Seasonal Coupling Between Intertidal Macrofauna and Sediment Column Porewater Nutrient Concentrations

Abstract

It is well established that dense bivalve assemblages play a major role in the processes of benthic nutrient regeneration in coastal marine ecosystems. In recent years, there is increasing evidence of the close relationship between nutrient concentrations in sediments and macrofauna‐influenced upward flux of nutrients that enhances benthic primary productivity. This coupling has been shown, to varying degree, for a variety of benthic communities dominated by both suspension and deposit feeders. The former, including semi‐infaunal mussel species, such as Musculista senhousia and Modiolus americanus , filter particulate matter from the water column; the latter, such as holothurians, consume high amounts of sediment bacteria, microalgae, and dead organic matter. Due to the complexity and multiplicity of mechanisms that govern nutrient cycling in coastal ecosystems, these studies highlight the need for integrated investigations on the variability of porewater nutrient concentrations and the composition, biology, and behavior of in situ macrofaunal species.

Seasonal patterns of pore-water nutrients, benthic chlorophyll a and sedimentary AVS in a macrobenthos-rich tidal flat

“…In that case, nutrient regeneration would occur at different periods of the year. In our study area, pore-water ammonium, phosphate and silicate concentrations, positively correlated with temperature (Magni & Montani, 2005c), followed similar temporal and spatial patterns. This suggests that in our study area major events of nutrient production and regeneration within the sediments are governed by concurrent processes.…”