【作者】 康庆浩；

【导师】 包振民；

【作者基本信息】 中国海洋大学 ， 海洋生物学， 2008， 博士

【摘要】 在很多水深较浅的海湾或沿岸水体中,滤食性双壳贝类通常具有重要的生态学作用,因为它们可以通过高效率的滤食活动将大量的浮游植物或其他悬浮颗粒物从水体中滤除。养殖贝类与其养殖水体环境之间的相互作用,一直是养殖生态学的研究热点之一,正受到人们的广泛关注。为了深入地了解贝类与其养殖水体的相互作用,尤其是贝类在沿岸水体净化过程中的作用,一方面需要了解贝类通过自身的生理和代谢活动如何对其周围造成的影响;另一方面,需要了解环境因子的变化对贝类生理和代谢活动的影响。本文着重研究了两种韩国主要海产经济贝类——紫贻贝和魁蚶在不同个体大小的情况下对环境因子的生理和代谢响应。本文的研究结果可以为评估紫贻贝的水质净化作用提供基础实验数据,进而可以为韩国富营养化海湾的水体质量控制提供有价值的参考数据。同时,也可以为魁蚶的养殖容量估计提供基础数据。作为滤食性动物,双壳贝类同时又是重要食源性病毒携带者。它们通过滤食水中的颗粒性物质,能够在体内组织中积累高浓度的病原性微生物,相对于其它海洋生物,滤食性贝类在传播食源性疾病方面具有相对较高的危险性。因此,本文测定了紫贻贝与魁蚶在个体大小不同情况下的细菌水平,研究了冷藏保存对紫贻贝和魁蚶的作用效果以及应用冷藏保存的必要性。虽然多种贝类对环境因子的生理响应以及其细菌学特征已经被广泛研究,但是只有很少的研究探讨了贝类个体大小(通常用贝类壳长表示)对其生理响应和细菌学特征的影响,因此本文着重研究了贝类个体大小对其生理和细菌学特征的影响。贝类生理和代谢活动对多种环境的变化都非常敏感。因此贝类的生理活动以及对其所生活的海湾或沿岸生态系统的控制能力受到多种环境因子的影响,比如温度、盐度、浮游植物浓度、金属离子浓度、溶解氧浓度、以及环境污染程度。对贝类而言,温度和盐度是最重要的两种环境因子。作为变温动物的贝类,其生理和代谢活动完全依赖于周围环境温度,同时,因为贝类通常分布于河口或较浅的海湾和沿岸水体中,所以其周围环境中盐度经常发生变化,进而会对贝类的生理和代谢活动产生影响。通常情况下,温度和盐度会呈现季节性变化,进而影响贝类的摄食和呼吸的生理活动。准确了解贝类对不同水温与盐度生理响应,特别是滤食与呼吸作用,是评估贝类对水体质量控制能力的基础。为了能够全面地了解养殖贝类与其周围环境的相互作用,同时初步评估其细菌污染程度,对其养殖环境的了解是十分必要的。进行紫贻贝养殖的Gwangyang湾(34°55ˊN, 127°50ˊE)是位于朝鲜半岛南部沿海的另一个规模较大的海湾。Gwangyang湾同样是韩国的一处重要海水养殖区域,其海域面积230 km2,最大水深35 m,平均水深10 m。数条季节性河流注入此海湾,各条河流的水质以及携带物的情况不同。随着经济活动的日益频繁以及人口不断增加,其中一些河流成为工业和养殖废水的排放渠道。海湾内的营养盐浓度以及浮游植物浓度明显受到临近区域人类活动和废水排放情况的影响。海湾内的海流情况受到潮汐的显著影响,在涨潮时,湾底处海流速度为10 cm s-1,湾口处海流速度为60 cm s-1;退潮时,湾底处海流速度为10 cm s-1,湾口处海流速度为80 cm s-1,涨、退潮时海流方向完全相反。在Gwangyang湾内的Myodo地区,一月份平均气温最低,为1°C,六月与八月平均气温最高,为26.0°C。12月平均降水量最小,为3 mm。八月份平均降水量最大,为361 mm。此地区月平均风速波动范围为1 m s-1至3 m s-1。最大风速中由4 m s-1至10 m s-1。在Gwangyang湾内的Suncheon地区,一月份平均气温最低,为1°C,八月平均气温最高,为26.0°C。12月平均降水量最小,为1.5 mm。九月份平均降水量最大,为551.8 mm。此地区月平均风速波动范围为0.8 m s-1至1.7 m s-1。最大风速中由一月份的1.7 m s-1至三月份的5.4 m s-1。在Gwangyang湾中,紫贻贝是优势养殖贝类。在Gwangyang湾中,紫贻贝养殖采用不同与传统方法的浮筏式养殖。Gwangyang湾周围分布有四座城镇(Gwangyang, Suncheon, Yeos, Hadong-gum),共有人口260,392人,以及圈养家禽家畜727,411头(只),拥有孵化场总面积198,270 m2。人类活动以及家禽家畜的排泄物已经对Gwangyang湾的水体质量造成了显著影响。进行魁蚶养殖的Gamag湾(34°40ˊN, 127°40ˊE)是位于朝鲜半岛南部沿海的一个规模较大的海湾。Gamag湾是韩国的一处重要海水养殖区域,其海域面积1,020 km2,最大水深40 m,平均水深9 m。海湾内的海流情况受到潮汐的显著影响,在涨潮时,湾底处海流速度为10 cm s-1,湾口处海流速度为40 cm s-1;退潮时,湾底处海流速度为10 cm s-1,湾口处海流速度为40 cm s-1,涨、退潮时海流方向完全相反。湾内月平均风速波动范围为3 m s-1至5 m s-1。一月份平均气温最低,为4°C,六月份平均气温最高,为26.1°C。11月平均降水量最小,为0.1 mm。六月份平均降水量最大,为330.5 mm。在各月观察到的最大风速中,一月份最低(11 m s-1),七月份最高(26 m s-1)。在Gamag湾中,魁蚶是优势养殖贝类,占据约一半的养殖面积。在Gamag湾中,魁蚶根据传统方法进行底播养殖。Gamag湾周围分布有五座城镇(Yeosu, Dolsan, Hwayang, Hwaieong, Nam-myeon),共有人口249,229人,以及圈养家禽家畜18,468头(只),拥有孵化场总面积312,352 m2。人类活动以及家禽家畜的排泄物已经对Gamag湾的水体质量造成了影响。为了评价滤食性贝类对Gwangyang湾水体质量的控制作用,6个温度梯度和5个盐度梯度下测定了不同个体大小紫贻贝(小: 21.0±1.2 mm;中: 31.1±2.2 mm;大: 50.6±3.3 mm)的清滤率和耗氧率的影响。结果表明,具有不同个体大小的3个组,都在20°C时表现出最大清滤率。清滤率最大值为4.53±0.22 Lg-1h-1,出现在最小个体组。具有不同个体大小的3个组,都在盐度为30时表现出最大清滤率。清滤率最大值为4.94±0.24 Lg-1h-1,出现在最小个体组。在温度实验中,当温度为25°C时,最大耗氧率为1.405±0.070 mgg-1h-1,出现在最小个体组。在盐度实验中,当盐度为40时,最大耗氧率为1.353±0.068 mgg-1h-1,出现在最小个体组。结果表明,紫贻贝的清滤率和耗氧率均随着个体大小的增加而降低。为了研究温度和盐度变化对不同个体大小魁蚶(小: 11.8±2.1mm;中: 21.8±1.1 mm;大: 30.1±3.0 mm)的清滤率和耗氧率的影响,实验在6个温度梯度和5个盐度梯度下进行,并根据中性红方法对其清滤率进行测定。结果表明,具有不同个体大小的3个组,都在20°C时表现出最大清滤率。清滤率最大值为1.89±0.12 Lg-1h-1,出现在最小个体组。在各组中,清滤率均随着盐度的升高(10至40)而升高,最大值为2.62±0.21 Lg-1h-1,出现在最小个体组。耗氧率随温度和盐度的变化趋势与清滤率相似,当温度为20°C时,最大耗氧率为0.189±0.003 mgg-1h-1,出现在最小个体组。当盐度为40时,最大耗氧率为0.308±0.018 mgg-1h-1,出现最小个体组。结果表明,魁蚶的清滤率和耗氧率均随着个体大小的增加而降低。为了能够了解具有不同个体大小的紫贻贝与魁蚶的细菌污染状况,以及评价采用冷藏储存方法的必要性,本次实验测定了:具有不同个体大小的紫贻贝与魁蚶的初始大肠杆菌数、粪大肠杆数和细菌总数;在冷藏与非冷藏条件下储藏的紫贻贝与魁蚶的大肠杆菌数、粪大肠杆菌数和细菌总数。在初始紫贻贝样品中,大肠杆菌数、粪大肠杆菌数和细菌总数分别为960±90 MNP 100g-1, 230±40 MNP 100g-1 and 8,910±870 CFU g-1,显著高于魁蚶样品中的大肠杆菌、粪大肠杆菌和细菌总数(450±60 MNP 100g-1, 90±30 MNP 100g-1 and 1,570±380 CFU g-1)。紫贻贝样品中细菌水平高于魁蚶样品的原因可能是由于紫贻贝养殖水体的污染程度高于魁蚶养殖水体。结果同时表明,紫贻贝的细菌水平随着个体大小(小: 18.7±4.0mm;中: 42.6±5.4 mm;大: 61.4±7.4 mm)的增加而降低。魁蚶的细菌水平随着个体大小(小: 30.0±2.0mm;中: 39.1±0.7 mm;大: 45.9±1.1 mm)的增加而降低。紫贻贝与魁蚶在冷藏(4±1°C)与非冷藏(28±1°C)条件下保存48h,以观察细菌含量变化。在冷藏条件下,紫贻贝样品的细菌抑制率显著高于魁蚶样品,说明冷藏储存对紫贻贝的作用效果优于对魁蚶的作用效果。经过48 h的冷藏储存,紫贻贝样品中的大肠杆菌、粪大肠杆菌和细菌总数分别为2,000±120 MNP 100g-1, 430±60 MNP 100g-1和10,780±1,240 CFU g-1,显著高于魁蚶样品中的大肠杆菌、粪大肠杆菌和细菌总数(850±70 MNP 100g-1, 130±30 MNP 100g-1和3,360±410 CFU g-1,)。结果表明,冷藏保存有效地抑制了紫贻贝和魁蚶样品中细菌的繁殖,但是冷藏保存只能维持较低的细菌水平,却无法降低原有细菌水平。经过48 h冷藏储存,紫贻贝与魁蚶样品中的细菌抑制率均随着其个体大小的增加而降低;紫贻贝样品中细菌抑制率(大肠杆菌抑制率39.4±4.5% ,粪大肠肝菌抑制率54.7±4.8,细菌总数抑制率78.1±8.1)显著高于魁蚶样品中细菌抑制率(大肠杆菌抑制率29.2±3.5% ,粪大肠肝菌抑制率40.9±4.7%,细菌总数抑制率72.3±8.1%)。更多还原

【Abstract】 As filter-feeding organisms, bivalves often play a significant ecological role in many shallow fjords and coastal water because the remove of phytoplankton and other suspended particles from the water. The interaction between shellfish and ambient environment has always been considered as a research focus of culture ecology and attached with more and more attentions. To get a clear understanding of interactions between cultured shellfish and their ambient environment, especially of the potential function of bivalves in coastal water purification, the knowledge of the influences of physiological and metabolic activities of shellfish on their ambient environment and the influences of environmental factors on physiological and metabolic activities is necessary.The aim of the present study was to evaluate the clearance and oxygen consumption rate of Mytilus galloprovincialis and Scapharca broughtonii, which are two common commercial shellfish in South Korea, with different shell sizes to various environmental factors. Results of this study may provide essential data to assess the cleaning potential of these bivalves. Depending on local eutrophication situation, this information could be of value for water quality control throughout south coast of South Korea. And the results also can provide essential data to estimate the carrying capacity for culture of S. broughtonii.Simultaneously, as filter feeding organisms, bivalve molluscs are an important source of foodborne diseases. These invertebrates can accumulate high levels of microbial pathogens within their internal tissues, so they are implicated more than other marine animals in seafood-borne illness. Therefore, the aim of the present study was also to have a better understanding of the contamination status of M. galloprovincialis and S. broughtonii with various shell length, and the effects of refrigerated storage on these two shellfishes, as well as the necessity of applications of refrigerated storage.Although the physiological responses and bacterial characteristics of many bivalves have been studied, but few studies discussed the effects of body size (commonly means shell sizes for bivalve) on physiological response and bacterial contamination. In present study, the influence of body size was focused on.The physiological indexes of shellfish are affected by many environmental factors, and further the controlling role of bivalves which live in estuarine and coastal environments are influenced by many environmental factors such as water temperature, salinity, algae concentrations, nutrient loads, dissolved oxygen and environmental pollutants. As poikilothermic animal which is often distributed in estuarine, shallow fjord and costal waters, water temperature and salinity which vary seasonally can cause significant changes in physiological activities that further influence the ability of the organisms to ingest the phytoplankton. Precise knowledge about the physiological response, especially the filtration and respiration, to different temperature and salinity is essential to evaluate the role of bivalves on water quality control.To comprehensively understand the relationship of shellfish and their environment and evaluate the seafood safety, the knowledge of the bays in which they are cultured is essential.Gwangyang Bay (34°55ˊ N, 127°50ˊ E), where the M. galloprovincialis was cultured, is a typical semi-enclosed water bay, connecting with the sea with a narrow mouth, with a surface area of 230 km2. Some seasonal streams empty into the bay with varying water and sediment loads. Some rivers have become canals of industrial and domestic waste discharge with the advance of economic activity and increase of population in the region. The changes of nutrient regime and phytoplankton structure are attributed to increased human activity in this region, changed water circulation and increased aquaculture. The maximum water depth is 35 m, and the average water depth is 10 m. The current exist in the bay are significantly affected by tidal current. The tidal current speed during the flood phase ranges from 10 cm s-1 (at the bottom of the bay) to 60 cm s-1 (at the bay mouth), and the range of tidal current speed during the ebb was from 10 cm s-1 (at the bottom of the bay) to 80 cm s-1 (at the bay mouth). In Myodo of Gwangyang bay, the monthly average water temperature ranged from 1°C in Jan to 26.0°C in Jul and Aug. The monthly average rainfall ranged from 3 mm in Dec to 361 mm to Aug. The monthly average wind speed ranged from 1 to 3 m s-1, and the monthly maximum wind speed ranged from 4 m s-1 in Oct to 10 m s-1. In Suncheon of Gwangyang bay, the monthly average water temperature ranged from 1.0°C in Jan to 26.0°C in Aug. The monthly average rainfall ranged from 1.5 mm in Nov to 551.8 to Sep. The monthly average wind speed ranged from 0.8 to 1.7 m s-1, and the monthly maximum wind speed ranged from 1.7 m s-1 in Jul to 5.4 m s-1 in Mar. Mediterranean mussels M. galloprovincialis is dominantly cultivated bivalves in Gwangyang Bay. In Gwangyang Bay, the M. galloprovincialis was farmed on cultivation raft which is different from traditional bottom sawing culture.Nearby Gwangyang Bay there are four towns (Gwangyang, Suncheon, Yeosu and Hadong-gum) which have a total population of 260,392 inhabitants, about 727,411 economic animals and about 198,270 m2 hatchery areas, having potential negative impacts on the bay.Gamag Bay (34°40ˊN , 127°40ˊ E), where the S. broughtonii was cultured, is a large embayment on the south coast of Korea peninsula. The Gamag Bay is an important mariculture area in South Korea which has a total water area of 1,020 km2. The maximum water depth is 40 m, and the average water depth is 9 m. The current exist in the bay are significantly affected by tidal current. The tidal current speed during the flood phase ranges from 10 cm s-1 (at the bottom of the bay) to 40 cm s-1 (at the bay mouth), and the range of tidal current speed during the ebb was from 10 cm s-1 (at the bottom of the bay) to 40 cm s-1 (at the bay mouth). The monthly average water temperature ranged from 4°C in Jan to 26.1°C in Aug. The monthly average rainfall ranged from 0.1 mm in Nov to 330.5 mm to Jun. The monthly average wind speed ranged from 3 to 5 m s-1, and the monthly maximum wind speed ranged from 11 m s-1 in Oct to 26 m s-1 in Jul. Ark shell S. broughtonii is dominantly cultivated bivalves in Gamag Bay. In Gamag Bay, this production is made according to traditional bottom sawing culture.Nearby Gamag Bay there are five towns (Yeosu, Dolsan, Hwayang, Hwaieong, and Nam-myeon) which have a total population of 249,229 inhabitants, about 18,468 economic animals, and about 312,352 m2 hatchery areas, having potential negative impacts on the bay.In order to provide essential data to evaluate the effect of filter-feeding bivalves on water quality of Gwangyang Bay in South Korea, the clearance and respiration rates of M. galloprovincialis with different shell length (S: 21.0±1.2 mm; M: 50.6±3.3 mm; L: 31.1±2 mm) were estimated under different temperature and salinity conditions. The results showed that, in all of the three groups, the highest clearance rates appeared at 20°C, and the highest one was 4.53±0.22 Lg-1h-1 in the group with the smallest shell length. The clearance rates of every group had the highest values at salinity 30, and the highest one is 4.94±0.24 Lg-1h-1 in the smallest shell length group. The highest respiration rates were 1.405±0.070 mgg-1h-1 at 25°C and 1.353±0.068 mgg-1h-1 at salinity 40 in the group with the smallest shell length. And the shell size was negatively correlated with clearance and oxygen consumption rates.To investigate the effects of temperature and salinity on clearance and oxygen consumption rate of S. broughtonii spat with different growth stages, this study was conducted under 6 different water temperatures and 5 different salinity conditions. The individuals were divided into three groups (S: 11.8±2.1mm; M: 21.8±1.1 mm; L: 30.1±3.0 mm) of different shell sizes and clearance rates were estimated by Neutral red. The results showed that in all of the three groups, the highest clearance rates appeared at 20°C, and the highest one was 1.89±0.12 Lg-1h-1 in the group with the smallest shell length. The clearance rates in every group increased with the rise of salinity in the range from 10 to 40, and the highest one is 2.62±0.21 Lg-1h-1 in the smallest shell length group. The trends of oxygen consumption rates were similar to clearance rates. The highest rates were 0.189±0.003 mgg-1h-1 at 20°C and 0.308±0.018 mgg-1h-1 at salinity of 40 in the group with the smallest shell length. And the results showed that the clearance and oxygen consumption rates were negatively correlated with shell size. With the aim of having a better understanding of the contamination status of M. galloprovincialis and S. broughtonii with various shell lengths, as well as the necessity of applications of refrigerated storage, in this study we determined: the initial level of coliform, fecal coliform and total plate count (TPC) in M. galloprovincialis and S. broughtonii with various shell length; the level of coliform, fecal coliform and total aerobic bacteria in these two shellfish under refrigerated and non-refrigerated storage conditions.The initial level of coliform, fecal coliform and TPC in M. galloprovincialis were 960±90 MNP 100g-1, 230±40 MNP 100g-1 and 8,930±870 CFU g-1, which were significant high than those in S. broughtonii (450±60 MNP 100g-1, 90±30 MNP 100g-1 and 1,570±380 CFU g-1). It should attribute to the higher contamination level of aquatic environment where M. galloprovincialis was cultured. The initial levels of coliform, fecal coliform and TPC in M. galloprovincialis were negatively correlated with shell length (S: 18.7±4.0mm; M: 42.6±5.4 mm; L: 61.4±7.4 mm). The initial levels of coliform, fecal coliform and TPC in S. broughtonii were also negatively correlated with shell length (S: 30.0±2.0mm; M: 39.1±0.7 mm; L: 45.9±1.1 mm).The bacteriological characteristics of these shellfish were determined after 48-h refrigerated (4±1°C) and non-refrigerated (28±1°C) storages. Under refrigerated conditions, the inhibitory rate of bacterial in M. galloprovincialis was significantly higher than that in S. broughtonii indicating that refrigerated storage was more effective for M. galloprovincialis than S. broughtonii.After 48 h refrigerated storage, the level of coliform, fecal coliform and TPC in M. galloprovincialis were 2,000±120 MNP 100g-1, 430±60 MNP 100g-1 and 10,780±1,240 CFU g-1, which were significantly higher than those in S. broughtonii (850±70 MPN 100g-1, 130±30 MNP 100g-1 and 3,360±410 CFU g-1). Refrigerated storage is an effective control measure to slow the rate of bacteria growth in live seafood, and thus can maintain the initial microbial status of the shellfish, but cannot improve it.After 48h refrigerated storage, the inhibitory rates in both M. galloprovincialis and S. broughtonii were negatively correlated with shell length. The inhibitory rates of bacterial were significantly different between M. galloprovincialis (39.4±4.5% for coliform, 54.7±4.8 for fecal coliform and 78.1±8.1 for TPC) and S. broughtonii (29.2±3.5% for coliform, 40.9±4.7 for fecal coliform and 72.3±8.1 for TPC).更多还原