Saprobity: a unified view of benthic succession models for coastal lagoons

Abstract

We briefly review and expand upon classic conceptual models describing the succession of benthic communities along a gradient of organic matter (OM) enrichment developed for freshwater (the Saprobity System), coastal marine (the Pearson-Rosenberg [P-R] model) and lagoon (the Guélorget-Perthuisot [G-P] model) ecosystems. Differences and similarities between various approaches and models are highlighted and the P-R and G-P models are unified under a single conceptual framework of habitat saprobity in coastal lagoons. We refer to saprobity as the state of an aquatic ecosystem resulting from the input and decomposition of OM and the removal of its catabolites. In addition to other factors, such as salinity, saprobity is viewed as a selection factor for species diversity. The higher the saprobity is, the more impaired the system is, with progressively poorer benthic communities characterized by species that are increasingly tolerant of reducing conditions and toxicity. In coastal lagoons, these processes are strongly driven by hydrodynamics, which govern the land-sea gradient. Based on our review and analysis, we find that saprobity can be a useful descriptor of ecosystem state as determined by OM metabolism, suitable for characterizing the natural conditions of coastal lagoons and assessing their quality.

Effects of organic pollution and physical stress on benthic macroinvertebrate communities from two intermittently closed and open coastal lagoons (ICOLLs)

“…In a recent revision of benthic conceptual models, a unifying conceptual benthic succession lagoonal model has been proposed -the saprobity system, that is, a gradient of organic matter enrichment shaping the benthic communities (Tagliapietra et al, 2012).…”

Patterns of seasonal variation in lagoonal macrozoobenthic assemblages (Mellah lagoon, Algeria)

“…These seasonal changes thus followed a regression/recovery pattern typical of opportunistic macrobenthic assemblages occurring in confined organic-enriched lagoon environments (Guelorget and Perthuisot, 1992;Como and Magni, 2009;Foti et al, 2014). This can be related to the high OM content of surface sediments found in Center, indicating a major organic enrichment which may lead to hypoxic conditions in summer Tagliapietra et al, 2012;Kanaya et al, 2015). In fact, organic matter in surface sediments is an important source of food for benthic fauna.…”

“…The microbial decomposition of OM involves physicochemical modifications to the medium which are selective for the biota. The main selection factors are low dissolved oxygen (DO) concentrations, leading to reducing conditions and lower pH, and the accumulation of the toxic by-products (ammonia and sulphide) of anaerobic metabolism (Hyland et al, 2005;Magni et al, 2008a;Tagliapietra et al, 2012;Kanaya et al, 2015).…”

Connectivity in Three European Coastal Lagoons

“…Guelorget and Perthuisot (1983) related the biological organization of lagoons to the concept of "confinement", defined as "the time of renewal of the elements of marine origin at any given point". This model has since been reinterpreted as related to other factors, such as saprobity (Tagliapietra and Sigovini 2012) and colonization rates and dispersal processes (Perez-Ruzafa and Marcos-Diego 1992). Hydrodynamic connectivity and larval dispersal are expected to strongly affect the internal structure and spatial organization of lagoon assemblages.…”