Preprints
https://doi.org/10.5194/egusphere-2022-1518
https://doi.org/10.5194/egusphere-2022-1518
20 Jan 2023
 | 20 Jan 2023

New insights into the Weddell Sea ecosystem applying a quantitative network approach

Tomás I. Marina, Leonardo A. Saravia, and Susanne Kortsch

Abstract. Network approaches can shed light on the structure and stability of complex marine communities. In recent years, such approaches have been successfully applied to study polar ecosystems, improving our knowledge on how they might respond to ongoing environmental changes. The Weddell Sea is one of the most studied marine ecosystems outside the Antarctic Peninsula in the Southern Ocean. Yet, few studies consider the known complexity of the Weddell Sea food web, which in its current form comprises 490 species and 16041 predator-prey interactions. Here we analysed the Weddell Sea food web, focusing on the species and trophic interactions that underpin ecosystem structure and stability. We estimated the strength for each interaction in the food web, characterised species position in the food web using unweighted and weighted food web properties, and analysed species’ roles with respect to the stability of the food web. We found that the distribution of the interaction strength (IS) at the food web level is asymmetric, with many weak interactions and few strong ones. We detected a positive relationship between species mean IS and two unweighted properties (i.e., trophic level and the total number of interactions). We also found that only a few species possess key positions in terms of food web stability. These species are characterised by high mean IS, mid to high trophic level, relatively high number of interactions, and mid to low trophic similarity. In this study, we integrated unweighted and weighted food web information, enabling a more complete assessment of the ecosystem structure and function of the Weddell Sea food web. Our results provide new insights, which are important for the development of effective policies and management strategies, particularly given the ongoing initiative to implement a Marine Protected Area (MPA) in the Weddell Sea.

Tomás I. Marina et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • CC1: 'Comment on egusphere-2022-1518', Oscar Godoy, 24 Jun 2023
    • AC1: 'Reply on CC1', Tomas Marina, 22 Aug 2023
  • RC1: 'Comment on egusphere-2022-1518', Anonymous Referee #1, 01 Sep 2023
    • AC2: 'Reply on RC1', Tomas Marina, 10 Nov 2023

Tomás I. Marina et al.

Tomás I. Marina et al.

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Short summary
The Weddell Sea is one of the most studied marine ecosystems outside the Antarctic Peninsula in the Southern Ocean. Yet, few studies consider the complexity of the Weddell Sea food web, which comprises 490 species and 16041 predator-prey interactions. Here we analysed a quantitative version of the Weddell Sea food web, where the interactions’ intensity is explicitly considered. We found that only a few species of marine mammals, sea birds, and fishes are important for the food web stability.