Oil uptake via marine snow: Effects on blue mussels (Mytilus sp.)

Area of Science:

• Marine biology
• Environmental toxicology
• Ecotoxicology

Background:

• Ocean oil spills can lead to oil settling on the seafloor via marine snow.
• Arctic and subarctic regions may experience significant benthic oil deposition.
• Potential impacts of oil-contaminated marine snow on benthic communities are not well understood.

Purpose of the Study:

• To investigate the effects of oil-contaminated marine snow (MOS) on blue mussels (Mytilus sp.).
• To compare the impacts of MOS with chemically-enhanced water-accommodated fraction (CEWAF) of oil on mussel health.
• To assess oil partitioning, DNA damage, clearance rate, and condition index in mussels.

Main Methods:

• Mussels were exposed to MOS or CEWAF for four days.
• Control groups received clean seawater with or without marine snow.
• Key endpoints included oil partitioning, DNA damage (comet assay), clearance rate, and condition index.
• Mussels underwent a ten-day recovery period in clean seawater.

Main Results:

• Oil partitioning patterns differed between seawater and MOS, but not significantly into mussel tissue between treatments.
• DNA damage remained below background levels, though CEWAF-T showed higher damage post-recovery.
• Mussels in CEWAF treatment had a reduced clearance rate compared to controls.
• All mussels except CEWAF-T showed an increased condition index post-exposure.

Conclusions:

• Oil-contaminated marine snow may mitigate negative effects of oil exposure on blue mussels.
• Aggregates might offer more concentrated nutrition, potentially buffering oil toxicity.
• Findings suggest marine aggregates play a role in the fate and impact of oil spills on benthic organisms.