Institute of Marine Science, University of Auckland, Private Bag, 92019, Auckland, New Zealand.
Energy & Environment Institute, University of Hull, Hull HU6 7RX, England.
Environ Sci Technol. 2020 Jul 7;54(13):7970-7982. doi: 10.1021/acs.est.0c00514. Epub 2020 Jun 9.
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 sediment) to assess the effects on microphytobenthos (MPB), a key deposit-feeding bivalve, , 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 were added to each chamber for a further 40 days. MPB biomass and composition were examined alongside 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 . In the light, nitrate + nitrate (NO) was significantly elevated and related to and MPB biochemical properties. Ammoniu (NH) concentrations increased but were variable in both the light and the dark. Our results suggest that increasing microfiber concentrations influence the interactions between and MPB and affect biogeochemical processing in coastal marine sediments.
微纤维通常在沉积物中的微塑料样本中占主导地位，但对于它们对底栖生物和功能的生态影响知之甚少。聚对苯二甲酸乙二醇酯（PET）微纤维被添加到 36 个沉积物室中，浓度为 6 个（0-0.5 克公斤沉积物），以评估其对微藻（MPB）的影响，这是一种关键的沉积食性双壳类动物和沉积物养分库。通过 12 小时的光/暗循环，18 个室中的 MPB 光合作用得到促进。另外 18 个室在黑暗条件下保持，以抑制光合作用。在 MPB 生长和稳定 35 天后，每个室中添加 4 个进一步 40 天。检查了 MPB 的生物量和组成，以及生物化学和行为特性以及孔隙水溶解无机养分浓度。微纤维的增加导致 MPB 生物量降低，与硅藻相关的脂肪酸（FA）减少，蓝藻增加。MPB 的变化与能量储备降低了高达 75%，并且 在 中 的 挖掘活动减少有关。在光下，硝酸盐+硝酸盐（NO）显著升高，并与 和 MPB 的生物化学特性相关。氨（NH）浓度增加，但在光和暗条件下均变化。我们的结果表明，增加微纤维浓度会影响 和 MPB 之间的相互作用，并影响沿海海洋沉积物中的生物地球化学过程。
