scholarly journals Summer Heatwave Impacts on the European Kelp Saccharina latissima Across Its Latitudinal Distribution Gradient

2021 ◽  
Vol 8 ◽  
Author(s):  
Nora Diehl ◽  
Michael Y. Roleda ◽  
Inka Bartsch ◽  
Ulf Karsten ◽  
Kai Bischof
Keyword(s):  
Distribution Patterns ◽  
Saccharina Latissima ◽  
Latitudinal Distribution ◽  
Meristematic Tissue ◽  
Local Responses ◽  
Temperature Regimes ◽  
Intraspecific Variations ◽  
Summer Temperatures ◽  
C And N ◽  
Population Resilience

Kelps are important foundation species in coastal ecosystems currently experiencing pronounced shifts in their distribution patterns caused by ocean warming. While some populations found at species’ warm distribution edges have been recently observed to decline, expansions of some species have been recorded at their cold distribution edges. Reduced population resilience can contribute to kelp habitat loss, hence, understanding intraspecific variations in physiological responses across a species’ latitudinal distribution is crucial for its conservation. To investigate potential local responses of the broadly distributed kelp Saccharina latissima to marine heatwaves in summer, we collected sporophytes from five locations in Europe (Spitsbergen, Bodø, Bergen, Helgoland, Locmariaquer), including populations exposed to the coldest and warmest local temperature regimes. Meristematic tissue from sporophytes was subjected to increasing temperatures of Δ+2, Δ+4 and Δ+6°C above the respective mean summer temperatures (control, Δ±0°C) characteristic for each site. Survival and corresponding physiological and biochemical traits were analyzed. Vitality (optimum quantum yield, Fv/Fm) and growth were monitored over time and biochemical responses were measured at the end of the experiment. Growth was highest in northern and lowest in southern populations. Overall, northern populations from Spitsbergen, Bodø and Bergen were largely unaffected by increasing summer temperatures up to Δ+6°C. Conversely, sporophytes from Helgoland and Locmariaquer were markedly stressed at Δ+6°C: occurrence of tissue necrosis, reduced Fv/Fm, and a significantly elevated de-epoxidation state of the xanthophyll cycle (DPS). The variations in phlorotannins, mannitol and tissue C and N contents were independent of temperature treatments and latitudinal distribution pattern. Pronounced site-specific variability in response to increasing temperatures implies that exceeding a threshold above the mean summer temperature exclusively affect rear-edge (southernmost) populations.

scholarly journals High Summer Temperatures Have No Role in Breaking Physical Dormancy Among Seeds of Fireprone Cistaceae: A Reinterpretation of Luna (2020)

2021 ◽  
Author(s):  
Byron B. Lamont ◽  
Geoffrey E. Burrows ◽  
Dylan Korczynskyj
Keyword(s):  
Heat Pulse ◽  
Summer Temperature ◽  
Ambient Conditions ◽  
Physical Dormancy ◽  
Future Studies ◽  
Retarding Effect ◽  
Temperature Regimes ◽  
Summer Temperatures ◽  
Unique Study ◽  
The Mediterranean Basin

Abstract In a unique study, Luna (2020) examined the viability and germination of 12 hard-seeded Cistaceae in the Mediterranean Basin by alternating a prolonged summer-type-temperature (50/20°C at 12 h cycles) treatment with a fire-type heat pulse. A re-analysis of their data shows that the summer treatment applied before the heat pulse was superfluous as similar high levels of germination under ambient conditions were attained with the heat pulse only. The abundance of hard seeds remaining when the summer treatment was applied after the heat pulse is better explained by ungerminated seeds having become hard again rather than not responding, i.e., showing secondary physical dormancy, and thus became ‘desensitized’ to their environment. While this response is adaptive, such a retarding effect will be limited in practice as most fires are expected in autumn, at least historically, and are thus close to the start of optimal winter conditions for germination. Future studies should concentrate on the fate of the water-gap plug during such alternating treatments and also ensure that realistic summer temperature regimes are used.

Factors influencing hydroids (Cnidaria: Hydrozoa) biodiversity and distribution in Arctic kelp forest

2008 ◽  
Vol 88 (8) ◽  
pp. 1567-1575 ◽  
Author(s):  
Marta Ronowicz ◽  
Maria Wlodarska-Kowalczuk ◽  
Piotr Kuklinski
Keyword(s):  
Kelp Forest ◽  
Distribution Patterns ◽  
Sediment Concentration ◽  
Saccharina Latissima ◽  
Kelp Forests ◽  
Laminaria Digitata ◽  
Alaria Esculenta ◽  
Algal Host ◽  
A Site ◽  
West Spitsbergen

The biodiversity and distribution patterns of epiphytic hydroids were studied in kelp forests (composed of Laminaria digitata, Saccharina latissima and Alaria esculenta) located in an Arctic glaciated fiord (Hornsund, west Spitsbergen). In total, twenty-eight species were found colonizing algae, stones connected to holdfast, and overgrowing the surface of other animals associated with kelps. The characteristics of the algal host (e.g. algae species, age, rhizoid volume or biomass) did not show any effect upon hydroid species richness or species composition. High hydroid biodiversity was strongly dependent on microsubstrate heterogeneity. The highest biodiversity as well as frequency of hydroid occurrence were noted at a site located furthest from the glacier and characterized by the lowest sediment concentration and sedimentation rate. Sexual reproduction also seemed to be inhibited by glacier-derived disturbance. Of ten fertile species found at the ‘clearest’ site only two were fertile at sites under the strong influence of such perturbations. Potential physical drivers of species occurrence were linked to the activity of tidal glaciers, particularly to high loads of mineral sedimentation and iceberg scouring.

scholarly journals Geographical traceability in grapes: possible applications of trace and ultratrace elements

2021 ◽  
Author(s):  
Carmela Vaccaro ◽  
Fabio Alessandro Faccia ◽  
Luigi Sansone ◽  
Elena Marrocchino
Keyword(s):  
Chemical Elements ◽  
Liquid Fraction ◽  
Distribution Patterns ◽  
Biological Variables ◽  
Icp Ms ◽  
Production Area ◽  
C And N ◽  
Scientific System ◽  
High Level ◽  
Ultratrace Elements

<p>In the last decades the demand for information and criteria, suitable for connecting products to their production regions, is becoming more urgent in order to protect the qualitative high-level productions by forgery. Wine is one of the products that could benefit of a scientific system of analysis able to define its production area. Features of the association between wine and territory are not only related to pedological but also to geographical aspects. Currently, several studies to define markers, such as isotopic ratios of O, C, and N, able to identify types of wine has been carried out, but they are not suitable to univocally define a specific type of wine in particular due to the high variability of some factors (temperature, age of the vineyard, period of such us isotopic…). Several samples of soils and grapes have been collected within the narrow area, characterized by quite heterogeneous lithologies, of the Euganei Hills area (NE of Italy) in order to identify possible markers typical of the growing area. The concentration of 25 elements (Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Ba, La, Ce, Nd, Pb, Th) have been determined on grapes by using ICP-MS and on soils by using XRF techniques. Moreover, grapes have been further refined and separated in two different fractions (one residual solid fraction and one liquid fraction). The concentration of Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu have been determined on both these fractions in order to implement and complete the distribution pattern of REEs in the samples. Areas with geochemically different soils have been identified and in each one of these areas have been collected grapes of Cabernet Franc and Cabernet Sauvignon.  Moreover, in most areas, several cultivars have been collected in order to better understand how biological variables could affect the assimilation of chemical elements from soils. Chemical composition of the grapes’ inorganic fraction seems more influenced by soils than by cultivar type. In fact, REEs distribution patterns tend to differ more considering the same cultivar grown in areas with different pedological features.</p>

HISTOCHEMICAL STUDIES OF ENZYME DISTRIBUTION IN SHOOT TIPS OF WHITE SPRUCE (PICEA GLAUCA (MOENCH) VOSS)

1963 ◽  
Vol 41 (10) ◽  
pp. 1509-1527 ◽  
Author(s):  
W. H. Vanden Born
Keyword(s):  
Picea Glauca ◽  
Succinic Dehydrogenase ◽  
White Spruce ◽  
Distribution Patterns ◽  
Shoot Tips ◽  
Shoot Tip ◽  
Quiescent Center ◽  
Meristematic Tissue ◽  
Stage Of Development ◽  
Enzyme Distribution

The relationship between morphological and metabolic or enzymic differentiation in shoot tips of white spruce has been investigated by histochemical methods revealing the distribution of several enzymes and other cellular constituents in tissues of the shoot tip at different times during the growing season. Most of the enzymes studied showed well-defined distribution patterns which varied with the stage of development of the shoot tip. Less seasonal variation was observed in the distribution of the other substances included.Activity of cytochrome oxidase and succinic dehydrogenase was high in the shoot apex during the flush of growth in the spring, indicating a high level of respiratory activity in that region, consistent with the rapid growth of the shoot. Peroxidase activity was associated particularly with meristematic or potentially meristematic tissue regions. The evidence substantiates the view that mitotic activity is greatest on the flanks of the apex and supports the existence of a quiescent center with relatively low activity in the apical mother cell zone, classically the origin of the primary stem tissues. High phosphatase activity was observed in the crown region and at the bases of needle and cone scale primordia.Young cones in fall or spring exhibited enzyme distribution patterns distinctly different from those in vegetative shoot tips. No evidence was obtained to indicate what enzyme or enzymes might be particularly involved in the differentiation of reproductive buds, but the results provide a basis for a further critical investigation of this differentiation by histochemical means.

Host Plant and Thermal Stress Induce Supernumerary Instars in Caterpillars

2019 ◽  
Vol 49 (1) ◽  
pp. 123-131
Author(s):  
Mariana Abarca ◽  
John T Lill ◽  
Martha R Weiss
Keyword(s):  
Thermal Stress ◽  
Host Plant ◽  
Development Time ◽  
Head Capsule ◽  
Compensatory Mechanism ◽  
Temperature Regimes ◽  
Size At Metamorphosis ◽  
Summer Temperatures ◽  
Typical Summer ◽  
Capsule Size

Abstract Environmental stressors may induce variation in the number of larval instars of holometabolous insects. Host plant quality and ambient temperature can both induce this life history shift in the silver-spotted skipper, Epargyreus clarus (Cramer 1775) (Lepidoptera: Hesperiidae). To better understand this phenomenon, we raised larvae on high-quality (kudzu) or low-quality (wisteria) host plants in growth chambers under three temperature regimes (20, 26, and 32°C) that were either constant or diurnally fluctuating (T ± 5°C), and recorded survival and incidence of supernumerary instars. Larvae feeding on the low-quality host and/or experiencing thermal stress were more likely to show supernumerary development (SD). A subset of treatments yielded a mix of SD and TD (typical development) individuals, allowing for comparisons between phenotypes. Under the most stressful treatment (20 ± 5°C, wisteria), development time was 9 days longer in SD than in TD individuals; by contrast, at typical summer temperatures (26 ± 5°C), also on wisteria, total development time did not differ between these two phenotypes. Head capsules of both second and third instars were smaller in SD individuals. A retrospective logistic regression analysis indicated that third-instar head capsule size could be used to predict expression of the SD phenotype. By the ultimate instar, however, there were no detectable differences in head capsule size, and SD and TD individuals did not differ in pupal mass, strongly suggesting that the SD phenotype functions as a compensatory mechanism allowing E. clarus larvae to achieve the same size at metamorphosis (a strong fitness correlate) as TD larvae.

Ecology of two large, net-spinning caddisfly species in a mountain stream: distribution, abundance, and metabolic response to a thermal gradient

1999 ◽  
Vol 77 (10) ◽  
pp. 1637-1644 ◽  
Author(s):  
Winsor H Lowe ◽  
F Richard Hauer
Keyword(s):  
Metabolic Response ◽  
Temperature Response ◽  
Distribution Patterns ◽  
Elevational Gradient ◽  
Mountain Stream ◽  
Northern Rocky Mountains ◽  
Food Quantity ◽  
Longitudinal Gradients ◽  
Summer Maximum ◽  
Summer Temperatures

We quantified the distribution and abundance of larvae of two species of caddisfly, Parapsyche elsis and Arctopsyche grandis (Trichoptera: Hydropsychidae), at 8 sites along a 560-m elevational gradient and a 36-km longitudinal gradient in a pristine mountain stream. Both species are widely distributed throughout the northern Rocky Mountains and have similar 2-year life-spans, similar catch-nets, and similar microhabitat requirements. However, the reach-scale distribution patterns were distinctly dissimilar. Parapsyche elsis larvae were most abundant in the upper reaches of the study stream, while A. grandis larvae were found only in lower stream segments. We examined the correlation between the stream gradient and the environmental variables that likely influence the distributions of these insects: temperature, food quantity and quality, current velocity, and substratum cobble size. Only those variables relating to temperature (i.e., annual degree-days, summer maximum) correlated with stream elevational and longitudinal gradients. Laboratory examination revealed a relationship between zones of temperature independence in the metabolism-temperature response of both species, maximum summer temperatures in the stream, and distribution of the two species. We propose that the physiological response of these species to stream temperature, with resulting bioenergetics, is the probable mechanism structuring the stream distribution and abundance patterns of these species.

Effects of environmental factors on the performance of Digitaria eriantha and Medicago sativa in monoculture and mixture

1997 ◽  
Vol 37 (3) ◽  
pp. 323 ◽  
Author(s):  
P. G. Tow ◽  
A. Lazenby ◽  
J. V. Lovett
Keyword(s):  
Medicago Sativa ◽  
Growth Patterns ◽  
North West ◽  
Far North ◽  
Temperature Regimes ◽  
Moisture Regimes ◽  
Digitaria Eriantha ◽  
Summer Temperatures ◽  
Spring Temperatures ◽  
Applied Nitrogen

Summary. A glasshouse experiment was conducted to test hypotheses concerning differences in environmental adaptation of Digitaria eriantha (digitaria) and Medicago sativa cv. Hunter River (lucerne), and advantages of growing them in mixture on a solodic soil on the Far North-West Slopes of New South Wales. The 2 species were grown in monoculture and mixture in simulated solodic soil profiles, at 2 temperature regimes, 2 levels of available nitrogen (0 and 0.25 g/container after each harvest), and 3 moisture levels (drought, adequate, flood), thus providing the range of conditions encountered in the field. The 2 species differed markedly in their response to temperature, which explains the complementary seasonal growth patterns in the field. Summer temperatures favoured digitaria growth while spring temperatures favoured lucerne growth. At summer temperatures, digitaria outyielded lucerne at all moisture regimes with applied nitrogen, as well as the flooded treatment without applied nitrogen. At spring temperatures, lucerne outyielded digitaria without nitrogen applied, as well as in the adequate moisture regimes with nitrogen applied. Yields of each species were reduced by periodic flooding and droughting; at their respective more favoured temperature regimes for growth, the percentage reduction in yield at individual harvests was higher in lucerne than in digitaria, especially for flooding. Flooding at summer temperatures had the worst effect on lucerne but summer droughting was almost as severe, especially with continued application of these treatments. Both species responded to nitrogen, the percentage dry matter increase being higher at summer than at spring temperatures. The species responded to temperature, moisture and nitrogen in the same way in mixture as in monoculture. The yield response of the mixture was dominated by that of the most responsive species at that regime. Monocultures rarely outyielded the mixture. The mixture sometimes significantly outyielded both monocultures, mainly with summer temperature, adequate moisture and low nitrogen. Long-term exploitation of the complementary temperature responses of the 2 species and their overall adaptation to the temperature regime of the Far North-West Slopes may depend on measures to minimise the effects of intermittent flooding and droughting in summer.

The influence of desert temperature cycles on the reproductive biology of Pseudodiplorchis americanus (Monogenea)

Parasitology ◽  
1991 ◽  
Vol 103 (1) ◽  
pp. 111-120 ◽  
Author(s):  
K. Tocque ◽  
R. C. Tinsley
Keyword(s):  
Reproductive Biology ◽  
Laboratory Data ◽  
Reproductive Development ◽  
Optimal Growth ◽  
First Year ◽  
Effective Period ◽  
Temperature Regimes ◽  
Soil Temperatures ◽  
Abiotic Control ◽  
Summer Temperatures

Pseudodiplorchis americanus has an extremely brief opportunity for transmission, restricted to less than 24 h in the year when the host (Scaphiopus couchii) enters water to breed. This strict annual cycle means that invading worms have 1 year to complete reproductive development. Despite this, a large proportion of the parasite suprapopulation is not prepared for transmission at the time of host breeding. The present study correlates detailed soil temperatures for one field site in S.E. Arizona, spanning 3·5 years, with laboratory data on parasite growth and reproductive development at a series of controlled temperatures. Development is totally inhibited at 16°C. Optimal growth and development occurs at 25°C and is slower at both 20°C and a diurnal cycle fluctuating between 20 and 34°C (mean 27°C) (simulating summer temperatures experienced by host and parasite). The effective period for accumulation of infective stages by P. americanus in any one season varies according to the timing of the summer rains in consecutive years. Between 1985 and 1988, the interval between host breedings varied from 11 to 13 months and the period when temperatures were above 20°C varied from 4 to 5·5 months per year. Since the first month post-infection (p.i.) consists of pre-reproductive development, first-year worms have only 3–4·5 months to produce infective larvae. In the shortest seasons, these worms may not be able to complete reproductive preparation in time for the first opportunity for transmission. In different parts of the geographical distribution of S. couchii, different cycles of temperature, rainfall and host breeding occur; varying temperature regimes represent an important abiotic control of P. americanus reproductive biology and transmission.

Low temperature induced metabolic changes in the shoot meristematic region of Marquillo × Kenya Farmer wheat dwarf 1 plants

1972 ◽  
Vol 50 (2) ◽  
pp. 285-293 ◽  
Author(s):  
J. D. Mahon ◽  
D. T. Canvin
Keyword(s):  
Inorganic Phosphate ◽  
Apical Meristem ◽  
Distribution Patterns ◽  
Organic Phosphate ◽  
Meristematic Tissue ◽  
Meristematic Region ◽  
Initial Decrease ◽  
Meristematic Activity ◽  
Cellular Destruction ◽  
Radiotracer Techniques

Marquillo × Kenya Farmer 1 (Mql × KF 1) wheat plants respond to very short 16° treatment by decreased meristematic activity of the apical meristem and extensive cellular destruction in young leaf and stem tissues. By radiotracer techniques the metabolism of 3H-thymidine, 32P, and 14C-leucine fed to intact shoot tissues of Mql × KF 1 and normal Marquillo (Mql) plants were studied.Immediately after the onset of 16° treatment, the incorporation of both 3H-thymidine and 32P into the DNA of Mql × KF 1 meristematic regions began to decline rapidly although the total uptake of label into the meristematic tissue remained constant. The incorporation of 32P into the RNA, the acid-soluble organic phosphate compounds, and phospholipids of the Mql × KF 1 meristems also declined during the first 24 h and the inorganic phosphate radioactivity increased. After the initial decrease, the proportion of radioactivity in the RNA and acid-soluble organic compounds increased to near control levels. The distribution patterns of both 3H-thymidine and 32P were unchanged in the meristematic region of Mql × KF 1 plants at 26° or Mql plants at 16° or 26°. Protein synthesis in meristematic regions, measured by the incorporation of 14C-leucine, responds to temperature similarly in Mql × KF 1 and Mql plants.The inhibitions of mitosis, phospholipid synthesis, and DNA synthesis were extremely rapid and reversible after short 16° exposures, and are thought to be close to the primary process of temperature lethality of Mql × KF 1 plants. Although it is not known if any of these processes are responsible for the others, it is proposed that the cellular destruction is caused by the inability of cells in the elongating regions to synthesize the phospholipid components of membranes.

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