气候变化领域集成服务门户(CCPortal): Seawater carbonate chemistry and primary and bacterial production in Antarctic coastal waters during austral summer

CCPortal

DOI	https://doi.org/10.1594/PANGAEA.902309
	Seawater carbonate chemistry and primary and bacterial production in Antarctic coastal waters during austral summer
	Westwood; Karen; Thomson; Paul G; van den Enden; Rick; Maher; L E; Wright; S; Davidson; Andrew T
发布日期	2019-06-06
数据集类型	dataset
英文关键词	Antarctic ; Biomass/Abundance/Elemental composition ; Coast and continental shelf ; Community composition and diversity ; Containers and aquaria (20- 1000 L or &lt ; 1 m**2) ; Entire community ; Laboratory experiment ; Other metabolic rates ; Pelagos ; Polar ; Primary production/Photosynthesis ; Respiration
英文简介	Polar waters may be highly impacted by ocean acidification (OA) due to increased solubility of CO2 at colder water temperatures. Three experiments examining the influence of OA on primary and bacterial production were conducted during austral summer at Davis Station, East Antarctica (68°35′ S, 77°58′ E). For each experiment, six minicosm tanks (650 L) were filled with 200 μm filtered coastal seawater containing natural communities of Antarctic marine microbes. Assemblages were incubated for 10 to 12 days at CO2 concentrations ranging from pre-industrial to post-2300. Primary and bacterial production rates were determined using NaH14CO3 and 14C-leucine, respectively. Net community production (NCP) was also determined using dissolved oxygen. In all experiments, maximum photosynthetic rates (Pmax, mg C mg/chl a/h) decreased with elevated CO2, clearly reducing rates of total gross primary production (mg C/L/h). Rates of cell-specific bacterial productivity (μg C/cell/h) also decreased under elevated CO2, yet total bacterial production (μg C/L/h) and cell abundances increased with CO2 over Days 0–4. Initial increases in bacterial production and abundance were associated with fewer heterotrophic nanoflagellates and therefore less grazing pressure. The main changes in primary and bacterial productivity generally occurred at CO2 concentrations > 2 × present day (> 780 ppm), with the same responses occurring regardless of seasonally changing environmental conditions and microbial assemblages. However, NCP varied both within and among experiments, largely due to changing nitrate + nitrite (NOx) availability. At NOx concentrations < 1.5 μM photosynthesis to respiration ratios showed that populations switched from net autotrophy to heterotrophy and CO2 responses were suppressed. Overall, OA may reduce production in Antarctic coastal waters, thereby reducing food availability to higher trophic levels and reducing draw-down of atmospheric CO2, thus forming a positive feedback to climate change. NOX limitation may suppress this OA response but cause a similar decline.
空间范围	Latitude: -68.583330 * Longitude: 77.966670
语种	英语
国家	国际
学科大类	气候变化
学科子类	气候变化
文献类型	数据集
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/215855
推荐引用方式 GB/T 7714	Westwood,Karen,Thomson,et al. Seawater carbonate chemistry and primary and bacterial production in Antarctic coastal waters during austral summer.2019-06-06.https://doi.org/10.1594/PANGAEA.902309.