Long-Term Experiment on Physiological Responses to Synergetic Effects of Ocean Acidification and Photoperiod in the Antarctic Sea Ice AlgaeChlamydomonassp. ICE-L

2014 ◽  
Vol 48 (14) ◽  
pp. 7738-7746 ◽  
Author(s):  
Dong Xu ◽  
Yitao Wang ◽  
Xiao Fan ◽  
Dongsheng Wang ◽  
Naihao Ye ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ocean Acidification ◽  
Physiological Responses ◽  
Synergetic Effects ◽  
Antarctic Sea Ice ◽  
Term Experiment ◽  
Long Term Experiment ◽  
The Antarctic

scholarly journals Dark metabolism: a molecular insight into how the Antarctic sea‐ice diatom Fragilariopsis cylindrus survives long‐term darkness

2019 ◽  
Vol 223 (2) ◽  
pp. 675-691 ◽  
Author(s):  
Fraser Kennedy ◽  
Andrew Martin ◽  
John P. Bowman ◽  
Richard Wilson ◽  
Andrew McMinn
Keyword(s):  
Sea Ice ◽  
Antarctic Sea Ice ◽  
Fragilariopsis Cylindrus ◽  
Dark Metabolism ◽  
The Antarctic ◽  
Insight Into

Effects of ocean acidification on the physiological performance and carbon production of the Antarctic sea ice diatom Nitzschia sp. ICE-H

2017 ◽  
Vol 120 (1-2) ◽  
pp. 184-191 ◽  
Author(s):  
Chang-Feng Qu ◽  
Fang-Ming Liu ◽  
Zhou Zheng ◽  
Yi-Bin Wang ◽  
Xue-Gang Li ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ocean Acidification ◽  
Physiological Performance ◽  
Carbon Production ◽  
Antarctic Sea Ice ◽  
The Antarctic

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 (10) ◽  
pp. 6391-6401 ◽  
Author(s):  
A. Torstensson ◽  
M. Hedblom ◽  
J. Andersson ◽  
M. X. Andersson ◽  
A. Wulff
Keyword(s):  
Growth Rate ◽  
Sea Ice ◽  
Ocean Acidification ◽  
Cold Water ◽  
Optimal Growth ◽  
Trophic Levels ◽  
Separate Experiment ◽  
Antarctic Sea Ice ◽  
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 (FA) content. Optimal growth rate was observed around 5 °C in a separate experiment. Carbon enrichment only promoted (6%) growth rate closer to the optimal growth, but not at the control temperature (−1.8 °C). At −1.8 °C and at ∼960 μatm pCO2, the total FA content was reduced relative to the ∼390 μatm treatment, although no difference between pCO2 treatments was observed at 2.5 °C. A large proportion (97%) of the total FAs comprised on average of polyunsaturated fatty acids (PUFA) at −1.8 °C. Cellular PUFA content was reduced at ∼960 relative to ∼390 μatm pCO2. Effects of carbon enrichment may be different depending on ocean warming scenario or season, e.g. reduced cellular FA content in response to elevated CO2 at low temperatures only, reflected as reduced food quality for higher trophic levels. Synergy between warming and acidification may be particularly important in polar areas since a narrow thermal window generally limits cold-water organisms.

scholarly journals Brief communication: Increasing shortwave absorption over the Arctic Ocean is not balanced by trends in the Antarctic

2017 ◽  
Vol 11 (5) ◽  
pp. 2111-2116 ◽  
Author(s):  
Christian Katlein ◽  
Stefan Hendricks ◽  
Jeffrey Key
Keyword(s):  
Sea Ice ◽  
Cloud Cover ◽  
Arctic Sea Ice ◽  
Shortwave Radiation ◽  
The Arctic ◽  
Sea Ice Extent ◽  
Antarctic Sea Ice ◽  
Arctic Sea ◽  
The Antarctic

Abstract. On the basis of a new, consistent, long-term observational satellite dataset we show that, despite the observed increase of sea ice extent in the Antarctic, absorption of solar shortwave radiation in the Southern Ocean poleward of 60° latitude is not decreasing. The observations hence show that the small increase in Antarctic sea ice extent does not compensate for the combined effect of retreating Arctic sea ice and changes in cloud cover, which both result in a total increase in solar shortwave energy deposited into the polar oceans.

Antarctic Sea-Ice Variations from Satellite Sensing in Relation to Climate

1975 ◽  
Vol 15 (73) ◽  
pp. 417-427 ◽  
Author(s):  
W. F. Budd
Keyword(s):  
Sea Ice ◽  
Large Scale ◽  
Sea Ice Extent ◽  
Antarctic Sea Ice ◽  
Mean Temperature ◽  
Single Location ◽  
Scale Temperature ◽  
One Year ◽  
The Antarctic

AbstractAn analysis of records of annual mean temperatures around Antarctica shows large-scale anomalies of thousands of kilometers extent with typical variations of a deg from one year to another From 1967 on, composite satellite photographs are available which show considerable variation in the sea-ice extent in different years up to about 5º of latitude. These largest differences seem to persist over entire seasons. In general there seems to be considerable association between the region around the Antarctic with the coldest temperatures and the regions of greatest sea-ice extent. An analysis of long-term records at a single location near the edge of the Antarctic sea ice indicates a strong correlation between variations in the annual mean temperature and the duration of the sea ice, such that a change of 1 deg in the annual mean temperature corresponds to about 70 d variation in the duration of the sea ice. A relation is obtained between variations of annual mean temperature and the mean extent of the sea ice, viz. a 1 deg change corresponds to approximately 2.5º latitude variation in the maximum sea-ice extent. The magnitude of the variations in the sea-ice extent observed from the satellite data in comparison with the large-scale temperature anomalies is compatible with the above relations, although some rotational shifts appear to take place.

scholarly journals Long-term acclimation to elevated p CO 2 alters carbon metabolism and reduces growth in the Antarctic diatom Nitzschia lecointei

2015 ◽  
Vol 282 (1815) ◽  
pp. 20151513 ◽  
Author(s):  
Anders Torstensson ◽  
Mikael Hedblom ◽  
My Mattsdotter Björk ◽  
Melissa Chierici ◽  
Angela Wulff
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Ocean Acidification ◽  
Carbon Metabolism ◽  
Physiological Responses ◽  
Bacterial Productivity ◽  
Short Term ◽  
The Antarctic ◽  
Slow Growing

Increasing atmospheric CO 2 levels are driving changes in the seawater carbonate system, resulting in higher p CO 2 and reduced pH (ocean acidification). Many studies on marine organisms have focused on short-term physiological responses to increased p CO 2 , and few on slow-growing polar organisms with a relative low adaptation potential. In order to recognize the consequences of climate change in biological systems, acclimation and adaptation to new environments are crucial to address. In this study, physiological responses to long-term acclimation (194 days, approx. 60 asexual generations) of three p CO 2 levels (280, 390 and 960 µatm) were investigated in the psychrophilic sea ice diatom Nitzschia lecointei . After 147 days, a small reduction in growth was detected at 960 µatm p CO 2 . Previous short-term experiments have failed to detect altered growth in N. lecointei at high p CO 2 , which illustrates the importance of experimental duration in studies of climate change. In addition, carbon metabolism was significantly affected by the long-term treatments, resulting in higher cellular release of dissolved organic carbon (DOC). In turn, the release of labile organic carbon stimulated bacterial productivity in this system. We conclude that long-term acclimation to ocean acidification is important for N. lecointei and that carbon overconsumption and DOC exudation may increase in a high-CO 2 world.

Impacts of Multiple Stressors on a Benthic Foraminiferal Community: A Long-Term Experiment Assessing Response to Ocean Acidification, Hypoxia and Warming

2021 ◽  
Vol 8 ◽  
Author(s):  
Joan M. Bernhard ◽  
Johannes C. Wit ◽  
Victoria R. Starczak ◽  
David J. Beaudoin ◽  
William G. Phalen ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Atmospheric Carbon Dioxide ◽  
Environmental Changes ◽  
Multiple Stressors ◽  
Term Experiment ◽  
Long Term Experiment ◽  
Species Responses ◽  
Combined Impact ◽  
The Impact

Ocean chemistry is changing as a result of human activities. Atmospheric carbon dioxide (CO2) concentrations are increasing, causing an increase in oceanic pCO2 that drives a decrease in oceanic pH, a process called ocean acidification (OA). Higher CO2 concentrations are also linked to rising global temperatures that can result in more stratified surface waters, reducing the exchange between surface and deep waters; this stronger stratification, along with nutrient pollution, contributes to an expansion of oxygen-depleted zones (so called hypoxia or deoxygenation). Determining the response of marine organisms to environmental changes is important for assessments of future ecosystem functioning. While many studies have assessed the impact of individual or paired stressors, fewer studies have assessed the combined impact of pCO2, O2, and temperature. A long-term experiment (∼10 months) with different treatments of these three stressors was conducted to determine their sole or combined impact on the abundance and survival of a benthic foraminiferal community collected from a continental-shelf site. Foraminifera are well suited to such study because of their small size, relatively rapid growth, varied mineralogies and physiologies. Inoculation materials were collected from a ∼77-m deep site south of Woods Hole, MA. Very fine sediments (&lt;53 μm) were used as inoculum, to allow the entire community to respond. Thirty-eight morphologically identified taxa grew during the experiment. Multivariate statistical analysis indicates that hypoxia was the major driving factor distinguishing the yields, while warming was secondary. Species responses were not consistent, with different species being most abundant in different treatments. Some taxa grew in all of the triple-stressor samples. Results from the experiment suggest that foraminiferal species’ responses will vary considerably, with some being negatively impacted by predicted environmental changes, while other taxa will tolerate, and perhaps even benefit, from deoxygenation, warming and OA.

Antarctic Sea-Ice Variations from Satellite Sensing in Relation to Climate

1975 ◽  
Vol 15 (73) ◽  
pp. 417-427 ◽  
Author(s):  
W. F. Budd
Keyword(s):  
Sea Ice ◽  
Large Scale ◽  
Sea Ice Extent ◽  
Antarctic Sea Ice ◽  
Mean Temperature ◽  
Single Location ◽  
Scale Temperature ◽  
One Year ◽  
The Antarctic

AbstractAn analysis of records of annual mean temperatures around Antarctica shows large-scale anomalies of thousands of kilometers extent with typical variations of a deg from one year to another From 1967 on, composite satellite photographs are available which show considerable variation in the sea-ice extent in different years up to about 5º of latitude. These largest differences seem to persist over entire seasons. In general there seems to be considerable association between the region around the Antarctic with the coldest temperatures and the regions of greatest sea-ice extent. An analysis of long-term records at a single location near the edge of the Antarctic sea ice indicates a strong correlation between variations in the annual mean temperature and the duration of the sea ice, such that a change of 1 deg in the annual mean temperature corresponds to about 70 d variation in the duration of the sea ice. A relation is obtained between variations of annual mean temperature and the mean extent of the sea ice, viz. a 1 deg change corresponds to approximately 2.5º latitude variation in the maximum sea-ice extent. The magnitude of the variations in the sea-ice extent observed from the satellite data in comparison with the large-scale temperature anomalies is compatible with the above relations, although some rotational shifts appear to take place.

scholarly journals Elevated temperature and decreased salinity both affect the biochemical composition of the Antarctic sea-ice diatom Nitzschia lecointei, but not increased pCO2

Polar Biology ◽  
2019 ◽  
Vol 42 (11) ◽  
pp. 2149-2164 ◽  
Author(s):  
Anders Torstensson ◽  
Carlos Jiménez ◽  
Anders K. Nilsson ◽  
Angela Wulff
Keyword(s):  
Climate Change ◽  
Lipid Peroxidation ◽  
Sea Ice ◽  
Ocean Acidification ◽  
Biochemical Composition ◽  
Fatty Acid Content ◽  
Separate Experiment ◽  
Ice Melt ◽  
Antarctic Sea Ice ◽  
The Antarctic

Abstract Areas in western Antarctica are experiencing rapid climate change, where ocean warming results in more sea ice melt simultaneously as oceanic CO2 levels are increasing. In this study, we have tested how increased temperature (from −1.8 to 3 °C) and decreased salinity (from 35 to 20 and 10) synergistically affect the growth, photophysiology and biochemical composition of the Antarctic sea-ice diatom Nitzschia lecointei. In a separate experiment, we also addressed how ocean acidification (from 400 to 1000 µatm partial pressure of CO2) affects these key physiological parameters. Both positive and negative changes in specific growth rate, particulate organic carbon to particulate organic nitrogen ratio, chl a fluorescence kinetics, lipid peroxidation, carbohydrate content, protein content, fatty acid content and composition were observed when cells were exposed to warming and desalination. However, when cells were subjected to increased pCO2, only Fv/Fm, non-photochemical quenching and lipid peroxidation increased (by 3, 16 and 14%, respectively), and no other of the abovementioned biochemical properties were affected. These results suggest that changes in temperature and salinity may have more effects on the biochemical composition of N. lecointei than ocean acidification. Sea-ice algae are important component of polar food webs, and their nutritional quality may be affected as a result of altered environmental conditions due to climate change and sea ice melt.

Evaluation of mineral fertilizer effects in a long-term experiment on a planted sward

2010 ◽  
Vol 59 (2) ◽  
pp. 295-314 ◽  
Author(s):  
Imre Kádár
Keyword(s):  
Festuca Arundinacea ◽  
Dactylis Glomerata ◽  
Mineral Fertilizer ◽  
Phleum Pratense ◽  
Agropyron Cristatum ◽  
Festuca Rubra ◽  
Festuca Pratensis ◽  
Term Experiment ◽  
Long Term Experiment

Egy műtrágyázási tartamkísérlet 32. évében, 2005-ben vizsgáltuk az eltérő N-, P- és K-ellátottsági szintek és kombinációik hatását a réti csenkesz (Festuca pratensis) vezérnövényű, nyolckomponensű, pillangós nélküli gyepkeverék termésére, fejlődésére és elemtartalmára. A termőhely mészlepedékes csernozjom talaja a szántott rétegben mintegy 3% humuszt, 3–5% CaCO3-ot és 20–22% agyagot tartalmazott, N és K elemekben közepesen, P és Zn elemekben gyengén ellátottnak minősült. A kísérlet 4N×4P×4K = 64 kezelést×2 ismétlést = 128 parcellát foglalt magában. A talajvíz 13–15 m mélyen helyezkedik el, a terület aszályérzékeny. A vizsgált 2005. évben azonban kielégítő mennyiségű (649 mm) csapadék hullott és annak eloszlása is kedvező volt. A gyep telepítése spenót elővetemény után 2000. szeptember 20-án történt gabona sortávra 60 kg·ha–1 vetőmaggal, amelynek 25%-át (15 kg) a réti csenkesz (Festuca pratensis); 21–21%-át (12,6 kg) a nádképű csenkesz (Festuca arundinacea) és az angol perje (Lolium perenne); 9%-át (5,4 kg) a taréjos búzafű (Agropyron cristatum), valamint 6–6%-át (3,6 kg) a vörös csenkesz (Festuca rubra), a réti komócsin (Phleum pratense), a zöld pántlikafű (Phalaris arundinacea) és a csomós ebír (Dactylis glomerata) tette ki. Főbb eredményeink: – A meghatározó N-trágyázás nyomán a szénatermés 5-szörösére emelkedett a két kaszálással a N-kontrollhoz viszonyítva. A maximális 10 t·ha–1 körüli légszáraz szénahozamokat a 300 kg N·ha–1·év–1 N-adag, valamint a 150 mg·kg–1 körüli AL-P2O5-, illetve 150 mg·kg–1 feletti AL-K2O-tartalom biztosította. Növénydiagnosztikai szempontból a nagy terméshez kötődő optimális elemtartalom 2% körüli N- és K-, illetve 0,2–0,3% P-koncentráció volt a szénában. – A két kaszálással felvett minimum (a 2 t·ha–1 körüli szénatermést adó N-kontroll) és maximum (a 10 t·ha–1 körüli szénahozamú, nitrogénnel és PK-vel jól ellátott talajok) elemmennyiségek a következőképpen alakultak: N 21–196 kg, K 39–188 kg, Ca 9–48 kg, Mg 4–22 kg, P 6–21 kg. – Az N×P és N×K kölcsönhatások kifejezettebbé váltak a 2. kaszálás idején. A P 0,18–0,55%, a NO3-N 86–1582 mg·kg–1, a Cu 4,7–7,4 mg·kg–1, a Mo 0,7–4,1 mg·kg–1 extrém értékeket jelzett az N×P kezelések függvényében. Az N×K kezelésekben a K 1,44–2,73%, a Mg 0,26–0,39%, a Na 71–2178 mg·kg–1, a Ba 4,1–9,6 mg·kg–1, a Cd 15–44 µg·kg–1 szélsőértékekkel volt jellemezhető. A Sr a 10–26 mg·kg–1 koncentrációtartományban módosult a P×K-ellátottság nyomán. Élettani, takarmányozástani szempontból az indukált kölcsönhatások nyomon követése elengedhetetlen, amennyiben olyan mérvű tápelemhiányok, illetve aránytalanságok jöhetnek létre, melyek anyagcserezavarokat okozhatnak a növényt fogyasztó állatban.

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