Download Elevated CO reduces biodiversity and community function in an

BENTHIC OA CONSORTIUM FINAL MEETING, PLYMOUTH MARINE LAB, 26TH – 28TH JUNE 2013.
Elevated CO2 reduces biodiversity and community function in an intertidal cryptic community. Steve Widdicombe, Piero Calosi, Nadja Christen, Rachel Hale & Louise McNeill
ARTIFICIAL SUBSTRATE UNITS (ASUS)
2 studies looking at cryptic communities
R. Hale, P. Calosi, L. McNeill, N. Mieszkowska & S. Widdicombe. 2011. Predicted levels of future ocean acidification and temperature rise could alter community structure and biodiversity in marine benthic communities. Oikos 120: 661‐674
N. Christen, P. Calosi, C.L. McNeill & S. Widdicombe. 2013. Structural and functional vulnerability to elevated pCO2 in marine benthic communities. Marine Biology
MOLLUSC AND ARTHROPOD DIVERSITY
Hale et al and Christen et al combined.
Diversity levels were similar between the 2 studies even though exposure times and temperatures were different.
Combining the results identifies some generic relationships.
Seawater acidification reduced species diversity in both molluscs and arthropods.
The nature of the relationship between diversity and pH was different in molluscs and arthropods. Loss of soft tissue biomass driven by Arthropods.
Loss of CaCO3 biomass driven by Molluscs.
Community
CaCO3 biomass
Seawater acidification reduces total community biomass.
Soft tissue biomass
SOFT TISSUE VS CaCO3 BIOMASS
KEY FINDINGS
CO2‐induced seawater acidification causes:
Changes in community structure and diversity, together with a reduction in soft tissue biomass. Relatively greater impacts on calcifiers than non‐calcifiers, with largest impacts on gastropod molluscs and serpulid polychaetes.
A switch to net dissolution status of communities at pH 7.6‐7.4 will likely lead to a reduction in the carbon sequestration capacity (ecosystem function) of marine intertidal benthic ecosystems. Changes in species diversity that may lead to the simplification of trophic complexity and food webs of marine intertidal benthic communities.
It is important to note that the limited exposure time (30 d / 60 d) does not allow to verify our results in the light of the effect of long‐term acclimation responses (see Dupont et al. 2012) and organisms’ further adaptation to decreasing pH (e.g. Collins & Bell 2004, and Calosi presentation), nor does it allow immigration and emigration of organisms.