Recent studies suggest aluminum (Al) likely plays a role in the ocean carbon cycle by altering the biological carbon fixation and carbon decomposition of marine diatoms. However, it remains speculative whether Al has similar effects on other ecologically important phytoplankton groups such as the globally important nitrogen-fixing cyanobacterium, Trichodesmium. Here we report the influence of Al on carbon fixation and decomposition in non-axenic cultures of Trichodesmium erythraeum IMS101 (CCMP 1985). By using radiocarbon, and adding oceanic relevant amounts of dissolved Al (yielding concentrations of 40 and 200 nM) along with non-Al-amended controls, we investigated the changes in particulate organic carbon (POC) of Trichodesmium (> 2 μm, Trichodesmium POC), and free-living bacteria (0.2–2 μm, bacterial POC), and dissolved organic carbon (< 0.2 μm, DOC) over a 116-day growth period. The results showed that the rates of increase of POC in the declining growth phase of T. erythraeum were significantly higher (by 11–14%) in the Al-enriched treatments than in the control, and this Al-enhanced carbon fixation is consistent with previous observations on marine diatoms. On the other hand, unlike diatoms, the POC from T. erythraeum decomposed faster in the Al-enriched treatments during the first decay phase when bacterial POC and DOC increased along with the decomposition of Trichodesmium POC. Further addition of the same amounts of Al (again calculated to increase the Al concentration by 40 and 200 nM) was performed on day 71. This treatment was designed to mimic Al supply from sediment after the settling of Trichodesmium colonies to the ocean bottom. Following this second addition, the decomposition rate of both Trichodesmium POC and DOC slowed down by 20–27% and 31–62%, respectively, during the second decay phase, when DOC and bacterial POC decreased. The study suggests that Al fertilization in the surface ocean via dust deposition may increase the net carbon fixation and associated nitrogen fixation by Trichodesmium, and thus the supply of new nitrogen to the euphotic zone, whereas Al from sediment may decrease the decomposition rate of decaying Trichodesmium settled to the ocean bottom.

最近的研究表明，铝（Al）可能通过改变海洋硅藻的生物碳固定和碳分解在海洋碳循环中发挥作用。然而，铝是否对其他生态上重要的浮游植物群（例如全球重要的固氮蓝藻、毛藻）具有类似的影响仍然是推测。在这里，我们报告了铝对红木霉IMS101非无菌培养物中碳固定和分解的影响(CCMP 1985)。通过使用放射性碳，并添加海洋相关量的溶解铝（产生浓度为 40 和 200 nM）以及非铝修正对照，我们研究了 Trichodesmium（> 2 μm、Trichodesmium POC）、自由生活细菌（0.2–2 μm，细菌 POC）和溶解有机碳（< 0.2 μm，DOC）超过 116 天的生长期。结果表明，富铝处理红斑藻生长衰退期的POC增加率显着高于对照（提高11%~14%），这与富铝处理的固碳效果一致。先前对海洋硅藻的观察。另一方面，与硅藻不同，红毛藻的 POC在第一个腐烂阶段在富铝处理中分解得更快，此时细菌 POC 和 DOC 随着毛藻的分解而增加概念验证。在第 71 天进一步添加相同量的 Al（再次计算以将 Al 浓度增​​加 40 和 200 nM）。这种处理旨在模拟毛藻菌落沉降到海底后沉积物中的 Al供应。第二次添加后，在第二个腐烂阶段，当 DOC 和细菌 POC 减少时，Trichodesmium POC 和 DOC的分解速率分别减慢了 20-27% 和 31-62%。研究表明，通过尘埃沉积在海洋表面施铝可能会增加毛藻的净碳固定和相关的固氮作用，从而向真光带供应新的氮，而沉积物中的铝可能会降低沉降到海底的腐烂毛藻的分解速率。