ABSTRACT Dissolved nutrient uptake and metabolism by periphyton in a central North Island gravel-bed river were investigated using recirculating in-situ chambers. Dissolved inorganic nitrogen (DIN) uptake was correlated with photosynthesis and chlorophyll but N uptake and carbon fixation were partly de-coupled indicating storage. Dissolved reactive phosphorus (DRP) uptake was only weakly correlated with photosynthesis. Diatoms and green algae relied on DRP in the water, but Cyanobacteria met part of their P needs from storage. Dissolved organic nutrients were excreted in both light and dark incubations, with approximately 50% of DIN uptake during photosynthesis excreted as DON. To simulate diurnal variations in nutrients, oxygen and pH existing computer models need to de-couple photosynthesis from nutrient uptake, allow for variable stoichiometry and better quantify recycling of organic nutrients.

中文翻译：

---

浅水、砾石河床中的养分衰减。I. 原位室实验

摘要 使用循环原位室研究了北岛中部砾石床河流中附生生物对溶解养分的吸收和代谢。溶解无机氮 (DIN) 吸收与光合作用和叶绿素相关，但 N 吸收和碳固定部分解耦，表明储存。溶解活性磷 (DRP) 吸收与光合作用仅微弱相关。硅藻和绿藻依赖于水中的 DRP，但蓝藻通过储存满足了它们对 P 的部分需求。溶解的有机营养物在明暗培养中都被排出体外，光合作用过程中大约 50% 的 DIN 吸收以 DON 形式排出。为了模拟养分、氧气和 pH 值的昼夜变化，现有的计算机模型需要将光合作用与养分吸收分离，