The Production And Emissions Of Ammonia And Phosphine From Antarctic Typical Sea Animal Excreta

Ammonia (NH3) volatilization and matrix-bound phosphine (MBP) from sea animal colonies provide an important nitrogen and phosphorus source for terrestrial ecosystems in the Antarctica. However, very little attention has been paid to quantify NH3 emissions and MBP from sea animal colonies and lake sediments. In NH3 study, penguin guano (ornithogenic materials) from four penguin colonies and the soils from one seal colony were collected in coastal Antarctica. In MBP study, penguin guano (ornithogenic materials) and one lake sediment were collected in coastal Antarctica; sea animal guano and one lake sediment were collected near the Yellow River Station in Arctica. Laboratory experiments of NH3 emission were conducted to investigate potential NH3 emissions from these samples and effects of freezing-thawing cycles (FTCs) and environmental factors on NH3 fluxes. The fluxes were extremely low (close to zero) from the frozen samples. Significantly enhanced NH3 emissions were observed following the thawing with the maximum flux of 17.4 mg NH3 kg-1 h-1 for emperor penguin guanos, 3.707 mg kg-1 h-1 for Adélie penguin guanos and 12.29 mg NH3 kg-1 h-1 for ornithogenic materials. The mean fluxes were 7.66±4.33 mg NH3 kg-1 h-1 from emperor penguin guano, 1.31±0.64 mgNH3 kg-1 h-1 from Adélie penguin guano and 0.33±0.39 mgNH3 kg-1 h-1 from seal colony soils during the thawing. NH3 emissions from penguin guano were higher than those from ornithogenic materials during FTCs. The specific NH3-N production rates (NH3-N/TN) from penguin guano and ornithogenic materials are considerably large with the range of 0.1-82.4‰. The temperature, total nitrogen concentration, total carbon concentration and pH were significant predictor variables for NH3 fluxes from penguin guano and ornithogenic materials. The NH3 fluxes exponentially increased with enhanced temperature and pH, and they showed a significant linear correlation with TN and TC concentration. The drying-wetting conversion and the ventilated conditions also had an important effect on NH3 emissions, indicating that in Antarctic field high wind speed stimulates ammonia emissions from sea animal excreta. This study showed that penguin guano and ornithogenic materials are significant NH3 emission sources. In coastal Antarctica, the freezing-thawing frequency for sea animal excreta and ornithogenic materials is considerably high throughout the summer, and FTC-induced NH3 emissions might account for a large proportion of annual flux from sea animal colonies. Stuyies of MBP were conducted to measure the variations of MBP concentration with depths. High concentrations of MBP present in the bottom or sub-surface sediments which have the strong reducing property. The mean concentrations of MBP in lake sediments were higher than those in sea animal guanos and ornithogenic materials. Clay sediments are favorable for MBP accumulation due to large surface area and adsorption pots, and larger water content, and neutral condition is also favor to the exsistence of MBP. TOC and alkaline phosphatase activity not only proved their effect on MBP in the sediments, but also showed that biological activity may control MBP production. There was no obvious correlation between MBP and soluble phosphorus, organic phosphorus and inorganic phosphorus. Metal salts had no significant effect on the concentrations of MBP. Those imply that MBP production and elimination are complicated, and more studies should be done. The results of this study are of great significance to further study the process of ammonia volatilization and MBP production, as well nitrogen and phosphorus biogeochemical cycle of Antarctic tundra ecosystems.