Nutrient subsidies from nekton in salt marsh intertidal creeks

Abstract

Motile organisms are thought to play a role in biogeochemical cycles in tidal systems, but few studies have addressed links between animal activities and dissolved nutrients. Our observations and experiments indicated that movements, feeding, and excretion by fishes and shrimps resulted in subsidies of NH in the natural intertidal pool. Nekton residing in intertidal pools generated the equivalent of 5% of the total NH z 4 imported to the creek. At night, nekton in pools contributed the equivalent of 12% of the NH z 4 and 4% of the PO 3{ 4 imported from the subtidal channel. As the tide flooded the intertidal creek, nutrient enriched pool water was pulsed up the creek and into the intertidal basin. Tidally controlled patterns of nekton movements and feeding result in retention and reintroduction of nutrients to the upper reaches of intertidal creek basins. Accordingly, nekton contribute to the recycling of nutrients through a positive feedback loop that may enhance primary production and invertebrate prey within salt marsh creek basins. We conclude that nekton can be important and underappreciated contributors of dissolved nutrients in tidal systems.

Monitoring Vegetation Dynamics at a Tidal Marsh Restoration Site: Integrating Field Methods, Remote Sensing and Modeling

“…There are several possible explanations for greater vegetation cover in these areas, despite their greater salinity, relating to either pre-or post-settlement processes. These might include greater seed deposition (Hopkins and Parker 1984), improved drainage (Schile et al 2011;Chapple and Dronova 2017) or increased moisture (Noe and Zedler 2000) ameliorating salinity stress, lower sulfide accumulations (King et al 1982), or nutrient subsidies from fish and invertebrates (Allen et al 2013). Frequently inundated areas near tidal creeks may also have faster development of the soil microbial community, which can be a precursor to vegetation development (Lynum et al 2020).…”

Intertidal migration of the four-eyed fish Anableps anableps in North Brazilian mangrove creeks

“…As natural mortality is assumed to be very low (vivipary) and their excretions are dispersed into the intertidal with the next tide, A. anableps likely function as an energetic loop that contributes to retaining production in the mangrove system. The important contribution of tidally migrating nekton organisms to the recycling of nutrients in marsh systems has been previously shown in the literature (Kneib 2000, Weinstein & Litvin 2000, Guest & Connolly 2004, Allen et al 2013.…”

Movements and site fidelity of grass shrimp (Palaemonetes pugio and P. vulgaris) in salt marsh intertidal creeks

“…Observations of movements also provide insights into the role of animals in ecosystem processes ranging from trophic transfer to nutrient regeneration (Welsh 1975;Lundberg and Moberg 2003;Allen et al 2013). In temperate coastal ecosystems, grass shrimp (Palaemonetes spp.)…”