四十里湾几种双壳贝类及污损动物的氮、磷排泄及其生态效应

对多种经济双壳贝类和养殖中的污损动物的N和P排泄进行了测定 ,包括排泄成分和排泄速率。在这些动物的N排泄中 ,NH4 N占主要部分 ,如笼式养殖的双壳贝类NH4 N占总N排泄的平均值范围为 70 8%— 80 1 % ;氨基酸是第二大排泄成分 ,平均占总N排泄的 1 0 %—2 5 %。其他形态的N ,如尿素、亚硝酸盐和硝酸盐也有检出。在P排泄中 ,有机磷 (DOP)约占总溶解磷 (TDP)排泄的 1 5 %— 2 7%。据估算 ,整个四十里湾所养殖的双壳贝类在夏季每天将排泄4 5 4t总溶解氮 ,其中NH4 N 3 36t、Amino N 0 69t、Urea N 0 2t。同时每天磷的排泄为 0 5 7tTDP ,其中DOP 0 1 5t。对面积为 1 3× 1 0 4 hm2 的海区而言 ,贝类的N、P排泄分别能满足浮游植物生产所需N、P的 44%和 40 %。高密度的贝类养殖对养殖生态系统营养循环的影响是很显著的。附着动物 (柄海鞘等 )的N、P排泄及其对营养循环的影响也不容忽视。     

黄骅沿海赤潮发生机制的初步探讨

报道了黄骅沿海赤潮发生的过程和形成赤潮的生物种类及造成的危害,并对赤潮成因作了初步分析。     

Do benthic biofilters contribute to sustainability and restoration of the benthic environment impacted by offshore cage finfish aquaculture?

Benthic biofilters were deployed under a cage fish farm and in two reference locations to assess the influence of the farm on the biofilters and the surroundings, as well as to verify the usefulness of this technology as a mitigation tool. The biofilters underneath the farm recruited a fouling community practically identical to that of the control biofilters, which included a variety of trophic strategies. The former showed a higher ¹⁵N enrichment, indicating that fouling beneath the farm was benefiting from the farm waste. The waste retention efficiency was low (0.02 g N m⁻² month⁻¹) beneath the farm. Benthic biofilters aggregated demersal wild fish around and within them. Pelagic wild fish also frequently used the biofilters beneath the farm, forming compact shoals around them. The increased complexity of the habitat below the fish farm enhanced biodiversity, but this improvement did not lead to the recovery of the sediments around the biofilters.     

A constitutive model for coal-fouled ballast capturing the effects of particle degradation

Rail tracks undergo degradation owing to particle breakage and fouling of ballast by various fines including coal and subgrade soil. As the ballast becomes fouled, its strength and drainage capacity are compromised, sometimes resulting in differential settlement and reduced track stability. This paper demonstrates a continuum mechanics based framework to evaluate the detrimental effect of fines on the strength, deformation and degradation of coal-fouled ballast under monotonic loading. An elastoplastic constitutive model that considers the effect of fines content and energy consumption associated with particle breakage during shearing is presented. This multiphase constitutive model is developed within a critical state framework based on a kinematic-type yield locus and a modified stress-dilatancy approach. A general formulation for the rate of ballast breakage and coal particle breakage during triaxial shearing is presented and incorporated into the plastic flow rule to accurately predict the stress–strain response of coal-fouled ballast at various confining pressures. The behaviour of ballast at various levels of fouling is analysed and validated by experimental data.     

AHLs的合成及其对污损硅藻生长的影响

用L-高丝氨酸内酯的氢溴酸盐与酰氯在Schotten-Baumann条件下反应,合成了6种N-酰基-L-高丝氨酸内酯类(AHLs)信号分子:N-丁酰基-L-高丝氨酸内酯、N-己酰基-L-高丝氨酸内酯、N-辛酰基-L-高丝氨酸内酯、N-癸酰基-L-高丝氨酸内酯、N-十二酰基-L-高丝氨酸内酯和N-十四酰基-L-高丝氨酸内酯,通过红外、核磁共振仪、气相-质谱联用仪对所有化合物进行了结构表征和纯度分析。同时检测合成的6种化合物对污损硅藻-柱鞘藻(Cylindrothecasp.)生长的影响,结果表明:合成的信号分子除侧链最短的N-丁酰基-L-高丝氨酸内酯外,其它在高浓度下均能抑制柱鞘藻的生长,其中C12-HSL和C14-HSL在较低浓度下对柱鞘藻的生长也具有明显的抑制效应。     

Offshore oil platforms and fouling communities in the southern Arabian Gulf (Abu Dhabi)

This study examined the fouling organisms on the legs of offshore oil platforms at two sites in the southern Arabian Gulf (offshore Abu Dhabi, United Arab Emirates). 100% of the metal structures was colonized by encrusting organisms. Both the number of individuals and the total biomass tended to decrease with depth. The total weight of dead shells always exceeded that of living organisms. Sessile filter feeders dominated the biomass, whereas small mobile forms had the largest number of individuals. The biomass at the deeper platform (22 m) was dominated by bivalves, barnacles and bryozoans, while polychaetes and amphipods had the greatest number of individuals. Biomass values here ranged from 1 g/0.1 m2 at 20 m to 147 g/0.1 m2 at 5 m; the corresponding individual numbers were 266 (20 m) and 11,814 indiv./0.1 m2 (5 m). The results at the shallower platform (11 m) differed in several respects: barnacles clearly dominated over bivalves, and sponges exceeded byrozoans, while total individual numbers fell due to a decline in polychaete dominance. Biomass values here ranged from 84 g/0.1 m2 at 10 m to 153 g/0.1 m2 at 0 m; the corresponding individual numbers were 695 (10 m) and 3,125 indiv./0.1 m2 (0 m). The potential role of such fouling communities on artificial structures in the Gulf is discussed.     

保山地区下仁和桥组页岩气成藏条件分析

通过野外调查及室内测试,对云南省保山地区早志留世浅海较深水环境沉积的下志留统下仁和桥组黑色笔石页岩进行了分析研究.初步认为下仁和桥组黑色页岩沉积厚度大且稳定,有机质丰度高、岩石成熟度高、有机质类型好、演化程度高、裂缝发育,具备页岩气藏的形成条件.     

Long-term coexistence of non-indigenous species in aquaculture facilities

Non-indigenous species (NIS) are a growing problem globally and, in the sea, aquaculture activities are critical vectors for their introduction. Aquaculture introduces NIS, intentionally or unintentionally, and can provide substratum for the establishment of other NIS. Little is known about the co-occurrence of NIS over long periods and we document the coexistence over decades of a farmed NIS (a mussel) with an accidently introduced species (an ascidian). Both are widespread and cause serious fouling problems worldwide. We found partial habitat segregation across depth and the position of rafts within the studied farm, which suggests competitive exclusion of the mussel in dark, sheltered areas and physiological exclusion of the ascidian elsewhere. Both species exhibit massive self-recruitment, with negative effects on the industry, but critically the introduction of NIS through aquaculture facilities also has strong detrimental effects on the natural environment.