Differential acclimation responses to irradiance and temperature in two co-occurring seaweed species in Arctic fjords

Arctic fjord systems experience large amplitudes of change in temperature and radiation regime due to climate warming and the related decrease in sea ice. The resultant increase in irradiance entering the water column influences photosynthetic activity of benthic and pelagic primary producers. The subtidal brown alga Desmarestia aculeata and the intertidal red alga Palmaria palmata populate the cold-temperate coasts of the North Atlantic, reaching the polar zone. To evaluate their acclimation potential, we collected both species in Kongsfjorden, Svalbard (78.9°N, 11.9°E), during the Arctic summer and exposed specimens to two different PAR levels (50 and 500 μmol photons m−2 s−1) and temperatures (0, 4 and 8 °C) for 21 days. Photosynthetic parameters and biochemical features (pigment concentration and antioxidants) were assessed. In general, high irradiance was the factor that generated a negative effect for D. aculeata and P. palmata in the photosynthetic parameters of the photosynthesis–irradiance curve and Fv/Fm. The pigment concentration in both species tended to decrease with increasing irradiance. Antioxidant level showed different trends for both species: in D. aculeata, antioxidant potential increased with high irradiance and temperature, while in P. palmata, it only increased with high irradiance. Both species showed responses to the interaction of irradiance and temperature, although D. aculeata was more sensitive to high irradiance than P. palmata. Our study shows how these species, which have similar geographical distribution in the North Atlantic and the Arctic but belong to different taxonomic lineages, have similar strategies of acclimation, although they respond differently to ecophysiological parameters.

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Change in the North Atlantic circulation associated with the mid-Pleistocene transition

Climate of the Past ◽

10.5194/cp-14-1639-2018 ◽

2018 ◽

Vol 14 (11) ◽

pp. 1639-1651 ◽

Cited By ~ 3

Author(s):

Gloria M. Martin-Garcia ◽

Francisco J. Sierro ◽

José A. Flores ◽

Fátima Abrantes

Keyword(s):

North Atlantic ◽

Major Change ◽

Water Masses ◽

Meridional Overturning Circulation ◽

The Arctic ◽

North Atlantic Current ◽

The North ◽

Oceanic Fronts ◽

Surface Circulation ◽

The North Atlantic

Abstract. The southwestern Iberian margin is highly sensitive to changes in the distribution of North Atlantic currents and to the position of oceanic fronts. In this work, the evolution of oceanographic parameters from 812 to 530 ka (MIS20–MIS14) is studied based on the analysis of planktonic foraminifer assemblages from site IODP-U1385 (37∘34.285′ N, 10∘7.562′ W; 2585 m b.s.l.). By comparing the obtained results with published records from other North Atlantic sites between 41 and 55∘ N, basin-wide paleoceanographic conditions are reconstructed. Variations of assemblages dwelling in different water masses indicate a major change in the general North Atlantic circulation during MIS16, coinciding with the definite establishment of the 100 ky cyclicity associated with the mid-Pleistocene transition. At the surface, this change consisted in the redistribution of water masses, with the subsequent thermal variation, and occurred linked to the northwestward migration of the Arctic Front (AF), and the increase in the North Atlantic Deep Water (NADW) formation with respect to previous glacials. During glacials prior to MIS16, the NADW formation was very weak, which drastically slowed down the surface circulation; the AF was at a southerly position and the North Atlantic Current (NAC) diverted southeastwards, developing steep south–north, and east–west, thermal gradients and blocking the arrival of warm water, with associated moisture, to high latitudes. During MIS16, the increase in the meridional overturning circulation, in combination with the northwestward AF shift, allowed the arrival of the NAC to subpolar latitudes, multiplying the moisture availability for ice-sheet growth, which could have worked as a positive feedback to prolong the glacials towards 100 ky cycles.

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Meridional Tripole Mode of Winter Precipitation over the Arctic and Continental North Africa–Eurasia

Journal of Climate ◽

10.1175/jcli-d-21-0212.1 ◽

2021 ◽

pp. 1

Author(s):

Xiaolin Liu ◽

Jianhua Lu ◽

Yimin Liu ◽

Guoxiong Wu

Keyword(s):

Time Series ◽

North Africa ◽

North Atlantic ◽

Hadley Cell ◽

The Arctic ◽

Positive Phase ◽

The North ◽

Ferrel Cell ◽

The North Atlantic ◽

Westerly Jets

AbstractWintertime precipitation is vital to the growth of glaciers in the northern hemisphere. We find a tripole mode of precipitation (PTM), with each pole of the mode extending zonally over the eastern hemisphere roughly between 30°W and 120°E, and the positive/negative/positive structure for its positive phase extending meridionally from the Arctic to the continental North Africa–Eurasia. The large-scale dynamics associated with the PTM is explored. The positive phase of the PTM is associated with the negative while eastward-shifted phase of the North Atlantic Oscillation (NAO) and a zonal band of positive SST anomaly in the tropics, together with a narrowed Hadley cell and weakened Ferrel cell. While being north-eastward tilted and separated from their North Africa-Eurasia counterpart in the climatological mean, the upper-tropospheric westerly jets over the east Pacific and north Atlantic become extending zonally and shifting southward and hence form a circumpolar subtropical jet as a whole by connecting with the westerly jets over the North Africa-Eurasia. The enhanced zonal winds over the north Atlantic promote more synoptic-scale transient eddies which are waveguided by the jet streams. The polar vortex weakens and cold air dips southward from the North Pole. Further diagnosis of the E-vectors suggests that transient eddies have a positive feedback on the weakening of Ferrel cell. Opposite features are associated with the negative phase of the PTM. The reconstructed time series using multiple linear regression on the NAO index and the tropical SST averaged over 20°S– 20°N, can explain 62.4% of the variance of the original the original precipitation time series.

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X. NATO and the Challenge in the North Atlantic and the Arctic

Whitehall Papers ◽

10.1080/02681307.2018.1508970 ◽

2018 ◽

Vol 93 (1) ◽

pp. 121-128 ◽

Cited By ~ 1

Author(s):

James G Foggo ◽

Alarik Fritz

Keyword(s):

North Atlantic ◽

The Arctic ◽

The North ◽

The North Atlantic

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Effect of gas-transfer-velocity parameterization choice on CO<sub>2</sub> air–sea fluxes in the North Atlantic and European Arctic

Ocean Science Discussions ◽

10.5194/osd-12-2591-2015 ◽

2015 ◽

Vol 12 (6) ◽

pp. 2591-2616

Author(s):

I. Wróbel ◽

J. Piskozub

Keyword(s):

North Atlantic ◽

World Ocean ◽

Software Tool ◽

The Arctic ◽

Gas Transfer ◽

Transfer Velocity ◽

Gas Transfer Velocity ◽

The North ◽

European Arctic ◽

The North Atlantic

Abstract. The ocean sink is an important part of the anthropogenic CO2 budget. Because the terrestrial biosphere is usually treated as a residual, understanding the uncertainties the net flux into the ocean sink is crucial for understanding the global carbon cycle. One of the sources of uncertainty is the parameterization of CO2 gas transfer velocity. We used a recently developed software tool, FluxEngine, to calculate monthly net carbon air–sea flux for the extratropical North Atlantic, European Arctic as well as global values (or comparison) using several available parameterizations of gas transfer velocity of different dependence of wind speed, both quadratic and cubic. The aim of the study is to constrain the uncertainty caused by the choice of parameterization in the North Atlantic, a large sink of CO2 and a region with good measurement coverage, characterized by strong winds. We show that this uncertainty is smaller in the North Atlantic and in the Arctic than globally, within 5 % in the North Atlantic and 4 % in the European Arctic, comparing to 9 % for the World Ocean when restricted to functions with quadratic wind dependence and respectively 42, 40 and 67 % for all studied parameterizations. We propose an explanation of this smaller uncertainty due to the combination of higher than global average wind speeds in the North Atlantic and lack of seasonal changes in the flux direction in most of the region. We also compare the available pCO2 climatologies (Takahashi and SOCAT) pCO2 discrepancy in annual flux values of 8 % in the North Atlantic and 19 % in the European Arctic. The seasonal flux changes in the Arctic have inverse seasonal change in both climatologies, caused most probably by insufficient data coverage, especially in winter.

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Carbon cycling in the Arctic Archipelago: the export of Pacific carbon to the North Atlantic

Biogeosciences Discussions ◽

10.5194/bgd-6-971-2009 ◽

2009 ◽

Vol 6 (1) ◽

pp. 971-994 ◽

Cited By ~ 1

Author(s):

E. H. Shadwick ◽

T. Papakyriakou ◽

A. E. F. Prowe ◽

D. Leong ◽

S. A. Moore ◽

...

Keyword(s):

Arctic Ocean ◽

North Atlantic ◽

Barents Sea ◽

Hydrological Cycle ◽

Dissolved Inorganic Carbon ◽

The Arctic ◽

Co2 Uptake ◽

The North ◽

The Arctic Ocean ◽

The North Atlantic

Abstract. The Arctic Ocean is expected to be disproportionately sensitive to climatic changes, and is thought to be an area where such changes might be detected. The Arctic hydrological cycle is influenced by: runoff and precipitation, sea ice formation/melting, and the inflow of saline waters from Bering and Fram Straits and the Barents Sea Shelf. Pacific water is recognizable as intermediate salinity water, with high concentrations of dissolved inorganic carbon (DIC), flowing from the Arctic Ocean to the North Atlantic via the Canadian Arctic Archipelago. We present DIC data from an east-west section through the Archipelago, as part of the Canadian International Polar Year initiatives. The fractions of Pacific and Arctic Ocean waters leaving the Archipelago and entering Baffin Bay, and subsequently the North Atlantic, are computed. The eastward transport of carbon from the Pacific, via the Arctic, to the North Atlantic is estimated. Altered mixing ratios of Pacific and freshwater in the Arctic Ocean have been recorded in recent decades. Any climatically driven alterations in the composition of waters leaving the Arctic Archipelago may have implications for anthropogenic CO2 uptake, and hence ocean acidification, in the subpolar and temperate North Atlantic.

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Modeling the climatic implications of the Guliya δ<sup>18</sup>O record during the past 130 ka

Climate of the Past Discussions ◽

10.5194/cpd-8-1885-2012 ◽

2012 ◽

Vol 8 (3) ◽

pp. 1885-1914

Author(s):

D. Xiao ◽

P. Zhao ◽

Y. Wang ◽

X. Zhou

Keyword(s):

North Atlantic ◽

Climate Model ◽

Surface Air Temperature ◽

Late Summer ◽

The Arctic ◽

The Past ◽

The North ◽

Precession Cycle ◽

The North Atlantic ◽

Anomalous Pattern

Abstract. Using an intermediate-complexity UVic Earth System Climate Model (UVic Model), the geographical and seasonal implications and an indicative sense of the historical climate found in the δ18O record of the Guliya ice core (hereinafter, the Guliya δ18O) are investigated under time-dependent orbital forcing with an acceleration factor of 100 over the past 130 ka. The results reveal that the simulated late-summer (August–September) Guliya surface air temperature (SAT) reproduces the 23-ka precession and 43-ka obliquity cycles in the Guliya δ18O. Furthermore, the Guliya δ18O is significantly correlated with the SAT over the Northern Hemisphere (NH), which suggests the Guliya δ18O is an indicator of the late-summer SAT in the NH. Corresponding to the warm and cold phases of the precession cycle in the Guliya temperature, there are two anomalous patterns in the SAT and sea surface temperature (SST) fields. The first anomalous pattern shows an increase in the SAT (SST) toward the Arctic, possibly associated with the joint effect of the precession and obliquity cycles, and the second anomalous pattern shows an increase in the SAT (SST) toward the equator, possibly due to the influence of the precession cycle. Additionally, the summer (winter) Guliya and NH temperatures are higher (lower) in the warm phases of Guliya late-summer SAT than in the cold phases. Furthermore, the Guliya SAT is closely related to the North Atlantic SST, in which the Guliya precipitation may act as a "bridge" linking the Guliya SAT and the North Atlantic SST.

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Polycyclic Aromatic Hydrocarbons in the North Atlantic Ocean and the Arctic Ocean: Spatial Distribution and Water Mass Transport

SSRN Electronic Journal ◽

10.2139/ssrn.3940194 ◽

2021 ◽

Author(s):

Mengyang Liu ◽

Minggang Cai ◽

Mengshan Duan ◽

Meng Chen ◽

Rainer Lohmann ◽

...

Keyword(s):

Spatial Distribution ◽

North Atlantic ◽

Aromatic Hydrocarbons ◽

Water Mass ◽

North Atlantic Ocean ◽

The Arctic ◽

The North ◽

The Arctic Ocean ◽

Polycyclic Aromatic ◽

The North Atlantic

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A Eurasian Ice-Sheet Study Using A Combined Ice-Sheet/ Ice-Shelf Numerical Model

Annals of Glaciology ◽

10.3189/s0260305500009125 ◽

1990 ◽

Vol 14 ◽

pp. 345-345

Author(s):

Dean R. Lindstrom

Keyword(s):

Numerical Model ◽

Mass Loss ◽

North Atlantic ◽

Ice Sheet ◽

The Arctic ◽

North Atlantic Current ◽

Ice Shelf ◽

The North ◽

The North Atlantic ◽

Atlantic Current

A numerical model which simultaneously computes grounded and ice-shelf flow was used to develop an equilibrium ice-sheet–ice-shelf system over Eurasia and the Arctic region. Present-day net accumulation rates and mean annual and July temperature values were used as base values for climatic variable specifications. The values were adjusted during the model run to account for changes in the ice-surface elevation and atmospheric CO2 concentration. The model-determined equilibrium ice-sheet configuration was used as input for additional runs to observe what effect removing the Arctic ice shelf and increasing the CO2 concentration from glacial to present-day values has on the ice sheet.At equilibrium, an ice shelf formed over the Arctic Ocean and Greenland and Norwegian seas. Ice easily grounded over the Barents, Kara, East Siberian, and Laptev seas. The grounded ice-sheet profile differs in Europe from most glacial geological reconstructions because the North Atlantic Current effect was not removed from the climatic adjustments. As a result, ice did not extend over the North Sea and onto the British Isles because of the North Atlantic Current's warming effect. Also, the precipitation rate over Europe was too high because of the moisture source the North Atlantic Current carries, and the ice sheet expanded beyond the field-determined ice-sheet margins in the region south-east of Finland.Removing most of the Arctic region's ice-shelf cover had little effect on the grounded ice sheet unless it rested upon a deformable sediment layer. The ice sheet was able to collapse within 10 000 years, however, when the CO2 concentration was gradually increased toward present-day values using the Vostok ice core's CO2 record from the last 18 000 years. Initially, most mass loss resulted from surface melting. Once the thickness decreased enough over some regions for the grounded ice to become ungrounded, however, most mass loss resulted from the ice shelf rapidly transporting the ice to the ice-shelf front and discharging it to the sea.

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The Impact of North Atlantic–Arctic Multidecadal Variability on Northern Hemisphere Surface Air Temperature

Journal of Climate ◽

10.1175/2010jcli3347.1 ◽

2010 ◽

Vol 23 (21) ◽

pp. 5668-5677 ◽

Cited By ~ 98

Author(s):

Vladimir A. Semenov ◽

Mojib Latif ◽

Dietmar Dommenget ◽

Noel S. Keenlyside ◽

Alexander Strehz ◽

...

Keyword(s):

Climate Variability ◽

Northern Hemisphere ◽

North Atlantic ◽

The Arctic ◽

Decadal Climate Variability ◽

Multidecadal Variability ◽

The North ◽

Hemisphere Surface ◽

The North Atlantic ◽

Decadal Climate

Abstract The twentieth-century Northern Hemisphere surface climate exhibits a long-term warming trend largely caused by anthropogenic forcing, with natural decadal climate variability superimposed on it. This study addresses the possible origin and strength of internal decadal climate variability in the Northern Hemisphere during the recent decades. The authors present results from a set of climate model simulations that suggest natural internal multidecadal climate variability in the North Atlantic–Arctic sector could have considerably contributed to the Northern Hemisphere surface warming since 1980. Although covering only a few percent of the earth’s surface, the Arctic may have provided the largest share in this. It is hypothesized that a stronger meridional overturning circulation in the Atlantic and the associated increase in northward heat transport enhanced the heat loss from the ocean to the atmosphere in the North Atlantic region and especially in the North Atlantic portion of the Arctic because of anomalously strong sea ice melt. The model results stress the potential importance of natural internal multidecadal variability originating in the North Atlantic–Arctic sector in generating interdecadal climate changes, not only on a regional scale, but also possibly on a hemispheric and even a global scale.

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