Campana, G.

Cordone, G.

De Troch, M.

Deregibus, D.

Doyle, S.

Momo, F.R.

Moreira, M.E.

Oro, E.B.

Quartino, M.L.

Sahade, R.

Salinas, V.

Saravia, L.A.

Tatián, M.

Tomás, M.

Torre, L.

Open Marine Archive

207 
 
S06: Changes in the foundation of the food web 
The food web of Potter Cove (Isla 25 de Mayo/King George Is.): 
complexity, structure and function 
Marina Tomás I.1, 2, 3, Vanesa Salinas1, 2, Georgina Cordone1, 2, Gabriela Campana3, 4, María Eugenia 
Moreira4, Dolores Deregibus4, Luciana Torre5, Ricardo Sahade5, 6, Marcos Tatián5, 6, Esteban Barrera 
Oro4, Marleen De Troch7, Santiago Doyle2, 3, María Liliana Quartino8, 9, Leonardo A. Saravia2 and 
Fernando R. Momo2, 3 
1  Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET),  Godoy Cruz 2290, PO Box 
C1425FQB Ciudad Autónoma de Buenos Aires, Argentina 
E-mail: tomasimarina@gmail.com 
2 Instituto de Ciencias, Universidad Nacional de General Sarmiento, J.M. Gutierrez 1150 PO Box 
B1613GSX Los Polvorines, Argentina 
3 INEDES, Universidad Nacional de Luján, Ruta 5 PO Box B6700ZAB Luján, Argentina 
4 Instituto Antártico Argentino, Cerrito 1248, PO Box C1010AAZ Ciudad Autónoma de Buenos Aires, 
Argentina 
5 Instituto de Diversidad y Ecología Animal, Consejo Nacional de Investigaciones Científicas y 
Técnicas/Universidad Nacional de Córdoba, Córdoba, Argentina 
6 Ecología Marina, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de 
Córdoba Av. Vélez Sarsfield 299, PO Box 5000 Córdoba, Argentina 
7  Marine Biology Laboratory, Ghent University, Krijgslaan 281/S8, PO Box B-9000 Ghent, Belgium 
8  Dirección Nacional del Antártico, Instituto Antártico Argentino, Departamento de Biología Costera  
 25 de mayo 1143, PO Box 1650 Buenos Aires, Argentina 
9  Museo Argentino de Ciencias Naturales B. Rivadavia, Av. A. Gallardo 470, PO Box C1405DJR 
Buenos Aires, Argentina 
 
The study of food web structure and complexity is central to better understand ecosystem 
functioning. A food-web approach includes both species and energy flows among them, providing a 
natural framework for characterizing species’ ecological roles and the mechanisms through which 
biodiversity influences ecosystem dynamics. Here we present for the first time a high-resolution 
food web for the Potter Cove marine ecosystem (Isla 25 de Mayo/King George Is.). We studied 
eleven food web properties to analyze network complexity, structure and topology. We found a 
linkage density of 3.4, a connectance of 0.04 and 45% of omnivory, as well as a path length of 1.8 
and a clustering coefficient of 0.08. Comparison of food web properties with other marine food 
webs revealed a particular combination of characteristics for Potter Cove ecological network: middle 
size (S = 91), low linkage density and connectance (not being an artifact of resolution or assembly 
procedure), low omnivory percentage, short path length and low clustering coefficient. Furthermore, 
relating the structure of the web to its dynamics, we found that the degree distribution (in- and out-
links) fit the best to an exponential model. For two of the three more connected functional groups, 
competition overlap graphs (only considering predator species) reflect high trophic interaction 
between demersal fish and niche specialization according to feeding strategies in amphipods. On 
the other hand, it can be inferred from the prey overlap graph (only considering prey species) that 
multiple energy pathways of carbon flux exist across benthic and pelagic habitats in Potter Cove 
ecosystem. Although alternative food sources might add robustness to the web, network properties 
results (low linkage density, connectance and omnivory, and short path length) points to fragility 
and potential trophic cascade effects. Our results suggest that species with a high number of links 
(e.g. Notothenia coriiceps, Ophionotus victoriae, Gondogeneia antarctica) could be considered 
keystones for the robustness of Potter Cove ecosystem. 
 
References 
- de Santana, C. N., Rozenfeld, A. F., Marquet, P. A., & Duarte, C. M. 2013. Topological properties of 
polar food webs. Marine Ecology Progress Series 474:15-26. 
- Dunne, J. A., Williams, R. J., & Martinez, N. D. 2004. Network structure and robustness of marine 
food webs. Marine Ecology Progress Series 273:291-302. 
- Link, J. 2002. Does food web theory work for marine ecosystems? Marine Ecology Progress Series 
230:1-9.  
- Pimm, S. L., Lawton, J. H., & Cohen, J. E. 1991. Food web patterns and their consequences. Nature 
350:669-674. 
- Wiencke, C., Ferreyra, G. A., Abele, D., & Marenssi, S. 2008. The Antarctic ecosystem of Potter 
cove, King-George Island (Isla 25 de Mayo): Synopsis of research performed 1999-2006 at the 
208 
 
Dallmann Laboratory and Jubany Station. Berichte zur Polar-und Meeresforschung (Reports on 
Polar and Marine Research), 571.  
  


The food web of Potter Cove (Isla 25 de Mayo/King George Is.): complexity, structure and function

The food web of Potter Cove (Isla 25 de Mayo/King George Is.): complexity, structure and function

Abstract

Similar works

Full text

Available Versions

Open Marine Archive