栉孔扇贝对无机砷的富集与排出特征研究

以栉孔扇贝(Chlamys,farreri)为试验生物,应用生物富集双箱动力学模型,研究了暴露在不同质量浓度的As<'3+>溶液中,栉孔扇贝对无机砷的耐受性;通过对富集与排出过程中栉孔扇贝体内无机砷含量的动态监测及对检测结果的非线性拟合,得出栉孔扇贝富集无机砷的吸收速率常数(k<,1>)、排出速率常数(k<,2>)、生...     

Combined effects of light intensity and NH^＋4-enrichment on growth,pigmentation, and photosynthetic performance of Ulva prolifera （Chlorophyta）

The aim of this study was to investigate the effects of light intensity and enhanced nitrogen supply on the growth and photosynthesis of the green-tide macroalga, Ulva prolifera. Thalli of U. prolifera were grown in natural or NH 4 +-enriched seawater under two different light intensities for 7 days, and then the growth rate, pigmentation, and photosynthetic performance of the thalli were evaluated. The results show that the relative growth rate(RGR) was markedly higher under the high light level than under the low light level. Enrichment with NH 4 + enhanced the RGR under high light intensity, but did not affect RGR under low light intensity. In low light conditions, NH 4 +-enrichment resulted in a marked decrease in the maximal photosynthetic rate( P m) and the maximum carbon fixation rate( V max), but it did not affect the half saturation constant for carbon( K 0.5) or the ratio of V max to K 0.5, which reflects the carbon acquisition efficiency. In high light conditions, P m, K 0.5, and the dark respiration rate( R d) increased under NH 4 + enrichment, but V max and the V max / K 0.5 ratio decreased. Regardless of the light intensity, NH 4 +-enrichment did not affect the apparent photosynthetic efficiency( α), which refl ects the ability of the alga to use light energy at low light levels. Under both low and high light intensities, the chlorophyll a(Chl a), chlorophyll b(Chl b), and carotenoids(Car) contents in thalli were higher in NH 4 +-enriched than in natural seawater, except that there was a decrease in the Chl b content of thalli in NH 4 +-enriched seawater under low light intensity. Therefore, NH 4 + enrichment improved the growth and photosynthetic performance of U. prolifera under high light intensity, but not under low light intensity. We discuss the possible mechanisms underlying these physiological responses.     

栉孔扇贝对镉的富集及释放规律的研究

通过暴露染毒方法研究了栉孔扇贝对镉离子(Cd2+)的35d富集与30d释放规律。结果表明:栉孔扇贝对镉有很强的富集性,体内的镉含量与暴露溶液里的Cd2+浓度呈正相关;栉孔扇贝对镉的释放速率随着暴露水体中镉浓度的增加而减慢。应用双箱动力学模型,通过非线性拟合得到了栉孔扇贝对Cd2+的吸收速率常数k1随着外部水体中镉浓度的增大而减小,生物富集系数BCF则随着外部水体中镉浓度的增大而减少。当镉浓度为0.05mg/L时BCF仅为3 730,而当镉浓度为0.000 5mg/L时BCF达到1.79×1011。平衡状态下栉孔扇贝体内镉含量(CAmax)随着水体中镉浓度增加急剧下降,与水体中镉浓度呈负相关;排出速率常数k2、生物学半衰期B1/2与低浓度镉无明显相关性,随着镉浓度的增大k2显著降低而B1/2显著增大。验证了双箱动力学模型适用于栉孔扇贝对Cd2+的生物富集与释放规律研究。     

石花菜的筏式施肥养殖试验

石花菜是一种广泛分布于我国北方沿海的经济海藻。它既生长于营养盐丰富的海区,也能呈大群落地分布于营养盐含量少的海区。因而人们认为石花菜是一种耐低氮的海藻。经过1981—1983年在黄渤海沿岸十几个点试养结果表明,秋季海洋中营养盐含量较高,石花菜生长良好,而同一海区的春季,营养盐含量较少,石花菜的颜色变淡,呈淡黄或黄绿色,藻体纤细,重量较     

室内受控条件下对虾养殖环境综合生物修复技术研究

本研究在室内受控条件下,在虾、贝、藻的多池内循环养殖的基础上,采用残饵污染控制技术减少残饵生成量,并针对对虾养殖中产生的主要目标污染物质及其存在形态,镶嵌以相应的生物修复技术,探讨了综合生物修复技术对对虾养殖生态系统自身污染的修复效果。研究结果表明:采用虾、贝、藻及生物滤池综合生物修复技术可有效降低养殖水体中的悬浮物、溶解无机碳和溶解有机碳的含量。残饵即时修复技术可显著减少残饵生成量,但梭鱼和沙蚕对沉积物的扰动作用对综合生物修复效果产生了一定的负面影响。综合生物修复技术中大型藻类对水体中溶解无机氮的修复能力略显不足,在实际修复过程中需充分考虑大型藻类固氮速率和系统内生物排氮速率的平衡关系,并确保能满足大型藻快速生长最佳的水层空间。单靠微生物滤池对水体中有机物的修复能力并不理想,需辅助增加泡沫分离等技术,提高系统对大分子胶体的去除能力。本研究为进一步构建现场对虾养殖环境的综合生物修复技术体系奠定了基础。