scholarly journals Seagrass Patch Complexity Affects Macroinfaunal Community Structure in Intertidal Areas: An In Situ Experiment Using Seagrass Mimics

Diversity ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 572
Author(s):  
Fernando G. Brun ◽  
José F. Cobo-Díaz ◽  
Vanessa González-Ortiz ◽  
José L. Varela ◽  
José Lucas Pérez-Lloréns ◽  
...  

Seagrasses, as key ecosystem engineers in coastal ecosystems, contribute to enhancing diversity in comparison with nearby bare areas. It has been proved mainly for epifauna, but data on infauna are still scarce. The present study addresses how seagrass structural complexity (i.e., canopy properties) affects the diversity of infaunal organisms inhabiting those meadows. Canopy attributes were achieved using seagrass mimics, which were used to construct in situ vegetation patches with two contrasting canopy properties (i.e., shoot density and morphology) resembling the two seagrass species thriving in the inner Cadiz Bay: Zostera noltei and Cymodocea nodosa. After three months, bare nearby areas, two mimicked seagrass patches (‘Zostera’ and ‘Cymodocea’), and the surrounding natural populations of Zostera noltei were sampled in a spatially explicit way. Shifts in organism diets were also determined using 15N and 13C analyses in available food sources and main infaunal organisms, mixing models, and niche metrics (standard ellipse area). Seagrass-mimicked habitats increased the species richness (two-fold), organism abundance (three to four times), and functional diversity compared with bare nearby areas. The clam Scrobicularia plana (deposit/filter feeder) and the worm Hediste diversicolor (omnivore) were dominant in all of the samples (> 85%) and showed an opposite spatial distribution in the reconstructed patches: whilst S. plana accumulated in the outer-edge parts of the meadow, H. diversicolor abounded in the center. Changes in the isotopic signature of both species depending on the treatment suggest that this faunal distribution was associated with a shift in the diet of the organisms. Based on our results, we concluded that facilitation processes (e.g., reduction in predation and in bioturbation pressures) and changes in food availability (quality and quantity) mediated by seagrass canopies were the main driving forces structuring this community in an intertidal muddy area of low diversity.

2021 ◽  
Vol 96 ◽  
pp. 107084
Author(s):  
Cui Zhibo ◽  
Su Zhaoqian ◽  
Hou Dandan ◽  
Li Genzong ◽  
Wu Jian ◽  
...  

1987 ◽  
Vol 44 (12) ◽  
pp. 2144-2154 ◽  
Author(s):  
M. Putt ◽  
G. P. Harris ◽  
R. L. Cuhel

Measurement of 1-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) enhanced fluorescence (FDCMU) suggested that photoinhibition of photosynthesis was frequently an artifact of in situ bottle incubations in Lake Ontario phytoplankton. In a seasonal study, FDCMU of all populations was depressed by bright light in an incubator. However, when the euphotic zone did not exceed the depth of the mixed layer, vertical transport of phytoplankton into either low-light or dark regions apparently allowed reversal of photoinhibition of FDCMU. Advantages of FDCMU as a bioassay of vertical mixing include rapidity of response time, ease of measurement in the field, and insensitivity of this parameter to changes in phosphorus status of the population. Because of seasonal changes in the photoadaptive response of natural populations, the rate constants and threshold light levels required to cause the response must be determined at each use if the method is to be quantitative.


2012 ◽  
Vol 20 (6) ◽  
pp. 32-37 ◽  
Author(s):  
Y. Zhu ◽  
M. Milas ◽  
M.-G. Han ◽  
J.D. Rameau ◽  
M. Sfeir

In-situ electron microscopy has gained considerable attention in recent years. It provides a “live” view of a material or device under study at various length scales. For example, by heating or cooling a sample one can study structural change at the atomic scale to understand the driving forces and mechanisms of phase transitions. By applying electric and magnetic fields on a ferroelectric or magnetic architecture in operation, one can directly observe how electric and magnetic domains switch, how anions and cations shift their positions, and how spins change their configuration across a domain wall, aiding the development of better electromagnetic devices. In the study of photovoltaic devices and junctions, a major challenge is to directly correlate light-induced electric currents with local structural inhomogeneities and dynamics. Such a capability would allow us to evaluate the performance of individual p-n junctions and to improve optoelectronic efficiency.


2021 ◽  
Author(s):  
Olivier Duriez ◽  
Jovan Andevski ◽  
Christopher G. R. Bowden ◽  
Alvaro Camiña-Cardenal ◽  
Hans Frey ◽  
...  

ABSTRACT Although vulture feeding stations are a widely used tool for vulture conservation in many regions worldwide, there has been some confusion about their functions and this is reflected in the range of terminology used. The origin of food supply at provisioning sites (both for in situ and ex situ situations) and the goals of feeding station managers (ranging from purely conservation of vultures to the necessity for carcass disposal) are two key aspects that are often neglected. We review the definitions and nomenclature for the provision of predictable anthropogenic food for vultures and vultures' role in sanitation in the landscape. We propose that “supplementary feeding stations for vultures” (SFSV) defines a particular case and this term should only be applied when a station has vulture conservation goals and a food supply coming from outside of the landscape (ex situ). We introduce the term “recycling station with vultures” (RSV) for cases when the goal is the elimination of carcasses and the food is sourced in situ (natural, NRSV) or ex situ (supplementary food, SRSV). This clarification of goals and terminology for feeding stations worldwide could have important consequences for the understanding and assessment of vulture conservation and management actions, among researchers and conservationists and also importantly among stakeholders and wider society.


1996 ◽  
Vol 26 (1) ◽  
pp. 53-63 ◽  
Author(s):  
C. T. Schafer ◽  
F. E. Cole ◽  
D. Frobel ◽  
N. Rice ◽  
M. A. Buzas

1999 ◽  
Vol 564 ◽  
Author(s):  
K. Barmak ◽  
G. A. Lucadamo ◽  
C. Cabral ◽  
C. Lavoie ◽  
J. M. E. Harper

AbstractWe have found the dissociation behavior of immiscible Cu-alloy thin films to fall into three broad categories that correlate most closely with the form of the Cu-rich end of the binary alloy phase diagrams. The motivation for these studies was to use the energy released by the dissociation of an immiscible alloy, in addition to other driving forces commonly found in thin films and lines, to promote grain growth and texture evolution. In this work, the dissociation behavior of eight dilute (3.3 ± 0.5 at% solute) binary Cu-systems was investigated, with five alloying elements selected from group VB and VIB, two from group VillA, and one from group 1B. These alloying elements are respectively V, Nb, Ta, Cr, Mo, Fe, Ru and Ag. Several experimental techniques, including in situ resistance and stress measurements as well as in situ synchrotron x-ray diffraction, were used to follow the progress of solute precipitation in approximately 500 nm thick films. In addition, transmission electron microscopy was used to investigate the evolution of microstructure of Cu(Ta) and Cu(Ag). For all eight alloys, dissociation occurred upon heating, with the rejection of solute and evolution of microstructure and texture often occurring in multiple steps that range over several hundred degrees between approximately 100 and 900°C. However, in most cases, substantial reduction in resistivity of the films took place at temperatures of interest to metallization schemes, namely below 400°C.


2018 ◽  
Vol 115 (25) ◽  
pp. 6416-6421 ◽  
Author(s):  
James B. Barnett ◽  
Constantine Michalis ◽  
Nicholas E. Scott-Samuel ◽  
Innes C. Cuthill

Poison dart frogs provide classic examples of warning signals: potent toxins signaled by distinctive, conspicuous coloration. We show that, counterintuitively, the bright yellow and blue-black color of Dendrobates tinctorius (Dendrobatidae) also provides camouflage. Through computational modeling of predator vision, and a screen-based detection experiment presenting frogs at different spatial resolutions, we demonstrate that at close range the frog is highly detectable, but from a distance the colors blend together, forming effective camouflage. This result was corroborated with an in situ experiment, which found survival to be background-dependent, a feature more associated with camouflage than aposematism. Our results suggest that in D. tinctorius the distribution of pattern elements, and the particular colors expressed, act as a highly salient close range aposematic signal, while simultaneously minimizing detectability to distant observers.


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