Modeling approach to regime shifts of primary production in shallow coastal ecosystems

TL;DR

This paper develops a competition model to analyze how nutrient input, temperature, and light influence regime shifts among seagrass, macroalgae, and phytoplankton in shallow coastal ecosystems.

Contribution

It introduces a new competition model capturing the effects of nutrients, temperature, and light on primary producer succession in coastal waters.

Findings

Different dominance regimes identified under varying nutrient and temperature conditions.

Succession patterns depend on resilience characteristics of each community.

Environmental forcing can induce regime shifts in primary producer dominance.

Abstract

Pristine coastal shallow systems are usually dominated by extensive meadows of seagrass species, which are assumed to take advantage of nutrient supply from sediment. An increasing nutrient input is thought to favour phytoplankton, epiphytic microalgae, as well as opportunistic ephemeral macroalgae that coexist with seagrasses. The primary cause of shifts and succession in the macrophyte community is the increase of nutrient load to water; however temperature plays also an important role. A competition model between rooted seagrass (Zostera marina), macroalgae (Ulva sp), and phytoplankton has been developed to analyse the succession of primary producer communities in these systems. Successions of dominance states, with different resilience characteristics, are found when modifying the input of nutrients and the seasonal temperature and light intensity forcing.