scholarly journals Effects of temperature on the behaviour and metabolism of an intertidal foraminifera and consequences for benthic ecosystem functioning

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Noémie Deldicq ◽  
Dewi Langlet ◽  
Camille Delaeter ◽  
Grégory Beaugrand ◽  
Laurent Seuront ◽  
...  
Keyword(s):  
High Temperature ◽  
Ecosystem Functioning ◽  
Photosynthetic Activity ◽  
Species Traits ◽  
Biogeochemical Cycles ◽  
Variable Environment ◽  
Sediment Reworking ◽  
Temperature Regimes ◽  
Slow Moving ◽  
Effects Of Temperature

AbstractHeatwaves have increased in intensity, duration and frequency over the last decades due to climate change. Intertidal species, living in a highly variable environment, are likely to be exposed to such heatwaves since they can be emerged for more than 6 h during a tidal cycle. Little is known, however, on how temperature affects species traits (e.g. locomotion and behaviour) of slow-moving organisms such as benthic foraminifera (single-celled protists), which abound in marine sediments. Here, we examine how temperature influences motion-behaviour and metabolic traits of the dominant temperate foraminifera Haynesina germanica by exposing individuals to usual (6, 12, 18, 24, 30 °C) and extreme (high; i.e. 32, 34, 36 °C) temperature regimes. Our results show that individuals reduced their activity by up to 80% under high temperature regimes whereas they remained active under the temperatures they usually experience in the field. When exposed to a hyper-thermic stress (i.e. 36 °C), all individuals remained burrowed and the photosynthetic activity of their sequestered chloroplasts significantly decreased. Recovery experiments subsequently revealed that individuals initially exposed to a high thermal regime partially recovered when the hyper-thermic stress ceased. H. germanica contribution to surface sediment reworking substantially diminished from 10 mm3 indiv−1 day−1 (usual temperature) to 0 mm3 indiv−1 day−1 when individuals were exposed to high temperature regimes (i.e. above 32 °C). Given their role in sediment reworking and organic matter remineralisation, our results suggest that heatwaves may have profound long-lasting effects on the functioning of intertidal muddy ecosystems and some key biogeochemical cycles.

scholarly journals Effects of light and temperature on lettuce seedlings.

1973 ◽  
Vol 21 (2) ◽  
pp. 102-109 ◽  
Author(s):  
K. Verkerk ◽  
C.J.T. Spitters
Keyword(s):  
High Temperature ◽  
Light Intensity ◽  
Leaf Area ◽  
Temperature Regime ◽  
Natural Light ◽  
Light Conditions ◽  
Subsequent Growth ◽  
High Temperature Regime ◽  
Temperature Regimes ◽  
Effects Of Temperature

In the first of 2 experiments lettuces were grown either under natural light conditions in the glasshouse in December and January or under 8- or 16-h daylengths, with several temperature regimes, and the leaf area per plant was measured after 22 and 45 days. Under natural light growth during the first 22 days was slight but subsequent growth was greatest with a light/dark temperature regime of 13/13 deg C, followed by one of 17/17 deg . With an 8-h day growth with diurnally changing temperatures was much greater than with constant ones, the best results being obtained with a regime of 25/17 deg . With a 16-h day the effect of diurnal temperature was much less marked and a constant high temperature regime of 21/21 deg gave better results than one of 25/17 deg . In the second experiment the plants were grown for 4 weeks under the same temperature regimes with 8- or 16-h daylengths, but the light intensity was varied by placing the plants at 2 vertical distances from the overhead lamps and all plants receiving a 16-h daylength were shaded by cheesecloth. The best results were obtained with a 16-h daylength with the plants placed close to the lamps; the effects of temperature were not so marked, but regimes of 25/17, 21/13 or 17/17 deg were the most satisfactory. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Growth of Honey Locust Seedlings during High Root-zone Temperature and Osmotic Stress

HortScience ◽  
1991 ◽  
Vol 26 (10) ◽  
pp. 1312-1315 ◽  
Author(s):  
William R. Graves ◽  
Lorna C. Wilkins
Keyword(s):  
Polyethylene Glycol ◽  
High Temperature ◽  
Root Zone ◽  
Temperature Treatment ◽  
Root Zone Temperature ◽  
Temperature Regimes ◽  
Honey Locust ◽  
Effects Of Temperature ◽  
Peg 8000 ◽  
Zone Temperature

Growth of honey locust (Gleditsia triacanthos var. inermis Willd.) seedlings was studied during exposure to reduced osmotic potential (ψπ) and high temperature in the root zone. Half-sib plants were cultured in solution. Root-zone temperature was increased from ambient (23C) to 35C for 0, 6, 12, or 24 hours·day -l. Within each temperature treatment, solution ψπ of -0.05, – 0.10, and – 0.20 MPa were maintained by additions of polyethylene glycol (PEG) 8000. Root and shoot dry weights decreased with increasing exposure to 35C among seedlings in -0.05-MPa solution and decreased for seedlings in - 0.10- and - 0.20-MPa solutions in all temperature regimes. Growth of epicotyls displayed similar trends, but epicotyls of plants in -0.20-MPa solution were longest with 6 hours·day-l at 35C. Significant interactions between effects of temperature and osmotic regimes indicated that water-stressed honey locust seedlings are relatively insensitive to elevated root-zone temperatures. However, related studies showed that PEG caused reductions in growth that could not be explained by decreases in ψπ and suggested that responses of honey locust to PEG differed from those when drought was imposed by withholding irrigation in an aggregate medium.

scholarly journals Substrate Acidification by Geranium: Temperature Effects

2008 ◽  
Vol 133 (4) ◽  
pp. 508-514 ◽  
Author(s):  
Matthew D. Taylor ◽  
Paul V. Nelson ◽  
Jonathan M. Frantz
Keyword(s):  
High Temperature ◽  
Dry Weight ◽  
Night Temperature ◽  
The Third ◽  
Temperature Regimes ◽  
Higher Temperature ◽  
Effects Of Temperature ◽  
Increasing Temperature ◽  
Substrate Ph ◽  
Tissue Phosphorus

Sudden pH decline (SPD) describes the situation where crops growing at an appropriate pH rapidly (within 1–2 weeks) cause the substrate pH to shift downward one to two units. ‘Designer Dark Red’ geraniums (Pelargonium ×hortorum Bailey) were grown in three experiments to assess possible effects of temperature on SPD. The first experiment tested the effect of four day/night temperature regimes (14 °C day/10 °C night, 18 °C day/14 °C night, 22 °C day/18 °C night, and 26 °C day/22 °C night) on substrate acidification. At 63 days after transplanting (DAT), substrate pH declined from 6.8 to 4.6 as temperature increased. Tissue phosphorus (P) of plants grown at the highest three temperatures was extremely low (0.10%–0.14% of dry weight), and P stress has been reported to cause acidification. It was not possible to determine if the drop in substrate pH was a singular temperature effect or a combination of high temperature and low P. To resolve this, a second experiment tested a factorial combination of the three highest temperatures from the first experiment and five preplant P rates (0, 0.065, 0.13, 0.26, or 0.52 g·L−1 substrate). Regardless of tissue P concentrations, which ranged from deficient to above adequate, substrate pH decreased with increasing temperature. At 63 DAT, in the 0.065 and 0.13 P treatments, tissue P was deficient and pH decreased with increasing temperature from 5.6 to 4.7 and 5.9 to 4.7, respectively. In the 0.26 P treatment, tissue P was adequate at the lowest temperature and there was no acidification. At the mid- and highest temperatures, tissue P was deficient and statistically equivalent, yet pH decreased to 5.2 and 4.7, respectively. In the highest P treatment, tissue P levels were unaffected by temperature, above adequate, and pH declined with each increase in temperature from 6.5 to 5.0. The results at 63 DAT once more showed that temperature acted independent of tissue P and caused geraniums to acidify the substrate. In the third experiment, the amount of acidity produced by roots of plants grown at the two highest temperatures used in the first two experiments was quantified. Plants grown at the higher temperature produced 28% more acid per gram dry root. The results herein indicate that high temperature can induce SPD by geranium.

scholarly journals Systemic Infection by Fusarium verticillioides in Maize Plants Grown Under Three Temperature Regimes

Plant Disease ◽  
2008 ◽  
Vol 92 (12) ◽  
pp. 1695-1700 ◽  
Author(s):  
A. Murillo-Williams ◽  
G. P. Munkvold
Keyword(s):  
High Temperature ◽  
Environmental Factors ◽  
Fusarium Verticillioides ◽  
Systemic Infection ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Kernel Infection ◽  
Temperature Regimes ◽  
Maize Plants ◽  
Systemic Development

Fusarium verticillioides causes seedling decay, stalk rot, ear rot, and mycotoxin contamination (primarily fumonisins) in maize. Systemic infection of maize plants by F. verticillioides can lead to kernel infection, but the frequency of this phenomenon has varied widely among experiments. Variation in the incidence of systemic infection has been attributed to environmental factors. In order to better understand the influence of environment, we investigated the effect of temperature on systemic development of F. verticillioides during vegetative and reproductive stages of plant development. Maize seeds were inoculated with a green fluorescent protein-expressing strain of F. verticillioides, and grown in growth chambers under three different temperature regimes. In the vegetative-stage and reproductive-stage experiments, plants were evaluated at tasseling (VT stage), and at physiological maturity (R6 stage), respectively. Independently of the temperature treatment, F. verticillioides was reisolated from nearly 100% of belowground plant tissues. Frequency of reisolation of the inoculated strain declined acropetally in aboveground internodes at all temperature regimes. At VT, the high-temperature treatment had the highest systemic development of F. verticillioides in aboveground tissues. At R6, incidence of systemic infection was greater at both the high- and low-temperature regimes than at the average-temperature regime. F. verticillioides was isolated from higher internodes in plants at R6, compared to stage VT. The seed-inoculated strain was recovered from kernels of mature plants, although incidence of kernel infection did not differ significantly among treatments. During the vegetative growth stages, temperature had a significant effect on systemic development of F. verticillioides in stalks. At R6, the fungus reached higher internodes in the high-temperature treatment, but temperature did not have an effect on the incidence of kernels (either symptomatic or asymptomatic) or ear peduncles infected with the inoculated strain. These results support the role of high temperatures in promoting systemic infection of maize by F. verticillioides, but plant-to-seed transmission may be limited by other environmental factors that interact with temperature during the reproductive stages.

Effects of Temperature on Leaf Expansion in Sunflower

1982 ◽  
Vol 9 (2) ◽  
pp. 209 ◽  
Author(s):  
HM Rawson ◽  
JH Hindmarsh
Keyword(s):  
Field Studies ◽  
Leaf Expansion ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Leaf Position ◽  
Leaf Emergence ◽  
Temperature Regimes ◽  
Effects Of Temperature ◽  
Increasing Temperature ◽  
Relative Change

Five commercial cultivars of sunflower were grown in cabinets at three temperature regimes, 32/22, 27/17 and 22/12°C, and with 15-h and 11-h photoperiods, and expansion of leaves 5-15 was followed. Leaves appeared faster with increasing temperature (0.022 leaves day-1 °C-1) and with increasing daylength. Areas of individual leaves increased linearly up the plant profile and, although final area per leaf (Amax) decreased with increasing temperature, the relative change was similar for each leaf position. Cultivars maintained their ranking for Amax across temperatures, and these rankings agreed with those in previous field studies. Within each temperature regime, both the expansion rate of leaves and the duration of expansion increased with leaf position. As temperature increased, leaves grew for shorter periods with a change of 1.04 days °C-1, but under the photon flux density used (500 �mol m-2 s-1, or about 25% full sunlight) expansion rates were greatest at the lowest temperature. Expansion rates were only one-third of those in field studies at comparable temperatures, but durations were similar. Cultivars that achieved the largest Amax did so via faster rates of expansion and not via longer durations: only one cultivar differed from the mean (20 days) duration of leaf expansion. All cultivars reached floral initiation progressively earlier with extension of photoperiod from 10 to 15 h, with the change for the most sensitive cultivars being 8 days and for the least sensitive 5 days. Rates of leaf emergence were linked with this sensitivity.

scholarly journals Functional trait responses to sediment deposition reduce macrofauna-mediated ecosystem functioning in an estuarine mudflat

2018 ◽  
Vol 15 (9) ◽  
pp. 2587-2599 ◽  
Author(s):  
Sebastiaan Mestdagh ◽  
Leila Bagaço ◽  
Ulrike Braeckman ◽  
Tom Ysebaert ◽  
Bart De Smet ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Ecosystem Functioning ◽  
River Estuary ◽  
Functional Trait ◽  
Sediment Deposition ◽  
Sediment Chemistry ◽  
Sediment Layer ◽  
Sediment Reworking ◽  
Macrobenthic Communities ◽  
The Impact

Abstract. Human activities, among which dredging and land use change in river basins, are altering estuarine ecosystems. These activities may result in changes in sedimentary processes, affecting biodiversity of sediment macrofauna. As macrofauna controls sediment chemistry and fluxes of energy and matter between water column and sediment, changes in the structure of macrobenthic communities could affect the functioning of an entire ecosystem. We assessed the impact of sediment deposition on intertidal macrobenthic communities and on rates of an important ecosystem function, i.e. sediment community oxygen consumption (SCOC). An experiment was performed with undisturbed sediment samples from the Scheldt river estuary (SW Netherlands). The samples were subjected to four sedimentation regimes: one control and three with a deposited sediment layer of 1, 2 or 5 cm. Oxygen consumption was measured during incubation at ambient temperature. Luminophores applied at the surface, and a seawater–bromide mixture, served as tracers for bioturbation and bio-irrigation, respectively. After incubation, the macrofauna was extracted, identified, and counted and then classified into functional groups based on motility and sediment reworking capacity. Total macrofaunal densities dropped already under the thinnest deposits. The most affected fauna were surficial and low-motility animals, occurring at high densities in the control. Their mortality resulted in a drop in SCOC, which decreased steadily with increasing deposit thickness, while bio-irrigation and bioturbation activity showed increases in the lower sediment deposition regimes but decreases in the more extreme treatments. The initial increased activity likely counteracted the effects of the drop in low-motility, surficial fauna densities, resulting in a steady rather than sudden fall in oxygen consumption. We conclude that the functional identity in terms of motility and sediment reworking can be crucial in our understanding of the regulation of ecosystem functioning and the impact of habitat alterations such as sediment deposition.

Effect of pinealectomy on the testicular response of the freshwater snake Natrix piscator to different environmental factors

1989 ◽  
Vol 67 (10) ◽  
pp. 2352-2357 ◽  
Author(s):  
C. Haldar ◽  
R. Pandey
Keyword(s):  
High Temperature ◽  
Pineal Gland ◽  
High Humidity ◽  
Testicular Function ◽  
Experimental Conditions ◽  
Gland Weight ◽  
Tropical Water ◽  
Water Snake ◽  
Temperature Regimes ◽  
Testicular Weight

The effects of different humidity, photoperiod, and temperature regimes on the testicular function of the tropical water snake Natrix piscator were investigated in both sham-operated and pinealectomized snakes. Moderate humidity (50 ± 5%) had no effect on the testis, but high humidity (85 ± 5%) increased the testicular weight and activity of sham-operated snakes after 3, 6, and 9 weeks. Exposures to 14L:10D or 24L:0D and high temperature (42 ± 2 °C) inhibited testicular weight and activity in sham-operated snakes, whereas exposure to 10L:14D or 0L:24D and a low temperature (20 ± 2 °C) had no effect. Pinealectomized snakes did not respond to any of these experimental conditions, but their testicular weight remained the same as that of the pinealectomized controls under natural environmental conditions. The pineal gland showed an opposite response to that of the testes. Pineal gland weight decreased under high humidity and increased under 14L:10D, 24L:0D, and high temperature. These findings suggest that the ecofactors humidity, photoperiod, and temperature play a role in the regulation of testicular function in this snake, and that the pineal gland is implicated in the mediation of these factors.

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