Effects of Ocean Acidification on Algal and Invertebrate Assemblages In Crustose Coralline Algae Dominated Kelp Systems

EPA Grant Number: FP917814
Title: Effects of Ocean Acidification on Algal and Invertebrate Assemblages In Crustose Coralline Algae Dominated Kelp Systems
Investigators: Muth, Arley F
Institution: The University of Texas at Austin
EPA Project Officer: Lee, Sonja
Project Period: September 1, 2016 through August 31, 2018
Project Amount: $132,000
RFA: STAR Graduate Fellowships (2015) RFA Text |  Recipients Lists
Research Category: Academic Fellowships


This research aims to explore how ocean acidification may affect kelp system assemblages by using a series of experiments that will focus on community shifts among differing pH and salinity levels.  In addition, broad range surveys will be conducted to observe kelp systems in varying oceanographic conditions from the Alaskan Arctic and southern Chile.


Experiments using cobbles from crustose coralline algae (CCA) dominant kelp systems, (Laminaia solidungula; Alaskan Arctic and Lessonia trabeculata; southern Chile), will be cultured under different pH and salinity levels to observe how these conditions affect the algal assemblages, specifically looking at how changes to productivity and growth of CCA play a role in community shifts.  Cobbles will also be used in a mobile grazer experiment to understand the affects of grazer diversity and behavior on algal assemblages.  Within kelp systems in the Alaskan Arctic and southern Chile, surveys will be conducted (coupled with continuous pH, temperature, and salinity measurements) in areas with different oceanographic conditions to detect natural variations in species assemblages and to help understand how these variations affect kelp systems.

Expected Results:

Although ocean acidification is expected to benefit kelp species productivity, changes in coverage of crustose coralline algae, sessile invertebrates and decreased mobile grazer densities have the potential to alter species assemblages. Opportunistic turf algae and biofilms may settle and expand, limiting substrate availability and light before kelp species are able to settle and become established. These interactions have the potential to cause shifts in dominance from kelp species to turf and opportunistic algal species.

Supplemental Keywords:

ocean acidification, kelp, recruitment, grazers, coralline algae;

Progress and Final Reports:

  • 2017
  • Final