烟台四十里湾浅海养殖生物及附着生物的化学组成、有机净生产量及其生态效应

对四十里湾养殖海区一些双壳贝类和藻类收获时的化学组成和有机净生产量进行了分析，不同双壳贝类软体有机碳含量差别不大，而N含量差异较大，栉孔扇贝软体N含量最高（12．36％），而牡蛎，毛坩相对较低（8％－9％），贻贝和菲律宾蛤仔贝壳N含量最高，为0．55％和0．56％，而栉孔扇贝壳则较低（0．1％），且贝壳，C，N，P在扇贝C，N，P总含量中所占的比例分别为6．2％，7．5％和6．9％，海带和石莼元素组成说明海区营养元素N的不足，海带的不同部位N含量差别很大，且在不同海区有较大变化，贻贝贝壳C，H，N和P含量在整个贻贝中占有相对大的比例，分别为30．4％，30．2％，31．8％，29．6％，菲律宾蛤仔，长牡蛎和中国蛤蜊等贝类贝壳中这些元素的相对含量也较高，布扇贝贝壳却较低，四十里湾海区每年因贝类和藻类的养殖，海区将至少减少850tN和78tP，其中贝壳的营养损失占据着相当比例，在海水交换受到一定限制，营养不很丰富，海区，养殖生物收获本身也会对海区的营养状况产生影响，根据贝壳N，P的含量，笔者认为在营养不很丰富的沿岸海区，贻贝，牡蛎最好不养或尽可能少养。     

象山港放流虾群亲虾的产卵回归和生物学性状

象山港放流对虾主群在浙江岛礁外侧海区越冬后,翌年春随着温度回升逐步向沿岸回归,回归路线大致与浙江海岸线垂直,主群出现在象山港口的六横南部及三门湾口部海域。少量亲虾在港内越冬。亲虾的交配率达99.7%,性腺发育正常,体长组成与黄渤海亲虾一致。为浙江近海自然繁殖提供了优质的亲虾基础。     

夏季杭州湾南岸慈溪滩涂泥螺种群空间分布格局

2004年7月对杭州湾南岸慈溪自然滩涂的泥螺种群进行了取样调查,分别采用Taylor幂法则、Iwao聚集格局回归分析法及Morisita指数公式计算和统计分析。结果表明:杭州湾南岸7个样地间泥螺种群密度差异极显著,种群空间格局在局域斑块尺度属于聚集型负二项分布。造成样地间密度差异的主要原因是人为干扰,泥螺种群的空间分布格局主要与滩涂上积水区域呈斑块状分布有关。     

乳山湾底质中硫化物和氧化-还原电位的分布与变化

2004年6、8和10月分别对乳山湾东流区共进行了3个航次的调查。调查结果表明,乳山湾东流区属于弱还原环境,表层沉积物中硫化物的含量基本呈北侧高、南侧低的趋势,而氧化-还原电位则呈北侧低、南侧高变化趋势。硫化物的垂直分布基本表现为随深度的增加而增加,氧化-还原电位的垂直分布基本表现为随深度的增加而降低。但是,由于受到贝类养殖的影响,出现了较多的例外情况。硫化物含量和氧化-还原电位随季节的变动较明显,硫化物含量8月最高,6月次之,10月最低;而氧化-还原电位则10月最高,6月次之,8月最低。贝类养殖对沉积环境中硫化物与氧化-还原电位有明显影响,养殖区硫化物的含量高于非养殖区,而氧化-还原电位则低于非养殖区。     

黄海玉筋鱼繁殖习性的初步研究

1999~2004年来,对黄海玉筋鱼渔场变动进行了全年跟踪调查。产卵期对沿海小型流动渔具及定置张网渔业进行了调查,研究其繁殖习性。研究结果表明,在黄海35N°以北近海,存在着范围很广的玉筋鱼产卵场,主要产卵场有3处,各自相互隔离。本文主要以北部产卵场为重点,开展该鱼繁殖习性的研究。北部产卵场玉筋鱼产卵盛期为11月,Ⅳ~V期卵巢内相同卵径的频率分布十分集中,为明显的单峰型,属一次性产卵类型。1龄玉筋鱼95%以上性成熟,作为小型鱼种,个体绝对生殖力很高,纯重在1.8~13.8g、体长在90~200mm,个体绝对生殖力一般在0.60~4.20×104粒,个体生殖力随年龄增长而增长。玉筋鱼群体组成简单,生殖群体最高仅为3龄,以1~2龄为主,年度发生量有波动,但不大。过度利用剩余群体以及对幼鱼的破坏,已导致了北部及西部产卵场的发生量连年锐减,实现可持续利用这一资源也是该项研究的重要目的之一。     

Is the decline of soil microbial biomass in late winter coupled to changes in the physical state of cold soils?

During winter when the active layer of Arctic and alpine soils is below 0 °C, soil microbes are alive but metabolizing slowly, presumably in contact with unfrozen water. This unfrozen water is at the same negative chemical potential as the ice. While both the hydrostatic and the osmotic components of the chemical potential will contribute to this negative value, we argue that the osmotic component (osmotic potential) is the significant contributor. Hence, the soil microorganisms need to be at least halotolerant and psychrotolerant to survive in seasonally frozen soils. The low osmotic potential of unfrozen soil water will lead to the withdrawal of cell water, unless balanced by accumulation of compatible solutes. Many microbes appear to survive this dehydration, since microbial biomass in some situations is high, and rising, in winter. In late winter however, before the soil temperature rises above zero, there can be a considerable decline in soil microbial biomass due to the loss of compatible solutes from viable cells or to cell rupture. This decline may be caused by changes in the physical state of the system, specifically by sudden fluxes of melt water down channels in frozen soil, rapidly raising the chemical potential. The dehydrated cells may be unable to accommodate a rapid rise in osmotic potential so that cell membranes rupture and cells lyse. The exhaustion of soluble substrates released from senescing plant and microbial tissues in autumn and winter may also limit microbial growth, while in addition the rising temperatures may terminate a winter bloom of psychrophiles.Climate change is predicted to cause a decline in plant production in these northern soils, due to summer drought and to an increase in freeze-thaw cycles. Both of these may be expected to reduce soil microbial biomass in late winter. After lysis of microbial cells this biomass provides nutrients for plant growth in early spring. These feedbacks, in turn, could affect herbivory and production at higher trophic levels.     

Distribution and spawning dynamics of capelin (Mallotus villosus) in Glacier Bay, Alaska: a cold water refugium

Pacific capelin (Mallotus villosus) populations declined dramatically in the Northeastern Pacific following ocean warming after the regime shift of 1977, but little is known about the cause of the decline or the functional relationships between capelin and their environment. We assessed the distribution and abundance of spawning, non‐spawning adult and larval capelin in Glacier Bay, an estuarine fjord system in southeastern Alaska. We used principal components analysis to analyze midwater trawl and beach seine data collected between 1999 and 2004 with respect to oceanographic data and other measures of physical habitat including proximity to tidewater glaciers and potential spawning habitat. Both spawning and non‐spawning adult Pacific capelin were more likely to occur in areas closest to tidewater glaciers, and those areas were distinguished by lower temperature, higher turbidity, higher dissolved oxygen and lower chlorophyll a levels when compared with other areas of the bay. The distribution of larval Pacific capelin was not sensitive to glacial influence. Pre‐spawning females collected farther from tidewater glaciers were at a lower maturity state than those sampled closer to tidewater glaciers, and the geographic variation in the onset of spawning is likely the result of differences in the marine habitat among sub‐areas of Glacier Bay. Proximity to cold water in Glacier Bay may have provided a refuge for capelin during the recent warm years in the Gulf of Alaska.     

乳山湾沉积物中酸挥发性硫化物(AVS)的分布变化特征

2005年12月和2006年3、6、9月,乳山湾滩涂底质环境调查中的16个站点的酸挥发性硫化物(AVS)含量的测定分析结果表明,表层沉积物中AVS具有明显的时、空变化。水平变化范围分别为:春季16·46~230·62mg/kg(干重,下同)、夏季33·65~568·48mg/kg、秋季23·49~350·69mg/kg、冬季15·77~190·96mg/kg,平均值分别为92·82、208·65、177·27和82·87mg/kg。对养殖区与非养殖区AVS含量进行比较,结果表明,养殖区明显高于非养殖区。在深度为0~20cm之间,AVS含量基本是随着深度的增加而增加。本文还就近几年乳山湾东流区表层底质中的AVS含量作了年际比较分析,结果表明,AVS含量年际变化不明显。     

北疆膜下滴灌棉田生育期土壤水盐的变化特征

针对北疆地区土壤盐化制约农业发展的问题,通过野外实地分层采集土样,分析北疆地区长期膜下滴灌农田种植前后土壤水分和盐分分布特征。统计学分析表明,种植期土壤含水量变异属于中等偏弱变异强度,土壤盐分的变异属于中等偏强变异程度,土壤盐分分布成自上而下先增大再减少的波动趋势。在空间分布上,土壤水分和盐分种植前后存在明显的差异,种植后在浅层土壤水分和盐分的含量成西高东低的变化分布。     

黔北杂交水稻高产栽培体系探讨

从自然条件、水稻种植水平、病虫草鼠害等方面分析了黔北水稻产量限制因素，系统地开展了高效集成技术的研究与应用，探索适宜黔北水稻实现高效的途径和技术模式。