Release and transformations of inorganic iodine by marine macroalgae

A number of field and laboratory studies on the impact of marine macroalgae on dissolved inorganic iodine speciation are presented. Within tidally isolated rock pools, the brown macroalga Fucus serratus was found to both release stored iodide and to facilitate the reduction of iodate to iodide. In contrast, no discernible changes in iodine speciation were observed in rock pools containing green macroalgae of the genus Ulva. Incubation experiments confirmed that the macroalgae Laminaria digitata, F. serratus and Kallymenia antarctica release iodide, though the rate of release varied between species and between specimens of the same species. Application of oxidative stress by treatment with cell wall derived oligoguluronate elicitors increased the efflux of iodide by L. digitata approximately 20-fold. The release of iodide by macroalgae may impact upon the formation of volatile iodine species (molecular iodine and iodocarbons) that are of importance in the coastal atmosphere.     

Microelectrona cladara gen.et sp.nov.:A New Protodikraneurini from the Eocene Baltic Amber(Hemiptera:Cicadomorpha:Cicadellidae:Typhlocybinae)

<正>A new genus Microelectrona gen.nov.and species Microelectrona cladara sp.nov.of the extinct tribe Protodikraneurini of the leafhoppers(Cicadeilidae:Typhlocybinae) from the Eocene Baltic amber is described. The piece of amber containing leafhopper inclusion is broken,unveiling some of the morphological structures,and enabling their studies using scanning electron microscopy.     

The biogeochemical effect of seaweeds upon close-to natural concentrations of dissolved iodate and iodide in seawater – Preliminary study with Laminaria digitata and Fucus serratus

Toward assessing the biogeochemical significance of seaweeds in relation to dissolved iodine in seawater, the effect of whole seaweeds (Laminaria digitata and Fucus serratus) upon iodide and iodate, at essentially natural concentrations, has been studied. The weeds were carefully removed from the sub-littoral zone of the Menai Straits and exposed to iodide and iodate at their natural temperature (6 °C), but under continuous illumination. Laminaria digitata was found to decrease the concentration of iodate with an exponential rate constant of 0.008–0.24 h⁻¹. This is a newly discovered process which, if substantiated, will require an entirely new mechanism. Generally, apparent iodide concentration increased except in a run with seawater augmented with iodide, where it first decreased. The rate constant for loss of iodide was 0.014–0.16 h⁻¹. Meanwhile, F. serratus was found not to decrease iodate concentrations, as did L. digitata. Indeed, after ∼30 h iodate concentrations increased, suggesting that the weed may take in iodide before oxidising and releasing it. If substantiated, this finding may offer a way into one of the most elusive of processes within the iodine cycle – iodide oxidation. With both seaweeds sustained long-term increases of apparent iodide concentration are most easily explained as a secretion by the weeds of organic matter which is capable of reducing the Ce(IV) reagent used in determination of total iodine. Modelling of the catalytic method used is provided to support this contention. The possibility of developing this to measure the strain that seaweeds endure in this kind of biogeochemical flux experiment is discussed. A Chemical Oxygen Demand type of approach is applied using Ce(IV) as oxidant. The results of the iodine experiments are contrasted with the several investigations of ¹³¹I interaction with seaweeds, which have routinely used discs of weed cut from the frond. It is argued that experiments conducted with stable iodine may measure a different variable to that measured in radio-iodine experiments.     

贵州麻江下司寒武系杷榔组棘皮动物 始海百合新类型化石

和凯里生物群一样,贵州寒武系杷榔动物群也含有丰富的棘皮动物始海百合化石,包括两个属种即俞氏贵州始海百合 GuizhoueocrinusyuiZhao,ParsleyetPeng,2007及殷氏原始球状始海百合(新属新种)Protogloboeocrinusyini(gen.etsp. nov.).其中新属种是近期在杷榔组分布区南部贵州麻江下司淑里村杷榔组上部发现的,是凯里组中球形球状始海百合(GloboeocrinusglobolusZhao, ParsleyetPeng,2008)的原始属种,两者均具有发育的吸盘、长的茎、近于球形或椭球形的萼及较长 的腕.但新属种茎呈倒长锥柱形,缝孔长卵形,腕枝数少,两者区别明显.Protogloboeocrinusyini(gen.etsp.nov.)的发现及研 究,不仅追溯到凯里组球形球状始海百合的原始属种,了解两者演化规律是茎变短,萼变球形,缝孔变为圆形,腕枝数量增加, 捕食能力增强.而且还增添了杷榔组始海百合的多样性及其分区性:杷榔组分布区北部仅见Guizhouocrinusyui,南部仅见 Protogloboeocrinusyini(gen.etsp.nov.)      

岩溶泉流量衰减曲线分析

由于岩溶含水介质的强烈非均质性和各向异性,如何有效认识岩溶含水层内部的水文地质特征为研究难点之一,岩溶泉衰减曲线分析为认识岩溶含水层的一种有效手段。总结了目前广泛用于泉流量衰减曲线分析的几种常见方法,主要包括指数型衰减、非指数型衰减分析方法以及综合型的衰减曲线分析方法,讨论了管道可能对泉流量衰减曲线的影响,最后提出了今后对岩溶泉流量衰减曲线分析拟解决的一些关键问题。     

Predation of the beetle Rhantus sikkimensis (Coleoptera: Dytiscidae) on the larvae of Chironomus Meigen (Diptera: Chironomidae) of the Darjeeling Himalayas of India

The dytiscid beetle Rhantus sikkimensis, Regimbart, 1899 (Coleoptera: Dytiscidae), a member of the freshwater insect communities of the Darjeeling Himalayas, were noted to predate on the coexisting larvae of Chironomus sp. Meigen. Evaluation of predation by R. sikkimensis on Chironomus sp. larvae, in the laboratory, revealed that a single adult morph of R. sikkimensis could kill and consume on an average 10–90 and 10–78 numbers of small and large Chironomus sp. larvae, respectively, per day, depending on the prey density. The attack rate ranged between 520 and 537, and the handling time ranged between 4.3 and 8.6 depending on the size of the preys. The predation varied with respect to predator density also, with a maximum of 151 larvae killed by three predators per day. Two indices of predation, ingestion rate (IR) ranging between 13.33 and 74.15 larvae/day/predator and clearance rate (CR) ranging between 19.67 and 39.99 L prey/day/predator, varied with the prey size and predator density, significantly, when the predation was observed for 9 consecutive days, at two predator densities. It was also noted that R. sikkimensis predated on an average 9.8 larvae of Chironomus sp. and 1 larva of Culex sp., when the larvae of both the species are present together as preys, showing a preference for the Chironomus sp. larvae.     

新发现的江河寄生性等足类——细角鳃虫的人工感染试验

珠江水系贺江段近年出现严重危害网箱养殖和江河鱼类资源的大型寄生虫病害．初步鉴定该虫隶属于甲壳纲．等足目．鳃虫科．细角鳃虫属．是国内新发现的淡水鱼类寄生虫。用该虫对草鱼、银鲫、麦鲮进行人工感染．结果表明：该虫具有很强的寄生能力．累积感染率为76．2％～100．0％；对寄生部位具有一定的选择性，以寄生在鳃部的比例（55．6％～72．0％）最大．胸鳍（11．7％～28．8％）次之；对试验鱼有较强的致死性；该虫吸血后体长（L）增长较大．体宽（W）基本不变；从寄主体上主动脱落的虫体，其L／W的增长率（16．32％～18．00％）较大，而一直寄生在寄主身上的虫体．其L／W的增长率则因各自摄食量的不同而存在较大的差异。     

云南洞穴盲金线鲃一新种(鲤形目:鲤科)

描记采于云南省邱北县一地下洞穴盲金线鲃一新种,以其头上骨质突形状如鹰喙命名鹰喙角金线鲃Sinocyclocheilus aquihornes sp.nov.。新种头形及完全退化的眼与分布于云南泸西阿庐古洞的透明金线鲃S.hyalinus Chen et Yang(1994)相近,但有下列特征可区别:1)角形如鹰喙,后者为一向前的直突起;2)侧线完全,侧线鳞为36,后者侧线不完全,侧线鳞孔9-11;3)背鳍起点位于体中点,至吻端的距离等于至尾鳍基的距离;后者背鳍起点位于体中点之后,至吻端的距离大于至尾鳍基的距离。     

IDENTIFICATION OF CYTOKININ IN A GREEN ALGAE EXTRACT

Isopentnyladenosine(i~6Ado) was identified, and trans-zeatin (trans-Z) and trans-zeatin riboside(trans-ZR) were detected by high pressure liquld chrmoatoguphy (HPLC) but not verified withchromatography - mass spectrometry (GC - M S ) analysis of cytokinin from the extracts of green algae (Ulvapertusa (Kjellm), Enteromopha compressa and Monostma sp). This indicated that the green algae mixturecontained cytokinin -like substances.