- • Anthropogenic carbon concentrations are estimated within the mixed layer using three different methods.
- • There is a large increasing rate of anthropogenic carbon penetration in the deep waters.
- • Undersaturated aragonite saturation state at sea surface could be reached before year 2060.
- • An alternative method for calculating anthropogenic carbon is purposed for regions with low carbonate system datasets.
It is arduous to gather a good spatial and temporal dataset of marine carbonate properties, especially in the Southern Ocean. In this study, we have reconstructed the carbonate system in the Gerlache Strait, a coastal zone of the Northern Antarctic Peninsula. We also analyzed the impact of ocean acidification by calculating the tipping points of the calcium carbonate saturation states and pH (i.e., when saturation state and pH goes below one and 7, respectively). Hydrographic and carbonate data from three distinct data sets (GOAL – 2013 to 2016, FRUELA – 1996, and World Ocean Database – 1965 to 2004) have been joined and used to reconstruct the carbonate system from the past 50 years. Temporal annual mean trends were determined depending on the water column depth-layer. The northern Gerlache Strait showed a significant increasing trend of CT concentrations (1.0024 ± 0.34 µmol kg–1) and related pH decreasing trend (–0.0026 ± 0.0009 sws) in the surface mixed layer (> 60 m). The properties variability is relatively different (magnitudes and signs) between the northern and southern sectors of the Gerlache Strait, which indicate that adjacent regions to the Gerlache Strait to the southwest and north, respectively, may major influence the regional carbonate dynamics. Results also show that episodic under-saturation conditions, in relation to aragonite within the surface mixed layer, may already occur, especially in regions close to large glaciers.
Lencina-Avila J. M., Goyet C., Kerr R., Orselli I. B. M., Mata M. M. & Touratier F., in press. Past and future evolution of the carbonate system in a coastal zone of the Northern Antarctic Peninsula. Deep Sea Research Part II: Topical Studies in Oceanography. Article (subscription required).