Microfibers often dominate sediment microplastic samples, but little is known about their ecological effects on benthic organisms and functions. Polyethylene terephthalate) (PET) microfibers were added to 36 sediment chambers at six concentrations (0–0.5 g kg^–1 sediment) to assess the effects on microphytobenthos (MPB), a key deposit-feeding bivalve, Macomona liliana, and sediment nutrient pools. MPB photosynthesis was promoted in 18 chambers through a 12 h light/dark cycle. Another 18 chambers were maintained under dark conditions to inhibit photosynthesis. After 35 days of MPB growth and stabilization, four M. liliana were added to each chamber for a further 40 days. MPB biomass and composition were examined alongside M. liliana biochemical and behavioral properties and porewater dissolved inorganic nutrient concentrations. Increasing microfibers resulted in lower MPB biomass, fewer diatom-associated fatty acids (FAs), and an increase in cyanobacteria. The changes in MPB coincided with up to 75% lower energy reserves and reduced burrowing activity in M. liliana. In the light, nitrate + nitrate (NO_x) was significantly elevated and related to M. liliana and MPB biochemical properties. Ammoniu (NH₄⁺) concentrations increased but were variable in both the light and the dark. Our results suggest that increasing microfiber concentrations influence the interactions between M. liliana and MPB and affect biogeochemical processing in coastal marine sediments.

中文翻译：

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聚酯微纤维对微底栖动物和沉积物动物的影响。

微纤维通常在沉积物微塑性样品中占主导地位，但对其底栖生物及其功能的生态影响知之甚少。将聚对苯二甲酸乙二酯（PET）超细纤维以六种浓度（0-0.5 g kg ^-1沉积物）添加到36个沉积室中，以评估对微生底栖动物（MPB），主要的沉积物饲喂双壳类，马科莫纳莉利亚娜和沉积物养分池的影响。通过12 h的明暗循环，在18个小室中促进了MPB的光合作用。将另外18个室保持在黑暗条件下以抑制光合作用。在MPB生长和稳定35天后，将4株M. liliana添加到每个隔室中，持续40天。MPB生物量和组成与M. liliana一起检查生化和行为特性以及孔隙水中溶解的无机养分浓度。增加的超细纤维导致较低的MPB生物量，较少的与硅藻相关的脂肪酸（FAs）和蓝细菌的增加。MPB的变化恰好使M. liliana的能量储备降低了75％，同时挖掘活动减少了。因此，硝酸盐+硝酸盐（NO _x）显着升高，并且与百合分枝杆菌和MPB生化特性有关。氨水（NH ₄ ⁺）浓度增加，但在明暗情况下均变化。我们的结果表明，超细纤维浓度的增加会影响M. liliana之间的相互作用 和MPB，并影响沿海海洋沉积物中的生物地球化学处理。