Geochemical ecosystem engineering by the mud shrimp Upogebia pugettensis (Crustacea: Thalassinidae) in Yaquina Bay, Oregon: Density‐dependent effects on organic matter remineralization and nutrient cycling

Abstract

We investigated the effect of the thalassinid mud shrimp Upogebia pugettensis on organic matter and nutrient cycling on Idaho Flat, an intertidal flat in the Yaquina River estuary, Oregon. Field studies were conducted to measure carbon and nitrogen remineralization rates and benthic fluxes relative to shrimp population density. Organic carbon remineralization rates estimated from incubations increased with burrow density. Similarly, benthic oxygen uptake increased linearly with burrow density. Shrimp bioirrigation enhanced carbon remineralization up to 2.9 times; its effects on nitrogen cycling were even more dramatic, enhancing ammonification rates up to 7 times, nitrification rates between 3 and 9 times, and estimated denitrification up to 4 times relative to portions of the tide flat lacking shrimp. Bioirrigation by shrimp also reduced pore-water inventories of dissolved inorganic nitrogen (DIN), resulting in DIN fluxes that increased exponentially with burrow density up to 15-fold relative to No-shrimp plots. For both C and N fluxes, the strongest densitydependent relationships occurred with burrow hole density rather than shrimp population density or biomass. Combined with population mapping of mud shrimp populations on Idaho Flat, we estimate that total areal C and DIN effluxes on the tide flat were enhanced 1.9 and 3.7 times, respectively, relative to areal fluxes expected if no shrimp were present. Mud shrimp thus perform as geochemical ecosystem engineers that strongly affect the flux and fate of C and N in Pacific estuaries.

Mediation of macronutrients and carbon by post-disturbance shelf sea sediment communities

“…A similar effect is also true for non-cohesive sediments which, due to their inherent mobility, host a high proportion of opportunistic species (Collie et al 2000), but these communities also harbour large deep-burrowing fauna (e.g. decapod crustaceans, spatangoid urchins) that can form extensive galleries (Lohrer et al 2004) and disproportionately augment oxygen uptake (Volkenborn et al 2012) and the flux of dissolved substances across the water-sediment interface (Osinga et al 1995;Bird et al 1999;D'Andrea and DeWitt 2009). The presence of these species, in particular the spatangoid Echinocardium cordatum, offers an explanation for the enhanced [NH 4 -N] observed in noncohesive sediment communities that have experienced a high frequency of fishing activity.…”

Use of extractable lipofuscin to estimate age ­structure of ghost shrimp populations in west coast estuaries of the USA

“…These thalassinidean shrimp inhabit vast expanses of the intertidal zone, affecting sediment stability and community composition through their burrowing activities and acting as geochemical engineers (MacGinitie 1934, Posey 1986, 1987, D'Andrea & DeWitt 2009). They are a pest to oyster aquaculture operations in Pacific Northwest estuaries, by causing oyster mortality via sedimentation during burrowing.…”

Indirect effects of bioturbation by the burrowing sandprawn Callichirus kraussi on a benthic foraging fish, Liza richardsonii

“…Of the biotic processes, bioturbation is known to be important in coupling benthic and pelagic compartments, but most studies in this area have focused on the ability of bioturbators to alter fluxes of nutrients from the benthos into the water column (e.g. Ziebis et al 1996, Lohrer et al 2004, D'Andrea & DeWitt 2009). This experiment, however, shows that benthic bioturbators that are strong ecosystem engineers can also influence benthic-pelagic coupling by modulating energy flow from benthic primary producers (microalgae in this case) to consumers in the pelagic environment (fish in this case).…”