刺参养殖池塘丝状绿藻与内源性生源要素（氮、磷）生态耦合动力学机制研究

In recent years, filamentous green algal bloom occurred frequently in sea cucumber aquaculture ponds with eutrophic sediment, which seriously affects the ecosystem nutrient cycle near offshore environments and restricts sustainable development of sea cucumber aquaculture in China. According to the fact, the coastal ponds farming sea cucumber and the prevalent species of filamentous green algae, Cladophora sp. and Spirogyra sp., are studied with the indoor simulation method combining the field investigation and in situ mesocosm. Basing on the influence of filamentous macroalgal life activities on the endogenous biogenic element dynamic accumulation in sediment-water-filamentous macroalgal system, the regulations of nutrients dynamic allocation in three phases, the properties of algal growth phases and its influence on nutrient levels and environmental parameters variation are studied during filamentous green algae growth. The interaction dynamics relationship among nutrients level in water and sediment, environmental parameters and algal growth stages are analyzed. The influence of growth and decomposition of filamentous macroalgae on nitrogen (N) and phosphorus (P) exchange and some environmental parameters at sediment-water interface are explored in three-phase system during the filamentous macroalgal production and decomposition process. The aims of this study are to illuminate filamentous green algal breakout event and the dialectical relationship between algal growth and nutrient distribution with major ecological environment, and to clarify the ecologic coupling mechanism of filamentous green algae and endogenous biogenic elements (nitrogen & phosphorus) in aquaculture ponds. The results can understand the dialectical relationship between algae and environment and enrich the basic theory about marine biogeochemistry, also provide the scientific reference for more offshore aquaculture resources and environment conservation and an important scientific guidance for the control and prevention of internal contaminated sediments and filamentous green algae outbreak in aquaculture ponds.

针对刺参养殖池塘内源性污染严重、丝状绿藻暴发频繁的问题，以暴发丝状绿藻代表种（刚毛藻Cladophora sp.和水绵Spirogyra sp.）为研究对象，拟以“大尺度时空变化视野、概括多项生态要素、综合分析耦合关系”的研究思路，对山东半岛沿海典型底质的刺参养殖池塘内源性生源要素（氮、磷营养盐）存在特征、丝状绿藻生长时期、生态参数等进行野外调查和室内模拟培养验证试验相结合的研究，采用主成分分析、多元协方差分析以及多元回归分析等数据分析平台，围绕藻生长时期动态变化、营养盐存在形态时空分布特征、生态因素相对重要性以及“藻-营养盐-生态因素”三者间的权衡关系等内容，研究耦合关系，阐释丝状绿藻暴发诱因、丝状绿藻与刺参养殖池塘内源性生源要素氮、磷生态耦合机制，科学认识藻类与环境耦合关系，为海水养殖生态环境养护提供理论依据，对刺参养殖池塘内源性污染以及丝状绿藻灾害的科学监控与防治具有重要的参考价值。

针对刺参养殖围堰内源性污染严重、丝状绿藻暴发频繁的问题，以暴发丝状绿潮藻-强壮硬毛藻为研究对象，探究该生态环境条件下大型丝状绿潮藻滋生、暴发、衰亡过程的原因及其引发的生态效益，开展了内源性生源要素（氮、磷营养盐）存在特征及其与生态环境参数间的关联度、丝状绿藻室内模拟培养系统建立、丝状绿藻与生源要素（氮、磷）生态耦合关系等研究内容。获得重要结果1、完成刺参养殖池塘营养盐形态及含量调查。1）营养盐含量呈现沉积物-间隙水-上覆水逐渐递减的顺序，藻体中营养盐含量与上覆水中营养盐范围一致，水中营养盐形态及浓度促进藻生长和暴发；2）水体中高N/P预示丝状绿藻可能利用高含量氮素，并且生长不受氮元素浓度限制，氮素利用与光合作用密切相关，该藻有高的光合作用效率；3）高酶活和完整的生态系统结构（高生物量）能促进净化功能。池塘胞外酶活性不高、初级生产者不多，外加夏季的高温促进酶活性，以及丝状绿藻无畏强光（360μmol/m2-s以上）抑制，促使该藻生长季节很容易大面积暴发。2、研究了影响强壮硬毛藻生长和光合作用的环境因素和营养盐因素，发现该藻对养殖池塘生态环境具有极强的适应性，1）以氯化铵为氮源时，氮磷比、pH、氮磷比和pH的交互作用、盐度和pH的交互作用对强壮硬毛藻特定生长率的影响极显著。2）以尿素为氮源时，各因素及交互作用对强壮硬毛藻特定生长率的影响均不显著。3）以硝酸钠为氮源时，盐度和pH对强壮硬毛藻特定生长率的影响极显著。3、藻的暴发能有效降低营养盐含量，消亡会增加水体中元素含量，藻暴发是对生态环境变化和自净化的一种自然调控现象，合理适量丝状藻类生物量有利池塘生态环境自净化的完成。研究结果科学认识藻类与环境耦合关系，为海水养殖资源环境养护提供理论依据，对刺参养殖池塘内源性污染以及丝状绿藻灾害的科学监控与防治具有重要的参考价值。