Benthic primary production and nutrient cycling in sediments with benthic microalgae and transient accumulation of macroalgae
Benthic primary production and nutrient cycling in sediments with benthic microalgae and transient accumulation of macroalgae
复制标题
DOI：
10.4319/lo.2003.48.6.2138
复制
发表时间：
2003-11-01
影响因子：
4.5
通讯作者：
Dalsgaard, T
中科院分区：
文献类型：
--
作者：
Dalsgaard, T
在丹麦的Limfjorden，Virksund和Ulbjerg这两个浅的地点，对沉积物反硝化作用和沉积物-水的氧和营养物质通量的年速率进行了量化。沉积物为桑迪，主要为双壳类，湿重在维尔克松为2，508 g m（-2），在乌尔比约为572 g m（-2）。底栖微藻群落全年存在，在夏季的1-2个月，漂浮的大型藻类部分覆盖沉积物。计算了包括和不包括大型藻类活动的沉积物的年度预算。在没有大型藻类的情况下，底栖初级生产力最高的Ulbjerg，这是每年的基础上，而Virksund异养。当包括大型藻类，这两个网站强烈的每年的基础上自养。从13%到58%的NH 4+矿化产生的保留在沉积物中的大型藻类的情况下，主要是因为NH 4+的同化的microphytobenthic社区。只有25%和38%的总NO3-吸收在Ulbjerg和Virksund，分别，在没有大型藻类，而在大型藻类的存在下，12%和39%的NO的吸收在这些网站被分解。硝酸盐吸收与底栖生物初级生产限制反硝化通过竞争NO3-释放NH 4+从沉积物在Virksund减少了50%以上，并在Ulbjerg，释放NH 4+吸收时，大型藻类被列入年度预算。大型藻类的营养吸收竞争与所有其他营养消耗过程，和大型藻类的瞬时发生完全改变了初级生产力和营养收支的两个网站。
Annual rates of sediment denitrification and sediment-water fluxes of oxygen and nutrients were quantified at two shallow locations, Virksund and Ulbjerg, in the Limfjorden, Denmark. The sediment was sandy and colonized mainly by bivalves with a wet weight of 2,508 g m(-2) at Virksund and 572 g m(-2) at Ulbjerg. A benthic microalgal community was present throughout the year, and for 1-2 months in the summer, floating macroalgae partly covered the sediment. Annual budgets for the sediment both including and excluding the activity of macroalgae were calculated. In the absence of macroalgae, the benthic primary production was highest at Ulbjerg, which was autotrophic on an annual basis, whereas Virksund was heterotrophic. When macroalgae were included, both sites were strongly autotrophic on an annual basis. From 13% to 58% of the NH4+ produced by mineralization was retained in the sediment in the absence of macroalgae, primarily because of the assimilation of NH4+ by the microphytobenthic community. Only 25% and 38% of the total NO3- uptake at Ulbjerg and Virksund, respectively, was denitrified in the absence of macroalgae, whereas in the presence of macroalgae, 12% and 39% of the NO; uptake was denitrified at those sites. Nitrate uptake associated with benthic primary production limited denitrification through competition for NO3- The release of NH4+ from the sediment at Virksund was reduced more than 50%, and at Ulbjerg, release of NH4+ changed to uptake when the macroalgae were included in the annual budget. Nutrient uptake by macroalgae competed with all other nutrient-consuming processes, and the transient occurrence of macroalgae totally changed both the primary productivity and the nutrient budgets for the two sites.