光强度对附着在玻片上的幼鲍饵料生物的影响

幼鲍初期饵料生物在玻片上附着生物量的消长与光强度的关系进行了试验。光强度超过2500Lux时微生物膜增长较快，膜脱落较早多光强度低于1000Lux时微生物膜净生产量较依；光强度在1500－2000Lux时有利于膜生物量的积累。舟形藻和菱形藻的纯培养在玻片上附着的生物量呈稳定性高速增长并能延迟生物膜脱落现象的发生．     

Remote sensing of particle backscattering in Chesapeake Bay: A 6-year SeaWiFS retrospective view

Traditional field techniques to monitor water quality in large estuaries, such as boat-based surveys and autonomous moored sensors, generally provide limited spatial coverage. Satellite imagery potentially can be used to address both of these limitations. Here, we show that satellite-based observations are useful for inferring total-suspended-solids (TSS) concentrations in estuarine areas. A spectra-matching optimization algorithm was used to estimate the particle backscattering coefficient at 400 nm, b_bp(400), in Chesapeake Bay from Sea-viewing Wide-Field-of-view Sensor (SeaWiFS) satellite imagery. These estimated values of b_bp(400) were compared to in situ measurements of TSS for the study period of September 1997–December 2003. Contemporaneous SeaWiFS b_bp(400) values and TSS concentrations were positively correlated (N = 340, r² = 0.4, P < 0.0005), and the satellite-derived b_bp(400) values served as a reasonable first-order approximation for synoptically mapping TSS. Overall, large-scale patterns of SeaWiFS b_bp(400) appeared to be consistent with expectations based on field observations and historical reports of TSS. Monthly averages indicated that SeaWiFS b_bp(400) was typically largest in winter (>0.049 m⁻¹, November–February) and smallest in summer (<0.031 m⁻¹, June–August), regardless of the amount of riverine discharge to the bay. The study period also included Hurricanes Floyd and Isabel, which caused large-scale turbidity events and changes in the water quality of the bay. These results demonstrate that this technique can provide frequent synoptic assessments of suspended solids concentrations in Chesapeake Bay and other coastal regions.     

Use of Cell-Specific PAM-Fluorometry to Characterize Host Shading in the Epiphytic Dinoflagellate Gambierdiscus toxicus

Abstract. Cell‐specific fluorescence characteristics were used to characterize the light tolerance of the toxic benthic dinoflagellate Gambierdiscus toxicus. The fluorescence parameter F_v : F_m was measured using pulse amplitude modulation (PAM) fluorometry on individual cells collected from foliose red algae growing in the sub‐tidal margin of South Water Cay, Belize. Samples were collected over several days during sunny and cloudy conditions and compared to samples incubated in situ. The data from individual cells were used to generate both F_v : F_m frequency histograms and averages. Maximum individual cell values of F_v : F_m reached 0.81 in pre‐dawn samples, a value near the theoretical maximum for PAM fluorometry. In field samples from macroalgal hosts, average F_v : F_m values declined only slightly during the day, but cells incubated in bottles under 47 % incident sunlight showed a significant mid‐day depression. In freshly collected samples, near‐maximum F_v : F_m values could be found in individual cells during the entire day; however, the frequency histograms indicated a greater range in F_v : F_m values during the afternoon than in the morning. In contrast, cultures of G. toxicus showed a tight distribution around a mean. Field samples showed a rapid recovery to near‐maximum F_v : F_m within 2 min when assayed using a standardized actinic light series. Similar results were obtained in laboratory cultures of G. toxicus grown at 73 µmol photons · m^‐2 · s^‐1, but not at 383 µmol photons · m^‐2 · s^‐1. These data provide empirical support for suggestions that G. toxicus exploits the three‐dimensional structure of the algal host thallus to minimize light exposure. This strategy permits G. toxicus, a high‐light intolerant species in culture, to thrive in shallow, well‐lit tropical seas. It may also partially explain the observed preference of G. toxicus for complex, foliose macroalgae as hosts.     

Mineral provinces and material provenance of the surficial sediments near the Zhongsha Islands in the South China Sea

1 IntroductionThe South China Sea is one of the northwesternPacific marginal basins, which is located atthe junc-tion region among Euro-Asia plate, Pacific plate andIndia plate. Owing to its unique geological charac-teristics, the South China Sea has beco…     

风云一号遥感器可见光通道大气程辐射之间的关系

本文利用光谱辐射计测量的大气程辐射资料,研究了相应于“风云一号”卫星上改进型甚高分辨率扫描辐射计(CAVHRR)4个可见光通道的大气程辐射量(N_a)之间的关系。结果表明它们满足((N_a(λ))/(N_a(λ_0)))=A(λ/λ_0)~B的关系。 经回归分析得:A为1.0887,B为3.6587。式中λ_0是CAVHRR第二通道的中心波长,即λ_0=0.875μm,λ是CAVHRR其他3个通道中心波长。     

Seasonal occurrence and growth of benthic algae in the Patos Lagoon estuary, Brazil

The seasonal occurrence of 94 benthic algal species, including Cyanophyta, was observed on a monthly basis over one year in the Patos Lagoon estuary (32°S, 52°W), Brazil, and showed three patterns of algal periodicity. An aseasonal group of 46 species was present throughout the year and two groups of 24 species each occurred either during summer and fall or winter and spring. The seasonal growth of 55 green, brown and red algae was correlated with monthly variations of salinity, water temperature, daylength and light radiation energy, which were measured daily in the estuary. Summer/fall peak growth was observed in 15 algae most of which correlated significantly with high salinities alone or in combination with other factors during this period. Growth peak of 11 species in winter/spring was principally a function of low water temperatures alone or together with a reduced light regime.Both periodicity of benthic algae and their seasonal growth, as a more sensitive measure of their floristic affinity, demonstrated the presence of cool temperate and tropical elements in this flora typical for warm temperate biogeographic regions. Correlations between seasonal variation of algal growth and selected environmental parameters aided in the evaluation of causal factors for algal seasonality.     

天然含铁闪锌矿的可见光催化还原活性研究

通过电子探针(EMPA)、X射线光电子能谱(XPS)、漫反射谱(DRS)、光致发光谱(PL)、透射电镜(TEM)、扫描电镜(SEM)和霍尔效应(Hall-effect)等测试手段对天然闪锌矿样品的半导体物理化学性能进行了表征分析。分析结果认为,天然闪锌矿良好的可见光响应性能主要源自其晶格内丰富的类质同像替代离子。此外,样品中的变价元素Fe能够参与价带光生空穴的捕获,提高导带光生电子的利用率,从而提高其光催化活性。样品中丰富的缺陷也有利于光催化活性的提高,大量的解理面和裂开面能够提供较完整的晶面增加反应活性点位,空位缺陷和晶格膨胀畸变等可以提高光生电子空穴对的分离效率。与其特殊的物理化学性质相符,天然闪锌矿光催化还原降解甲基橙的实验证明了其较高的可见光催化还原活性。本研究结果也预示着天然半导体矿物闪锌矿作为一种新的低成本、高效率的可见光催化材料将在环境污染治理领域具有一定的应用前景。     

塔里木盆地一次浮尘天气的卫星云图特征

根据常规气象观测资料、GMS-5静止气象卫星的红外云图和可见光图像，分析了1999年4月25至5月4日塔里木盆地浮尘天气。分析结果表明，红外云图和可见光图像能够监测盆地浮尘的变化，浮尘呈灰色，纹理均匀，边界清晰。浮尘区的TBB在0～-15℃之间变化，与地面能见度有着较好的对应关系，大范围浮尘区的反射率在30％～36％之间，浮尘区反射率等值线稀疏，云区反射率等值线密集。