响应面法优化鱿鱼(Ommastrephes bartrami)皮胶原蛋白提取液脱色工艺

采用活性炭吸附法脱除鱿鱼(Ommastrephes bartrami)皮胶原蛋白提取液中色素,优化脱色条件,以进一步利用鱿鱼皮胶原蛋白。在确定该色素特征吸收波长为420 nm条件下,分别研究了活性炭添加量、脱色时间、溶液p H值和脱色温度对鱿鱼皮胶原蛋白液色素脱除效果影响。在单因素实验基础上,选择脱色时间30 min,进行活性炭添加量、溶液p H值、脱色温度三因素三水平BoxBehnken中心组合响应面分析试验。结果表明,活性炭吸附鱿鱼皮胶原蛋白液色素最佳条件为活性炭添加量4.2%,溶液p H值2.27,脱色温度35°C,该条件下鱿鱼皮胶原蛋白液的脱色率为45.6%,蛋白质和氨基酸损耗率分别为19.65%和22.93%。脱色后鱿鱼皮胶原蛋白的甘氨酸含量最高(136.02 mg/g,相对含量23.05%),谷氨酸、精氨酸和脯氨酸含量也较高,而半胱氨酸和蛋氨酸总量不到1%,符合水产蛋白氨基酸和I型胶原蛋白氨基酸特点。     

两种区域电离层拟合模型比较研究

建立了单基准站和多基准站的三角级数模型和多项式模型,设计了利用邻近站数据进行两种模型内外符合精度检验的方法,分析了两种模型在精度方面的差异。     

蒽与苯并[a]芘对海洋微藻致毒影响的比较研究

新月菱形藻 ,球等鞭金藻 870 1和亚心形扁藻 ,分别用不同浓度的蒽和苯并 [a]芘胁迫72 h,测定三种藻的生长速率 ,叶绿素 a含量。实验表明 ,三种微藻对蒽的敏感性由高到低依次为新月菱形藻、球等鞭金藻 870 1和亚心形扁藻 ,它们 72 h的半抑制浓度 EC50 分别是 0 .0 6 0 mg/L、0 .0 6 5mg/L和 0 .0 94 mg/L。而对苯并 [a]芘的敏感性由高到低依次为亚心形扁藻、新月菱形藻和球等鞭金藻 870 1,它们的 72 h· EC50 分别是 0 .0 76 mg/L、0 .0 88mg/L 和 >0 .10 mg/L(在本实验范围内未测到 )。叶绿素 a含量与各自的相对增长率呈一定的正相关。不同的海洋微藻对蒽和苯并 [a]芘的敏感性不同。     

硝基苯和间苯二酚对3 种海洋微藻的毒理效应

通过研究硝基苯和间苯二酚对海洋微藻的毒理效应,旨在提示化工废水污染对水环境破坏的严重性,揭示海洋微藻类净化废水的潜在应用。本试验用塔玛亚历山大藻(Alexandrium tamarense)、海链藻(Thalassiosira weissflogii)和绿色巴夫藻(Pavlova viridis)为供试藻种,以微藻生长量及叶绿素 a 的变化为参数,研究不同质量浓度的硝基苯和间苯二酚对3种海洋微藻的毒理效应。结果表明：硝基苯对塔玛藻和巴夫藻的生长具有一定的抑制作用,质量浓度为12mg/L时抑制率分别为22.9%和20.04%,但对海链藻的生长在一定程度上有促进作用。间苯二酚对海链藻和巴夫藻的生长具有抑制作用,质量浓度为12mg/L 时其抑制率分别为26.11%和23.6%,对塔玛亚历山大藻的生长有一定的促进作用。对塔玛亚历山大藻和巴夫藻而言,在硝基苯质量浓度为3mg/L 时,叶绿素 a 含量均达到最低,其叶绿素 a含量分别为对照组的68.6%和50.9%,对于海链藻,硝基苯对其叶绿素a的影响波动不大。间苯二酚对3种海洋微藻叶绿素 a 含量的影响为绿色巴夫藻>海链藻>塔玛亚历山大藻,其叶绿素 a 含量分别是对照组的1.1%,24.9%,88%。     

Diet of Littoraria scabra, while vertically migrating on mangrove trees: Gut content, fatty acid, and stable isotope analyses

The snail, Littoraria scabra, is a dominant grazer on tropical mangrove trees, and may play an important role in the food web dynamics of these ecosystems. Its daily vertical migration to avoid tidal submersion results in exposure to varying food types and abundances. A comprehensive diet analysis – gut contents, fatty acid profiles, and stable isotopes (δ¹⁵N and δ¹³C) – was conducted on snails migrating along mangrove trees and snails maintained in non-tidal mesocosms at Nananu-i-ra, Fiji Islands. In addition, fatty acid profiles and stable isotope signatures were obtained from surface scrapings of mangrove roots, trunks, branches, and leaves. Results from this multi-technique study indicate that L. scabra is mainly a generalist herbivore, which easily shifts diets depending on food availability, and which also has the ability to ingest and assimilate zooplankton. Ingestion of greater quantities of diverse foods (i.e., microalgae, foliose/corticated macrophytes, filamentous algae, mangrove tissues, zooplankton) takes place in the bottom areas of mangrove trees (roots and trunks) during low tides, while top areas (branches and leaves) provide limited food resources for snails feeding during high tides. However, snails preferentially assimilate microalgae and bacteria, regardless of their feeding habitat (different areas within mangrove trees and non-tidal mesocosms). The daily vertical movements of this snail result in variable feeding times, ingestion of different food types and amounts, and different assimilations. These findings also suggest that organic matter derived from mangrove tissues may not be readily transferred to higher trophic levels through this grazing pathway.     

Spectral reflectance measurements of estuarine waters

Shapes and variations of reflectance spectra in estuarine water were investigated for the purpose of monitoring chlorophyll in situ by optical means. A survey undertaken in an estuarine environment, using reflectance measurements between 400 and 850 nm with a full-width half maximum (FWHM) of about 2 nm, revealed that the first derivative in the neighbourhood of the chlorophyll absorption band shows a defined spectral region which can be used to estimate chlorophyll concentrations. Correlation between chlorophyll and the first derivative was found to be low, but a good relationship exists between the ratio of the reflectance R680/R670 and chlorophyll concentrations. Based on dissolved organic carbon measurements, it is assumed that chromophoric dissolved organic compounds mask the absorption band of chlorophyll in the blue part of the spectrum, resulting in a low correlation coefficient in that spectral range. Therefore, the use of the red bands is an alternative for measuring photosynthetic pigments in coastal water at longer wavelengths. Results presented here demonstrate that the spectral locations of bands in the visible are not adequate and that hyperspectral data are required for positioning the very narrow bands for measuring chlorophyll at longer wavelengths.     

应用TM数据估算沿岸海水表层时绿素浓度模型研究

本研究以大亚湾为实验区，以陆地卫星ＴＭ数据为信息源，结合表层海水叶绿素浓度实测资料建立模型。在对叶绿素光谱特征及遥感估算叶绿素浓度机理研究基础上，选取了ＴＭＩ—ＴＭ４波段的７５种波段组合为子因素，以叶绿素浓度为母因素，利用灰色系统理论，分析各波段组合与叶绿素浓度之间的关联度。将关联度最大的５种波段组合分别建模，得到５个估算表层海水叶绿素浓度的反演模型。误差分析表明，各模型的最大相对误差在１９％以下，平均绝对相对误差在１１．２％以下，相对标准误差在６．７％以下，模型精度较高。研究表明：（ＴＭ３×ＴＭ４）是估算沿岸海水表层叶绿素浓度的最佳波段组合，采用（ＴＭ３×ＴＭ４）与ＴＭ１、ＴＭ２或ｌｎ（ＴＭ十ＴＭ２）、Ｉｎ（ＴＭ１×ＴＭ２）之比值并不能改善估算精度。     

北部湾海域叶绿素a质量浓度时空分布研究

叶绿素a质量浓度是水体富营养化的重要指标,及时和有效地对水体叶绿素a质量浓度进行监测和评价,对环境保护十分必要。本文基于2011年至2016年的卫星遥感数据,分析了北部湾海表叶绿素a质量浓度的时空分布特征。研究结果表明:北部湾叶绿素a质量浓度有明显的月变化和季节性变化,北部湾叶绿素a月平均质量浓度在8月和1月分别达到峰值,北部湾冬季与夏季的叶绿素a季平均质量浓度高于春季和秋季,夏季北部湾海域表层的叶绿素a质量浓度开始迅速升高,秋季北部湾中南部叶绿素a质量浓度呈下降的趋势。在空间分布上,北部湾近岸海域叶绿素a质量浓度平均水平较高,叶绿素a质量浓度高值区集中在湾北部雷州半岛西部沿岸的浅水区海域,而低值区在湾中部以及湾南部的深水区海域。     

Towards a more ecologically relevant assessment of the impact of heavy metals on the photosynthesis of the seagrass, Zostera capricorni

This in situ study used photosynthetic activity (measured as chlorophyll a fluorescence) and photosynthetic pigment concentrations to assess the effect of copper, cadmium, lead and zinc on the seagrass Zostera capricorni. Custom-made portable in situ exposure (PIE) chambers were developed so seagrasses could be dosed within the meadow. Z. capricorni was exposed to 0.1 and 1 mg l⁻¹ of metal solutions for 10 h. During this time and for the subsequent four-day recovery period, the effective quantum yield of photosystem II (PS II) (ΔF/Fm^′) was measured. While the results were variable, copper and zinc exposed samples had a depressed ΔF/Fm^′ during the exposure period. Samples exposed to zinc recovered to pre-exposure levels but those exposed to copper did not. Cadmium and lead did not impact on the chlorophyll a fluorescence and the chlorophyll pigment data supported these findings. This study presents an innovative new application of chlorophyll a fluorescence stress assessment.     

Diets of alpine galaxias (Galaxias paucispondylus Stokell) and longjawed galaxias (G. prognathus Stokell) in a South Island,New Zealand,high‐country stream

Thedietsofthealpinegalaxias(Galaxias paucispondylus Stokell, 1938) and the longjawed galaxias (G. prognathus Stokell, 1940) were studied in Deep Creek, a high‐country stream in the central South Island of New Zealand. Both species are small, slender fish with entirely freshwater life cycles. Their diets were very similar and consisted of aquatic invertebrates, dominated by the larvae of Deleatidium spp. (Ephemeroptera), Hydrobiosis spp. (Trichoptera), and Chironomidae (Diptera). Although diets partly reflected what was available in the stream, both fish selected soft‐bodied prey in preference to cased or harder shelled prey. Both species are probably nocturnal feeders.