Influence of sublittoral microphytobenthos on the oxygen and nutrient flux between sediment and water. A laboratory continuous-flow study
Influence of sublittoral microphytobenthos on the oxygen and nutrient flux between sediment and water. A laboratory continuous-flow study
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滨海微型底栖植物对沉积物和水体之间氧气和养分通量的影响。
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
K. Pettersson
中科院分区：
文献类型：
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作者：
K. Sundbäck;V. Enoksson;W. Granéli;K. Pettersson
利用室内连续流培养系统，研究了夏季近岸微型底栖植物对桑迪质和泥质沉积物-水界面氧和无机营养盐（N、P、Si）通量的影响。沉积物收集在7月在15米深的非潮汐，分层海湾东南卡特加特。为了测试盐跃层以下与表面沃茨相比无机营养物含量较高是否能刺激微型植物底栖生物的生长，使用了2个营养物浓度水平。昼夜变化被发现在L/D核心，但不是在黑暗的核心，氧，溶解无机氮和磷含量的水覆盖的沉积物。沉积物中NH_4 ~+、NO_3 ~-和~ 0 ~ ~-的释放通量在光照期间呈下降趋势，偶尔出现净吸收。光诱导的O2生产，以及A通量（0，和营养盐的昼夜通量之间的差异），叶绿素a含量和藻类细胞数量之间的相关性，在沉积物中，表明减少IN和POA 3的输出是由光合生物介导的。没有研究硅的昼夜变化，但从L/D核心的Si（OH）的显著较低的流出量，甚至吸收量支持这一结论。这表明硅藻在沉积物和水之间的营养盐通量中起主要作用。此外，LID和黑暗的核心之间的孔隙水营养梯度的差异点的重要性，沉积物相关的生物。每日（24小时）净通量的营养物质主要是出沉积物，但幅度取决于光照条件和沉积物类型。除泥质柱和桑迪柱中的NO3和NO2外，其余营养盐的日净流出量在U D柱中均显著低于暗化柱。记录了桑迪沉积物中Si（OH）4和NO3在L/D柱样中的净吸收。淤泥质沉积物中营养盐的通量显著高于桑迪沉积物（NO3-除外），特别是在长期黑暗条件下。营养盐富集对近岸底栖微藻的丰度没有显著影响。结果表明，m~crophytobenthos可以影响沉积物-水交换的无机营养盐，即使在近岸深度，当测量营养盐通量永久黑暗的核心从深度约15米的卡特加特海峡，夏季通量率将被高估的一个因素在2和6之间变化，取决于沉积物类型。
Influence of sublittoral microphytobenthos on the flux of oxygen and inorganic nutrients ( N , P, Si) at the sediment-water interface was studied using undisturbed cores of sandy and muddy sediment incubated in a laboratory continuous-flow system, either in darkness or with a 16/8 h L/D cycle at in situ light level during summer. Sediment was collected In July at 15 m depth in a non-tidal, stratified bay in SE Kattegat. To test whether the higher content of inorganic nutrients below the halocline, compared with surface waters, could stimulate microphytobenthic growth, 2 levels of nutrient concentrations were used. Diel variations were found In L/D cores, but not in darkened cores, for oxygen, dissolved inorganic nitrogen and phosphorus content in the water overlying the sediment. The flux of NH4+, NO3and ~ 0 ~ ~ out of the sediment decreased during light periods and occasionally a net uptake was recorded. Light-induced O2 production, and correlations between A fluxes (differences between day and night fluxes of 0, and nutrients), chlorophyll a content and algal cell numbers in the sediment, indicate that the decreased outflux of IN and POA3was mediated by photosynthetic organisms. Diel variations were not studied for silicon, but a significantly lower outflux, or even an uptake, of Si(OH), from L/D cores supports this conclusion. This suggests that diatoms play a major role in the nutrient flux between sediment and water. Also, the differences in pore-water nutrient gradients between LID and dark cores point to the importance of sediment-associated organisms. Daily (24 h) net fluxes of nutrients were primarily out of the sediment, but the magnitude depended on both light conditions and sediment type. Daily net outflux was significantly lower in U D cores than in darkened cores for all nutrients except NO3in muddy cores and NO2in sandy cores. Net uptake in L/D cores was recorded for Si(OH)4 and NO3In sandy sediment. Outflux of nutrients was significantly higher from muddy sediments in comparison w ~ t h sandy sediments (except NO3-), especially in permanent darkness. No significant effect of nutrient enrichment on the abundance of sublittoral benthic microalgae could be shown. Results suggest that m~crophytobenthos can influence sediment-water exchange of inorganic nutrients even at sublittoral depths, and when measuring nutrient flux in permanently darkened cores from depths around 15 m in the Kattegat, summer flux rates will be overestimated by a factor varying between 2 and 6, depending on sediment type.