Bay is 19% greater than the average flood tide volume entering the bay. The long-term net outflow averages 472 m3 s−1. Two studies in shelf waters describe the response to wind forcing during spring and summer months in 2004 and during fall and winter months in 2004–2005. During the spring–summer study, southeasterly winds have a distinct shoreward component, and a two-layer pattern appears. Surface layers move shoreward while near-bottom layers move seaward. During the winter study, the resultant wind direction is parallel to the Keys and to the local isobaths. The entire water column moves in a nearly downwind direction, and across-shelf transport is relatively small. During the summer wet season, Florida Bay water should be warmer, fresher, and thus less dense than Atlantic shelf waters. Ebbing bay water should move onto the shelf as a buoyant plume and be held close to the Keys by southeasterly winds. During the winter dry season, colder and saltier Florida Bay water should leave the tidal channels with relatively high density and be concentrated in the near-bottom layers. But little across-shelf flow occurs with northeasterly winds. The study suggests that seasonally changing wind forcing and hydrographic conditions serve to insulate the reef tract from the impact of low-quality bay water.  相似文献   

3.
Spatial variations in the sinking export of organic material were assessed within the Hudson Bay system (i.e., Hudson Bay, Hudson Strait and Foxe Basin) during the second oceanographic expedition of ArcticNet, on board the CCGS Amundsen in early fall 2005. Sinking fluxes of particulate organic material were measured using short-term free-drifting particle interceptor traps deployed at 50, 100 and 150 m for 8–20 h at eight stations. Measurements of chlorophyll a (chl a), pheopigments (pheo), particulate organic carbon (POC), biogenic silica (BioSi), protists, fecal pellets and bacteria were performed on the collected material. In parallel, sea surface salinity and temperature were determined at 121 stations in the Hudson Bay system. Three hydrographic regions presenting different sedimentation patterns were identified based on average surface salinity and temperature. Hudson Strait was characterized by a marine signature, with high salinity (average=32.3) and low temperature (average=2.1 °C). Eastern Hudson Bay was strongly influenced by river runoff and showed the lowest average salinity (26.6) and highest average temperature (7.6 °C) of the three regions. Western Hudson Bay showed intermediate salinity (average=29.4) and temperature (average=4.4 °C). Sinking fluxes of total pigments (chl a+pheo: 3.37 mg m−2 d−1), diatom-associated carbon (19.8 mg m−2 d−1) and BioSi (50.2 mg m−2 d−1) at 50 m were highest in Hudson Strait. Eastern Hudson Bay showed higher sinking fluxes of total pigments (0.52 mg m−2 d−1), diatom-associated carbon (3.29 mg m−2 d−1) and BioSi (36.6 mg m−2 d−1) compared to western Hudson Bay (0.19, 0.05 and 7.76 mg m−2 d−1, respectively). POC sinking fluxes at 50 m were low and relatively uniform throughout the Hudson Bay system (50.0–76.8 mg C m−2 d−1), but spatial variations in the composition of the sinking organic material were observed. A large part (37–78%) of the total sinking POC was unidentifiable by microscopic observation and was qualified as amorphous detritus. Considering only the identifiable material, the major contributors to the POC sinking flux were intact protist cells in Hudson Strait (28%), fecal pellets in eastern Hudson Bay (52%) and bacteria in western Hudson Bay (17%). A significant depth-related attenuation of the POC sinking fluxes (average loss between 50 and 150 m=32%) and a significant increase in the BioSi:POC ratio (average increase between 50 and 150 m=76%) were observed in Hudson Strait and eastern Hudson Bay. For all other sinking fluxes and composition ratios, we found no statistically significant difference with depth. These results show that during fall, the sinking export of total POC from the euphotic zone remained fairly constant throughout the Hudson Bay system, whereas other components of the organic sinking material (e.g., chl a, BioSi, fecal pellets, protist cells) showed strong spatial variations.  相似文献   

4.
A month-long investigation of phytoplankton biomass and primary production (PP) was carried out during a harmful algal bloom (HAB) in Daya Bay, China, in 2003. During the bloom, the phytoplankton community was dominated by Scrippsiella trochoidea and Chattonella marina. The phytoplankton biomass (Chl a) and PP reached peak levels of 519.21 mg m−3 and 734.0 mgC m−3 h−1, respectively. Micro-phytoplankton was the key contributor to Chl a and PP in a cage-culture area and in the adjacent HAB-affected waters, with percentages of up to 82.91% and 84.94%, respectively. The HAB had complicated relationships with hydrological and meteorological factors in Daya Bay. However, the water around the cage-culture area always showed statistically greater phytoplankton biomass and nutrient loadings than in adjacent waters, suggesting that this was the “trigger area” of the bloom. The spatial and temporal distribution of diverse HABs in Daya Bay, their ecological characteristics, and their environmental impacts are also discussed in this paper.  相似文献   

5.
Initial dispersion of material in complex-shaped embayments is examined using observations and scaling based in Crail Bay, Pelorus Sound, New Zealand in autumn of 2005. These observations show the highly variable nature of dispersive transport in an embayment with multiple headlands. Acoustic current profiler-derived typical flow speeds were around 0.05 m s−1 which resulted in drifter-derived short-term (<6 h) horizontal eddy diffusivities of the order of 1 m2 s−1 which is somewhat larger than the empirical paradigm. Microstructure estimates of the turbulent kinetic energy dissipation rate were in the range 10−9–10−7 m2 s−3, with some evidence that sidewalls influence the variability and that headlands increase the dissipation rate by at least and order of magnitude. A new parameter relating horizontal diffusivity to circulation and the tide is proposed. This and other scaling comparisons indicate that the headlands in Crail Bay create similar effects to those studied in other systems. However, the long decay times estimated for eddies here implies that they likely interact with other headlands, unlike some previously studied examples.  相似文献   

6.
吴兴华  李翀  陈磊  赵荧  李媛  王浩 《湖泊科学》2018,30(1):121-129
于2015年2月26-27日在香溪河库湾高岚河段拟多甲藻(Peridiniopsis)水华发生地昼夜监测其在水体中的垂直迁移,分别在6个时间段(8:00、12:00、16:00、20:00、0:00、4:00)分层取样分析拟多甲藻在水中的叶绿素a浓度、细胞密度、碳酸酐酶(CA)与碱性磷酸酶(AP)活性;分析总磷(TP)、溶解性总磷(DTP)、溶解性反应磷(SRP)与溶解性有机磷(DOP)浓度在水中的垂直分布.结果显示,水华发生期拟多甲藻为绝对优势种,监测的6个时段中,拟多甲藻呈显著的昼夜垂直迁移规律,正午12:00,表层细胞密度最大,可达5.2×10~6cells/L,凌晨0:00表层细胞密度最低,仅为0.4×10~6cells/L;TP与DTP浓度无垂直分布规律,但SRP与DOP浓度呈现显著的垂直分布规律,SRP浓度随水深增加而减小,DOP浓度随水深增加而增加;CA活性日间高于夜间,日间CA活性呈垂直分布规律,随水深增加而减小,但夜间无垂直分布规律;AP活性在水中昼夜呈极其显著的垂直分布规律,随着水深增加逐渐增加.相关性分析结果表明,拟多甲藻细胞密度与水深、DOP浓度呈极显著负相关,水深与CA和AP活性分别呈极其显著负相关与正相关,拟多甲藻细胞密度与CA和AP浓度分别呈极其显著正相关与负相关.因此,拟多甲藻的垂直迁移行为可能是对日间迁移至表层获取光能和无机碳来源、夜间迁移至水下获取磷源的一种适应.  相似文献   

7.
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8.
Zhao J  Cao W  Yang Y  Wang G  Zhou W  Sun Z 《Marine pollution bulletin》2008,56(10):1795-1801
A moored optical buoy was deployed in the Pearl River estuarine waters for a 15-day period. A four-day algal bloom event occurred during this study period. Both chlorophyll a concentration and algal cell density (a proxy for biomass) changed dramatically before and after the event. The chlorophyll concentration at a 2.3 m depth rose from 5.15 mg/m−3 at 15:00 h on August 19 to 23.62 mg/m−3 at 9:00 h on August 21, and then decreased to 3.24 mg/m−3 at 15:00 h on August 24. The corresponding cell density ranged from 1.57 × 105 to 1.76 × 106 cells/L. We used normalized fluorescence line height (NFLH) and normalized fluorescence intensity (NFI) in order to determine fluorescence activity. Combined with the in situ sampling dataset, we were able to correlate natural fluorescence (NFLH and NFI) with chlorophyll a concentrations, and found correlation coefficients of 0.72 and 0.75, respectively. We also found correlations between natural fluorescence and cell density, with correlation coefficients of 0.71 and 0.65, respectively. These results indicate that applying continuous time series of natural fluorescence can reflect changes in biomass. This technique will prove extremely useful for in situ and real-time observations using an optical buoy. Although there are still problems to solve in the real-time observation of natural fluorescence in algal bloom events, we discuss the primary factors affecting fluorescence signals and suggest possible methods for mitigating these issues.  相似文献   

9.
In this paper we are proposing an alternative method for determination of density variations of the crust from constrained inversion of the terrestrial gravity data. The main features of the method can be summarized as follows: (i) Constructing a band-pass filter to remove the long and short wavelength signals from the terrestrial gravity data. (ii) Using an iterative method for stabilization and solution of the inverse problem. The mentioned regularization method is first validated by simulated gravity data and next the methodology is used for development of a new regional density variation model of the crust in three layers based on real gravity data in geographical area of Iran. Application of the band-pass filter to the latter data resulted the residual gravitation variations in the range of − 300 to 50 (mGal) which next based on the iterative method resulted following ranges for residual densities: −120 to 40 (kg/m3) in first layer, −40 to 40 (kg/m3) in second layer, and − 40 to 40 (kg/m3) in third layer.  相似文献   

10.
从细菌、浮游植物、浮游动物、底栖动物和有机碎屑等几个方面分析了养鱼对伊乐藻种植区(以下简称为有草区)和无草区水域环境的影响。结果表明:两个区域存在着显著的差异性。有草区由于生长着茂密的水生植被,对环境压迫的缓冲能力增强,水生生物的群落结构较为稳定,物种多样性指数高于无草区,有机物的沉降速率也大大低于无草区。与此相比,无草区对环境压迫的缓冲能力较差,水体浮游植物数量增加,富营养化加剧。通过本项实验可以看出,人工种植伊乐藻对养鱼区水质有着明显地控制作用,是发展生态渔业的一条有效途径。  相似文献   

11.
Ecological environment changes in Daya Bay, China, from 1982 to 2004   总被引：7，自引：0，他引：7  
Data collected from 12 marine monitoring stations in Daya Bay from 1982 to 2004 reveal a substantial change in the ecological environment of this region. The average N/P ratio increased from 1.377 in 1985 to 49.09 in 2004. Algal species changed from 159 species of 46 genera in 1982 to 126 species of 44 genera in 2004. Major zooplankton species went from 46 species in 1983 to 36 species in 2004. The annual mean biomass of benthic animals was recorded at 123.10 g m−2 in 1982 and 126.68 g m−2 in 2004. Mean biomass and species of benthic animals near nuclear power plants ranged from 317.9 g m−2 in 1991 to 45.24 g m−2 in 2004 and from 250 species in 1991 to 177 species in 2004. A total of 12-19 species of hermatypic corals and 13 species of mangrove plants were observed in Daya Bay from 1984 to 2002.  相似文献   

12.
Lake Atitlan, one of the most important lakes not only in Central America but in the whole world, is facing serious problems with increasing water pollution. Over the last several decades, the uncontrolled nutrient input into the lake has lead to high P levels and low N:P ratios, initiating cyanobacterial blooms. The first bloom occurred in December of 2008, followed by more extensive bloom in October 2009. The blooms are formed by cyanobacteria from the rare planktic Lyngbya hieronymusii/birgei/robusta complex. Based on the species morphology, the Atitlan population corresponds to L. robusta and this is the first case of reported bloom of this species worldwide. Remote sensing images documented that at the maximum bloom development, 40% of the 137 km2 of the lake area were covered by dense patches of Lyngbya, with the chlorophyll a concentration reaching over 100 μg L−1. The only toxins detected in the 2009 bloom were trace levels of cylindrospermopsin and saxitoxin with 12 and 58 ng g−1, respectively. The nitrogen fixation followed a pattern expected in non-heterocytous cyanobacteria, i.e., the nitrogenase activity was minimal during the day, while during the night the activity reached 2.2 nmol C2H4 μg Ch a−1 h−1. Delta 15N of −0.86‰ was well in the range given for nitrogen fixing organisms. The cell C, N and P content was 36.7%, 5.9% and 0.9%, respectively, resulting in the molar ratio of 105:14.4:1. A well designed and executed lake monitoring program, strict control of nutrient input into the lake, and public education are the necessary prerequisites for potential prevention of even more severe blooms than the one from 2009.  相似文献   

13.
An outdoor experiment testing the effect of water flea (Daphnia longispina) and zebra mussels (Dreissena polymorpha) on physical and chemical water parameters and chlorophyll concentration changes was carried out in 12 containers filled with 150 l of unfiltered water from a lowland reservoir. During the 11 weeks of the experiment, the following physical, chemical and biological measurements were recorded: temperature (°C), oxygen concentration (mg dm−3), pH, conductivity (S cm−1), concentration of phosphate phosphorus (PO4-P) and ammonia nitrogen (NH4-N) (g dm−3), total nitrogen (TN) and total phosphorus (TP) (g dm−3), phytoplankton community structure and chlorophyll a concentration (g dm−3). The amount of ammonia ions was the highest in the treatment with zooplankton, while phosphate ions reached the highest values in treatments with zebra mussels. The results confirmed the ability of Daphnia to increase the NH4:PO4 ratio, whereas excretion from zebra mussels resulted in a decrease in both the N:P ratio (ranging from 9 to 13) and the NH4:PO4 ratio in water. In both treatments containing zebra mussels, P-rich water enabled sudden growth of Chlorophyta, resulting in blooms of Hydrodictyon reticulatum after 3–4 weeks of the experiment. Such phenomena were not observed in the control and Daphnia treatments. Our results indicate that zebra mussels, in contrast to Daphnia, may increase the symptoms of water eutrophication and contribute to blooms of expansive phytoplankton species.  相似文献   

14.
河蚬(Corbicula fluminea)为太湖优势大型底栖动物,通过受控实验研究其对富营养水体的水质改善效果.根据太湖河蚬的自然丰度设置4组密度处理,分别为无河蚬对照组、低密度河蚬组(生物量为130 g/m2)、中密度河蚬组(260 g/m2)和高密度河蚬组(520 g/m2).结果表明:河蚬滤食显著降低悬浮物浓度与叶绿素a含量,低、中、高密度河蚬组水体悬浮物浓度较对照组分别降低了20.85%、34.90%和53.79%,叶绿素a浓度分别降低了23.29%、48.32%和71.17%;放置河蚬还降低了水体TN、TP浓度,但是中密度河蚬组与高密度河蚬组没有显著差异.分析认为,河蚬通过滤食作用降低水体浊度、改善光照条件,有利于底栖藻类的生长及沉水植物的恢复,对富营养水体的生态修复具有重要意义;就太湖而言,河蚬对水质的改善效果可能受沉积物再悬浮造成的营养盐释放等因素的制约.  相似文献   

15.
A tracer plume was created within a thin aquifer by injection for 299 d of two adjacent “sub‐plumes” to represent one type of plume heterogeneity encountered in practice. The plume was monitored by snapshot sampling of transects of fully screened wells. The mass injection rate and total mass injected were known. Using all wells in each transect (0.77 m well spacing, 1.4 points/m2 sampling density), the Theissen Polygon Method (TPM) yielded apparently accurate mass discharge (Md) estimates at three transects for 12 snapshots. When applied to hypothetical sparser transects using subsets of the wells with average spacing and sampling density from 1.55 to 5.39 m and 0.70 to 0.20 points/m2, respectively, the TPM accuracy depended on well spacing and location of the wells in the hypothesized transect with respect to the sub‐plumes. Potential error was relatively low when the well spacing was less than the widths of the sub‐plumes (>0.35 points/m2). Potential error increased for well spacing similar to or greater than the sub‐plume widths, or when less than 1% of the plume area was sampled. For low density sampling of laterally heterogeneous plumes, small changes in groundwater flow direction can lead to wide fluctuations in Md estimates by the TPM. However, sampling conducted when flow is known or likely to be in a preferred direction can potentially allow more useful comparisons of Md over multiyear time frames, such as required for performance evaluation of natural attenuation or engineered remediation systems.  相似文献   

16.
Distribution, abundance and life history characteristics of Mysis relicta were studied in the Feldberg Lake District (Lake Breiter Luzin, Lake Schmaler Luzin, Lake Zansen) located in northeastern Germany. Between July 2001 and November 2002 mysids were collected by vertical net hauls. In order to determine the impact of the current trophic conditions on the distribution of mysids in these lakes, oxygen concentration, total phosphorus, chlorophyll a and water transparency were also measured. All investigated lakes are mesotrophic at present. Lake Breiter Luzin exhibited great seasonal and spatial variations in mysid abundance. Density of adults and juveniles had a mean of 44.9 ± 57.1 and 68.7 ± 99.6 m−2, respectively. Highest abundance of adults was 110.4 ± 76.5 m−2 in summer, lowest abundances of 2.0 ± 4.0 m−2 occurred in spring. For juveniles, highest density of 218.4 ± 174.6 m−2 was detected in summer and lowest of 0.8 ± 1.8 m−2 in winter. No mysids were caught in any of the daytime hauls, but they were widely distributed throughout the water column at night. Size frequency distribution of mysids suggested that reproduction occurred year-round, the most consistent influx of juveniles occurred in early summer and a smaller second cohort in autumn. Highest mysid abundance was 189.2 ± 318.6 adults and 127.0 ± 66.3 juveniles m−2 in Lake Schmaler Luzin, and 59.6 ± 5.6 adults and 79.4 ± 11.2 juveniles m−2 in Lake Zansen. There were great spatial differences in abundance in both lakes.  相似文献   

17.
The upcoming deployment of satellite-based microwave sensors designed specifically to retrieve surface soil moisture represents an important milestone in efforts to develop hydrologic applications for remote sensing observations. However, typical measurement depths of microwave-based soil moisture retrievals are generally considered too shallow (top 2–5 cm of the soil column) for many important water cycle and agricultural applications. Recent work has demonstrated that thermal remote sensing estimates of surface radiometric temperature provide a complementary source of land surface information that can be used to define a robust proxy for root-zone (top 1 m of the soil column) soil moisture availability. In this analysis, we examine the potential benefits of simultaneously assimilating both microwave-based surface soil moisture retrievals and thermal infrared-based root-zone soil moisture estimates into a soil water balance model using a series of synthetic twin data assimilation experiments conducted at the USDA Optimizing Production Inputs for Economic and Environmental Enhancements (OPE3) site. Results from these experiments illustrate that, relative to a baseline case of assimilating only surface soil moisture retrievals, the assimilation of both root- and surface-zone soil moisture estimates reduces the root-mean-square difference between estimated and true root-zone soil moisture by 50% to 35% (assuming instantaneous root-zone soil moisture retrievals are obtained at an accuracy of between 0.020 and 0.030 m3 m−3). Most significantly, improvements in root-zone soil moisture accuracy are seen even for cases in which root-zone soil moisture retrievals are assumed to be relatively inaccurate (i.e. retrievals errors of up to 0.070 m3 m−3) or limited to only very sparse sampling (i.e. one instantaneous measurement every eight days). Preliminary real data results demonstrate a clear increase in the R2 correlation coefficient with ground-based root-zone observations (from 0.51 to 0.73) upon assimilation of actual surface soil moisture and tower-based thermal infrared temperature observations made at the OPE3 study site.  相似文献   

18.
From December 1997 to December 1998, benthic algal biomass and the input of allochthonous coarse particulate organic matter (CPOM) were investigated in bi-weekly intervals at two sampling stations (shaded and sunny) of the Weidlingbach, a fourth order sandstone stream in the Wienerwald. A total of 41 benthic algal taxa was collected, belonging to the groups Cyanobacteria (4 taxa), Bacillariophyceae (33), Rhodophyta (1), Chrysophyceae (1) and Chlorophyta (2). At the shaded site, periphyton dry mass ranged from 13 g m−2 in April to 440 g m−2 in August (annual mean = 93 g m−2), at the sunny site from 3 g m−2 in May to 512 g m−2 in late fall (annual mean = 70 g m−2). Based on the algal carotenoid pattern, Bacillariophyceae were most abundant in fall and winter while Chlorophyceae dominated during summer. Mean annual standing stock of chlorophyll-a was 8.65 μg cm−2 at the shaded station and 7.53 μg cm−2 at the sunny site. Annual allochthonous CPOM input rates ranged from 382 to 665 g dry mass m−2 for aerial input and from 1006 to 1062 g DM m−1 of stream length for lateral input. Lateral input rates were influenced by the bank inclination; the temporal distribution of aerial input showed an autumnal maximum (61-65% of the total). Direct CPOM input was significantly highest (P<0.05) during the period of defoliation from October to November. In the course of this period, 61.1% (shaded) to 64.9% (sunny) of the annual CPOM dropped into the brook, yielding daily input rates of 6.6 to 4.0 g DM m−2. From December to September, daily direct input rates decreased to 0.84 g DM m−2 (shaded) and 0.44 g DM m−2 (sunny). At both sites, retention capacity was high; 70% of marked leaves released along transects were retained by coarse sediment particles within 40 m from the starting point. The annual mean of periphyton dry mass made up 52% of CPOM standing stock at the shaded site and 39% at the sunny site.  相似文献   

19.
为探究长江中下游富营养化浅水湖泊的浮游植物初级生产力季节性演替特征及其驱动因子,本研究于2020年4月(春)、8月(夏)、10月(秋)及2021年1月(冬)对湖北长湖浮游植物进行采样调查,同时运用黑白瓶测氧法及VGPM模型估算法分别估算了其浮游植物生产力水平,并探究驱动初级生产力季节性变化的主要环境因子。结果显示,4个季节共鉴定出浮游植物194种,其中绿藻门(95种,49%)和硅藻门(40种,21%)居绝对优势地位;黑白瓶法测得浮游植物水柱总生产力(Pt)季节变化为:夏季((1841.24±345.93) mg C/(m2·d))>秋季((1324.14±208.34) mg C/(m2·d))>春季((847.50±247.72) mg C/(m2·d))>冬季((711.43±133.52) mg C/(m2·d)),其中M2站位在夏季采样时(2424.66 mg C/(m2·d))水柱总生产力最高;在垂直空间上,浮游植物总生产力(G...  相似文献   

20.
From 15 to 28 August in 2007, a Chaetoceros socialis bloom was detected in the Pearl River Estuary water with chlorophyll a concentration (Chl a) up to 30 mg m−3 and cell density up to 106 cells L−1. Time series of bio-optical measurements was obtained at a single site (114.29°E, 22.06°N) with the mooring of marine optical buoy. Light absorption properties of seawater experienced large variability throughout the algal bloom. Absorption by colored dissolved organic matter (CDOM) was one of the dominant optical components of the light absorption (30–70%) especially for pre- and post-bloom waters, and it tended to decrease with Chl a during the algal bloom. Absorption by phytoplankton was another dominant optical component (18–50%) and increased rapidly with Chl a. Phytoplankton and accompanying material played dominant roles in light absorption as indicated by the relationship between absorption coefficient and Chl a. At high pigment concentrations, water samples showed significantly lower specific phytoplankton absorption, compared with pre- and post-bloom conditions, with the specific phytoplankton concentration at 443 nm varied between 0.011 and 0.022 m2 mg−1 and that at 676 nm between 0.007 and 0.018 m2 mg−1; small values of blue-to-red ratio of phytoplankton were also observed. These lower values were associated with variations in phytoplankton size structure. Spectral variability of phytoplankton absorption and total absorption (not including the fixed background absorption by pure water itself) could be expressed as simple linear functions linking absorption at one wavelength to the absorption at the other wavelengths, with the slope of the relationship changing with wavelength. The absorption coefficients by non-algal particles and CDOM follow the general exponential functions with remarkably limited variability in the exponent with means of 0.0105 and 0.0166 nm−1, respectively. These spectral dependencies of absorption coefficients provide useful information for retrieving inherent optical properties from reflectance data in a remote-sensing context.  相似文献   

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