The Response of Molting Homarus Americanus to Ocean Acidification Projections

Author

Erin Lyn McLean, University of Rhode IslandFollow

Date of Award

2016

Degree Type

Thesis

Degree Name

Master of Science in Biological and Environmental Sciences (MSBES)

Department

Biological Sciences

First Advisor

Brad Seibel

Abstract

Marine calcifiers, especially those in their larval and juvenile stages, are thought to be most vulnerable to ocean acidification (OA) due to the effects of carbon dioxide (CO₂) on growth and shell mineralogy. However, recent evidence is contradictory. We monitored molting activity, length and weight in early benthic phase juvenile American lobster Homarus americanus (Milne-Edwards 1837) under elevated CO₂ conditions (500 µatm, 1100-1300 µatm, and 2000-2700 µatm) to determine how OA affects growth at this life stage. Molted shells were analyzed for magnesium (Mg²⁺) and calcium (Ca²⁺) content by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Exposure to higher CO₂ partial pressures over a 90-120 day period affected the length of the intermolt period and caused decreased length and weight growth increments. The higher concentrations of CO₂ also changed the magnesium to calcium (Mg:Ca) ratio present in the mineralized shell. Shells from lobsters in the medium and high CO₂ treatments had an overall higher Mg:Ca than lobsters in the control CO₂ treatment. Lobsters in the medium and high CO₂ treatments were also more susceptible to shell disease. Taken together, these results suggest juvenile lobsters may remain smaller for a longer period of time and be more vulnerable to disease and/or shell dissolution in a high CO₂ ocean.

Recommended Citation

McLean, Erin Lyn, "The Response of Molting Homarus Americanus to Ocean Acidification Projections" (2016). Open Access Master's Theses. Paper 824.
https://digitalcommons.uri.edu/theses/824