Ecological and physiological controls of species composition in green macroalgal blooms
Ecological and physiological controls of species composition in green macroalgal blooms
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DOI：
10.1890/07-0494.1
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发表时间：
2008-05-01
期刊：
影响因子：
4.8
通讯作者：
Fredrickson, Kerri
中科院分区：
文献类型：
--
作者：
Nelson, Timothy A.;Haberlin, Karalon;Fredrickson, Kerri
大型绿色藻华极大地改变了海洋群落的结构和功能，特别是通过窒息对商业渔业至关重要的海草和其他初级生产者以及在封闭的海湾中创造缺氧条件。自下而上的因素被认为是这些水华的主要驱动因素，但人们越来越关注物种组成的生物控制。在美国华盛顿州，花朵通常以石莼属植物为主。潮间带和潮下带。研究人员检查了可能导致这种空间差异的因素，包括竞争、食草动物偏好、盐度、光驯化、营养需求和对营养富集的反应。卵子标本在潮间带中比石莼属生长得更快，但在潮下带中则没有明显更快。与石莼相比，石莼能够更好地适应强光环境，并且更能耐受低盐度。石莼的组织氮含量、叶绿素、叶绿素b：叶绿素a、蛋白质含量均高于石莼。这些差异表明氮的有效性可能会影响物种组成。在选择实验中，一组五只食草动物更喜欢石莼而不是石莼。因此，自下而上的因素使石莼在潮间带占主导地位，而对食草动物的抵抗似乎使石莼在潮下带占主导地位。虽然洞藻属于相同的功能形式组，但它们在功能上并不冗余。
Green macroalgal blooms have substantially altered marine community structure and function, specifically by smothering seagrasses and other primary producers that are critical to commercial fisheries and by creating anoxic conditions in enclosed embayments. Bottom-up factors are viewed as the primary drivers of these blooms, but increasing attention has been paid to biotic controls of species composition. In Washington State, USA, blooms are often dominated by Ulva spp. intertidally and Ulvaria obscura subtidally. Factors that could cause this spatial difference were examined, including competition, grazer preferences, salinity, photoacclimation, nutrient requirements, and responses to nutrient enrichment. Ova specimens grew faster than Ulvaria in intertidal chambers but not significantly faster in subtidal chambers. Ulva was better able to acclimate to a high-light environment and was more tolerant of low salinity than Ulvaria. Ulvaria had higher tissue N content, chlorophyll, chlorophyll b : chlorophyll a, and protein content than Ulva. These differences suggest that nitrogen availability could affect species composition. A suite of five grazers preferred Ulva to Ulvaria in choice experiments. Thus, bottom-up factors allow Ulva to dominate the intertidal zone while resistance to grazers appears to allow Ulvaria to dominate the subtidal zone. While ulvoid algae are in the same functional-form group, they are not functionally redundant.