Emery
Kyle A.
Emery
Kyle A.
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PreprintQuantifying the effects of commercial clam aquaculture on C and N cycling : an integrated ecosystem approach( 2016-05) Murphy, Anna E. ; Emery, Kyle A. ; Anderson, Iris C. ; Pace, Michael L. ; Brush, Mark J. ; Rheuban, Jennie E.Increased interest in using bivalve cultivation to mitigate eutrophication requires a comprehensive understanding of the net carbon (C) and nitrogen (N) budgets associated with cultivation on an ecosystem scale. This study quantified C and N processes related to clam (Mercenaria mercenaria) aquaculture in a shallow coastal environment (Cherrystone Inlet, VA) where the industry has rapidly increased. Clam physiological rates were compared with basin-wide ecosystem fluxes including primary production, benthic nutrient regeneration, and respiration. Although clam beds occupy only 3% of the ecosystem’s surface area, clams filtered 7-44% of the system’s volume daily, consumed an annual average of 103% of the phytoplankton production, creating a large flux of particulate C and N to the sediments. Annually, N regenerated and C respired by clam and microbial metabolism in clam beds were ~3-fold and ~1.5-fold higher, respectively, than N and C removed through harvest. Due to the short water residence time, the low watershed load, and the close vicinity of clam beds to the mouth of Cherrystone Inlet, cultivated clams are likely subsidized by phytoplankton from the Chesapeake Bay. Consequently, much of the N released by mineralization associated with clam cultivation is ‘new’ N as it would not be present in the system without bivalve facilitation. Macroalgae that are fueled by the enhanced N regeneration from clams represents a eutrophying process resulting from aquaculture. This synthesis demonstrates the importance of considering impacts of bivalve aquaculture in an ecosystem context especially relative to the potential of bivalves to remove nutrients and enhance C sinks.
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ArticleSpatial synchrony cascades across ecosystem boundaries and up food webs via resource subsidies(National Academy of Sciences, 2024-01-02) Walter, Jonathan A. ; Emery, Kyle A. ; Dugan, Jenifer E. ; Hubbard, David M. ; Bell, Tom W. ; Sheppard, Lawrence W. ; Karatayev, Vadim A. ; Cavanaugh, Kyle C. ; Reuman, Daniel C. ; Castorani, Max C. N.Cross-ecosystem subsidies are critical to ecosystem structure and function, especially in recipient ecosystems where they are the primary source of organic matter to the food web. Subsidies are indicative of processes connecting ecosystems and can couple ecological dynamics across system boundaries. However, the degree to which such flows can induce cross-ecosystem cascades of spatial synchrony, the tendency for system fluctuations to be correlated across locations, is not well understood. Synchrony has destabilizing effects on ecosystems, adding to the importance of understanding spatiotemporal patterns of synchrony transmission. In order to understand whether and how spatial synchrony cascades across the marine-terrestrial boundary via resource subsidies, we studied the relationship between giant kelp forests on rocky nearshore reefs and sandy beach ecosystems that receive resource subsidies in the form of kelp wrack (detritus). We found that synchrony cascades from rocky reefs to sandy beaches, with spatiotemporal patterns mediated by fluctuations in live kelp biomass, wave action, and beach width. Moreover, wrack deposition synchronized local abundances of shorebirds that move among beaches seeking to forage on wrack-associated invertebrates, demonstrating that synchrony due to subsidies propagates across trophic levels in the recipient ecosystem. Synchronizing resource subsidies likely play an underappreciated role in the spatiotemporal structure, functioning, and stability of ecosystems.