Small-scale variations in mussel (Mytilus spp.) dynamics and local production

A mussel bed was sampled monthly at four intertidal levels (mid: 2.15; mid-low: 1.65; low: 1.2 and sublittoral fringe: 0.7 m from chart datum) from July 1979 to July 1980 at Pointe-Mitis in the St. Lawrence estuary. A strong spring reduction of abundance (both in density and biomass) suggested that the mussel bed was being degraded. Community perturbation was attributed to ice scour. Partial reestablishment of the mussel bed (all age classes) was observed during late spring and early summer and occurred mainly at the mid-low intertidal level. Changes in the size structure of the mussel bed with level suggest that the annual windstorm regime may be an important factor in the dynamics of the bed. Mean body mass decreased at the three lower shore levels but increased at the highest shore level. Overall, net secondary production (assessed by the increment-summation method) was negative due to the decrease in mean body mass. Annual production rates (kJ m⁻² y⁻¹) from the mid intertidal level to the sublittoral fringe were 1130, − 4072, − 4013 and − 3258, respectively, while P/B ratios (y⁻¹) were 0.17, − 0.69, − 0.50 and − 0.45. The calculated production and the productivity (potential production) are compared and used to provide insight into the condition of the mussel bed.     

Oestrogenic markers and reduced population fertile egg production in a sand goby partial life-cycle test

Understanding the ecological significance of oestrogenic biomarker responses, seen in field surveys of some UK estuarine fish, requires a suitable model to link biochemical and reproductive effects. The sand goby (Pomatoschistus minutus) is a common inshore fish that has been successfully bred in laboratory aquaria. Juvenile sand goby were continuously exposed to 17beta-oestradiol (E2) during gonadal maturation, and their subsequent reproductive success investigated. Exposure endpoints included hepatic vitellogenin (VTG) mRNA expression and maturation (male nuptial colouration, sperm duct gland- and gonado-somatic indices (SDGSI, GSI)). Reproductive endpoints included spawning behaviour, brood size, fertility and population-level fertile egg production. Measured E2 exposure concentrations were <5 (controls), 17, 71 and 530 ngl(-1). Male maturation decreased with increasing E2 concentration. VTG mRNA expression increased with E2 concentration, but not with duration of exposure. Reproductive endpoints showed progressive impairment with increasing E2 concentration. For most endpoints, the lowest observed effect concentration (LOEC) was 71 ngl(-1), and EC50s were in the range 87-165 ngl(-1). Pre-breeding male colouration, VTG expression and SDGSI were good predictors of subsequent population-level fertile egg production, but GSI was not. The sensitivity of oestrogenic markers in sand goby are comparable to those used in other species, and feral fish populations exhibiting such oestrogenic responses at molecular and organ levels are likely to have reduced fertile egg production.     

南海大鹏湾夜光藻种群生态及其赤潮成因分析

分析了１９９０年３月－－１９９２年６月南海大鹏湾夜光藻种妲民环境因子之间的动态关系。研究发现，夜光藻的生存水温的高限可达２８．６℃左右，但其最适不温范围为２０－２２℃而适温范围可扩到１６－２５℃。所以，每年夏季高温季节，大鹏湾的夜光藻因无法忍受高温（３０℃）而自然死亡，秋季再由外洋海流将其营养细胞带回。夜光藻的最适盐度应在２９－３３之间，但盐度线般与夜光藻的咱群变动没有明显的相关关系，不过暴雨或梅     

微齿喜马拉雅低额溞生长及种群增长的研究

于1990年6月在哈尔滨市东北林业大学实验林场一水池中采到微齿喜马拉雅低额，根据实验结果应用生物统计学方法对它的生长和种群增长进行研究。结果表明，在不同温度条件下性成熟时间与水温的关系为，雌性（10-30℃）：h=8072t－1.313（r=0．985P＜0.01）；雄性（5－25℃）：h=1074t-0.855（r=0.9844，P＜0.01）。在20±1℃条件下，其体长增长模型为：lt=3.334-27345e－0.1117t。龄期（X）与年龄（t，d）的关系为：雌体：t=0·07l69X2＋1.3808X－l·7361；雄体：t=0.8425X2＋2.534x－l.8600。内禀增长率（rm）为0．4076。种群增长呈“logistic”型，其方程式为：     

分布混合分析的深入研究及其在南极磷虾种群结构中的应用

介绍分布混合分析的理论，并运用分布混合分析估计南极磷虾种群体长分布概率密度函数的参数，首次给出体长取样间有效性和方差ａ＾２下限的数学分析。概率密度函数式为Ｑ（ｘ）＝ｋ∑ｊ＝１ｐｊｑ（ｘ；ｕｊ，ｑｊ），式中ｘ是随机变量体长的取值；Ｋ是年龄组数；ｐｊ是第Ａｊ年龄组的强度；ｑ（ｘ；ｕｊ，ｑｊ）是均值为ｕｊ；方差为ａ＾２ｊ的正态分布。Ｐｊ，ｕｊ，δｊ，ｊ＝１，２，…，Ｋ是待估计的参数。求解这些参数的最大似     

绥芬河大麻哈鱼类种群生态的初步研究

3种大麻哈鱼的洄游期、种群组成、数量变动等进行了调查研究。结果认为:溯河期依每年河流生态条件而有变化;驼背大麻哈鱼为单一龄组型,马苏大麻哈鱼为双龄组型,大麻哈鱼为多龄组型;其主要产卵场分布于绥芬河中、上游河区,我国河区种群数量较多。     

厦门港海区真刺唇角水蚤不同季节种群的同工酶分析

于1989年10月—1990年1月在厦门港海区采集真刺唇角水蚤,对其不同季节种群4种酶的6个酶区,即:苹果酸酶(ME)、苹果酸脱氢酶(MDH)、醛氧化酶(AOX_1,AOX_2)和酯酶(EST_1,EST_2)进行了分析。结果表明,苹果酸酶和苹果酸脱氢酶是单态的,而其余的两种酶是多态的。除了EST_2之外,冬春种群与夏秋种群在其余5个酶区的等位基因频率非常相似;EST_2在有的个体不出现酶带,冬春种群的表达频率高于夏秋种群。温度对EST有明显的影响,在55℃中EST_1和EST_2全部失活;在45℃以下各温度组中EST_1的表达频率全部为1,但在EST_2则有所变化,变化规律与自然种群的相近。     

塔玛亚历山大藻(Alexandrium tamarense)和中肋骨条藻(Skeletonema costatum)种间竞争及UV-B辐射胁迫对其影响

采用共培养的方法,研究了塔玛亚历山大藻和中肋骨条藻种群竞争关系对UV-B辐射增强的响应变化.结果表明,不同的接种密度对塔玛亚历山大藻和中肋骨条藻种群竞争有明显的影响.当塔玛亚历山大藻和中肋骨条藻的接种比例为A∶S = 1∶4时,中肋骨条藻在竞争中占优势; 当接种例为A∶S = 1∶1时,虽然塔玛亚历山大藻在竞争中占优势,但也受到了中肋骨条藻的抑制; 接种比例为A∶S = 4∶1时,塔玛亚历山大藻的生长竞争优势更加明显.UV-B辐射增强(在预备实验的前提下,选择1.4J/m2)可改变塔玛亚历山大藻和中肋骨条藻种群竞争的关系,使塔玛亚历山大藻种群竞争能力降低,中肋骨条藻种群竞争能力大大提高,从而导致处理Ⅰ(A∶S = 1∶4)中,中肋骨条藻在竞争优势更加明显,在处理Ⅱ(A∶S = 1∶1)中,中肋骨条藻在竞争中占一定的优势.     

胶州湾3种哲水蚤种群动态的研究

本文研究了胶州湾内小拟哲水蚤(Paracalanus parvus Claus),双刺纺锤水蚤(Acartia bifilosa Giesbrecht)和太平洋纺锤水蚤(A.pacifica Steuer)3种哲水蚤一年内的种群结构和种群数量的季节变化规律,并讨论了体长的季节变化及其与温度之间的关系。     

夜光遥感支持下的城市人口核密度空间化及自相关分析

基于福建省福州市鼓楼区街道社区人口统计数据、夜光遥感影像、Landsat8影像,融合核密度与回归方程,绘制30 m栅格空间分辨率的人口密度图并进行空间自相关分析。方法:① 采用核密度方法对69个社区人口计算生成人口密度分布图。建立786个居民小区点的人口密度与夜光遥感的常规QQ分位图,检测出人口密度存在较大的误差区域:五凤街道和洪山镇。② 建立人口密度与夜光遥感、Landsat8线性分解的不可渗透表面影像之间的二元二次回归方程,修正两个区域的人口密度误差。③ 采用高/低聚类分析、热点分析、聚类和异常值分析,得到鼓楼区人口高聚类属性,显示了鼓楼区最大商业圈区域与人口密度最大居民点区域,展示了人口聚类的空间局部差异性格局。结果:① 研究中所采用的人口空间化技术融合了2种空间化方法:核密度与回归方程。生成30 m栅格空间分辨率的人口密度图。② 鼓楼区人口密度均值分为3种类型:11 000、25 000和50 000人/ km²,人口密度分布近似正态分布。③ 当鼓楼区人口密度均值大于33 000人/ km²,不可渗透表面灰度值与人口密度相关性更强。反之,夜光亮度值与人口密度相关性更强。