scholarly journals Exploring the use of compound-specific carbon isotopes as a palaeoproductivity proxy off the coast of Adélie Land, East Antarctica

2021 ◽  
Vol 18 (19) ◽  
pp. 5555-5571
Author(s):  
Kate E. Ashley ◽  
Xavier Crosta ◽  
Johan Etourneau ◽  
Philippine Campagne ◽  
Harry Gilchrist ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Carbon Isotopes ◽  
Coastal Zone ◽  
Primary Productivity ◽  
Open Water ◽  
Phytoplankton Productivity ◽  
Antarctic Sea Ice ◽  
Projected Changes ◽  
The Antarctic

Abstract. The Antarctic coastal zone is an area of high primary productivity, particularly within coastal polynyas, where large phytoplankton blooms and drawdown of CO2 occur. Reconstruction of historical primary productivity changes and the associated driving factors could provide baseline insights on the role of these areas as sinks for atmospheric CO2, especially in the context of projected changes in coastal Antarctic sea ice. Here we investigate the potential for using carbon isotopes (δ13C) of fatty acids in marine sediments as a proxy for primary productivity. We use a highly resolved sediment core from off the coast of Adélie Land spanning the last ∼ 400 years and monitor changes in the concentrations and δ13C of fatty acids along with other proxy data from the same core. We discuss the different possible drivers of their variability and argue that C24 fatty acid δ13C predominantly reflects phytoplankton productivity in open-water environments, while C18 fatty acid δ13C reflects productivity in the marginal ice zone. These new proxies have implications for better understanding carbon cycle dynamics in the Antarctica coastal zone in future palaeoclimate studies.

scholarly journals Fatty acid carbon isotopes: a new indicator of marine Antarctic paleoproductivity?

2020 ◽  
Author(s):  
Kate Ashley ◽  
James Bendle ◽  
Xavier Crosta ◽  
Johan Etourneau ◽  
Philippine Campagne ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Carbon Isotopes ◽  
Coastal Zone ◽  
Primary Productivity ◽  
Open Water ◽  
Phytoplankton Productivity ◽  
Antarctic Sea Ice ◽  
Projected Changes ◽  
The Antarctic

Abstract. The Antarctic coastal zone is an area of high primary productivity, particularly within coastal polynyas where large phytoplankton blooms and drawdown of CO2 occur. Reconstruction of historical primary productivity changes, and the associated driving factors, could provide baseline insights on the role of these areas as sinks for atmospheric CO2, especially in the context of projected changes in coastal Antarctic sea ice. Here we investigate the potential for using carbon isotopes (δ13C) of fatty acids in marine sediments as a proxy for primary productivity. We use a highly resolved sediment core from off the coast of Adélie Land spanning the last ~ 400 years and monitor changes in the concentrations and δ13C of fatty acids along with other proxy data from the same core. We discuss the different possible drivers of their variability and argue that C24 fatty acid δ13C predominantly reflects phytoplankton productivity in open water environments, while C18 fatty acid δ13C reflects productivity in the marginal ice zone. These new proxies have implications for better understanding carbon cycle dynamics in the Antarctica coastal zone in future paleoclimate studies.

scholarly journals Synergism between elevated <i>p</i>CO<sub>2</sub> and temperature on the Antarctic sea ice diatom <i>Nitzschia lecointei</i>

2013 ◽  
Vol 10 (4) ◽  
pp. 6637-6669 ◽  
Author(s):  
A. Torstensson ◽  
M. Hedblom ◽  
J. Andersson ◽  
M. X. Andersson ◽  
A. Wulff
Keyword(s):  
Fatty Acids ◽  
Growth Rate ◽  
Fatty Acid ◽  
Sea Ice ◽  
Optimal Growth ◽  
Control Temperature ◽  
Antarctic Sea Ice ◽  
Acyl Lipid ◽  
Lipid Fatty Acid ◽  
The Antarctic

Abstract. Polar oceans are particularly susceptible to ocean acidification and warming. Diatoms play a significant role in sea ice biogeochemistry and provide an important food source to grazers in ice-covered oceans, especially during early spring. However, the ecophysiology of ice living organisms has received little attention in terms of ocean acidification. In this study, the synergism between temperature and partial pressure of CO2 (pCO2) was investigated in relationship to the optimal growth temperature of the Antarctic sea ice diatom Nitzschia lecointei. Diatoms were kept in cultures at controlled levels of pCO2 (∼390 and ∼960 μatm}) and temperature (−1.8 and 2.5 °C) for 14 days. Synergism between temperature and pCO2 was detected in growth rate and acyl lipid fatty acid content. Carbon enrichment only promoted (3%) growth rate closer to the optimal growth, but not at the control temperature (−1.8 °C). Optimal growth rate was observed around 5 °C in a separate experiment. Polyunsaturated fatty acids (PUFA) comprised up to 98% of the total acyl lipid fatty acid pool at −1.8 °C. However, the total content of fatty acids was reduced by 39% at elevated pCO2, but only at the control temperature. PUFAs were reduced by 30% at high pCO2. Effects of carbon enrichment may be different depending on ocean warming scenario or season, e.g. reduced food quality for higher trophic levels during spring. Synergy between temperature and pCO2 may be particularly important in polar areas since a narrow thermal window generally limits cold-water organisms.

scholarly journals Surface Albedo of the Antarctic Sea Ice Zone

2005 ◽  
Vol 18 (17) ◽  
pp. 3606-3622 ◽  
Author(s):  
Richard E. Brandt ◽  
Stephen G. Warren ◽  
Anthony P. Worby ◽  
Thomas C. Grenfell
Keyword(s):  
Sea Ice ◽  
Surface Albedo ◽  
Near Infrared ◽  
Field Experiments ◽  
Climate Models ◽  
Solar Spectrum ◽  
Open Water ◽  
Visual Observation ◽  
Antarctic Sea Ice ◽  
The Antarctic

Abstract In three ship-based field experiments, spectral albedos were measured at ultraviolet, visible, and near-infrared wavelengths for open water, grease ice, nilas, young “grey” ice, young grey-white ice, and first-year ice, both with and without snow cover. From the spectral measurements, broadband albedos are computed for clear and cloudy sky, for the total solar spectrum as well as for visible and near-infrared bands used in climate models, and for Advanced Very High Resolution Radiometer (AVHRR) solar channels. The all-wave albedos vary from 0.07 for open water to 0.87 for thick snow-covered ice under cloud. The frequency distribution of ice types and snow coverage in all seasons is available from the project on Antarctic Sea Ice Processes and Climate (ASPeCt). The ASPeCt dataset contains routine hourly visual observations of sea ice from research and supply ships of several nations using a standard protocol. Ten thousand of these observations, separated by a minimum of 6 nautical miles along voyage tracks, are used together with the measured albedos for each ice type to assign an albedo to each visual observation, resulting in “ice-only” albedos as a function of latitude for each of five longitudinal sectors around Antarctica, for each of the four seasons. These ice albedos are combined with 13 yr of ice concentration estimates from satellite passive microwave measurements to obtain the geographical and seasonal variation of average surface albedo. Most of the Antarctic sea ice is snow covered, even in summer, so the main determinant of area-averaged albedo is the fraction of open water within the pack.

scholarly journals A late spring surge in the open water of the Antarctic sea ice pack

1999 ◽  
Vol 26 (10) ◽  
pp. 1481-1484 ◽  
Author(s):  
Andrew B. Watkins ◽  
Ian Simmonds
Keyword(s):  
Sea Ice ◽  
Open Water ◽  
Late Spring ◽  
Antarctic Sea Ice ◽  
The Antarctic ◽  
Ice Pack

scholarly journals Physical Processes determining the Antarctic Sea Ice Environment

1997 ◽  
Vol 50 (4) ◽  
pp. 759 ◽  
Author(s):  
Ian Allison
Keyword(s):  
Sea Ice ◽  
Thickness Distribution ◽  
Arctic Basin ◽  
Open Water ◽  
Ice Cover ◽  
Dynamic Processes ◽  
Surface Absorption ◽  
Antarctic Sea Ice ◽  
Ocean Atmosphere ◽  
The Antarctic

The Antarctic sea ice zone undergoes one of the greatest seasonal surface changes on Earth, with an annual change in extent of around 15 × 10 6 km 2 . This ice, and its associated snow cover, plays a number of important roles in the ocean-atmosphere climate system: the high albedo ice cover restricts surface absorption of solar radiation and acts as a barrier to the exchange of mass and energy between the ocean and atmosphere, and salt rejected by the growing ice cover affects the ocean structure and circulation. Additionally, a number of sea ice feedback processes have the potential to play an important role in climate change. The extent to which a sea ice cover modifies ocean-atmosphere interaction is primarily determined by the thickness and concentration of the ice, but these themselves are determined by ocean and atmospheric interaction. The thickness distribution of the pack is determined by both thermodynamic and dynamic processes: most important at the geophysical scale are the dynamic processes of ice drift and deformation, and of lead formation. Compared to the ice cover in the central Arctic Basin, the Antarctic sea ice is highly mobile. Drifting buoy studies show that the Antarctic pack can move at speeds of up to 60 km per day or greater, and that around most of the Antarctic coast, the drift of the pack ice is generally divergent, with divergence rates of 10% or more per day being observed under some circumstances. Consequently there is generally some open water within the Antarctic pack and much of the total ice mass forms by rapid growth within these areas. This influences the crystal structure of the ice and results in a considerable portion of the Antarctic pack (up to 25% in spring-time) having a thickness of less than 0 · 3 m. In general much of the Antarctic sea ice only grows thermodynamically to about 0·5 m thick, with thickness increases beyond that resulting from the deformational processes of rafting and ridge-building.

Phytoplankton community structure and productivity in relation to the hydrological regime of the Gulf of Carpentaria, Australia, in summer

1994 ◽  
Vol 45 (3) ◽  
pp. 265 ◽  
Author(s):  
PC Rothlisberg ◽  
PC Pollard ◽  
PD Nichols ◽  
DJW Moriarty ◽  
AMG Forbes ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Organic Matter ◽  
Community Structure ◽  
Primary Productivity ◽  
Stable Carbon Isotopes ◽  
Hydrological Regime ◽  
Carbon Isotope Ratio ◽  
Phytoplankton Production ◽  
Phytoplankton Productivity ◽  
Light Intensities

To describe the influence of hydrology on the phytoplankton communites of the Gulf of Carpentaria, six phytoplankton parameters were measured on five transects: productivity, biomass, community structure, phospholipid-derived fatty acids, ratios of stable carbon isotopes and the relationship between photosynthesis and irradiance. The mean (�s.e.) estimate of depth-integrated phytoplankton productivity was 914�185 mgC m-2 day-' (n=9). In the shallow (<30 m) coastal waters, the productivity was 1430�400 mgC m-2 day-1 (n = 3). At the offshore stations (=30 m), it was 660 �108 mgC m-2 day-1 (n = 6). At both the shallow and the offshore stations, primary productivity was distributed equally between the phytoplankton size fractions 0.6-2.0�m and > 10�m, with little in between. The highest rates of growth occurred within a very narrow light regime: self-shading limited growth in deeper water (at light intensities less than 125 mol s-1 m-2), and growth was photoinhibited in shallow water (at light intensities greater than 150 mol s-1 m-2). The resulting biomass-specific primary productivity (mgC mChla-1 day-1) maximum did not coincide with the depth of either the chlorophyll a maximum or the highest nutrient concentration. The natural carbon isotope ratio for the particulate matter showed that little land-derived carbon was exported beyond a narrow coastal fringe (about 10 to 20 km). The profiles of phospholipid fatty acids also showed that particulate organic matter was dominated by algal-derived compounds, which confirms that the bulk of the organic matter in the offshore Gulf of Carpentaria is of marine origin. Therefore, during the summer in this study, the stratified waters of the central gulf were both biologically and hydrologically independent of the coastal water and not influenced by terrestrial runoff. The phytoplankton production in the central gulf is maintained by nutrient supplies from internal sources, such as those that are remineralized in and resuspended from the sediment.

Platelet Aggregation in Finnish Men and Its Relation to Fatty Acids in Platelets, Plasma and Adipose Tissue

1985 ◽  
Vol 54 (03) ◽  
pp. 563-569 ◽  
Author(s):  
M K Salo ◽  
E Vartiainen ◽  
P Puska ◽  
T Nikkari
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Platelet Aggregation ◽  
Acid Composition ◽  
Saturated Fatty Acids ◽  
Free Living ◽  
Ω3 Fatty Acids ◽  
Induced Aggregation

SummaryPlatelet aggregation and its relation to fatty acid composition of platelets, plasma and adipose tissue was determined in 196 randomly selected, free-living, 40-49-year-old men in two regions of Finland (east and southwest) with a nearly twofold difference in the IHD rate.There were no significant east-southwest differences in platelet aggregation induced with ADP, thrombin or epinephrine. ADP-induced platelet secondary aggregation showed significant negative associations with all C20-C22 ω3-fatty acids in platelets (r = -0.26 - -0.40) and with the platelet 20: 5ω3/20: 4ω 6 and ω3/ ω6 ratios, but significant positive correlations with the contents of 18:2 in adipose tissue (r = 0.20) and plasma triglycerides (TG) (r = 0.29). Epinephrine-induced aggregation correlated negatively with 20: 5ω 3 in plasma cholesteryl esters (CE) (r = -0.23) and TG (r = -0.29), and positively with the total percentage of saturated fatty acids in platelets (r = 0.33), but had no significant correlations with any of the ω6-fatty acids. Thrombin-induced aggregation correlated negatively with the ω3/6ω ratio in adipose tissue (r = -0.25) and the 20: 3ω6/20: 4ω 6 ratio in plasma CE (r = -0.27) and free fatty acids (FFA) (r = -0.23), and positively with adipose tissue 18:2 (r = 0.23) and 20:4ω6 (r = 0.22) in plasma phospholipids (PL).The percentages of prostanoid precursors in platelet lipids, i. e. 20: 3ω 6, 20: 4ω 6 and 20 :5ω 3, correlated best with the same fatty acids in plasma CE (r = 0.32 - 0.77) and PL (r = 0.28 - 0.74). Platelet 20: 5ω 3 had highly significant negative correlations with the percentage of 18:2 in adipose tissue and all plasma lipid fractions (r = -0.35 - -0.44).These results suggest that, among a free-living population, relatively small changes in the fatty acid composition of plasma and platelets may be reflected in significant differences in platelet aggregation, and that an increase in linoleate-rich vegetable fat in the diet may not affect platelet function favourably unless it is accompanied by an adequate supply of ω3 fatty acids.

EFFECT OF GINGER, LEMURU FISH OIL SAPONIFICATION AND OLIVE OIL ON COMPOSITION FATTY ACID OF BEEF

2014 ◽  
Vol 4 (1) ◽  
pp. 31-39
Author(s):  
Siwitri Kadarsih
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fish Oil ◽  
Olive Oil ◽  
Rice Bran ◽  
Dry Matter ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Omega 3 ◽  
Omega 6

The objective was to get beef that contain unsaturated fatty acids (especially omega 3 and 6), so as to improve intelligence, physical health for those who consume. The study design using CRD with 3 treatments, each treatment used 4 Bali cattle aged approximately 1.5 years. Observations were made 8 weeks. Pasta mixed with ginger provided konsentrat. P1 (control); P2 (6% saponification lemuru fish oil, olive oil 1%; rice bran: 37.30%; corn: 62.70%; KLK: 7%, ginger paste: 100 g); P3 (lemuru fish oil saponification 8%, 2% olive oil; rice bran; 37.30; corn: 62.70%; KLK: 7%, ginger paste: 200 g). Konsentrat given in the morning as much as 1% of the weight of the cattle based on dry matter, while the grass given a minimum of 10% of the weight of livestock observation variables include: fatty acid composition of meat. Data the analyzies qualitative. The results of the study showed that the composition of saturated fatty acids in meat decreased and an increase in unsaturated fatty acids, namely linoleic acid (omega 6) and linolenic acid (omega 3), and deikosapenta deikosaheksa acid.Keywords : 

Fatty Acid Profile and In Vitro Anticancer Activity of Two Marine Sponge- Associated Bacteria

2020 ◽  
Vol 16 (9) ◽  
pp. 1273-1280
Author(s):  
Giuseppina Tommonaro ◽  
Ali M. El-Hagrassi ◽  
Walid Fayad ◽  
Carmine Iodice ◽  
Kamel H. Shaker ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Colorectal Carcinoma ◽  
Cell Line ◽  
Marine Sponge ◽  
Hct116 Cell ◽  
Associated Bacteria ◽  
Sponge Associated Bacteria ◽  
Human Colorectal Carcinoma

Background: Colorectal cancer represents one of the prominent causes of mortality worldwide in men and women. The objective of this study was to search for new potential anticancer compounds, both in prevention and treatment of colorectal cancer. The anticancer potential of marine bacterial extracts against Human colorectal carcinoma cell line (HCT116) was evaluated as well as the partial identification of bioactive metabolites. Methods: All bacterial extracts were tested for their cytotoxicity against HCT116 cell line by means of MTT assay. The highly cytotoxic dichloromethane extracts of marine sponge-associated bacteria Vibrio sp. and Bacillus sp. were analyzed by GC-MS. Results: Two fractions, Vib3 and Bac3, exhibited a very interesting cytotoxicity against human colorectal carcinoma (HCT116) cell line, with a percentage of cytotoxicity of 96.04 % and 29.48 %, respectively. Discussion: The GC-MS analysis revealed the presence of two major fatty acids, palmitic and oleic acids, in Vib3 fraction and fatty acid esters and phenolic compounds in Bac3 fraction. Conclusion: Based on previous literature, it may be hypothesized that the anticancer activity of bacterial extracts could be, at least partially, to the fatty acids fraction.

Sign in / Sign up

Export Citation Format

Share Document