Photosynthesis and community respiration at three depths during a period of stable phytoplankton stock in a eutrophic brackish water culture pond
Photosynthesis and community respiration at three depths during a period of stable phytoplankton stock in a eutrophic brackish water culture pond
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DOI：
10.3354/meps094229
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发表时间：
1993
影响因子：
2.5
通讯作者：
Jp Szyper;J. Ebeling
中科院分区：
文献类型：
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作者：
Jp Szyper;J. Ebeling
微咸水土池中14 d密集但稳定的浮游植物种群（0.2hm0.7m深）为不稳定性研究提供了基线。说明池塘作为自然系统缩影的潜力。通过每30分钟在3个深度取样一次的氧和无机碳的昼夜曲线分析，评估了初级生产力和群落呼吸。营养元素中，只有无机氮略有增加，日间净生产量（dNPP）为0 ~ 0.26m01m-2d-1，碳吸收量为0.01 ~ 0.22m01m-·d。夜间呼吸（nR）近似匹配dNPP，导致低平均昼夜净生产（NPP）。白天呼吸（dR）的最小估计值显著大于nR和dNPP，最小总生产（GPP = dR + dNPP）平均2.5倍dNPP估计dR随dNPP变化在稳定负反馈中，dNPP和NPP均随光照强度的增加而变化，但nRd ~ d不随光照强度的增加而变化。dNPP和nR均随深度的增加而降低。潜在NPP主要集中在上层，种群和氧循环对弱光干扰的抵抗力比假定池塘深度为1.0 m的模型预测的更强。这与池塘的深度较浅有关，在大多数日期，池塘允许足够的光穿透到底层，以获得正的dNPP
A 14 d perlod of dense but stable phytoplankton stock in a brackish water earthen pond (0 2 ha area 0 7 m depth) was charactenzed to provide a baseline for study of instablllty Results ~l lustrate the potential of ponds to serve as microcosms of natural systems Pnmary production and community respiration were assessed by diel curve analysls of oxygen and inorganic carbon sampled every 30 min at 3 depths Neither stocks nor dlel oxygen regimes were destablllzed by 2 Isolated days of low light, the flrst accompanied by heavy rainfall Among nutrlent elements, only Inorganic nitrogen exhiblted marginally l im~tlng values Daytime net production (dNPP) of oxygen ranged from 0 to 0 26 m01 m-2 d-l , carbon uptake from 0 01 to 0 22 m01 m-'d.' Nlghttime respiration (nR) approximately matched dNPP, resulting in low mean diel net production (NPP) Minimal estimates of daytime respiration (dR) were substantially greater than nR and dNPP, minimal gross production (GPP = dR + dNPP) averaged 2 5 times dNPP Est~mated dR vaned wlth dNPP In a stabilizing negative feedback, poss~bly mediated by photosynthet~c products Both dNPP and NPP vaned with diel irradiance but nR d ~ d not Both dNPP and nR decreased with depth, posltlve NPP was concentrated in the upper layer Stocks and oxygen cycles were more resistant to disturbance by low light than predicted by models assuming 1 0 m pond depth We suggest for further examination that stability was related to the shallow depth of thls pond, which permitted sufficient light penetration to the bottom layer for positlve dNPP on most dates