Carlyn Scott, College of Marine Science
Kendra Daly
The 2010 Deepwater Horizon oil spill released nearly five million barrels of oil into the northeast Gulf over the course of 87 days. Kendra Daly, biological oceanography professor at the College of Marine Science, sent out a camera imaging system to understand the impact that the oil would have on marine snow.
Marine snow particles are small detrital particles or aggregates characterized by size (>0.5mm), and typically composed of phytoplankton, fecal pellets, fragmented body parts of zooplankton, and mucus feeding webs. Since the aggregates are dense and can sink rapidly, marine snow is an essential component of ocean ecosystems, removing materials — and their carbon — from the surface waters to the depths of the ocean.
In a study published in the , Daly used a camera imaging system to evaluate marine snow directly after and in the years following the oil spill. Her team deployed a towed system called SIPPER (Shadowed Image Particle Profiling Evaluation Recorder) to collect more than 117 million images of marine snow in the water column in the northeastern Gulf from 2010 to 2014. They used computer image detection and classification software to identify organisms and marine snow.
They found that within the spill region, marine snow formed larger aggregates than areas without oil. This indicates that the oil integrated into marine snow may have resulted in more compact particles with higher sinking rates, removing more particles from the upper water column.
A towed camera imaging system, the Shadowed Image Particle Profiling Evaluation Recorder, was used to evaluate the impact of the oil spill on plankton and marine snow.
The study identified the types of organisms incorporated within the aggregates such as diatoms and radiolarians. These organisms increased the effective size of the marine snow, causing them to be longer or stickier due to the physical attributes of the plankton, such as spines and elongated chains, which increased the sinking rates of the snow.
In addition, the dinoflagellate Noctiluca was observed on the surface of marine snow aggregates, likely feeding on the oil droplets, as observed in previous studies in spill regions.
This study provided a scope of the impact of the DWH oil spill on an essential ecological process in the Gulf, as well as baseline data on marine snow dynamics in the northeast Gulf, which can be used to further model development and assess future perturbations, such as oil spills, and the effects of climate change on biogeochemical cycles in this region.