The role of platelet ice microalgae in seeding phytoplankton blooms in Terra Nova Bay (Ross Sea, Antarctica): a mesocosm experiment

Polar Biology ◽  
2008 ◽  
Vol 32 (3) ◽  
pp. 311-323 ◽  
Author(s):  
Olga Mangoni ◽  
Maria Saggiomo ◽  
Monica Modigh ◽  
Giulio Catalano ◽  
Adriana Zingone ◽  
...  
2007 ◽  
Vol 19 (1) ◽  
pp. 83-92 ◽  
Author(s):  
L. Lazzara ◽  
I. Nardello ◽  
C. Ermanni ◽  
O. Mangoni ◽  
V. Saggiomo

We investigated the physical conditions of the Spring pack ice environment at Terra Nova Bay to understand their influence on the structure and physiology of sympagic microalgae. Bio-optical methods were used to study the availability and spectral quality of solar radiation, both inside and underneath the ice cover. Pack ice thickness was around 2.5 m, with a temperature between −2 and −7°C. On average, only 1.4% of surface PAR penetrated to the bottom ice and less than 0.6% below platelet ice level. Surface UV-B radiation under the bottom ice was 0.2–0.4%. Biomass concentrations up to 2400 mg Chl a m−3, dominated by two species of diatoms (Entomoneis kjellmannii and Nitschia cf. stellata), showed marked spatial and temporal patterns. Maximum values were in the platelet ice during the first half of November, and in the bottom ice two weeks later. Strong shade adaptation characteristics emerged clearly and explained the relevant abundance of microalgae within the sea ice, with specific absorption coefficients (a*) as low as 0.005 m2 (mg Chl a)−1 and the photo-acclimation index (Ek) in the range of in situ irradiance. The biomass specific production values were low, around 0.12–0.13 mg C mg Chl a−1 h−1. The hypothesis suggesting bottom ice colonization by platelet ice microalgae is supported here.


1999 ◽  
Vol 63 (S1) ◽  
pp. 113-121 ◽  
Author(s):  
Riccardo Cattaneo-Vietti ◽  
Mariachiara Chiantore ◽  
Cristina Misic ◽  
Paolo Povero ◽  
Mauro Fabiano

1998 ◽  
Vol 17 (1-4) ◽  
pp. 411-424 ◽  
Author(s):  
M. Chiantore ◽  
R. Cattaneo-Vietti ◽  
G. Albertelli ◽  
C. Misic ◽  
M. Fabiano

2017 ◽  
Vol 166 ◽  
pp. 26-36 ◽  
Author(s):  
Maria Saggiomo ◽  
Michel Poulin ◽  
Olga Mangoni ◽  
Luigi Lazzara ◽  
Mario De Stefano ◽  
...  

2008 ◽  
Vol 20 (5) ◽  
pp. 441-454 ◽  
Author(s):  
Stefano Cozzi

AbstractHigh-resolution trends of nutrients and DOM are analysed, with respect to nitrate and ammonium uptakes, in two coastal stations placed on the annual land-fast ice at Terra Nova Bay. The highest accumulations of dissolved inorganic nitrogen (87.2 µmol N dm-3), reactive phosphorus (14.1 µmol P dm-3) and reactive silicon (22.9 µmol Si dm-3) were observed in the bottom ice, although this process was preceded by a nutrient decrease in an interior sea ice layer. In the upper layer of sea ice, DOM was rather constant in concentration and P-deficient (C:N:P = 377:34:1–579:53:1). In the bottom and platelet ice, the accumulation of DOM (1277 µmol C dm-3; 108.2 µmol N dm-3; 7.67 µmol P dm-3) occurred with lower C:N:P ratios (123:14:1–59:7:1), because of a major contribution of fresher organic matter. Nitrate (< 7.33 µmol N dm-3 d-1) and ammonium (< 2.85 µmol N dm-3 d-1) uptakes in the bottom ice were higher than in the platelet ice. The comparison between the data of N-uptake and the concomitant release of total dissolved nitrogen in the bottom ice indicated that the microbial community may be subjected to low growths in situ and high releases of dissolved nitrogen, when it accumulates in this sea ice habitat.


2021 ◽  
pp. 103510
Author(s):  
Alessandro Cau ◽  
Claudia Ennas ◽  
Davide Moccia ◽  
Olga Mangoni ◽  
Francesco Bolinesi ◽  
...  

2011 ◽  
Vol 52 (57) ◽  
pp. 291-300 ◽  
Author(s):  
Stefan Kern ◽  
Stefano Aliani

AbstractWintertime (April–September) area estimates of the Terra Nova Bay polynya (TNBP), Antarctica, based on satellite microwave radiometry are compared with in situ observations of water salinity, temperature and currents at a mooring in Terra Nova Bay in 1996 and 1997. In 1996, polynya area anomalies and associated anomalies in polynya ice production are significantly correlated with salinity anomalies at the mooring. Salinity anomalies lag area and/or ice production anomalies by about 3 days. Up to 50% of the variability in the salinity at the mooring position can be explained by area and/or ice production anomalies in the TNBP for April–September 1996. This value increases to about 70% when considering shorter periods like April–June or May–July, but reduces to 30% later, for example July–September, together with a slight increase in time lag. In 1997, correlations are smaller, less significant and occur at a different time lag. Analysis of ocean currents at the mooring suggests that in 1996 conditions were more favourable than in 1997 for observing the impact of descending plumes of salt-enriched water formed in the polynya during ice formation on the water masses at the mooring depth.


2004 ◽  
Vol 23 (2) ◽  
pp. 141-146 ◽  
Author(s):  
Maria De Domenico ◽  
Angelina Lo Giudice ◽  
Luigi Michaud ◽  
Marcello Saitta ◽  
Vivia Bruni

PLoS ONE ◽  
2016 ◽  
Vol 11 (4) ◽  
pp. e0153254 ◽  
Author(s):  
Roksana Majewska ◽  
Peter Convey ◽  
Mario De Stefano

1999 ◽  
Vol 11 (2) ◽  
pp. 261-264 ◽  
Author(s):  
Filippo Mangani ◽  
Michela Maione ◽  
Luciano Lattanzi

CCl3F (or CFC-11) and CCl2F2 (or CFC-12) were determined in air samples collected, during subsequent summer Antarctic campaigns, in different sampling sites in the Ross Sea Region. The samples were analysed by GC-ECD after enrichment. Data obtained since 1988–89 were plotted to observe the trend of CFCs atmospheric concentration levels. A decrease in the rate of increase of CFC-12 concentration was observed, whilst the concentration of CFC-11 was actually seen to be decreasing.


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