scholarly journals Asymmetric responses to simulated global warming by populations of Colobanthus quitensis along a latitudinal gradient

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3718 ◽  
Author(s):  
Ian S. Acuña-Rodríguez ◽  
Cristian Torres-Díaz ◽  
Rasme Hereme ◽  
Marco A. Molina-Montenegro
Keyword(s):  
Global Warming ◽  
Latitudinal Gradient ◽  
Biomass Accumulation ◽  
South Shetland Islands ◽  
Plant Populations ◽  
Colobanthus Quitensis ◽  
Growing Seasons ◽  
Long Term Experiment ◽  
Foliar Traits ◽  
The Antarctic

The increase in temperature as consequence of the recent global warming has been reported to generate new ice-free areas in the Antarctic continent, facilitating the colonization and spread of plant populations. Consequently, Antarctic vascular plants have been observed extending their southern distribution. But as the environmental conditions toward southern localities become progressively more departed from the species’ physiological optimum, the ecophysiological responses and survival to the expected global warming could be reduced. However, if processes of local adaptation are the main cause of the observed southern expansion, those populations could appear constrained to respond positively to the expected global warming. Using individuals from the southern tip of South America, the South Shetland Islands and the Antarctic Peninsula, we assess with a long term experiment (three years) under controlled conditions if the responsiveness of Colobanthus quitensis populations to the expected global warming, is related with their different foliar traits and photoprotective mechanisms along the latitudinal gradient. In addition, we tested if the release of the stress condition by the global warming in these cold environments increases the ecophysiological performance. For this, we describe the latitudinal pattern of net photosynthetic capacity, biomass accumulation, and number of flowers under current and future temperatures respective to each site of origin after three growing seasons. Overall, was found a clinal trend was found in the foliar traits and photoprotective mechanisms in the evaluated C. quitensis populations. On the other hand, an asymmetric response to warming was observed for southern populations in all ecophysiological traits evaluated, suggesting that low temperature is limiting the performance of C. quitensis populations. Our results suggest that under a global warming scenario, plant populations that inhabiting cold zones at high latitudes could increase in their ecophysiological performance, enhancing the size of populations or their spread.

scholarly journals Asymmetric responses to simulated global warming by populations of Colobanthus quitensis along a latitudinal gradient

2017 ◽  
Author(s):  
Ian S. Acuña-Rodríguez ◽  
Cristian Torres-Díaz ◽  
Rasme Hereme ◽  
Marco A. Molina-Montenegro
Keyword(s):  
Global Warming ◽  
Latitudinal Gradient ◽  
Biomass Accumulation ◽  
South Shetland Islands ◽  
Plant Populations ◽  
Colobanthus Quitensis ◽  
Growing Seasons ◽  
Long Term Experiment ◽  
Foliar Traits ◽  
The Antarctic

The increase in temperature as consequence of the recent global warming has been reported to generate new ice-free areas in the Antarctic continent, propitiating the colonization and spread of plant populations. Consequently, antarctic vascular plants have been observed extending their southern distribution. But as the environmental conditions toward southern localities are progressively far apart from these species’ physiological optimum, the colonization of new sites and ecophysiological responses could be decreased. However, if processes of local adaptation are the main cause of the observed southern expansion, those populations could appear constrained to respond positively to the expected global warming. Using individuals from the southern tip of South America, the South Shetland Islands and the Antarctic Peninsula, we assess with a long term experiment (3 years) under controlled conditions if the responsiveness of Colobanthus quitensis populations to the expected global warming, is related with their different foliar traits and photoprotective mechanisms along their latitudinal gradient. In addition, we tested if the release of the stress condition by the global warming in theses cold environments increase the ecophysiological performance. For this, we describe the latitudinal pattern of net photosynthetic capacity, biomass accumulation, and number of flowers under current and future temperatures -by warming- respective to each site of origin after three growing seasons. Overall, was showed a clinal trend was found in the foliar traits and photoprotective mechanisms in the evaluated C. quitensis populations. On the other hand, an asymmetric response to warming was observed for southern populations in all ecophysiological traits evaluated, suggesting that low temperature is limiting the performance of C. quitensis populations, mainly in those from southern. Our results suggest that under a global warming scenario those plant populations that inhabiting cold zones at high latitudes could be improved in their ecophysiological performance, enhancing the size of populations or their spread.

scholarly journals Asymmetric responses to simulated global warming by populations of Colobanthus quitensis along a latitudinal gradient

2017 ◽  
Author(s):  
Ian S. Acuña-Rodríguez ◽  
Cristian Torres-Díaz ◽  
Rasme Hereme ◽  
Marco A. Molina-Montenegro
Keyword(s):  
Global Warming ◽  
Latitudinal Gradient ◽  
Biomass Accumulation ◽  
South Shetland Islands ◽  
Plant Populations ◽  
Colobanthus Quitensis ◽  
Growing Seasons ◽  
Long Term Experiment ◽  
Foliar Traits ◽  
The Antarctic

The increase in temperature as consequence of the recent global warming has been reported to generate new ice-free areas in the Antarctic continent, propitiating the colonization and spread of plant populations. Consequently, antarctic vascular plants have been observed extending their southern distribution. But as the environmental conditions toward southern localities are progressively far apart from these species’ physiological optimum, the colonization of new sites and ecophysiological responses could be decreased. However, if processes of local adaptation are the main cause of the observed southern expansion, those populations could appear constrained to respond positively to the expected global warming. Using individuals from the southern tip of South America, the South Shetland Islands and the Antarctic Peninsula, we assess with a long term experiment (3 years) under controlled conditions if the responsiveness of Colobanthus quitensis populations to the expected global warming, is related with their different foliar traits and photoprotective mechanisms along their latitudinal gradient. In addition, we tested if the release of the stress condition by the global warming in theses cold environments increase the ecophysiological performance. For this, we describe the latitudinal pattern of net photosynthetic capacity, biomass accumulation, and number of flowers under current and future temperatures -by warming- respective to each site of origin after three growing seasons. Overall, was showed a clinal trend was found in the foliar traits and photoprotective mechanisms in the evaluated C. quitensis populations. On the other hand, an asymmetric response to warming was observed for southern populations in all ecophysiological traits evaluated, suggesting that low temperature is limiting the performance of C. quitensis populations, mainly in those from southern. Our results suggest that under a global warming scenario those plant populations that inhabiting cold zones at high latitudes could be improved in their ecophysiological performance, enhancing the size of populations or their spread.

scholarly journals Biology of generative reproduction of Colobanthus quitensis (Kunth) Bartl. from King George Island, South Shetland Islands

2011 ◽  
Vol 32 (2) ◽  
pp. 139-155 ◽  
Author(s):  
Irena Giełwanowska ◽  
Anna Bochenek ◽  
Ewa Gojło ◽  
Ryszard Görecki ◽  
Wioleta Kellmann ◽  
...  
Keyword(s):  
Embryo Sac ◽  
Pollen Grains ◽  
South Shetland Islands ◽  
Egg Cell ◽  
Strong Wind ◽  
King George Island ◽  
Natural Conditions ◽  
Shetland Islands ◽  
Colobanthus Quitensis ◽  
The Antarctic

Biology of generative reproduction of Colobanthus quitensis (Kunth) Bartl. from King George Island, South Shetland Islands Our macroscopic observations and microscopic studies conducted by means of a light microscope (LM) and transmission electron microscope (TEM) concerning the re-production biology of Colobanthus quitensis (Caryophyllaceae) growing in natural conditions in the Antarctic and in a greenhouse in Olsztyn (northern Poland) showed that this plant develops two types of bisexual flowers: opening, chasmogamous flowers and closed, cleistogamous ones. Cleistogamy was caused by a low temperature, high air humidity and strong wind. A small number of microspores differentiated in the microsporangia of C. quitensis, which is typical of cleistogamous species. Microsporocytes, and later microspores, formed very thick callose walls. More than twenty spheroidal, polypantoporate pollen grains differentiated in the microsporangium. They germinated on the surface of receptive cells on the dry stigma of the gynoecium or inside the microsporangium. A monosporic embryo sac of the Polygonum type differentiated in the crassinucellar ovule. During this differentiation the nucellus tissue formed and stored reserve materials. In the development of generative cells, a male germ unit (MGU) with differentiated sperm cells was observed. The smaller cell contained mainly mitochondria, and the bigger one plastids. In the process of fertilization in C. quitensis only one nucleus of the sperm cell, without cytoplasm fragments, entered the egg cell, and the proembryo developed according to the Caryophyllad type. Almost all C. quitensis ovules developed and formed perispermic seeds with a completely differentiated embryo both under natural conditions in the Antarctic and in a green-house in Olsztyn.

scholarly journals Distribution of trace elements in benthic infralittoral organisms from the western Antarctic Peninsula reveals no latitudinal gradient of pollution

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Paula De Castro-Fernández ◽  
Luis Cardona ◽  
Conxita Avila
Keyword(s):  
Trace Elements ◽  
Antarctic Peninsula ◽  
Latitudinal Gradient ◽  
Anthropogenic Pollution ◽  
South Shetland Islands ◽  
Rocky Shores ◽  
Odontaster Validus ◽  
The World ◽  
Global And Local ◽  
The Antarctic

AbstractAntarctica is considered one of the most pristine regions on Earth, but evidences of global and local anthropogenic pollution exist. Chromium (Cr), lead (Pb) and mercury (Hg) are bioaccumulated and sometimes biomagnified through the trophic web. We aim to determine whether a latitudinal gradient of these trace elements exists in benthic organisms along the rocky shores of the Antarctic Peninsula and the South Shetland Islands. Levels of Cr, Pb, and Hg were measured by ICP-MS in two macroalgae (Palmaria decipiens and Desmarestia anceps or Desmarestia menziesii), one gastropod (Nacella concinna), two starfishes (Odontaster validus and Diplasterias brucei), and suspended particulate organic matter (SPOM) from five sampling sites ranging in latitude from 62°11′17″S to 67°33′47″S. Levels of trace elements differed among sites and species, but no latitudinal gradient was observed for these pollutants. Levels of Hg and Pb in animals were consistent with biomagnifications along the food web, as were higher is starfish than in limpets. However, macroalgae and SPOM are unlikely to be the main primary producers supporting those consumers, as Hg levels in macroalgae and Pb levels in SPOM were much higher than in animals. The levels of trace elements detected were similar or higher than in other Antarctic places and other regions of the world, thus indicating that the Antarctic Peninsula area is as polluted as the rest of the world.

Growth ofPseudotsuga menziesiiandTsuga heterophyllaseedlings along a light gradient: resource allocation and morphological acclimation

1997 ◽  
Vol 75 (9) ◽  
pp. 1424-1435 ◽  
Author(s):  
D. Mailly ◽  
J. P. Kimmins
Keyword(s):  
Leaf Morphology ◽  
Biomass Accumulation ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Low Light ◽  
Growing Seasons ◽  
Light Levels ◽  
Light Gradient ◽  
Relative Light Intensity

Silvicultural alternatives that differ in the degree of overstory removal may create shady environments that will be problematic for the regeneration of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Gradients of light in the field were used to compare mortality, growth, and leaf morphological acclimation of two conifer species of contrasting shade tolerances: Douglas-fir and western hemlock (Tsuga heterophylla (Raf.) Sarg.). Results after two growing seasons indicated that Douglas-fir mortality occurred mainly at relative light intensity (RLI) below 20%, while western hemlock mortality was evenly distributed along the light gradient. Height, diameter, and biomass of the planted seedlings increased with increasing light for both species but at different rates, and maximum biomass accumulation always occurred in the open. Douglas-fir allocated more resources to stem biomass than western hemlock, which accumulated more foliage biomass. Increases in specific leaf area for Douglas-fir seedlings occurred at RLI ≤ 0.4 and red/far red (R/FR) ratio ≤ 0.6, which appear to be the minimal optimum light levels for growth. Conversely, western hemlock seedlings adjusted their leaf morphology in a more regular pattern, and changes were less pronounced at low light levels. These results, along with early mortality results for Douglas-fir, suggest that the most successful way to artificially regenerate this species may be by allowing at least 20% of RLI for ensuring survival and at least 40% RLI for optimum growth. Key words: light, light quality, leaf morphology, acclimation.

The summer diet of demersal fish at the South Shetland Islands

1997 ◽  
Vol 9 (4) ◽  
pp. 407-413 ◽  
Author(s):  
Masanori Takahashi ◽  
Tetsuo Iwami
Keyword(s):  
Marine Ecosystem ◽  
Stomach Contents ◽  
Demersal Fish ◽  
South Shetland Islands ◽  
Fish Prey ◽  
Shetland Islands ◽  
Antarctic Marine ◽  
Dietary Component ◽  
Gobionotothen Gibberifrons ◽  
The Antarctic

The stomach contents of demersal fish in late January 1982 were analysed. Samples were taken at 100, 300 and 500 m depth south of Elephant Island, Bransfield Strait and north of Livingston Island, and at 800 m to the east of Smith Island. Fifty four taxa of fish belonging to 11 families were collected. The diets of 2101 fish representing 38 taxa were examined. These were classified into three categories, fish feeders, krill feeders and benthos feeders. Fish prey species fed on krill and/or benthos. Krill was a major dietary component for 32 (84.2%) out of 38 taxa. Gobionotothen gibberifrons was distributed at all 10 stations (100–800 m in depth) and its diet comprised krill and benthos. The present findings verify the importance of krill in the Antarctic marine ecosystem and indicate that krill is consumed by benthic fish at greater depths than previously reported.

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