江西柘林湖水华蓝藻——长孢藻(Dolichospermum)的形态多样性及其分子特征

长孢藻是具有产多种蓝藻毒素及异味物质潜在能力的丝状异形胞蓝藻.为了探究长孢藻的生物学特性,我们从江西柘林湖分离24株长孢藻,经形态鉴定分成4个种类,分别为浮游长孢藻(Dolichospermum planctonicum)、近亲长孢藻(D. affine)、卷曲长孢藻(D. circinale)、螺旋长孢藻(D. spiroides). 16S rRNA基因序列表明柘林湖长孢藻与日本等地区的长孢藻高度相似,但只有近亲长孢藻与日本近亲长孢藻在分子系统进化树上聚为一支.基于16S-23S rRNA之间高变异性的ITS序列分析,4种长孢藻的D1-D1'螺旋结构相同,藻丝为直型的浮游长孢藻、近亲长孢藻与藻丝为弯型的卷曲长孢藻、螺旋长孢藻的Box-B、V3螺旋结构差异较大.通过对毒素和异味的分子生物学检测显示24株长孢藻均不产毒,但是4株浮游长孢藻及1株卷曲长孢藻含有土腥素合成基因.本研究不仅对柘林湖水华蓝藻的多样性以及潜在生态风险提供科学的基础资料,也在流域层面上为鄱阳湖的水生态系统研究和保护提供了一定的科学基础.     

P-T-t path of metamorphism for the Julin Group and its geodynamical implications in Yuanmou, Yunnan

The metamorphic complex of the Julin Group occurs in the Yuanmou area of Yunnan Province on the western margin of the Yangtze Platform, and connects with the Kangdian metamorphic complex to the north. Based on the detailed petrographic observations and studies of garnet growth zoning, aP-T-t path has been reconstructed for the staurolite-kyanite zone in the Julin Group. This path is characterized by (1) a counter-clockwise evolutional trend, (2) a quicker increase of temperature than that of pressure in the initial prograde metamorphism, but slower near the peak, then temperature and pressure simultaneously reaching the peak metamorphic conditions, and (3) a slow near-isobaric cooling during the retrograde process. TheP-T-t path for prograde metamorphism is closely related to magmatic accretion in the arc setting. The magmatic accretion model, metamorphism type and tectonic setting may be compared with the global Grenville tectono-metamorphic events, and related to the assembly of the Rodinia at the late Mesoproterozoic-early Neoproterozoic (∼1.0 Ga). The retrogradeP-T-t path shows a slow near-isobaric cooling, indicating sustained heat supplies from the upper mantle and no rapid erosion. This heat source may be originated from the Neoproterozoic (∼0.82 Ga) breakup of the Rodinia.     

On the geomagnetic and ionospheric responses to an intense storm associated with weak IMF Bz and high solar wind dynamic pressure

A study of the geomagnetic storm of July 13–14, 1982, and its ionospheric response is presented using the low-latitude magnetic index, Dst, and interpreted using solar wind interplanetary data: proton number density, solar wind flow speed, interplanetary magnetic field southward component B _Z , and solar wind dynamic pressure. The F2 region structure response to the geomagnetic storm was studied using foF2 data obtained during the storm from a network of various ionosonde stations. Our results appear to show simultaneous abrupt depletion of foF2 that occurred at all latitudes in both the East Asian and African/European longitudinal zone during the period: 18:00–19:00 UT on July 13 and is as result of an abrupt increase in the dynamic pressure between 16:00 and 17:00 UT. The dynamic pressure increased from 3.21 to 28.07 nPa within an hour. The aforementioned abrupt depletion of foF2 simultaneously resulted in an intense negative storm with peak depletion of foF2 at about 19:00 at all the stations in the East Asian longitudinal zone. In the African/European longitudinal zone, this simultaneous abrupt depletion of foF2 resulted in intense negative storm that occurred simultaneously at the low latitude stations with peak depletion at about 20:00 UT on July 13, while the resulting negative storm at the mid latitude stations recorded peak depletion of foF2 simultaneously at about 2:00 UT on July 14. The present results indicate that most of the stations in the three longitudinal zones showed some level of simultaneity in the depletion of foF2 between 18:00 UT on July 13 and 2:00 UT on July 14. The depletion of foF2 during the main phase of the storm was especially strongly dependent on the solar wind dynamic pressure.     

Surface rupture zone of the 1303 Hongtong M=8 earthquake, Shanxi Province

Based on the latest displacement of Huoshan piedmont fault, Mianshan west-side fault and Taigu fault obtained from the beginning of 1990‘s up to the present, the characteristics of distribution and displacement of surface rupture zone of the 1303 Hongtong M = 8 earthquake, Shanxi Province are synthesized and discussed in the paper. If Taigu fault, Mianshan west-side fault and Huoshan piedmont fault were contemporarily active during the 1303 Hongtong M = 8 earthquake, the surface rupture zone would be 160 km long and could be divided into 3 segments, that is, the 50-km-long Huoshan piedmont fault segment, 35-km-long Mianshan west-side fault segment and 70-km-long Taigu fault segment, respectively. Among them, there exist 4 km and 8 km step regions. The surface rupture zone exhibits right-lateral features. The displacements of northern and central segments are respectively 6～7 m and the southern segment has the maximum displacement of 10 m. The single basin-boundary fault of Shanxi fault-depression system usually corresponds to M ≈ 7 earthquake, while this great earthquake (M = 8) broke through the obstacle between two basins. It shows that the surface rupture scale of great earthquake is changeable.     

U-Pb isotopic compositions of the ultrahigh pressure metamorphic (UHPM) rocks from Shuanghe and gneisses from Northern Dabie zone in the Dabie Mountains,central China: Constraint on the exhumation mechanism of UHPM rocks

The occurrence of ultrahigh pressure (UHP) minerals, such as coesite and diamond in crustal rocks in orogenic belts suggests that a huge amount of continental crust can be subducted to man-tle depth during the continental-continental collision[1—6]. This…     

Tectonic and geochemical characteristics and reserved conditions of a mantle source gas accumulation zone in eastern China

Along both sides of the Tancheng-Lujiang Fracture Zone in eastern China, a series of mantle source gas pools constitute a massive-scale tectonic accumulation zone in NNE direction, with the mantle geochemical characteristics of high concentrations of C0₂ and He, high³He/⁴He-⁴⁰Ar/³⁶Ar ratio system and high δ¹³Coo₂ ratios (the main frequency, -3.4%— 4.6%), showing no difference from the tectonic framework of the area. In the area, the tectonic environment is a rift formed as a result of diapiric mantle injection and crust thinning to form graben-type basins and lithospheric fractures. The mantle-derived volcanic rocks and inclusions are well-developed and a high geothermal zone (mantlesource) exists in the area. The characteristics of the three components (solid, liquid and gas) of mantle, concentrated all over the same tectonic space zone, show that the rift system is of a good tectonic environment or passage for mantle degassing and gas migration. The main types of the gas pools are volcano, fault-block, anticline, buried hill and so on, but most of them are combination traps closely related with fracture. For the mantle source gas pools, rift is an optimum tectonic region, and nearby lithospheric fracture, mantle source volcanic rocks or basement uplifts are a favourable structural location when reservoir-caprock association develops.     

无磷条件诱导铜绿微囊藻(Microcystis aeruginosa)释放挥发性有机化合物对莱茵衣藻(Chlamydomonas reinhardtii)的影响

为了揭示磷(P)营养缺乏对蓝藻释放挥发性有机化合物(VOCs)的影响及其对其他藻类的化感作用,以形成蓝藻水华的主要种类铜绿微囊藻(Microcystis aeruginosa)为材料,在无P培养条件下对其释放的VOCs进行分析,同时测定VOCs对莱茵衣藻(Chlamydomonas reinhardtii)生长、光合色素含量和光合性能的影响.结果表明,采用无P培养基培养铜绿微囊藻24 h后,其释放的VOCs种类和含量均明显增加,与标准培养基培养相比,VOCs总释放量增加了73.4%,并出现7种新化合物.将铜绿微囊藻释放的VOCs通入莱茵衣藻溶液中,在标准培养基中铜绿微囊藻释放的VOCs对莱茵衣藻生长无显著影响,而无P条件下释放的VOCs则明显抑制莱茵衣藻生长,其响应指数(RI)为-0.25.此外,莱茵衣藻光合色素含量、光系统II(PSII)最大光化学量子产量(Fv/Fm)、有效光化学量子产量[Y(II)]、光化学淬灭系数(q P)和光合电子传递速率(ETR)也明显降低,而非光化学淬灭系数(NPQ)则明显升高,其RI为0.26.由此可见,蓝藻在富营养化水体中大量繁殖以及P自身沉降特性导致的P缺乏会促进蓝藻释放VOCs,同时这些VOCs在保持蓝藻营养竞争优势和水体藻类多样性减少中具有化感抑制作用.     

铁对拟柱孢藻(Cylindrospermopsis raciborskii)和角星鼓藻(Staurastrum spp.)季节动态和生长的影响——以广东大沙河水库为例

拟柱孢藻（Cylindrospermopsis raciborskii）和角星鼓藻（Staurastrum spp.）是热带亚热带浮游植物群落中的常见优势种类,为了解铁对2种浮游植物季节动态和生长的影响,本文通过对典型热带水库的野外调查,分析铁与2种藻生物量和相对生物量的季节动态的关系,并通过室内实验分别以无机磷（KH₂PO₄）和有机磷（C₆H₁₃O₉P）为磷源,比较3种铁浓度（0.029、0.29和0.689 mg/L）下拟柱孢藻（C.raciborskii,N8）和角星鼓藻（Staurastrum sp.,FACHB-1449）的比生长速率、铁载体产量和碱性磷酸酶活性的差异.结果显示,拟柱孢藻和角星鼓藻是浮游植物群落的主要优势种类,两者的生物量最大占到总生物量的82%以上;两者对环境变量响应的区别主要体现在对溶解性铁浓度变化的响应差异上,拟柱孢藻生物量与溶解性铁有显著的线性回归关系,但角星鼓藻的生物量与铁没有显著线性回归关系.室内实验中,拟柱孢藻N8的比生长速率在无机磷源铁浓度为0.689 mg/L条件下最大,为0.098±0.01 d^-1,2种磷源条件下比生长速率均随铁浓度降低而显著降低,6个实验组均检到铁载体：6个实验组角星鼓藻FACHB-1449的比生长速率没有明显差异,平均为0.079±0.001 d^-1,均未检出铁载体,磷源和铁浓度对其比生长速率的影响不显著;有机磷源条件下,拟柱孢藻N8实验组碱性磷酸酶活性均显著高于角星鼓藻FACHB-1449实验组,拟柱孢藻N8实验组酶活性随铁浓度降低而显著降低,但角星鼓藻FACHB-1449各实验组的碱性磷酸酶活性无明显差异.以上结果表明,水体中溶解性铁的供应对拟柱孢藻的种群动态和优势有重要作用,与角星鼓藻相比,拟柱孢藻的生长更易受到铁的限制,尤其在无机磷缺乏、磷源主要以有机磷形式供应时,铁对拟柱孢藻生长的限制作用增强.     

浙江文成-泰顺交界M4.2地震烈度调查与震害特征

2014年9月12日至2014年10月31日,在浙江文成-泰顺交界的珊溪水库区域发生了最大震级M4.2地震。珊溪水库地区曾在2002、2006年分别发生过最大震级为ML3.9、ML4.6的地震序列,受这2次地震作用影响,震区房屋已经遭受了一定程度的破坏。2014年地震现场调查发现,震区震感明显,房屋受损现象较为普遍,震害具有叠加效应,出现了"小震致灾"的现象。另外,在震中附近的一些道路边坡上,地震还引发了规模较小的崩塌、滑坡等地质灾害。     

Microfracture processes in the breakdown zone during dynamic shear rupture inferred from laboratory observation of near-fault high-frequency strong motion

High-frequency velocities are measured during stick-slip motion in the immediate vicinity of a fault in a granite sample to reveal the microscopic process taking place in the breakdown zone defined in the slip-weakening model. It is found that 1) the onset time of the observed strong motion approximately coincides with the local rupture onset time, 2) the observed near-fault high-frequency strong-motion duration is approximately proportional to the local breakdown time, and 3) the power spectra of strong motions exhibit significant amplitudes at frequencies above the value off _max, wheref _max is a cut-off frequency relevant to rupturing the breakdown zone. These observations suggest that the high-frequency motion would be due to the incoherent brittle microfracture whose characteristic scale is much shorter than the breakdown zone size. We present a stochastic fault model to synthesize the near-fault high-frequency velocity waveforms. In the model, a number of small circular subfaults are distributed randomly on the fault and the rupture onset time of an individual subfault is assumed to be random. The main features of the observed velocity waveforms are well explained by this numerical modeling. It is concluded that approximately half of the total energy of high-frequency elastic waves observed at a point is radiated from the propagating breakdown zone. We emphasize the importance of the observation of near-fault high-frequency strong motions for large shallow earthquakes.     

江西盛源盆地橄榄玄粗岩系列火山岩长石矿物特征及成因信息

江西盛源盆地橄榄玄粗岩系列火山岩中的长石矿物特征为：斜长石斑晶具有反环带结构和交代净边结构,基质中存在大量的斜长石微晶,且在电子探针下研究发现基质中斜长石微晶具有钾长石环边的矿物学特点,为此类火山岩归属于橄榄玄粗岩系列火山岩提供了矿物学证据。通过对长石矿物组合特征进行研究,探讨该地区橄榄玄粗岩系列火山岩的成因以及成岩时的物理化学条件等方面的信息。     

Gas contents and CO2 isotope studies on fluid inclusion in ultra-high pressure metamorphic rock from Shuanghe area, Dabie Mountain

Step heating experiments on ultra-high pressure (UHP) mcks from the Dabie Mountain shows a majority of CO₂ in fluid inclusion (excluding H₂O); CO is also a significant component, with a small content of N₂ and CH₄. Carbon isotopic composition of CO₂ in fluid of metamorphic climax stage (-25%0- -30%0) is different from that of mantle carbon, indicating that UHP rocks did not experience obvious transformation by mantle fluids despite their subduction depth. CO₂ was derived from carbon matter in the pmtoliths of UHP rocks in a relatively confined system, showing that the UHP rocks subsided quickly and uplifted quickly from the mantle. Current organization: Research Institute of Petroleum Exploration and Development, Beijing 100083, China.     

九寨沟M_S7.0地震对巴颜喀拉块体东北缘活动断裂影响的有限元模拟

在详细调研地震地质资料的基础上,构建了巴颜喀拉地块东北缘三维有限元模型。以九寨沟M_S7.0地震同震位错为荷载,模拟计算了九寨沟地震的发生对巴颜喀拉块体东北缘主要活动断裂加卸载效应的影响。模拟结果显示,九寨沟地震的发生对龙日坝断裂、虎牙断裂、青川-平武断裂西段、迭部-白龙江断裂西段和东段、临潭-宕昌断裂东段,以及处于甘青川交界危险区内的东昆仑断裂东段、塔藏断裂西段,处于六盘山南-西秦岭东危险区的西秦岭北缘断裂东段表现为库仑应力加载;对岷江断裂、塔藏断裂东段库仑应力卸载效应显著。     

动、静水条件下苦草(Vallisneria natans L.)对沉积物磷释放的影响

在浅水湖泊中,沉降在沉积物中的营养盐易受到水流的扰动再释放出来,而沉水植物可以在一定程度减少营养盐的释放.借助自主开发的生态水槽,在40 d的实验周期内检测动、静水条件下有、无苦草(Vallisneria natans L.)时沉积物、上覆水中磷含量变化,旨在为沉水植物对湖泊沉积物营养盐释放量的影响估算及水环境质量评价提供科学依据.结果表明:动水条件下,沉积物在没有苦草的保护下总磷含量下降21.8%,而有苦草的保护下总磷含量下降17.7%.苦草根系从周围沉积物中吸收磷,1~4 cm沉积物层的吸收量高于4~8 cm沉积物层.动水槽的上覆水中总溶解态磷浓度和总颗粒态磷浓度均大量增加,并且总颗粒态磷浓度相对于总溶解态磷浓度占较大比例.苦草减少了沉积物中磷的释放,并对上覆水中正磷酸盐有明显的吸收作用.     

尼泊尔8.1级地震后青藏高原NE向地震活动条带的形成及其意义

针对2015年4月25日发生于印度板块北边界中段的尼泊尔8.1级地震后,青藏高原中强以上地震活动呈现NE向条带分布的现象,本文将区域地质构造动力环境和以GPS水平位移为约束的数值模拟相结合,初步分析研究了这一地震活动条带的基本特征和形成机理;进而将其与1996年前后出现在青藏高原及东北部邻区的"西藏榭通门-内蒙古包头"NE向地震活动条带、以及该条带形成后强震活动由东向西的迁移状况进行比较,探讨了目前的NE向地震活动条带对未来强震活动趋势的预示意义。结果认为:尼泊尔8.1级地震后青藏高原NE向中强以上地震活动条带,是在印度板块北推挤压动力持续作用下,因青藏高原NE向构造应力加强引起的构造活动响应,并与尼泊尔大地震低角度逆冲错动和地壳介质能量传递影响有关;而未来地震趋势可能使该条带附近强震活动"填空",进而使该条带东、西两侧较大范围强震活动性增强。     

广东省千灯湖拟柱孢藻(Cylindrospermopsis raciborskii)的形态和产毒能力的株间差异及系统进化

拟柱孢藻(Cylindrospermopsis raciborskii)是一种入侵蓝藻,能够产生拟柱孢藻毒素(cylindrospermopsin,CYN),严重危害人类健康.现有研究表明该藻已在我国广泛分布,更是华南地区常见的水华蓝藻,但目前对其产毒和起源还缺乏了解.本研究以中国广东省千灯湖分离出的10株拟柱孢藻为材料,对它们的生长、形态和产毒特性进行了观测,并构建了基于nif H和rpo C1基因的双基因系统进化树.结果表明,10株拟柱孢藻藻丝体形态均呈笔直型,除QDH1藻株外,其他的拟柱孢藻均可产生端生异形胞,厚壁孢子也常有出现;10藻株丝体的平均长度在41.0~77.7μm之间,宽度在2.433~3.125μm之间,它们的长宽比值差异显著.10藻株的比生长速率差异极显著,为0.075~0.174 d-1.检测发现10株藻中仅QDH7藻株可检测到6个CYN合成酶基因,液相色谱串联质谱法(LC-MS/MS)分析表明该藻株主要产生deoxy-CYN异构体,其浓度可达1745.19 ng/mL.系统进化分析表明千灯湖的拟柱孢藻与澳大利亚、欧洲和国内其他地区的藻株同源性较高,但基于rpo C1和nif H基因不能区分千灯湖的产毒藻株和非产毒藻株.本研究证实了广东省水体中存在产毒拟柱孢藻,需防范这类新型产毒蓝藻水华所带来的生态风险.     

Anomalously high b-values in the South Flank of Kilauea volcano, Hawaii: evidence for the distribution of magma below Kilauea's East rift zone

The pattern of b-value of the frequency–magnitude relation, or mean magnitude, varies little in the Kaoiki-Hilea area of Hawaii, and the b-values are normal, with b=0.8 in the top 10 km and somewhat lower values below that depth. We interpret the Kaoiki-Hilea area as relatively stable, normal Hawaiian crust. In contrast, the b-values beneath Kilauea's South Flank are anomalously high (b=1.3–1.7) at depths between 4 and 8 km, with the highest values near the East Rift zone, but extending 5–8 km away from the rift. Also, the anomalously high b-values vary along strike, parallel to the rift zone. The highest b-values are observed near Hiiaka and Pauahi craters at the bend in the rift, the next highest are near Makaopuhi and also near Puu Kaliu. The mildest anomalies occur adjacent to the central section of the rift. The locations of the three major and two minor b-value anomalies correspond to places where shallow magma reservoirs have been proposed based on analyses of seismicity, geodetic data and differentiated lava chemistry. The existence of the magma reservoirs is also supported by magnetic anomalies, which may be areas of dike concentration, and self-potential anomalies, which are areas of thermal upwelling above a hot source. The simplest explanation of these anomalously high b-values is that they are due to the presence of active magma bodies beneath the East Rift zone at depths down to 8 km. In other volcanoes, anomalously high b-values correlate with volumes adjacent to active magma chambers. This supports a model of a magma body beneath the East Rift zone, which may widen and thin along strike, and which may reach 8 km depth and extend from Kilauea's summit to a distance of at least 40 km down rift. The anomalously high b-values at the center of the South Flank, several kilometers away from the rift, may be explained by unusually high pore pressure throughout the South Flank, or by anomalously strong heterogeneity due to extensive cracking, or by both phenomena. The major b-value anomalies are located SSE of their parent reservoirs, in the direction of motion of the flank, suggesting that magma reservoirs leave an imprint in the mobile flank. We hypothesize that the extensive cracking may have been acquired when the anomalous parts of the South Flank, now several kilometers distant from the rift zone, were generated at the rift zone near persistent reservoirs. Since their generation, these volumes may have moved seaward, away from the rift, but earthquakes occurring in them still use the preexisting complex crack distribution. Along the decollement plane at 10 km depth, the b-values are exceptionally low (b=0.5), suggesting faulting in a more homogeneous medium.     

The cysts ofCeratium hirundinella: Their dynamics and role within a eutrophic (Lake Sempach,Switzerland)

The dynamics of theCeratium hirundinella population and the abundance of dinocysts in the plankton and sediments were studied in Lake Sempach in 1988. In 1987, a rich population ofCeratium (380 cells ml^–1) accompanied byPeridinium spp. developed in the lake. The dinocysts were found entrapped in a kind of flocs, in the deepest part of the lake, in the upper flocculent layer. The number of viable cysts ofCeratium in the sediments decreased gradually from April to July 1988. TheCeratium population increased slowly starting in April, and reached a maximum number in August (31 cells ml^–1).Peridinium willei reached 100 cells ml^–1. Newly formed cysts ofCeratium were recorded in the plankton and sediments at the end of July — beginning of August. They appear in the sediments as separate cells. Their number increased gradually, reaching a maximum of 600 cysts l^–1 at the end of October.Ceratium formed more cysts than didPeridinium, but the rate of survival of theCeratium cysts appears to be lower than that ofPeridinium cysts. In addition to their biological functions, the cysts also have an impact on the ecosystem as carriers of nutrients from down to up and from up to down.     

不同超声强度下微囊藻群体沉降及其上浮过程对光照和温度的响应

以太湖微囊藻群体为研究对象,研究低频超声作用下,4种超声强度和不同处理时间对微囊藻群体的抑制效应,试图得出最优超声参数,同时探讨超声处理后的微囊藻群体对光照和温度的响应.结果表明,当超声强度为0.0353 W/cm~3、处理时间为60 s时,藻细胞沉降量高达80%,且此时藻细胞浓度和叶绿素a浓度均保持不变,表明超声未破碎藻细胞,细胞内含物不会泄漏污染水质,因此作为最优超声参数.随后,对超声处理后的微囊藻群体在不同光照和温度条件下进行恢复培养,结果表明光照和温度均能影响微囊藻群体的浮力恢复,但光照的影响更明显,当光照度为2000 lx时,藻细胞在培养120 h后漂浮率恢复至对照组水平.超声后的藻细胞在较低温度(≤20℃)下漂浮率无显著变化,而在较高温度(25℃)下,培养72 h后漂浮率迅速升高,至120 h能恢复至对照组水平的80%左右.因此,野外超声控藻应选择低光强、低温的时段,采用间歇式多次处理,抑制微囊藻群体上浮,使其彻底沉降.     

基质类型对耳萝卜螺(Radix auricularia)-苦草(Vallisneria spiralis)牧食关系的影响

沉水植物和螺类都是水生生态系统的重要组成部分,两者的牧食关系也是水生食物网中重要的一环,而不同的基质类型可能会影响两者的生长和改变沉水植物对螺类牧食的防御策略.以耳萝卜螺（Radix auricularia）和苦草（Vallisneria spiralis）为对象,研究基质类型、螺类牧食对沉水植物的生长及防御策略的影响,以及基质类型及沉水植物对螺类生长和生理特征的影响.研究发现,螺类牧食和基质类型对苦草生长和元素特征具有显著的影响,存在螺类牧食时,泥沙基质和沙基质苦草的相对生长速率显著降低,泥沙、沙和泥基质苦草地上生物量分别减少了67.74%、58.58%和17.84%,根冠比分别升高了177.51%、217.23%和1.44%;且泥沙基质中苦草的叶片数显著低于无牧食组.不同基质类型下,牧食对苦草总碳含量无显著影响,但泥和泥沙组中,螺类牧食使苦草的总氮含量均显著降低,碳氮比均显著升高;沙基质下,螺类牧食使苦草总酚含量显著降低.基质类型对螺类的形态特征（除壳宽外）、生长及元素含量均无显著影响.总体来看,基质类型对耳萝卜螺牧食和苦草防御策略具有一定程度的影响,但对螺类的生长及元素特征基本无影响.本研究可以为牧食理论的研究提供基础数据支持,也可为沉水植被恢复、水生生态系统稳定提供参考,但基质类型对螺草牧食关系的长期影响,仍需进一步深入研究.