滤食性贝类筏式养殖对浅海生态环境影响的基础研究

IOCAS-IR > 海洋环流与波动重点实验室

	滤食性贝类筏式养殖对浅海生态环境影响的基础研究
	周毅
学位类型	博士
	2000
学位授予单位	中国科学院海洋研究所
学位授予地点	中国科学院海洋研究所
学位专业	海洋生物学
关键词	双壳贝类养殖模式生态环境筏式养殖
摘要	近年来，由于对海区不合理的开发，我国浅海贝类筏式养殖接连遭受重创，这亟需从理论上和实践中确定养殖容量和养殖模式。本文在我国北方典型养殖海湾四十里湾对筏式养殖的贝类开展了现场生理生态学研究，对贝类对浮游植物等悬浮颗粒物的处理过程即贝类对颗粒有机物及营养元素C、N、P的摄食、吸收、排泄、排粪和生长进行了剖析，分析了贝类在沿岸养殖生态系中的物质和营养循环中所扮演的角色，为海区贝类养殖容量和养殖模式的最终确定提供了基础数据。另外，本文还对海水、沉积物及生物体中磷的分析方法进行了大量的实验工作。主要结果如下：① 比较系统地评述了双壳贝类的生物沉积(biodeposition)的原理、测定方法及其生态效应。贝类通过生物沉积在沿岸生态系中的物质和营养循环中扮演着重要的角色。国际上已有不少研究专门报道了贝类在海区现场的生物沉积。而在我国，这方面的研究却罕见。② 综述了双壳贝类各种形态的 N 和 P 排泄及其生态效应。对于我国广泛养殖的栉孔扇贝、海湾扇贝和牡蛎等双壳贝类的TDN、TP排泄尚未见报道。 ③ 在6～7月，在四十里湾的不同养殖海区(8个站位)对扇贝的生物沉积进行了现场测定。在整个四十里湾海区，一龄栉孔扇贝(壳高 41.1±4.1mm，软体干重 0.48±O.10 g/ind))每个每天所产生生物沉积物干重平均为59.9mg，对颗粒有机质(POM)、颗粒有机碳(POC)、颗粒有机氮(PON)和颗粒有机磷(POP)的生物沉积速率范围及平均值分别为： 6.88、3.09、0.392 和 0.022mg/ind·d。还在一个站位测定了海湾扇贝(壳高 24.6±2.3mm；软体干重 O.14g/ind)的生物沉积速率为 24.3mg/ind·d，或179.2mg/g·d。不同站位一龄栉孔扇贝的生物沉积速率有较大变化，这主要与饵料浓度不同有关。二龄栉孔扇贝(壳高60.9±8.2mm；软体干重1.91±0.32 g/ind)的生物沉积速率平均为 112.7mg/ind·d，对POM、POC、PON和POP的沉积速率分别是一龄扇贝的1.85倍、1.68倍、1.77倍和2.33倍。养殖海区与非养殖海区比较，前者近海底沉积速率是后者的 1.51～3.47 倍。根据以上数据，作者计算了中等规格栉孔扇贝(用壳高 41.1±4.8mm 扇贝估算)在四十里湾在夏季每天的生物沉积量达 162 吨(干重)，或18.6tPOM、8.37tPOC、1.06tPON和60kgPP。在四十里湾的贝类筏式养殖海区，可以估计贝类每年因生物沉积的生产而循环427tN和98.OtP(包括20.0t OP的贡献)，它们能分别满足浮游藻类生产所需求N和P的17.0％和28.3％(其中OP贡献 6.9％)。可见，贝类在养殖生态系的物质和营养盐循环中扮演着重要的角色。高密度、大面积的贝类养殖使大量的生物沉积物聚集于海底，可能对海区环境产生冲击。作者分析，98年8月份烟台养殖区赤潮的发生很可能与海底生物沉积物营养盐的快速释放以及栉孔扇贝大面积死亡而使浮游藻类失去了摄食控制有关，而风平浪静和养殖笼对水流的阻挡也为赤潮的发生提供了有利条件。④ 采用半现场流水系统法测定了栉孔扇贝在不同养殖密度、不同养殖模式(扇贝单养、贝藻混养、贝藻参混养)中的生物沉积。实验时间尺度大，前后计80天。结果说明扇贝的生物沉积速率与其养殖密度呈反比关系。养殖密度的高低影响饵料浓度的变化(两者呈负相关的对数函数关系)，而饵料浓度的高低直接决定着扇贝的生物沉积速率的高低，两者呈正相关关系(生物沉积速率与POC和叶绿 a 分别呈对数和指数函数关系)。不仅生物沉积物的数量与养殖密度(或饵料浓度)有关，生物沉积物的质量同样与养殖密度(或饵料浓度)有关。栉孔扇贝的养殖使沉积物的有机质含量及C、N 和 P 含量降低，且密度越高，它们的含量越低。这反映了扇贝对环境的适应能力。在海带和扇贝的混养模式中，海带对扇贝生物沉积物的数量和质量不构成影响，当然这是在海带不影响浮游植物数量的前提下得出的结果。而实际上在自然海区两者可能是竞争关系。⑤ 对从海区取回到实验室的多种滤食性动物，包括经济双壳贝类(栉孔扇贝、海湾扇贝、长牡蛎、贻贝、菲律宾蛤仔等)和养殖中的污损动物(栖海鞘、玻璃海鞘、藤壶、玟斑稜蛤)的 N 和 P 排泄进行了测定，包括排泄成分和排泄速率。在N排泄中，NH_4-H 占主要部分，如笼式养殖的双壳贝类 NH_4-N 占总N排泄的70％以上，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10～25％。其它形态的N，如尿素、亚硝酸盐和硝酸盐也有检出，如双壳贝类尿素氮在总氮排泄中占 2～5％。但在双壳贝类中未检出尿酸氮。比较而言，海鞘、藤壶的尿素氮相对高一些。在P排泄中，OP约占TDP排泄的15～27％。栉孔扇贝TDP排泄速率为0.281μmol/h·ind。作者以实验室测定结果计算，在整个四十里湾的夏季，所养殖的双壳贝类每天将排泄4.54t总溶解氮，其中NH_4-N 3.36t、Amino-N 0.69t、Urea-N 0.2t。同时每天磷的排泄为0.57t TDP，其中OP O.15t。对面积为1.3 * 10~4hm~2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％。尽管Urea-N所占比例有限，但也能满足海区浮游植物所需 N 的 2％左右。以上说二月高密度的贝类养殖对海区生态系统营养盐循环的影响是很显著的。附着动物(柄海鞘等)的N、P 排泄也不容忽视，它们分别能满足浮游藻类生产所需 N、P 的 ll％和 12％。它们一方面通过排泄和排粪加速营养盐和物质的循环对浮游植物的生长产生刺激作用；另一方面，对藻类产生摄食控制，如果海区中滤食性动物太多，即使营养盐再丰富也难以使浮游植物大量繁殖，这无疑将影响滤食性动物的生长速率。⑥ 运用近年来发展起来的生物沉积法对四十里湾半现场流水系统中贝类的滤水率、吸收率、生长率、生态效率等生理生态学参数进行了测定。栉孔扇贝(收获时规格0.194～0.412g软体干重/ind)滤水率平均为3.65 1/ind·h。扇贝放养密度和饵料浓度没有显著关系。扇贝的总摄食率平均为3.98mg/ind·h，对POM、POC、PON的摄食率范围为0.84～1.87、0.335～0.748、0.0515～O.1293mg/ind·h。扇贝的摄食率随放养密度的升高而降低，与POM呈正相关关系。扇贝的吸收速率受密度和饵料浓度的影响不明显。扇贝对N的吸收效率较C、P稍高，对总有机质的吸收效率为75.9±4.1％，如此高的吸收效率与低饵料浓度有关。扇贝氨基酸泄漏所损失的能量高于排氨的能量损失。代谢能与吸收能呈明显的正相关关系。SFG与饵料浓度呈正相关关系。总生长效率K1(* 100)变化较大，范围为20～49；净生长效率K，K_2(* 100)随POM的升高而升高。扇贝对N的总生态效率范围为6.2～12.8％(平均9.9％)，这高于对C(平均5.9％)和P(平均4.1％)的总生态效率。扇贝对POC、PON和PP的生长余力(SFG_C、SFG_N、SFG_P)平均分别为197、46.8和6.2μg/ind·h，它们分别与POC、PON和PP呈正比关系。扇贝对N的净生长率高于对C和P的净生长率。在N的预算中，如果仅考虑NH_4-N的排泄而忽视其它形态氮的排泄，将会产生很大偏差(平均约20％)。扇贝贝壳生长所需的能量在整个扇贝生长所需能量的9.0～15.1％(平均 11.2％)；贝壳C、N和P在扇贝生长中所占的比例分别为10.5～17.8％、9.4～16.1％和8.7～15.O％。可见，贝壳不管在能量预算还是在元素预算中都不应该被忽视。理论计算而得到的SFG和SFG_C、SFG_N、SFG_P与扇贝的实际生长和扇贝C、N、P的实际增长量之间呈正相关关系，但前者明显过高地估计了扇贝的生长。⑦ 运用生物沉积法在四十里湾养殖海区现场对栉孔扇贝的生理生态学特征进行了研究。不同海区扇贝的滤水率有变化，一龄扇贝(41.1±4.1mm，软体干重 0.48±O.10g/ind)滤水率变化范围为 0.72～2.54(平均 1.27)1/ind·h 或 1.65～5.97(平均 2.61)1/g·h。与半现场研究结果一致，滤水率与TPM没有明显关系，而摄食率却与TPM呈正相关关系。二龄扇贝(软体干重 1.91±0.32g/ind)滤水率为 2.09～3.99(平均 3.10)1/ind·h。吸收速率与POM(或TDM)呈正相关关系，与饵料质量(POM/TPM)无明显的相关关系。吸收效率AE_(POM)与TPM(或POM)没有相关关系，却与饵料质量呈明显的正相关关系。扇贝对POC、PON和PP的吸收效率平均分别为68.9％、64.0％和63.6％。不同海区SFG差别很大。一龄扇贝SFG范围为-O.174～24.08 J/ind·h，SFG与饵料浓度POM呈正相关关系。SFG负值的出现主要与低饵料浓度有关。SFG_C、SFG_N、SFG_P分别与POC、PON和PP呈正相关关系。在N的生长余力计算中，如果仅考虑NH_4-N排泄，而不考虑其它形态N的排泄，就可能产生相当大的偏差，偏差范围为11～360％，这高于半现场的偏差值，显然SFG_N越低，产生的偏差就越大。这说明在饵料不足、扇贝生长受到限制的环境下进行N生长余力的计算时必须考虑其它形态N的排泄。⑧ 对四十里湾养殖海区一些双壳贝类和藻类的化学组成和有机净生产量进行了讨论。不同双壳贝类的软体有机碳含量差别不大，而N含量差异较大。栉孔扇贝N含量最高(占软体干重的12.36％)，而牡蛎、毛蚶软体N含量相对较低，为 8～9％。从双壳贝类贝壳的组成来看，贻贝和菲律宾蛤仔贝壳中N含量最高，分别为 0.55％和 0.56％；而栉孔扇贝贝壳N含量相对较低，在 O.1％左右。贻贝贝壳有机磷含量 (308ppm) 也明显高于栉孔扇贝贝壳(62.1 ppm)。不同海区海带的 C/N 比值较高，变化明显，范围为17.36～30.23。石莼与此相似。大型藻类高 C/N 比值说明海区营养元素N的不足。海带的不同部位N含量差别很大，中带部和边叶在不同海区有较大变化，即对环境的营养状况比较敏感。紫贻贝贝壳中C、H、N 和 P 的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％和 29．6％。
其他摘要	Owing to irrational exploitation, the shellfish raft culture industry has been continuously inflicted by casualties, which urgently needs to ascertain carrying capacity and culture methods in coastal areas. In this paper, studies on the characteristics of physiological ecology of sea raft-cultured bivalves and the processing of suspended particulate materials by bivalves, i.e. ingestion, absorption, excretion and defecation of particulate carbon, nitrogen and phosphorus nutrients by mollusks, are conducted in order to understand the role played by bivalves in material and nutrient circulation of coastal culture ecosystem. In addition, a more accurate and simplified ignition method is developed for determination of inorganic, organic and total phosphate in sediments and organisms. The main results are as follows. ① Biodeposit production by the scallop Chlamys farreri in summer in raft culture areas of Sishili Bay, Yantai, has been determined in situ in eight stations. The result shows that biodeposit of 59.9mg is produced every day by a one-year-old scallop with shell height of 41.1±4.1 mm and soft body dry weight of 0.48±0.10g/ind, and the mean biodeposition rates of POM, POC and PON by the scallops are 6.88, 3.09, 0.392 and 0.022 mg/ind·d, respectively. In one station, biodeposition rate of the bay scallop Argopecten irradians, whose shell height is 24.6±2.3mm and soft body dry weight is 0.14 g/ind, is 24.3 mg/ind·d or 179.2mg/g·d. The biodeposition rates of the one-year-old Chlamys farreri vary in different areas of the bay, which is mainly related to total suspended particulate matter. The average biodeposition rate of two-year-old Chlamys farreri with shell height of 60.9±8.2mm, soft body dry weight of 1.91±0.32 g/ind is 112.7 mg/ind·d, and POM, POC, POON and POP deposition rates of the scallop are respectively 1.85, 1.68, 1.77 times as high as that of the one-year-old scallop. Compared to non-culture areas, the deposition rate of particulate matter near the bottom in shellfish culture areas is 1.51～3.47 times as high as that of the former. The everyday biodeposit production by all of the cultivated scallops in the Sishili bay in summer is 162 t (dry weight), or 186t POP, 8.37 t POC, 1.06t PON and 60kg PP. It is estimated that 427t N and 98.0t P are circulated and regenerated every year owing to biodeposit production by scallops, which can meet the annual demands for 17.0% and 28.3% of N and P respectively for pelagic primary production of the whole bay. ② Biodeposit production by Chlamys farreri was also determined in semi-field water-flowing systems within longer length of time (80days). The results show that the biodeposition rate is negatively correlated to scallop, or positively correlated to food concentration which varies with scallop density. Both the quantity and the quality of the biodeposit are related to food concentration. The higher the number of scallops, the lower the organic matter content or C, N and P content of the sediments, which reflects the scallop's ability to adapt to the environment. In Laminaria japonica and Chlamys farreri polyculture patterns, there is no marked effect of the kelp on biodeposit production of the scallop, but in the field, the kelp culture may reduce the biodeposition rate of the scallop via effects on phytoplankton production. ③ N and P excretion by various filter feeding organisms collected from coastal culture areas, including Chlamys farreri, Argopecten irradians, Mytilus edulis, Crassostrea gigas, Ruditapes philippinarum and fouling organisms (Styela clave, Ciona intestinalis, Balanus amphitrite and Trapezium liratum), were studied. In N excretion, NH_4-N is the main form, which accounts for more than 70% (mean 70.8～80.1%) of TN excretion. Although ammonia is the dominant form of nitrogen excreted by the species, amino acids are the second main component of N excretion in all studied organisms, which amounts to 10～25% of TN excretion. Other forms of N excretion by the species are urea, nitrite and nitrate, but no significant amount of uric acid is measured in these bivalve species. As regards P excretion, organic phosphorus constituted 15～27% of the total phosphorus excretion. The calculated everyday excretion rates of N and P of all raft cultured bivalves in Sishili Bay in summer can meet 11% and 12% respectively of N and P demands for pelagic primary production of the whole bay. ④ The physiological responses of scallops to changing environmental conditions were researched in semi-field water-flowing system using a recently developed biodeposition method . The clearance rate of the scallop Chlamys farreri with soft body dry weight range from 0.194～0.412g/ind at the end of the experiment has a mean of 3.65 1/ind·h, which shows that there is no positive relationship between stocking density and food concentration. The average ingestion rate of the scallop is 3.98mg/ind·h. Negative correlation is found between ingestion rate and scallop density; however, ingestion rate is positively correlated to POM. Absorption efficiency of scallops is not affected by stocking density and POM. By comparison, N absorption efficiency is somewhat higher than that of C or P. The mean POM absorption efficiency is 75.9%, which is relatively high, and may be attributable to low food concentration. The energy loss by excretion of amino acid is higher than the loss by the excretion of ammonia. The gross ecology efficiency of N (mean 9.9%) is higher than that ofC(5.9%) or P(4.1%).The C, N and P scopes for growth are 197, 46.8 and 6.2 μg/ind·h, respectively, and positively correlated to POC, PON and PP respectively. In the nitrogen budget, if only NH_4-N is considered and other forms of nitrogen such as amino acids are neglected, significant errors (about a mean of 20%) may arise. The energy needed by shell growth of scallop accounts for 9.0～15.1% (average 12.2%) of the total energy needed for growth. The C, N and P production in shell amounts to 10.5 ～17.8%, 9.4～16.1% and 8.7～15% respectively of the total production. It is concluded that whether in energy or element budget, the shell should not be neglected. The calculated SFG, or SFG_C, SFG_N and SFG_P is positively correlative to the actual growth of the scallops, but the caculated indices are an overestimate of the growth of the scallops. ⑤ Physio-ecological parameters were also determined in situ in Sishili Bay, and similar results were obtained with semi-field systems. The clearance rate of one-year old Chlamys farreri with shell height of 41.1±4.1 mm and soft body dry weight of 0.72～2.54 (average 1.27)l/ind·h. CR is also not correlated to TPM, while FR is markedly correlative to TPM. AE of POC, PON and PP are 68.9%, 64.0% and 63.6%, respectively. SFG varies with different areas, -0.174～24.08 J/ind/ind·h, and are mainly controlled by the TPM. SFG_C, SFG_N and SFG_P are correlative to POC, PON and PP respectively. In the calculation of SFG, if only NH_4-N is considered and other forms of N are not considered, relatively significant error occurs in the range of 11～360%, which is higher than that obtained in semi-field experiments. Especially, when food supply is not enough and the growth of scallop is constrained, other forms of N must be considered.
页数	200
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/821
专题	海洋环流与波动重点实验室海洋生态与环境科学重点实验室
推荐引用方式 GB/T 7714	周毅. 滤食性贝类筏式养殖对浅海生态环境影响的基础研究[D]. 中国科学院海洋研究所. 中国科学院海洋研究所,2000.

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