scholarly journals The effect of serial correlation in environmental conditions on estimates of extreme events

2021 ◽  
Vol 242 ◽  
pp. 110092
Author(s):  
Ed Mackay ◽  
Guillaume de Hauteclocque ◽  
Erik Vanem ◽  
Philip Jonathan
Keyword(s):  
Extreme Events ◽  
Environmental Conditions ◽  
Serial Correlation

scholarly journals Assessing biomass and primary production of microphytobenthos in depositional coastal systems using spectral information

2021 ◽  
Author(s):  
Pascalle Jacobs ◽  
Jaime Pitarch ◽  
Jacco C. Kromkamp ◽  
Catharina J.M. Philippart
Keyword(s):  
Primary Production ◽  
Extreme Events ◽  
Environmental Conditions ◽  
Food Supply ◽  
Benthic Microalgae ◽  
List Type ◽  
Benthic Primary Production ◽  
Coastal Systems ◽  
Benthic Biomass ◽  
Summer Temperatures

ABSTRACTIn depositional intertidal coastal systems, primary production is dominated by benthic microalgae (microphytobenthos) inhabiting the mudflats. This benthic productivity is supporting secondary production and supplying important services to humans including food provisioning. Increased frequencies of extreme events in weather (such as heatwaves, storm surges and cloudbursts) are expected to strongly impact the spatiotemporal dynamics of the microphytobenthos and subsequently their contribution to coastal food webs. Within north-western Europe, the years 2018 and 2019 were characterized by record-breaking summer temperatures and accompanying droughts. Field-calibrated satellite data (Sentinel 2) were used to quantify the seasonal dynamics of microphytobenthos biomass and production at an unprecedented spatial and temporal resolution during these years. We demonstrate that the Normalized Difference Vegetation Index (NDVI) should be used with caution in depositional coastal intertidal systems, because it may reflect import of remains of allochthonous pelagic productivity rather than local benthic biomass. We show that the reduction in summer biomass of the benthic microalgae cannot be explained by grazing but was most probably due to the high temperatures. The fivefold increase in salinity from January to September 2018, resulting from reduced river run-off during this exceptionally dry year, cannot have been without consequences for the vitality of the microphytobenthos community and its resistance to wind stress and cloud bursts. Comparison to historical information revealed that primary productivity of microphytobenthos may vary at least fivefold due to variations in environmental conditions. Therefore, ongoing changes in environmental conditions and especially extreme events because of climate change will not only lead to changes in spatiotemporal patterns of benthic primary production but also to changes in biodiversity of life under water and ecosystem services including food supply. Satellite MPB data allows for adequate choices in selecting coastal biodiversity conservation and coastal food supply.HIGHLIGHTSExpected seasonality changes require large-scale and high-resolution coastal dataNDVI of tidal flats reflects local benthic biomass and allochthonous phytoplanktonHigh summer temperatures reduced biomass and productivity of benthic microalgaeLong-term data revealed a five-fold variation in MPB biomass and productionSatellite MPB data allow for adequate conservation of coastal biodiversity

scholarly journals Assessing biomass and primary production of microphytobenthos in depositional coastal systems using spectral information

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0246012
Author(s):  
Pascalle Jacobs ◽  
Jaime Pitarch ◽  
Jacco C. Kromkamp ◽  
Catharina J. M. Philippart
Keyword(s):  
Primary Production ◽  
Extreme Events ◽  
Environmental Conditions ◽  
Food Supply ◽  
Western Europe ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Benthic Microalgae ◽  
Benthic Primary Production ◽  
Coastal Systems

In depositional intertidal coastal systems, primary production is dominated by benthic microalgae (microphytobenthos) inhabiting the mudflats. This benthic productivity is supporting secondary production and supplying important services to humans including food provisioning. Increased frequencies of extreme events in weather (such as heatwaves, storm surges and cloudbursts) are expected to strongly impact the spatiotemporal dynamics of the microphytobenthos and subsequently their contribution to coastal food webs. Within north-western Europe, the years 2018 and 2019 were characterized by record-breaking summer temperatures and accompanying droughts. Field-calibrated satellite data (Sentinel 2) were used to quantify the seasonal dynamics of microphytobenthos biomass and production at an unprecedented spatial and temporal resolution during these years. We demonstrate that the Normalized Difference Vegetation Index (NDVI) should be used with caution in depositional coastal intertidal systems, because it may reflect import of remains of allochthonous pelagic productivity rather than local benthic biomass. We show that the reduction in summer biomass of the benthic microalgae cannot be explained by grazing but was most probably due to the high temperatures. The fivefold increase in salinity from January to September 2018, resulting from reduced river run-off during this exceptionally dry year, cannot have been without consequences for the vitality of the microphytobenthos community and its resistance to wind stress and cloud bursts. Comparison to historical information revealed that primary productivity of microphytobenthos may vary at least fivefold due to variations in environmental conditions. Therefore, ongoing changes in environmental conditions and especially extreme events because of climate change will not only lead to changes in spatiotemporal patterns of benthic primary production but also to changes in biodiversity of life under water and ecosystem services including food supply. Satellite MPB data allows for adequate choices in selecting coastal biodiversity conservation and coastal food supply.

The role of measurement error on the interpretation of otolith increment width in the study of growth in larval fish

2001 ◽  
Vol 58 (11) ◽  
pp. 2204-2212 ◽  
Author(s):  
P Pepin ◽  
J F Dower ◽  
H P Benoît
Keyword(s):  
Measurement Error ◽  
Growth Rates ◽  
Environmental Conditions ◽  
Serial Correlation ◽  
Larval Fish ◽  
Increment Width ◽  
Growth Increments ◽  
Otolith Increment ◽  
Clear Increase

Patterns in increment widths and the associated measurement error were studied in the otoliths of radiated shanny (Ulvaria subbifurcata) larvae sampled from the field. Mean increment widths increased with larval age, whereas the relative measurement error decreased. Furthermore, the level of serial correlation in increment widths showed a clear increase with age. When measurement error was taken into consideration, the pattern of serial correlation indicates that an individual's growth increments did not show the effect of changes in local environmental conditions for at least 3 days, independent of age. Only after that period can we hope to detect the effect of environmental influences on increment widths (and by inference growth rates). The patterns of measurement error and serial correlation will have direct impacts on our ability to find the influence of environmental conditions on growth rates of individual larvae and determine patterns of selective loss in a population of larval fish.

Is the differential response of riparian plant performance to extreme drought and inundation events related to differences in intraspecific trait variation?

2014 ◽  
Vol 41 (6) ◽  
pp. 609
Author(s):  
Yasmijn A. M. van der Knaap ◽  
Rien Aerts ◽  
Peter M. van Bodegom
Keyword(s):  
Extreme Events ◽  
Environmental Conditions ◽  
Plant Performance ◽  
Additive Effects ◽  
Multiple Traits ◽  
Trait Variation ◽  
Intraspecific Trait Variation ◽  
Drought Tolerant ◽  
Tolerant Species ◽  
Riparian Plant

Previous research on the impacts of extreme events has focussed mainly on plant performance. Selective effects of extremes suggests that appropriate traits to withstand extremes, or the ability to modulate traits, may increase the competitive advantage and survival of a species. We tested how multiple extreme events affect riparian plant performance, and whether this relates to intraspecific trait variation. We hypothesised that species tolerant to extreme environmental conditions would show highest intraspecific trait variation. We conducted a greenhouse experiment where 25 wet to drought-tolerant species (grasses and herbs) were subjected to single and double 10 day drought and inundation events, and all combinations thereof. We measured plant performance and multiple traits. Performance was severely reduced, with clear synergistic, non-additive effects of extreme events. Adverse effects were stronger for wet-tolerant than drought-tolerant species and for grasses than herbs. Three traits were identified as predictors of species responses to extremes. Despite known trait variation for these species, no variation occurred under these conditions, indicating that responses are difficult to explain from impacts of mean environmental conditions. Our results indicate that multiple events may lead to quantitatively different impacts than single events, which hampers predicting plant response to a future climate.

scholarly journals Large-Scale Environmental Conditions Related to Midsummer Extreme Rainfall Events around Japan in the TRMM Region

2018 ◽  
Vol 31 (17) ◽  
pp. 6933-6945 ◽  
Author(s):  
Atsushi Hamada ◽  
Yukari N. Takayabu
Keyword(s):  
Extreme Events ◽  
Environmental Conditions ◽  
Large Scale ◽  
Southern China ◽  
Extreme Rainfall ◽  
Extreme Rainfall Events ◽  
Near Surface ◽  
Rainfall Events ◽  
Precipitation Characteristics ◽  
Large Scale Flow

The precipitation characteristics of extreme events in August determined from 13 years of satellite data around Japan in the TRMM observation region and their relationship with large-scale environmental conditions are examined. Two types of extreme events, extreme rainfall and extreme convective events, are defined in each analysis grid box using maximum near-surface rainfall and maximum 40-dB Z echo-top height in each event, respectively. There are clear differences in precipitation characteristics between the two types of extreme events. Extreme rainfall events are more organized precipitation systems than the extreme convective events, with relatively lower echo-top heights and very low lightning activity. There are also clear differences in the related environmental conditions, where the environments related to the extreme rainfall events are somewhat convectively stable and very humid in almost the entire troposphere. These facts are consistent with our previous studies and reinforce the importance of warm-rain processes in extremely intense precipitation productions. The environments related to the extreme rainfall events exhibit a zonally extended moist anomaly in the free troposphere from southern China to the east of Japan, indicating that the excessive moisture transported from the west by a large-scale flow may partially play a role in producing environmental conditions favorable for extreme rainfall. On the other hand, the environments related to extreme convective events are not associated with free-tropospheric moisture inflow. The relationships with the tropical cyclones and upper-tropospheric dynamical fields are also examined, and are found to be clearly different between the extreme rainfall events and extreme convective events.

scholarly journals A new method to simulate the hydrological state of soil under natural conditions

2009 ◽  
Vol 44 (8) ◽  
pp. 843-851 ◽  
Author(s):  
Anna-Katharina Wild ◽  
Michael Thomas Marx ◽  
Gerhard Eisenbeis
Keyword(s):  
Community Structure ◽  
Water Content ◽  
Extreme Events ◽  
Environmental Conditions ◽  
Soil Parameters ◽  
Natural Conditions ◽  
Natural Habitats ◽  
Artificial Flood ◽  
Number Of Individuals

Micro, macro and mesofauna in the soil often respond to fluctuating environmental conditions, resulting in changes of abundance and community structure. Effects of changing soil parameters are normally determined with samples taken in the field and brought to the laboratory, i.e. where natural environmental conditions may not apply. We devised a method (STAFD - soil tubes for artificial flood and drought), which simulates the hydrological state of soil in situ using implanted cores. Control tubes were compared with treatment tubes in which floods of 15, 30, 60 and 90 days, and droughts of 60, 90 and 120 days were simulated in the field. Flooding and drought were found to reduce number of individuals in all soil faunal groups, but the response to drought was slower and not in proportion to the expected decrease of the water content. The results of the simulated floods in particular show the value of the STAFD method for the investigation of such extreme events in natural habitats.

Vibration Isolator System for Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 182-183
Author(s):  
K. Ohi ◽  
M. Mizuno ◽  
T. Kasai ◽  
Y. Ohkura ◽  
K. Mizuno ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Magnetic Fields ◽  
Environmental Conditions ◽  
Vibration Isolator ◽  
Air Conditioners ◽  
Vibration Isolators ◽  
Large Size ◽  
Electron Microscopes

In recent years, with electron microscopes coming into wider use, their installation environments do not necessarily give their performance full play. Their environmental conditions include air-conditioners, magnetic fields, and vibrations. We report a jointly developed entirely new vibration isolator which is effective against the vibrations transmitted from the floor.Conventionally, large-sized vibration isolators which need the digging of a pit have been used. These vibration isolators, however, are large present problems of installation and maintenance because of their large-size.Thus, we intended to make a vibration isolator which1) eliminates the need for changing the installation room2) eliminates the need of maintenance and3) are compact in size and easily installable.

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