Responses of bloom forming and non-bloom forming macroalgae to nutrient enrichment in Hawai'i, USA
Responses of bloom forming and non-bloom forming macroalgae to nutrient enrichment in Hawai'i, USA
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DOI：
10.1016/j.hal.2012.03.008
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发表时间：
2012-05-01
期刊：
影响因子：
6.6
通讯作者：
Smith, Celia M.
中科院分区：
文献类型：
--
作者：
Dailer, Meghan L.;Smith, Jennifer E.;Smith, Celia M.
几十年来，在夏威夷毛伊岛的农业和城市化地区周围的浅水沿海沃茨中，石莼和沙菜的大型藻类水华一直是一个问题。观察结果强调了这些水华与邻近土地利用中营养水平升高之间的对应关系，但几乎没有证据表明营养富集对该地区水华和非水华大型藻类的影响。为了确定营养水平的升高是否会影响H。在Musciformis生理学方面，我们进行了营养强化（+N，+P和+N+P）实验，并测量了生长，光合状态和色素吸收。藻胆素色素在不加磷和加磷处理中显著降低，而在加氮处理中保持不变，表明H. musciformis可以利用藻胆素储存N.我们进行了第二个更大的实验，在水华形成物种Spicifera，H。musciformis和U.莴苣和常见的非开花形成物种，Dictyota acutiloba。所有样品最初都耗尽了潜在的N储存，并测量了生长、光合状态和N吸收速率; musciformis和U.莴苣还评估了微量营养吸收、%组织N和Δ N-15值。生长速率D. acutiloba，尖叶隐翅虫H. musciformis和U.莴苣随污水添加量的增加而增加，TN和NO3-浓度以及水华形成物种的浓度高2倍。所有物种的光合能力和饱和辐照度的增加%污水添加和浓度的TN和NO3-。联合莴苣是最敏感的低N条件下，证明了光捕获效率的下降。所有物种在24小时内都利用了大量的N。H. musciformis和U.莴苣还（1）利用微量营养元素：铁、锰、钼和锌，（2）在低氮条件下降低%组织氮，（3）响应于高氮条件而增加%组织氮，（4）随着废水排放物添加量的增加而表达升高的Δ N-15值。这些结果表明，在夏威夷，水华形成物种H。musciformis和U.莴苣对营养水平的降低和增加有类似的生理反应。(C)2012 Elsevier B. V.保留所有权利。
Macroalgal blooms of Ulva lactuca and Hypnea musciformis have been problematic in shallow coastal waters around agricultural and urbanized regions of Maui, Hawai'i for decades. Observations have highlighted the correspondence between these blooms and elevated nutrient levels from the adjacent land-use, however little evidence exists regarding the effects of nutrient enrichment on the blooming and non-blooming macroalgae in the area. To determine if elevated nutrient levels influence H. musciformis physiology, we conducted a nutrient enrichment (+N, +P, and +N+P) experiment and measured growth, photosynthetic status, and pigment absorbance. Phycobilin pigments were significantly reduced in the no addition and +P treatment and maintained in those with N additions, suggesting that H. musciformis can use phycobilins to store N. We conducted a second, larger experiment with additions of secondarily-treated wastewater effluent on the bloom forming species Acanthophora spicifera, H. musciformis, and U. lactuca and the common non-bloom forming species, Dictyota acutiloba. All samples were initially depleted of potential N stores and measured for growth, photosynthetic status, and N uptake rates; H. musciformis and U. lactuca were also assessed for micro nutrient uptake, % tissue N, and delta N-15 values. Growth rates of D. acutiloba, H. musciformis, and U. lactuca increased with increasing % wastewater effluent addition and concentrations of TN and NO3- and those of the bloom forming species were 2-fold higher. All species increased photosynthetic capacity and saturation irradiance with increasing % wastewater effluent addition and concentrations of TN and NO3-. U. lactuca was the most sensitive to low N conditions, evidenced by declines in light capturing efficiency. All species utilized a substantial amount of N over 24 h. H. musciformis and U. lactuca also (1) utilized micro nutrients: iron, manganese, molybdenum, and zinc, (2) decreased % tissue N in low N conditions, (3) increased % tissue N in response to elevated N conditions, and (4) expressed elevated delta N-15 values with increasing additions of wastewater effluent. These results demonstrate that in Hawai'i, the bloom forming species H. musciformis and U. lactuca, have similar physiological responses to decreased and increased nutrient levels. (C) 2012 Elsevier B.V. All rights reserved.