Effects of land-based sources on water quality in the Omerli reservoir (Istanbul,Turkey)     

Enis Morkoç  Vildan Tüfekçi  Huseyin Tüfekçi  Leyla Tolun  Fatma Telli Karakoç  Tuğba Güvensel 《Environmental Geology》2009,57(5):1035-1045

The Omerli reservoir is located on the northeastern side of the Istanbul City. It is one of the most important sources of drinking water with a surface area of 23.1 km² and a volume of 220 × 10⁶ m³ in the Marmara Region. Water quality characteristics of the lake investigated from May 2002 to April 2003 enabled us to identify the effect of waste loads on water quality of Omerli Lake. The following parameters were measured in the lake water: temperature (16.1°C), conductivity (250 μS/cm), secchi disk depth (1.9 m), dissolved oxygen (DO) (9.36 mg/L), nutrients [ortho-phosphate (78.9 μg/L), nitrate + nitrite (707.5 μg/L) and ammonia-nitrogen (264 μg/L)], chlorophyll a (9.43 μg/L), total organic carbon (3.33 mg/L), total suspended solids (4.54 mg/L), total poly aromatic hydrocarbon (t-PAH) (0.69 μg/L) and copper (24.5 μg/L). T-PAH (16.5 mg/g-dry-w), Cu (96.5 μg/g-dry-w), organic carbon (org-C) (2.0%) and N (0.44%) were determined in the surface sediment. The values of chlorophyll a and DO in the upper layer were relatively high and low secchi disk depths indicates eutrophic state. There are five channels discharging water, including waste water, into the lake. All channels were sampled during six occasions in order to cover variations between seasons. The following parameters were measured: total organic carbon, total phosphorus, total kjeldahl nitrogen, ammonia and total suspended solids with the flow rates. The Göçbeyli stream has the highest flow into the lake (1.5 × 10⁸ m³/year) but most of the nutrients were discharged from the Pa?aköy channel. It is accounting for 81% of ammonia and 80% of total phosphorus into the lake. Three scenarios were run using AQUATOX model: (1) all existing inflows are discharging into the lake (present situation); (2) none is discharging; (3) all are discharging except the Pa?aköy channel. The first scenario produced concentrations consistent with measurements in the lake. In all stations, a phytoplankton peak value was predicted during November and December 2002, and January 2003. In the second scenario, as expected, a significant decrease in the concentrations was predicted. In the third scenario, a small improvement in the water quality was obtained. To significantly improve the state of the lake, instead of entering Pa?aköy channel, wastewater should bypass the lake.  相似文献   

Vertical and horizontal distribution of fluorescent dissolved organic matter in the Southern Ocean   总被引：3，自引：0，他引：3  

Youhei Yamashita  Ayumi Tsukasaki  Tamihito Nishida  Eiichiro Tanoue 《Marine Chemistry》2007,106(3-4):498-509

The vertical and horizontal distribution of fluorescent dissolved organic matter (FDOM), determined by fluorescence intensity at 320 nm excitation and 420 nm emission, were clarified in nine stations on two transects at the Southern Ocean, including a subtropical, subantarctic, polar frontal and Antarctic zone. All vertical profiles of fluorescence intensity showed that levels were lowest in the surface waters, increased with increasing the depth in mid-depth waters ( 2000 m), and then stayed within a relatively narrow range from there to the bottom. Such vertical profiles of FDOM were similar to those of nutrients, but were adverse to dissolved oxygen. In water columns below the temperature-minimum subsurface water (dichothermal waters) in the Antarctic zone and below the winter mixed layer in the other zones, we determined the relationships of fluorescence intensity to concentrations of nutrients and apparent oxygen utilization (AOU) over the entire area of the present study, and found significant linear correlations between the levels of fluorescence intensity and nutrient concentrations (r =  0.70 and 0.71 for phosphate and nitrate + nitrite, respectively) and AOU (r = 0.91). From the strong correlation coefficient between fluorescence intensity and AOU, we concluded that FDOM in the Southern Ocean is formed in situ via the biological oxidation of organic matter. The regeneration of the nutrients/consumption of the oxygen/formation of FDOM was active in mid-depth waters. However, the correlations between fluorescence intensities and nutrients and AOU were different in the mid-depth water masses, Subantarctic Mode Water (SAMW), and Antarctic Intermediate Water (AAIW), indicating that the sources of organic matter responsible for FDOM formation were different. A considerable amount of FDOM in the SAMW is thought to be produced by the remineralization of DOM in addition to sinking particulate organic matter, while DOM is less responsible for FDOM formation in the AAIW.  相似文献   

《向阳红九号》调查船的空气微生物     

陈皓文  王波 《海洋科学进展》1997,(2)

本文对《向阳红九号》调查船做了空气微生物的监测，结果表明：平均全船舱内空气微生物总量、空气真菌含量、空气真菌量占空气微生物总量的百分数分别是３７３０．９ＣＦＵｍ－３，１６８．１ＣＦＵｍ－３和１５．３×１０－２。尚未超过国家对客船规定的卫生标准，但有２１×１０－２的测定结果已超标。两次测定间的差异主要由空气扰动状况所致；层间及舱室间的差异是因人员工作生活习惯等造成的。结果还表明，较好条件的上层乃至全船舱室大有改善环境卫生条件的必要。  相似文献   

The water quality of the Ria de Aveiro lagoon, Portugal: from the observations to the implementation of a numerical model   总被引：1，自引：0，他引：1  

Lopes JF  Dias JM  Cardoso AC  Silva CI 《Marine environmental research》2005,60(5):594-628

  相似文献   

Effects of point-source nutrient addition and mussel removal on epibiotic assemblages in Perumytilus purpuratus beds   总被引：2，自引：0，他引：2  

Nelson Valdivia  Martin Thiel   《Journal of Sea Research》2006,56(4):271-283

The objective of this study was to evaluate the effects of point-source nutrient addition and mussel removal on species diversity of the epibenthic assemblage of the purple mussel Perumytilus purpuratus. It was hypothesised that mussels cushion the effects of disturbance on the associated organisms and thereby favour species diversity in patches with added nutrients. In order to test this hypothesis, a two-factorial field experiment was conducted at an exposed rocky shore of northern-central Chile in which nutrient addition and mussel removal were manipulated with two levels. Experimental units consisted of 100-cm² mussel plots that were sampled after two months of experimental manipulations. Local nutrient addition was done with coated slow-release fertilisers. Mussel removal treatments consisted in three destructive events applied throughout the experimental phase, and each event consisted in the removal of 20% of the mussel biomass from each plot. While point-source nutrient addition had only minor effects on diversity, mussel removal had significant and negative effects on faunal species richness and the abundance of suspension-feeders and sessile organisms. The abundance of predators/scavengers significantly decreased with mussel removal in the presence of nutrient addition. Grazers and mobile organisms were very abundant in the mussel assemblage but their abundance remained unaffected by treatments. Finally, species richness and total abundance of algae were also not affected by the treatments. Although the duration of our experiment was relatively short, we suggest that the effects of local nutrient addition are of minor importance at the study site in comparison to the effects of mussel removal. Based on our results and previous studies conducted in soft-bottom systems, we suggest that physical and biological stress acting on exposed hard-bottom communities overshadows the potential effects of local nutrient addition.  相似文献   

沉积物中营养盐对大鹏湾赤潮影响的初步探讨     

杨炼锋  李锦蓉  余汉生 《海洋与湖沼》1995,26(S1):83-87

1991年3月中旬在南海大鹏湾海域用小型箱式采泥器采集了0－2cm和5－7cm层的样品。对所采样品用比色法测定了沉积物中可被交换的溶解态营养盐含量。分析结果表明：表层沉积物中可被交换的活性磷酸盐含量很高，N／P值很低。另外，根据同时采集的水样分析结果：水体中活性磷酸盐的浓度很低，且N／P值很高。1992年3月的调查结果又证实：在上覆水中活性磷酸盐的浓度很高，且N／P值很低。因此，我们认为进一步研究表层沉积物和上覆水中活性磷酸盐对水体的供给与大鹏湾赤潮的关系对研究大鹏湾赤潮的成因有重要意义。  相似文献   

长江干流营养盐通量的初步研究   总被引：34，自引：4，他引：34  

沈志良 《海洋与湖沼》1997,28(5):522-528

分别于1988年2月（冬季）和1986年6月（夏季）利用比色法对长江干流上游至河口水中营养盐进行测定，根据所测定的营养盐含量和长江径流量计算营养盐通量。结果表明，冬季重庆至河口长江水中NO3－N，NH4-N，TIN，PO4-P和SiO3-Si的平均浓度分别为52.2±66μmol／L，51.8±16.9μmol／L，105.3±11.4μmol／L，0.55±0．06μmol／L和75.2±23.6μmol／L.夏季NO3-N,NH4-N,TIN和SiO3-Si的平均浓度分别为69.0±17.0μmol／L,4.0±1.7μmol／L，73.3±15.6μmol／L和55.8±16.4μmol／L。冬季营养盐通量（除NO2－N外）自上游至下游逐渐增加，它们主要来自中、下游流域。夏季NO3－N，TIN和SiO3－Si通量从上游至下游也有明显的增加趋势，NO3－N和TIN，上游和中、下游几乎各占一半，SiO3-Si主要来自中、下游。夏季NO3－N，TIN，PO4－P和SIO3－Si通量明显高于冬季。  相似文献   

Nutrient fluxes from deep sediment support nutrient budget in the oligotrophic waters of the Gulf of Aqaba     

Mohammed Rasheed  Saber Al-Rousan  Riyad Manasrah  Fuad Al-Horani 《Journal of Oceanography》2006,62(1):83-89

The role of deep sediment in supporting nutrient budget in the Gulf of Aqaba has been investigated by estimating the flux of inorganic nitrogen, phosphate and silicate. Fluxes were calculated directly by pore water profiles and indirectly by chamber incubations carried out onboard the RV Meteor cruise. The results showed that maximum potential fluxes calculated by chamber incubations were higher than those calculated by porewater profiles for all nutrients (6.4–28.5 fold). This has been attributed to the additional flux due to bioturbation and flux from advective porewater exchange in the case of chamber incubation, while porewater fluxes represent diffusive ones. Using a rough estimation considering flux results in addition to the sediment area and water mass of the Gulf of Aqaba, we estimate that 3.3 × 10⁵, 6.4 × 10⁴ and 6.5 × 10⁶ kg year⁻¹ of inorganic nitrogen, phosphate and silicate respectively are effused from deep sediments to the water column. This quanitity would certainly support the primary productivity in the oligotrophic water in the Gulf of Aqaba.  相似文献   

龙须菜（Gracilaria lemaneiformis）在营养限制胁迫后对NH4-N的超补偿吸收研究   总被引：3，自引：0，他引：3  

李大鹏  林贞贤 《海洋与湖沼》2005,36(4):307-312

采用营养限制胁迫处理的方法,研究龙须菜对NH4-N的超补偿吸收现象.龙须菜在低营养限制胁迫(饥饿)下培养10天后,恢复营养盐培养3天,测定其对NH4-N吸收速率.N吸收实验结果表明,对NH4-N(采用靛酚蓝分光光度法测定)表现出较强的超补偿吸收能力.与持续正常培养的对照组和持续受高浓度营养盐胁迫的处理组比较,各组在培养第一天时对NH4-N的吸收速率差异明显,饥饿处理组最高为17.73μmol/(g·h),对照组最高为12.25μmol/(g·h),高营养盐处理组最高只有6.12μmo1/(g·h).随着培养时间的推移,对照组与处理组之间的差异逐渐减小,培养到第三天时吸收速率趋于一致.而各组对NO3-N(采用锌镉还原萘乙二胺分光光度法测定)的吸收速率都很小,最高为饥饿处理组只有1.49μmol/(g·h),说明龙须菜优先选择吸收NH4-N.实验结束后称重发现对照组、饥饿处理组和饱和组生长率(SGR)分别为5.85%、5.44%、5.02%,ANOVA方差分析表明,三者存在显著差异(P=0.0046＜0.05),证实大型海藻也存在超补偿生长的现象.  相似文献   

Impact of the 1997–1998 El Niño and 1999 La Niña on nutrient supply in the Gulf of Alaska     

F. A. Whitney  D. W. Welch 《Progress in Oceanography》2002,54(1-4)

Nutrient surveys of the Gulf of Alaska, from 1997 through 1999, show that coastal waters of British Columbia and southern Alaska experienced nitrate depletion each spring and summer. Through the 1997–1998 El Niño, waters with less than 1 μM NO₃ covered 250,000 km² area greater than 1999. Silicate levels as low as 0.2 μM were observed in coastal waters, suggesting that diatom growth may have been nutrient limited both in 1998 and 1999. Detailed sampling off the southern coast of British Columbia revealed that 1998 nitrate levels were only half the average of that during the 1970s winter, were depleted 1 month earlier in spring and remained low throughout the summer. Satellite images show that, compared to 1997 and 1999, chlorophyll levels were much lower in the spring of 1998 throughout the coastal waters of the Gulf of Alaska. Conditions changed dramatically during the 1999 La Niña, with ocean-mixed layer depths increasing by 20 m in winter and 40 m in spring when compared to that during 1997–1998 El Niño. Winter nutrient levels increased and summer upwelling returned. Over the past several decades, a trend towards greater stratification of coastal waters appears to be affecting the supply of nutrients to the mixed layer. The effects of stratification were especially obvious during the 1998 El Niño.  相似文献