Abstract:

This dataset contains marine aggregate pictures from the Mesocosm 1 experiment using a Scanning Electron Microscope during the period of August-October 2015. These data show the formation and morphology of aggregates changes between the mesocosm treatments of control, oil (as WAF, water accommodated fraction) and dispersant/WAF (CEWAF, chemically enhanced WAF) in the water column.

Suggested Citation:

Chin, Wei-Chun; Chiu, Meng-Hsuen (James). 2017. Scanning Electron Microscopy (SEM) observation of morphologies of sediments from a mesocosm experiment studying formation of marine aggregates with oil and dispersant. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N79Z92X6

Purpose:

To study the composition of marine aggregates in sediment. These data show the formation and morphology of aggregates changes between the mesocosm treatments of control, oil (as WAF, water accommodated fraction) and dispersant/WAF (CEWAF, chemically enhanced WAF) in the water column.

Data Parameters and Units:

Control.tif - control seawater after 120 hours, SEM operated at 20 kV, 88.3 mm distance, 200x magnification CEWAF 400X.tif - seawater and CEWAF after 120 hours, SEM operated at 20 kV, 9.01 mm distance, 400x magnification CEWAF 1000X.tif - seawater and CEWAF after 120 hours, SEM operated at 20 kV, 9.01 mm distance, 1000x magnification CEWAF_2000X.tif - seawater and CWAF after 120 h, 20 kV, 9.03 mm distance, 2000x magnification DECWAF_400x.tif – seawater and DECWAF after 120 h, 20 kV, 9.05 mm distance, 400x magnification DCEWAF_1000x – seawater and DECWAF after 120 h, 20 kV,9.10 mm, 1000x magnification WAF_200x.tif- seawater and WAF after 120 h, 20 kV, 8.83 mm distance, 200x magnification HV: High voltage model Spot: spot size of electron beam Det Etd: Electric detector Sig SE: Signal, second electron WD: working distance Mag: magnification Micrometer

Methods:

The mesocosm treatments consisted of 70 L tanks of seawater with 200 mL of concentrated natural particles added to each of the Control (seawater, no oil, no Corexit), WAF (water accommodated fraction of oil, added to seawater with an initial estimated oil equivalency [EOE] of 2 mg/L with an EOE of 0 mg/L after 112 hrs), CEWAF (chemically enhanced WAF with Corexit added to oil at a 20:1 ratio, with an initial EOE of 61.6 mg/L and an EOE of 4.2 mg/L after 112 hr), DCEWAF (diluted CEWAF, initial EOE of 8 mg/L, and an EOE of 0.4 mg/L after 112 hr). The bottom sediments, in mg/L normalized to carbon, were found to be comprised of 0.02, 0.02, 0.01, 0.005 polysaccharides in the Control, WAF, DCEWAF, and CEWAF treatments, respectively, and 0.07, 0.08, 0.03, 0.02 proteins in the respective treatments. The mesocosm bottom samples were filtrated with 0.22μm Isopore Membrane Filters (Millipore, USA) and dry in 65℃ for overnight. The filtered sediment samples were deposited thin layer of Au.

Instruments:

FEI Quanta 200 ESEM system

Individual Files: