To predict the response of the European flat oyster (Ostrea edulis) and Pacific cupped oyster (Crassostrea gigas/Magallana gigas) populations to environmental changes, it is key to understand their life history traits. The Dynamic Energy Budget (DEB) theory is a mechanistic framework that enables the quantification of the bioenergetics of development, growth and reproduction from fertilization to death across different life stages. This study estimates the DEB parameters for the European flat oyster, based on a comprehensive dataset, while DEB parameters for the Pacific cupped oyster were extracted from the literature. The DEB parameters for both species were validated using growth rates from laboratory experiments at several constant temperatures and food levels as well as with collected aquaculture data from the Limfjorden, Denmark, and the German Bight. DEB parameters and the Arrhenius temperature parameters were compared to get insight in the life history traits of both species. It is expected that increasing water temperatures due to climate change will be beneficial for both species. Lower assimilation rates and high energy allocation to soma explain O. edulis’ slow growth and low reproductive output. Crassostrea gigas’ high assimilation rate, low investment in soma and extremely low reserve mobility explains the species’ fast growth, high tolerance to starvation and high reproductive output. Hence, the reproductive strategies of both species are considerably different. Flat oysters are especially susceptible to unfavourable environmental conditions during the brooding period, while Pacific oysters’ large investment in reproduction make it well adapted to highly diverse environments. Based on the life history traits, aquaculture and restoration of O. edulis should be executed in environments with suitable and stable conditions.
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RBINS Staff Publications 2022
The passive sampling technique of diffusive gradients in thin-film (DGT) is widely used to determine 1D profiles (using Chelex-100 resin) and 2D images (using suspended particulate reagent-iminodiacetate resin, abbreviated as SPR-IDA resin) of metals in sediment pore waters and in oxic/anoxic soils. However, when deployed in anoxic sediments with high metal concentrations, Fe and Mn concentrations determined with the Chelex-100 resin gel were ~ 5 times higher than concentrations measured with the SPR-IDA resin gel. This discrepancy suggests that the SPR-IDA resin gel is saturated faster than the Chelex-100 resin gel. Here, we tested the adsorption capacity of the SPR-IDA resin gel and compared it to the Chelex-100 resin gel. Fe and Mn binding capacities on a SPR-IDA gel disc are less than 0.1 μmoles, which means that they are far below those on a Chelex-100 gel disc (around 3.2 μmoles), while competition with stronger binding metals such as Cu and Cd further lowers Fe and Mn capacities. This restricts the SPR-IDA resin gel to be used in contaminated marine sediments. We propose the use of a ground Chelex-100 resin, which is prepared by grinding Chelex-100 resin in a ball-mill prior to gel preparation. The capacities of Fe and Mn on a ground Chelex-100 resin gel disc are around 1.6 μmoles, more than 16 times higher than the capacity on SPR-IDA gel disc. In addition, the bead size of the ground Chelex-100 resin is small enough (~ 10 μm) to allow high resolution LA-ICP-MS imaging of Fe, Mn and trace metals in sediment pore waters as well as soils.
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