Greenhouse Gas Emissions From Native and Non-native Oysters

Abstract

Non-native species introductions are associated with a range of ecosystem changes such as habitat destruction, competition with native species, and biodiversity losses. Less well known is the role non-native species play in altering biogeochemical processes, such as the emission of greenhouse gases (GHGs). In this study we used laboratory incubations to compare seasonal (spring, summer, fall) emissions of the GHGs nitrous oxide (N 2 O), methane (CH 4), and carbon dioxide (CO 2) from native (Crassostrea virginica) and non-native (Ostrea edulis) oysters collected from a northern temperate estuary (Duxbury Bay, Massachusetts, USA). We observed strong seasonal signals in GHG fluxes, where C. virginica was the higher GHG emitter, and produced on average twice as much N 2 O (0.39 nmol g −1 dry tissue weight hr −1) and 20 times as much CH 4 (1.31 nmol g DTW −1 hr −1) compared to O. edulis (0.16 nmol N 2 O g DTW −1 hr −1 and 0.07 nmol CH 4 g DTW −1 hr −1). C. virginica also had significantly (p < 0.001) higher summer maximum production rates of CO 2 compared to O. edulis (53.4 µmol g DTW −1 hr −1 and 45.4 µmol g DTW −1 hr −1 , respectively). Despite these differences, chlorophyll-a consumption rates between the species were similar (p = 0.95). These results suggest that the non-native O. edulis is a lower GHG emitter than the native C. virginica and highlight that, at least in terms of GHG emissions, this non-native species introduction may not be detrimental to the environment.

Negligible Greenhouse Gas Release from Sediments in Oyster Habitats

“…In a broader management context, locating oyster restoration projects and oyster farms in areas with low dissolved nutrient concentrations may limit the total GHG production. Furthermore, there is substantial evidence for direct release of N 2 O from oysters ,, and that rates of oyster N 2 O release can be predicted by the amount of dissolved inorganic nitrogen (DIN) in the water column, with N 2 O consumption by oysters when no DIN is present . Locating new oyster habitats in areas of low DIN may help to reduce total N 2 O production and emissions from the system.…”

“…Sediment respiration and production of CO 2 and CH 4 typically follow seasonal patterns of organic matter deposition and temperature, with the highest rates of production within a month or two of organic matter deposition and higher rates of respiration as temperature increases. , NO x availability is an important control on aquatic N 2 O production, so water-column N 2 O concentrations and sediment N 2 O production in temperate estuaries are typically highest in spring when NO x availability is high. − We expect that sediment GHG cycling in oyster habitats follows these seasonal patterns. Similarly, direct GHG release from oysters varies across seasons and appears to be regulated by temperature and nutrient availability. , Thus quantifying seasonal changes in sediment GHG flux across oyster habitats may provide a more robust estimate of their GHG footprint.…”

“…Similarly, direct GHG release from oysters varies across seasons and appears to be regulated by temperature and nutrient availability. 26,27 Thus quantifying seasonal changes in sediment GHG flux across oyster habitats may provide a more robust estimate of their GHG footprint.…”

Interactions between bivalve filter feeding and oceanographic forcing drive the fluxes of organic matter and nutrients at an estuarine-coastal interface

“…Here it was stipulated that estuaries can either have a net export, or import, of organic carbon and nutrients, depending on the influences of biogeochemical processes in sediments, geomorphology, trophic processes, tidal flushing and exogenous forcing (e.g. Newell et al 2016, McCarthy et al 2019. Efforts to integrate total fluxes of organic matter and nutrients across a range of marine systems have further highlighted the pivo tal role of estuaries in biogeochemical cycling in the coastal ocean (Nixon 1980, Childers et al 2000, Snelgrove et al 2018.…”

Hiding in plain sight: The secret contribution of the solitary ascidian Herdmania grandis to temperate reef nitrous oxide production

“…Our current understanding about benthic invertebrate organisms and N cycling is largely based on research involving bivalves (Stief et al 2009;Welsh et al 2015;McCarthy et al 2019), sponges (Hoffmann et al 2009;Fiore et al 2013), and corals (Middelburg et al 2015), with only a few studies targeting ascidians (Heisterkamp et al 2010;Evans et al 2017). This is surprising given the abundance of ascidians across temperate reef systems, and the fact that the range of large solitary ascidians appears to be expanding as oceans warm (Gewing et al 2019).…”