Quantifying the Effects of Commercial Clam Aquaculture on C and N Cycling: an Integrated Ecosystem Approach

Murphy, Anna E.; Emery, Kyle A.; Anderson, Iris C.; Pace, Michael L.; Brush, Mark J.; Rheuban, Jennie E.

doi:10.1007/s12237-016-0106-0

Cited by 19 publications

(17 citation statements)

References 79 publications

(11 reference statements)

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“…While oyster reefs and clam aquaculture can enhance N removal compared to reference sediments, certain conditions may result in net N regeneration. Clam aquaculture, which utilize a predator exclusion net in ecosystems with low water column nitrate and short residence time may be a source of new N from mineralization and excretion (Murphy et al 2016b). The high efflux of NH4 + at the clam aquaculture site is due in part to the presence of live bivalves in the sediment cores, indicating the direct control that infaunal bivalves and their associated microbiota have on overall benthic flux and N cycle process rates.…”

Section: Resultsmentioning

confidence: 99%

“…However, nitrogen regeneration associated with bivalves can also be disproportionately high relative to the Last Updated: 26 October 2017 aerial coverage of the bivalves. Clam aquaculture occupies 3% of the subtidal bottom in Cherrystone Inlet, Virginia but nitrogen regeneration is equal to about half of the watershed nitrogen load (Murphy et al 2016b). Similarly, at a mussel farm in Sacca di Goro, Italy, mussels covered only 5% of the area but excretion accounted for 25% of total DIN regeneration in the system (Nizzoli et al 2011).…”

Section: Discussionmentioning

confidence: 99%

“…The predator exclusion net and the high density of may contribute to greater organic enrichment of sediment (Newell 2004), resulting in reduced and sulfidic conditions that promote DNRA (Murphy et al 2016a). While natural clam beds still exists in the US, clam aquaculture is becoming a more common feature in the coastal landscape (Murphy et al 2016b, Emery 2015).…”

Section: Introductionmentioning

confidence: 99%

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Differential Effects of Bivalves on Sediment Nitrogen Cycling in a Shallow Coastal Bay

Smyth

Murphy

Anderson

et al. 2017

Estuaries and Coasts

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In coastal ecosystems, suspension-feeding bivalves can remove nitrogen though uptake and assimilation or enhanced denitrification. Bivalves may also retain nitrogen through increased mineralization and dissimilatory nitrate reduction to ammonium (DNRA). This study investigated the effects of oyster reefs and clam aquaculture on denitrification, DNRA, and nutrient fluxes (NOx, NH4 + , O2). Core incubations were conducted seasonally on sediments adjacent to restored oyster reefs (Crassostrea virginica), clam aquaculture beds (Mercenaria mercenaria) which contained live clams, and bare sediments from Smith Island Bay, Virginia, USA. Denitrification was significantly higher at oyster reef sediments and clam aquaculture site than bare sediment in the summer; however DNRA was not enhanced. The clam aquaculture site had the highest ammonium production due to clam excretion. While oyster reef and bare sediments exhibited seasonal differences in rate processes, there was no effect of season on denitrification, DNRA or ammonium flux at the clam aquaculture site. This suggests that farm management practices or bivalve metabolism and excretion may override seasonal differences. When water column nitrate concentration was elevated, denitrification increased in clam aquaculture site and oyster reef sediments but not in bare sediment; DNRA was only stimulated at the clam aquaculture site. This, along with a significant and positive relationship between denitrification and sediment organic matter, suggests that labile carbon limited nitrate reduction at the bare sediment site. Bivalve systems can serve as either net sinks or sources of nitrogen to coastal ecosystems, depending mainly on the type of bivalve, location and management practices. Supplemental Table 1: Number of clams per core by season.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Differential Effects of Bivalves on Sediment Nitrogen Cycling in a Shallow Coastal Bay

Smyth

Murphy

Anderson

et al. 2017

Estuaries and Coasts

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“…Increased light and nutrient cycling can increase benthic and littoral primary production, which can move up the food web (Castorani et al 2015). Marine mussels, clams, freshwater mussels, and invasive bivalves (see the following section) stimulate macrophyte growth, which increases secondary production (Murphy et al 2016, Peterson & Heck 2001. Bivalves can also stimulate production in adjacent habitats.…”

Section: Stimulation Of Primary and Secondary Productionmentioning

confidence: 99%

Bivalve Impacts in Freshwater and Marine Ecosystems

Vaughn

Hoellein

2018

Annu. Rev. Ecol. Evol. Syst.

211

126

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Bivalve molluscs are abundant in marine and freshwater ecosystems and perform important ecological functions. Bivalves have epifaunal or infaunal lifestyles but are largely filter feeders that couple the water column and benthos. Bivalve ecology is a large field of study, but few comparisons among aquatic ecosystems or lifestyles have been conducted. Bivalves impact nutrient cycling, create and modify habitat, and affect food webs directly (i.e., prey) and indirectly (i.e., movement of nutrients and energy). Materials accumulated in soft tissue and shells are used as environmental monitors. Freshwater mussel and oyster aggregations in rivers and estuaries are hot spots for biodiversity and biogeochemical transformations. Historically, human use includes food, tools, currency, and ornamentation. Bivalves provide direct benefits to modern cultures as food, building materials, and jewelry and provide indirect benefits by stabilizing shorelines and mitigating nutrient pollution. Research on bivalve-mediated ecological processes is diverse, and future synthesis will require collaboration across conventional disciplinary boundaries.

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“…So, higher denitrification rates delivered intensified nitrogen regeneration in the sediments. Similarly, studies of hard clams (Mercenaria mercenaria) showed increased fluxes of ammonium and phosphate compared to uncultivated sediments; denitrification rates were also enhanced, but only for parts of the growth season (Table 10.1, Murphy et al 2016b). In the same study, DNRA was stimulated throughout the growth season and appeared to be the favoured nitrogen cycling process over denitrification, enhancing nitrogen flux to the water column.…”

Section: Chemical Reactions In the Sedimentmentioning

confidence: 93%

Nutrient Extraction Through Bivalves

Petersen

Holmer

Termansen

et al. 2018

Goods and Services of Marine Bivalves

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Ecosystem services provided by marine bivalves in relation to nutrient extraction from the coastal environment have gained increased attention to mitigate adverse effects of excess nutrient loading from human activities, such as agriculture and sewage discharge. These activities damage coastal ecosystems and require action from local, regional, and national environmental management. Marine bivalves filter particles like phytoplankton, thereby transforming particulate organic matter into bivalve tissue or larger faecal pellets that are transferred to the benthos. Nutrient extraction from the coastal environment takes place through two different pathways: (i) harvest/removal of the bivalves-thereby returning nutrients back to land; or (ii) through increased denitrification in proximity to dense bivalve aggregations, leading to loss of nitrogen to the atmosphere. Active use of marine bivalves for nutrient extraction may include a number of secondary effects on the ecosystem, such as filtration of particulate material. This leads to partial transformation of particulate-bound nutrients into dissolved nutrients via bivalve excretion or enhanced mineralization of faecal material. In this chapter, concepts in relation to nutrient extraction by bivalves are presented and discussed in relation to nutrient cycling and additional effects of enhancing bivalve communities. In addition, meth

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Quantifying the Effects of Commercial Clam Aquaculture on C and N Cycling: an Integrated Ecosystem Approach

Cited by 19 publications

References 79 publications

Differential Effects of Bivalves on Sediment Nitrogen Cycling in a Shallow Coastal Bay

Differential Effects of Bivalves on Sediment Nitrogen Cycling in a Shallow Coastal Bay

Bivalve Impacts in Freshwater and Marine Ecosystems

Nutrient Extraction Through Bivalves

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