Bubble reduction after decompression in the prawn Palaemon elegans by pretreatment with hyperbaric oxygen

Area of Science:

• Marine Biology
• Physiology
• Biomedical Engineering

Background:

• Bubbles in decompression are theorized to originate from pre-existing micronuclei.
• Previous studies showed hyperbaric oxygen (HBO2) pretreatment reduces bubbles in prawns post-decompression from 203 kPa.

Purpose of the Study:

• To investigate the effect of two higher HBO2 pretreatment pressures (405 and 709 kPa) on bubble formation in prawns.
• To assess bubble reduction across a range of decompression pressures (203-810 kPa).

Main Methods:

• Prawns underwent 5-minute HBO2 pretreatment at either 405 kPa (Series A) or 709 kPa (Series B).
• Control groups were exposed to air only.
• Following pretreatment, prawns were exposed to air to nitrogen saturation, then rapidly decompressed and observed for bubbles under a microscope.

Main Results:

• Series A (405 kPa HBO2): Significantly reduced bubble count after decompression from 203, 304, and 405 kPa (p < 0.05). Total gas volume remained unaffected.
• Series B (709 kPa HBO2): Significantly reduced bubble count after decompression from 203, 304, 507, and 608 kPa (p < 0.05).
• Total gas volume was reduced at 507 and 608 kPa decompression levels with 709 kPa HBO2 pretreatment.

Conclusions:

• HBO2 pretreatment at 405 kPa is sufficient to significantly reduce bubble formation upon decompression from multiple pressure levels.
• Higher HBO2 pressures may offer greater bubble reduction across a wider range of decompression scenarios.