Multiple timescale processes drive ecosystem metabolism in eelgrass (Zostera marina) meadows
Multiple timescale processes drive ecosystem metabolism in eelgrass (Zostera marina) meadows
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多个时间尺度过程驱动鳗草（Zostera marina）草甸的生态系统新陈代谢
DOI：
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
K. McGlathery
中科院分区：
文献类型：
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作者：
J. Rheuban;P. Berg;K. McGlathery
底栖生态系统与上覆水柱之间的氧通量是代谢状况的一种衡量指标，也是碳循环常用的替代指标。在本研究中，我们在美国弗吉尼亚州沿海海湾的一片修复后的大叶藻（Zostera marina L.）草甸中，使用涡度相关技术按季节测量了氧通量。在5次集中的野外考察中，我们涵盖了氧代谢和生物量的季节变化，并在夏末有重叠观测，以观察年际变化。高分辨率的测量使得我们能够在多个时间尺度上确定代谢的驱动因素：从分钟到小时、每天以及每月到季节。夜间每小时通量与流速之间存在很强的相关性，这种相关性随海草茎密度和温度的季节变化而变化。白天没有观察到类似的关系。在10月和8月观察到全天氧通量存在滞后效应，这很可能是由于下午呼吸作用（R）增强所致。10月，在相同辐照度下，下午的群落净生产比上午低90%。根据这种滞后效应，我们计算出白天的呼吸作用可能比夜间大2.5倍。全年中，每日总初级生产（GPP）和呼吸作用的量值密切相关，接近1∶1的比例，这反映了在每日到季节的时间尺度上GPP和呼吸作用之间的紧密耦合。我们的研究结果记录了氧通量的动态特性，当对其进行时间积分时，会转化为在每日到季节时间尺度上高度变化的生态系统代谢速率。必须考虑这种变化才能准确确定营养状况。
The oxygen flux between benthic eco- systems and the overlying water column is a measure of metabolic status and a commonly used proxy for carbon cycling. In this study, oxygen flux was meas- ured seasonally using the eddy correlation technique in a restored eelgrass (Zostera marina L.) meadow in the Virginia coastal bays (USA). In 5 intensive field campaigns, we covered seasonal variation in oxygen metabolism and biomass with overlap in late summer to observe interannual variability. The high-resolution measurements allowed identification of the drivers of metabolism at multiple timescales: minute to hourly, daily, and monthly to seasonally. There was a strong correlation between nighttime hourly fluxes and current velocity that varied seasonally with seagrass shoot density and temperature. No similar relationship was observed during the day. A hysteresis effect in oxygen flux throughout the day was observed during October and August that was most likely due to in- creased respiration (R) in the afternoon. In October, net community production was 90% lower in the af- ternoon than in the morning at the same irradiance. From this hysteresis, we calculated that daytime R may be up to 2.5-fold larger than nighttime R. The magnitudes of daily gross primary production (GPP) and R were well correlated throughout the year with close to a 1:1 ratio that reflected a tight coupling be- tween GPP and R on daily to seasonal timescales. Our results document the dynamic nature of oxygen fluxes that, when integrated over time, translate into highly variable rates of ecosystem metabolism over daily to seasonal timescales. This variation must be incorpo- rated to accurately determine trophic status.
影响因子：
2.5
作者：
Glud, Ronnie N.;Berg, Peter;Rysgaard, Soren
通讯作者：
Rysgaard, Soren