Analysis of Physical and Biogeochemical Control Mechanisms on Summertime Surface Carbonate System Variability in the Western Ross Sea (Antarctica) Using In Situ and Satellite Data

Abstract

In this study, carbonate system properties were measured in the western Ross Sea (Antarctica) over the 2005–2006 and 2011–2012 austral summers with the aim of analysing their sensitivity to physical and biogeochemical drivers. Daily Advanced Microwave Scanning Radiometer 2 (AMSR2) sea ice concentration maps, obtained prior to and during the samplings, were used to analyse the sea ice evolution throughout the experiment periods. Monthly means and 8-day composite chlorophyll concentration maps from the Moderate-resolution Imaging Spectroradiometer (MODIS) Aqua satellite at 4-km resolution were used to investigate inter-annual and basin scale biological variability. Chlorophyll-a concentrations in surface waters estimated by MODIS satellite data contribute to descriptions of the variability of carbonate system properties in surface waters. Mean values of carbonate system properties were comparable across both investigated years; however, the 2012 data displayed larger variability. Sea ice melting also had a pivotal role in controlling the carbonate system chemistry of the mixed layer both directly through dilution processes and indirectly by favouring the development of phytoplankton blooms. This resulted in high pH and ΩAr, and in low CT, particularly in those areas where high chlorophyll concentration was shown by satellite maps.

Response of the Pacific Sector of the Southern Ocean to Wind Stress Variability From 1995 to 2017

“…The joint use of in situ and satellite data has proven its effectiveness in several regions of the global ocean. This approach is even more useful in the SO (e.g., Ansorge et al, 2015;Aulicino et al, 2018;Cotroneo et al, 2013) and its marginal seas (e.g., Mangoni et al, 2017;Menna et al, 2019;Misic et al, 2017;Rivaro et al, 2017Rivaro et al, , 2018Rivaro et al, , 2019, where in situ data collection is often limited to the summer season and/or affected by the severe sea state and weather conditions. The yearly time series of the EKE field, derived from altimeter data, are compared to the temporal evolution of the zonal wind stress, the ACC baroclinic transport from XBT data, and climate indices (see section 3).…”

Assessment of Annual Physico-Chemical Variability via High-Temporal Resolution Monitoring in an Antarctic Shallow Coastal Site (Terra Nova Bay, Ross Sea)

“…The greatest change in the carbonate system occurred in January, confirming the effect of melting freshwater (SIC range: 0-0.1), which also affected TA, resulting in a minimum of 2292 µmol kg SW −1 [66,71]. pH T showed a second positive peak with 8.33, and lowestimated pCO 2 concentrations of approx.…”

“…In December, the sea ice melting exerted a possible influence on controlling the carbonate system chemistry of the site both directly through dilution processes and indirectly by favoring the development of phytoplankton blooms, as observed in McMurdo Sound [46]. Differently from other studies considering mixed layers [66], at the shallow coastal site in TNB, the increase in pH T recorded at the end of the year (the maximum peak during this period with a value of 8.35) was accompaigned by maximum values for both estimated saturation states (Ω Ca = 4.42; Ω Ar = 2.78). While pCO 2 displayed the minimum value, with 176 µatm, and a dilution of TA was recorded.…”

Connectivity Analysis Applied to Mesoscale Eddies in the Western Mediterranean Basin

“…Eddies also have an impact on the biological activity and fishing stocks distribution all around the global ocean [73][74][75][76][77]. They also represent a unique and powerful system for larvae and juvenile dispersal during their early pelagic life stages [78][79][80] providing significant opportunities/limitations for habitat expansion, maintenance of sustainable population sizes, and the exchange of genetic material between geographically distant populations.…”