Reynier Márcia V, Tâmega Frederico T S, Daflon Sarah D A, Santos Maurício A B, Coutinho Ricardo, Figueiredo Marcia A O
LABTOX-Environmental Analysis Laboratory, University City, Rio de Janeiro, Brazil.
Marine Biodiversity Institute, Rio de Janeiro, Brazil.
Environ Toxicol Chem. 2015 Jul;34(7):1572-7. doi: 10.1002/etc.2938. Epub 2015 May 15.
Discharge of drill cuttings into the ocean during drilling of offshore oil wells can impact benthic communities through an increase in the concentrations of suspended particles in the water column and sedimentation of particles on the seafloor around the drilling installation. The present study assessed effects of water-based drill cuttings, barite, bentonite, and natural sediments on shallow- and deep-water calcareous algae in short-term (30 d) and long-term (90 d) experiments, using 2 species from Peregrino's oil field at Campos Basin, Brazil: Mesophyllum engelhartii and Lithothamnion sp. The results were compared with the shallow-water species Lithothamnion crispatum. Smothering and burial exposures were simulated. Oxygen production and fluorescence readings were recorded. Although less productive, M. engelhartii was as sensitive to stress as Lithothamnion sp. Mesophyllum engelhartii was sensitive to smothering by drill cuttings, barite, and bentonite after 60 d of exposure and was similarly affected by natural sediments after 90 d. These results indicate that smothering by sediments caused physical effects that might be attributable to partial light attenuation and partial restriction on gas exchange but did not kill the calcareous algae in the long term. However, 1-mo burial by either natural sediments or drill cuttings was sufficient after 60 d for both species to reduce oxygen production, and the algae were completely dead under both sources of sediments.
在海上油井钻探过程中，将钻屑排放到海洋中，会导致水柱中悬浮颗粒浓度增加以及钻台周围海底颗粒沉降，从而影响底栖生物群落。本研究通过短期（30天）和长期（90天）实验，评估了水基钻屑、重晶石、膨润土和天然沉积物对浅水和深水钙质藻类的影响，实验使用了巴西坎波斯盆地佩雷格里诺油田的两个物种：恩氏中叶藻和石枝藻属。将结果与浅水物种皱波石枝藻进行了比较。模拟了窒息和掩埋暴露情况。记录了氧气产量和荧光读数。尽管恩氏中叶藻的生产力较低，但它对压力的敏感度与石枝藻属相同。暴露60天后，恩氏中叶藻对钻屑、重晶石和膨润土的窒息敏感，90天后对天然沉积物也有类似反应。这些结果表明，沉积物的窒息造成了物理影响，这可能归因于部分光衰减和部分气体交换受限，但从长期来看并没有杀死钙质藻类。然而，对于这两个物种而言，60天后，无论是天然沉积物还是钻屑进行1个月的掩埋，都足以降低氧气产量，并且在两种沉积物来源下藻类均完全死亡。
