Potential environmental effects of CO2 leakage in the marine and terrestrial environments

1. Marine impacts and
risk assessment
Dr Steve Widdicombe

2. Impact of CO2 on seawater chemistry
CO2, H+ and bicarbonate levels ↑
Carbonate levels ↓

3. CO2 as a key component in physiological complexity
Low ocean pH and high CO2
and reduced HCO3-
Calcification site ion equilibria - Na+/H+-exchange etc.
Epithelia (gill, gut, kidney)
calcification - H+ Ω
Brain
(from Pörtner 2008 and Pörtner et al. 2005)
protein synthesis rate
ventilation rate
metabolic equilibria
CO2 H2O Chemosensory
HCO3- H2 O Neurons pHi ↓
H+i 2 K+
- ATP-
ase H+e
3 Na+ Adenosine
accumulation
Na+ +
- and release
(some groups)Operculum
H+
Heart Muscle
HCO3-
Cl-
- - functional
H+
blood capacity
-
membrane
Na+ pigment
gene
expression ( + or - )
intracellular space extracellular space Tissues

4. Rapidly growing evidence of biological effects
Individuals response;
calcification, acid-base balance, growth, photosynthesis,
respiration, reproduction, immune function,……..
Early life stages

5. Calcification continues even under extreme CO2 conditions

6. Physiological plasticity
umol oxygen/day/g animal
140
120
100
± 95% CI
80
60
40
20
0
8 7.7 7.3 6.8
pH
length mm ± 95% CI
30
25
20
15
10
5
0
8 7.7 7.3 6.8
pH treatment
Lowered pH causes significant increase in
established
respiratory rate 40
% calcium/ g of arm ± 95% CI
regrowth
35
30
Regrowth significantly longer at lowered pH 25
20
pH significantly affects calcium content in arm 15
10
regrowth 5
0
8 7.7 7.3 6.8
Arm regrowth has significantly higher calcium pH
content than established arms

7. The unseen cost
control 7.7
7.3 6.8
Reproductive Digestive Respiratory
pH 8.0 pH 7.6
intestinal brush
Developing eggs
border goblet cells
pH 7.2 pH 6.8
Mature eggs
membrane basal membrane
coelomic fluid
Degenerating eggs

8. Animal behaviour

9. Impacts on the whole organism
GROWTH
FEEDING
REPRODUCTION
MAINTENANCE
Important to consider how changes in
Whole one physiological process can affect
other, interdependent process.
Organism
Physiological Trade-Offs
Approach

10. Interaction with other Environmental Stressors
Thermal windows for animals
(may include shifts through acclimatization)
Individual
performance
loss of performance, abundance
Topt
Tpej
Scope for aerobic performance
onset of anaerobiosis
Population
Tpej distribution
CO2 (Biogeography)
onset of denaturation
hypoxia
Tcrit Tcrit
Tden
T (°C) Biodiversity
passive - active - passive range
short - long - short term tolerance
H.O. Pörtner and A.P. Farrell (2008) Science 322, 690-692

11. Impact of habitat type
Sand Mud
2 weeks 20 weeks 20 weeks
√S = 1.245 + 0.537pH √S = -53.49 + 15.74pH – 1.68pH² √S = -46.71 + 13.8pH – 0.906pH²
7
6.0 5
6
5.5 4
5
3
√S
√S
5.0 4
2 3
4.5
1 2
4.0
0 1
5.5 6.0 6.5 7.0 7.5 8.0
5.5 6.0 6.5 7.0 7.5 8.0 5.5 6.0 6.5 7.0 7.5 8.0
log10NI = -5.476 + 2.102pH – 0.14pH²
log10NI = -2.708 + 1.303pH – 0.086pH² log10NI = -19.28 + 5.668pH – 0.379pH²
2.4 2.5
Log10NI
2.0
2.3
2.25
log10NI
2.2 1.5
2.0
2.1 1.0
2.0 1.75
0.5
1.9 1.5
1.8 0 5.5 6.0 6.5 7.0 7.5 8.0
5.5 6.0 6.5 7.0 7.5 8.0 5.5 6.0 6.5 7.0 7.5 8.0
Seawater pH 0.9
J = 0.2326 + 0.070pH
Communities made up of both tolerant and intolerant species 0.8
J
0.7
Polychaetes – Crustaceans – Molluscs – Echinoderms
0.6
Differences within as well as between taxonomic groups 0.5
Community and species response was affected by sediment type 5.5 6.0 6.5 7.0 7.5 8.0
Acidification will result in communities that are taxonomically and Seawater pH
functionally different.
S. Widdicombe, et al (2009) Effects of CO2 induced seawater acidification on infaunal diversity and sediment nutrient fluxes. Mar Ecol Prog Ser 379: 59-75.

12. Microbes
Thick pink Cyanobacteria (Oscillatoria sp.) mat at pH 7.5 and 7

13. Surviving in a stressful environment
Marine organisms are extremely sensitive to changes in seawater
carbon chemistry
Many organisms possess physiological or behavioural mechanisms
for dealing with short term exposure to environmental stress
However, most “coping” mechanisms incur a biological or ecological
cost that will reduce an organism’s “performance” in the long-term
Impact of leaks will be dependant on both the severity, the longevity
and the nature of the perturbation.
Differences between species, life stages, habitats etc will dictate the
impact of leaks on biodiversity and community structure
Impacts will depend on “when” and “where” leaks occur
Consequences go beyond biological consideration – socio-economics
Data needed from experiments that include ecological interactions

14. Organism health
32 day study on Mytilus
edulis looking at several
immune parameters
OA suppressed
phagocytosis in mussels
after 32 days, reducing
normal immune capacity

15. Organisms can make different “decisions” under different conditions
The mussel, Mytilus edulis, maintained under one of five pH
treatments (8.05, 7.8, 7.6, 7.35 or 6.5) and one of two
temperatures (12ºC or 16ºC) for a total of 90 days
Immune response measured in surviving mussels after 83
days of exposure to low pH and increased temperature, (T0)
Remaining mussels in each aquaria inoculated with pathogenic
bacteria, Vibrio tubiashii
Immune response measured again 24 hours (T1) and 7 days
(T7) after bacterial challenge
Antibacterial activity of mussel haemolymph
1.2
T0 Post
1.0
*
0.4
inoculation * At low pH mussels have
0.3
reduced ability to fight
Change in Growth Inhibition
0.8
Growth Inhibition
0.6
0.2
bacterial. Infection. Yet
on exposure to bacteria
0.4 0.1
mussels at low pH are
0.2 0.0 able to increase
antibacterial activity
0.0 -0.1
8.00 7.80 7.60 7.35 6.50 8.00 7.80 7.60 7.35 6.50
pH pH
Ellis et al (in review), "Balancing the cost of climate change: mussels trade-off their
immune system to manage stress.", Nature Climate Change.

16. Assessing Risk
Predicting the impact of leakage
on marine ecosystems and their
function is key to appreciating the
potential risks
In doing so we need to
remember that the ecosystem is a
complex web of interactions
between organisms (from micro to
mega) and processes (chemical,
physical and biological)
Consequences depend on the
sensitivity and importance of the
marine systems at risk

17. High CO2 exposure systems