Effects of Higher CO2 and Temperature on Exopolymer Particle Content and Physical Properties of Marine Aggregates
Effects of Higher CO2 and Temperature on Exopolymer Particle Content and Physical Properties of Marine Aggregates
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较高的 CO2 和温度对海洋骨料外聚合物颗粒含量和物理性能的影响
DOI：
10.3389/fmars.2018.00500
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发表时间：
2019
影响因子：
3.7
通讯作者：
A. Engel
中科院分区：
文献类型：
--
作者：
Carolina Cisternas;Cindy Lee;T. Tang;R. D. De Jesus;A. Engel
我们研究了未来的海洋条件，特别是温度和二氧化碳之间的相互作用，可能会影响海洋聚集体的形成和物理性质。最初，充满沿海海水的中型生态系统经历了三种不同的CO2浓度和温度处理：（1）750 ppm CO2，16°C，（2）750 ppm CO2，20°C和（3）390 ppm CO2，16°C。硅藻占主导地位的浮游植物水华在围隔中诱导营养盐。在辊槽中使用的海水从围隔在不同阶段的盛开，我们测量下沉速度，大小，叶绿素a，颗粒有机碳和氮，和外聚合物颗粒含量的聚集体生产的过剩密度和质量计算从下沉速度和大小的聚集体。正如在以前的实验中已经看到的，没有明显的差异，在整体营养吸收，叶绿素a浓度，或外聚合物颗粒浓度可能与酸化处理中的围隔。此外，在滚筒槽实验（RTEs）过程中形成的聚集体中，我们观察到在开花前，开花和开花后期间的处理之间的化学组成没有统计学上的显著差异。然而，物理特性是不同的，并表现出协同效应的温暖的温度和较高的CO2在开花前期间，在这个时候，温度有较大的影响比CO2的总下沉速度。在与温暖和酸化处理（未来的条件）的RTE，聚集体更大，更重，沉淀速度比聚集体形成在目前的一天或只有酸化条件。然而，在后开花期，在当前和未来条件下形成的聚集体具有相似的物理性质。在环境温度下的酸化罐中，聚集体比在相同温度下但在当前CO2下或在更温暖和酸化条件下形成的聚集体更慢、更小和密度更小。因此，常温下酸化池中形成的团聚体沉降速度比其他两种情况慢。我们的研究结果指出了海洋酸化和变暖改变下沉聚集体物理性质的潜力，但也强调了未来实验调查多种环境压力因素的必要性，以澄清每个因素的重要性。
We investigated how future ocean conditions, and specifically the interaction between temperature and CO2, might affect marine aggregate formation and physical properties. Initially, mesocosms filled with coastal seawater were subjected to three different treatments of CO2 concentration and temperature: (1) 750 ppm CO2, 16°C, (2) 750 ppm CO2, 20°C, and (3) 390 ppm CO2, 16°C. Diatom-dominated phytoplankton blooms were induced in the mesocosms by addition of nutrients. In aggregates produced in roller tanks using seawater taken from the mesocosms during different stages of the bloom, we measured sinking velocity, size, chlorophyll a, particulate organic carbon and nitrogen, and exopolymer particle content; excess density and mass were calculated from the sinking velocity and size of the aggregates. As has been seen in previous experiments, no discernable differences in overall nutrient uptake, chlorophyll-a concentration, or exopolymer particle concentrations could be related to the acidification treatment in the mesocosms. In addition, in the aggregates formed during the roller tank experiments (RTEs), we observed no statistically significant differences in chemical composition among the treatments during Pre-Bloom, Bloom, and Post-Bloom periods. However, physical characteristics were different and showed a synergistic effect of warmer temperature and higher CO2 during the Pre-Bloom period; at this time, temperature had a larger effect than CO2 on aggregate sinking velocity. In RTEs with warmer and acidified treatment (future conditions), aggregates were larger, heavier, and settled faster than aggregates formed at present-day or only acidified conditions. During the Post-Bloom, however, aggregates formed under present and future conditions had similar physical properties. In acidified tanks at ambient temperature, aggregates were slower, smaller and less dense than those formed at the same temperature but under present CO2 or under warmer and acidified conditions. Thus, the sinking velocity of aggregates formed in acidified tanks at ambient temperature was slower than the other two cases. Our findings point out the potential of ocean acidification and warming to modify physical properties of sinking aggregates but also emphasize the need of future experiments investigating multiple environmental stressors to clarify the importance of each factor.
影响因子：
4.9
作者：
Iversen, M. H.;Ploug, H.
通讯作者：
Ploug, H.
影响因子：
4.5
作者：
J. Taucher;J. Jones;A. James;M. Brzezinski;C. Carlson;U. Riebesell;U. Passow
通讯作者：
J. Taucher;J. Jones;A. James;M. Brzezinski;C. Carlson;U. Riebesell;U. Passow