Fall 2011 Writing 20:Ocean Acidification September 5, 2011 Lecture 2 “Physiological and Ecosystem Effects of Ocean Acidification: Potential Direct and Indirect Effects Some of this lecture obtained from

Outline Physiological processes – Different types – Acclimation and adaptation Ecosystem-level effects – Ecosystem concepts – Different types – Biodiversity & regime shifts Types of studies, experiments

Physiological Processes Calcification Photosynthesis Hypercapnia (too much CO 2 in blood) Nutrient uptake and limitation Reduced gene expression Sensory perception

Physiological Processes Calcification Photosynthesis Hypercapnia (too much CO 2 in blood) Nutrient uptake and limitation Reduced gene expression Sensory perception

Photosynthesis Two different species of algae OA could lead to shifts in algal species composition

Physiological Processes Calcification Photosynthesis Hypercapnia (too much CO 2 in blood) Nutrient uptake and limitation Reduced gene expression Sensory perception

Outline Physiological processes – Different types – Acclimation and adaptation Ecosystem-level effects – Ecosystem concepts – Different types – Biodiversity & regime shifts Types of studies, experiments

Acclimation means the ability of an organism to change its phenotype, or expressed trait so that it can survive in an environment as it changes. Adaptation means the ability of a population of organisms to change its genotype, or its genes in the DNA, over successive generations (evolution). - generation times are important - genetic diversity is important

Example of possible acclimation Byrne et al. 2011, Mar. Biol.

Outline Physiological processes – Different types – Acclimation and adaptation Ecosystem-level effects – Ecosystem concepts – Different types – Biodiversity & regime shifts Types of studies, experiments

Ecosystem Definition: A spatial explicit unit of Earth where living things and the environment interact Perturbations (like ocean acidification) can have various direct and indirect effects: – Shifts in species composition and trophic cascade (food web) effects – Temporal and spatial shifts in ecosystem functions – All of these can change the structure, energy flow, and other functions of the ecosystem => regime shift

Different Types of Ecosystems Likely to be Affected by OA Tropical coral reefs Pelagic ecosystems (pelagic = open water) Coastal/ benthic (benthic = bottom substrate) Deep sea High latitude

Regime shifts Kroeker et al PNAS

Outline Physiological processes – Different types – Acclimation and adaptation Ecosystem-level effects – Ecosystem concepts – Different types – Biodiversity & regime shifts Types of studies, experiments