Cuttlefish Buoyancy in Response to Food Availability and Ocean Acidification

Area of Science:

• Marine Biology
• Oceanography
• Climate Change Science

Background:

• Atmospheric CO2 is rising, causing ocean acidification (OA) and decreasing ocean pH.
• OA affects marine calcifying organisms, including the cuttlebone of the common cuttlefish (Sepia officinalis).
• Nutritional status influences cuttlebone structure and buoyancy.

Purpose of the Study:

• To investigate the combined effects of OA and food availability on cuttlefish newborn buoyancy.
• To assess the impact on cuttlebone weight/area ratio as a proxy for calcification.

Main Methods:

• Exposed cuttlefish hatchlings to OA conditions (980 μatm CO2).
• Manipulated food availability (fed vs. non-fed).
• Measured buoyancy and cuttlebone weight/area ratio.

Main Results:

• OA negatively affected hatching success but increased cuttlebone weight/area ratio in fed newborns.
• Starvation, not OA, significantly increased the proportion of hatchlings with buoyancy loss ('floating').
• Buoyancy loss under starvation correlated with a decreased cuttlebone weight/area ratio.

Conclusions:

• Cuttlefish buoyancy is significantly impacted by starvation.
• Nutritional condition is crucial for understanding calcifying organisms' responses to ocean acidification.
• The study highlights the interplay between environmental stressors and organismal physiology.