Burrowing-site selection by the soldier crab Mictyris guinotae Davie, Shih & Chan, 2010 (Decapoda: Brachyura: Mictyridae)

2020 ◽  
Vol 40 (2) ◽  
pp. 147-151
Author(s):  
Satoshi Takeda

Abstract The soldier crab Mictyris guinotae Davie, Shih & Chan, 2010 inhabiting sandy tidal flats in the Ryukyu Is., Japan, are deposit feeders in two regions: its upper habitat where it burrows and the shoreline. The crabs usually migrate between these two regions during the period of emergence at the daytime and night-time low tide. The aim of this study was to determine which kind of sediments are chosen by the crabs when burrowing. Experiments designed to investigate burrowing-site selection revealed that the crabs preferably burrowed in sediment that had been conditioned through feeding by conspecific crabs, but not in sediment that had been conditioned by conspecific crabs walking on its surface. Moreover, the crabs never showed any preference for burrowing in sediment that had been conditioned through feeding by the competitor fiddler crab Austruca perplexa (H. Milne Edwards, 1852); both soldier (prey) and fiddler (predator) crabs sympatrically inhabit the tidal flat, but segregate their habitats with a transition area. These results suggest that chemical cues in sediment conditioned through feeding by conspecific soldier crabs affect where crabs burrow.

2021 ◽  
Vol 537 ◽  
pp. 151516
Author(s):  
Emily E. Waddell ◽  
Wendy E.D. Piniak ◽  
Kathleen A. Reinsel ◽  
James M. Welch

2020 ◽  
Vol 71 (7) ◽  
pp. 737
Author(s):  
Taiga Kunishima ◽  
Katsunori Tachihara

Soft-substrate tide pools are considered important habitats for fishes from an ecological perspective. However, the ecological roles of such pools and use patterns by fish remain unclear, especially regarding differences between estuarine and coastal tidal flats. In this study, quantitative sampling using the quadrat method was performed in the estuarine and coastal tidal flats on Okinawa-jima Island of subtropical Japan during four seasons. Ecological roles of soft-substrate tide pools were classified as follows: (1) permanent habitat for residents; (2) nursery ground for transients; and (3) waiting area until high tide for accidental species. Within these classifications, the ecological role and value of tide pools for transient fishes varied between the tidal flat types. The habitat value of tide pools is higher for residents than for transient species because the habitat is not replaceable for residents because of their specific ability to survive there. By contrast, transient and accidental species use the tide pools as temporary habitats; however, their high diversity affects the variation in community structure on Okinawa-jima Island. Our results suggest that we should consider not only species diversity, but also habitat use patterns of individual species, together with their life history, when evaluating habitat value with regard to conservation and management of each tidal flat.


2019 ◽  
Vol 41 (5) ◽  
pp. 621-639
Author(s):  
Juan F Saad ◽  
Maite A Narvarte ◽  
Mariza A Abrameto ◽  
Viviana A Alder

ABSTRACT Tidal flats are exceptionally dynamic coastal ecosystems. Tides are their main source of energy, whose influence decreases landwards (as land elevation increases), thus shaping physical, chemical and biological gradients. In this study, we assess whether the structure of nano- and microplankton varies along a spatial gradient in San Antonio Bay (SAB, SW Atlantic), a semi-desert coastal ecosystem with a wide tidal flat and a macrotidal regime. We hypothesize that the tidal effect shapes SAB’s both taxonomical groups and size spectrum. The seasonal sampling of 9 sites revealed that diatoms and small flagellates were the most abundant groups, together accounting for over 75% of total density in practically all sites and seasons. High densities of meroplanktonic stages of Ulva lactuca were recorded in spring at the innermost sites, accounting for over 95% of all planktonic cells. Slopes of the size spectrum analysis were in line with highly productive inshore waters (mean, −0.64) and showed that larger phytoplankton was the main contributor to total biomass, despite its decreasing importance toward inner sites. The spatial and seasonal variations found for lower trophic web compartments provide evidence of the importance of tidal transport in ruling phytoplankton structure in tidal flats under strong macrotidal regimes.


2012 ◽  
Vol 36 (4) ◽  
pp. 457-468 ◽  
Author(s):  
Yin Jia ◽  
Yao Yong-qiang ◽  
Wang Hong-shuai ◽  
Li Lin ◽  
You Xian-long ◽  
...  

Soil Research ◽  
2014 ◽  
Vol 52 (2) ◽  
pp. 140 ◽  
Author(s):  
A. G. B. M. Albuquerque ◽  
T. O. Ferreira ◽  
G. N. Nóbrega ◽  
R. E. Romero ◽  
V. S. Souza Júnior ◽  
...  

Wetland soils, especially those under a semi-arid climate, are among the least studied soils in the tropics. The hypersaline tidal flats on the north-eastern Brazilian coast, locally named apicum, are coastal wetland ecosystems in the peripheral portions of semi-arid estuaries. Despite their great ecological importance, they have been highly impacted by anthropogenic activities. Morphological and analytical data of six soil profiles, representative of the different coastal compartments (mangroves, apicum and coastal tablelands) of the north-eastern Brazilian coast, were examined to better understand the pedogenesis of apicum soils. The hypersaline tidal flat soils were classified as Typic Fluvaquents and Typic Sulfaquents with the following main characteristics: predominance of sand fraction (62–77%); presence of high-activity clays (>24 cmolc kg–1 clay); clay fraction comprising kaolinite, illite, smectite and an interstratified smectite/illite; exchangeable complex dominated by Na+ (ESP ≥15%); elevated levels of salinity (electrical conductivity, EC 25–44 dS m–1); alkaline pH values (7.5–9.5). The sandy texture and quartz-dominated composition of the hypersaline, tidal flat soils indicate a pedogenesis associated with the superficial addition of mineral material. This upbuilding process would have lowered the watertable (relatively to the ground level) and decreased the flooding frequency by the tides, favouring salinisation and solonisation processes at the hypersaline tidal flats. Furthermore, the still-existing hydromorphism would have promoted the maintenance of gleisation and sulfidisation. The presence of pyrite on the hyper-saline tidal flat soils further corroborates the formation of apicum soils from/over buried mangroves.


Geographies ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 292-314
Author(s):  
Chao Xu ◽  
Weibo Liu

Tidal flats are playing a critical role in the coastal environment, which mainly rely on satellite images to map the distribution on large spatiotemporal scales. Much effort has been made to monitor and analyze the spatiotemporal dynamics of tidal flats in order to provide worthwhile references for scientists and lawmakers. Instead of considering the dynamics of tidal flats only, this study implemented a series of comprehensive analyses on the tidal flats along the coast of Florida during the period 1984–2020. First, the analyses on the pixel level examined the spatiotemporal characteristics of tidal flat dynamics and the interactions with lands and permanent water. Second, the contiguous pixels of tidal flats were assembled as objects, and two geometric attributes were calculated and used to track the temporal patterns of tidal flat dynamics on this level. Finally, the Mann–Kendall test and Sen’s slope estimator were applied to identify and quantify the significant trends of tidal flat dynamics on the two levels. The results highlighted the differences in tidal flat distributions and dynamics between the Gulf Coast and Atlantic Coast, which further verified effective GIS representations and analyses that could be applied to other coastal studies.


2021 ◽  
Vol 8 ◽  
Author(s):  
Zehua Zhong ◽  
Zhan Hu

Reclamation is one of the most prominent anthropogenic activities affecting tidal flat morphology and the related ecosystem service. Two representative types of reclamation are upper-flat enclosure and lower-flat enrockment. From a historical perspective, different type of reclamation was adapted in different areas in ancient China. As previous studies on reclamation are often site-specific, the reason that leads to such a difference is unclear. The intertidal dynamic equilibrium theory (DET) provides a comprehensive framework for this quest. Here, we extend the DET with additional effects of reclamation. A model based on DET (DET-ESTMORF) was applied to investigate the impact of reclamation on tidal flats. The model was validated by comparing our results against previous records and observations. Results show that both types of reclamation induce morphological adjustment by enhancing local accretion, which upset the previous equilibrium. Specifically, upper-flat enclosure drives tidal flats into evolution toward wave dominance, whereas lower-flat enrockment causes adjustment toward tidal dominance. Next, the impact of reclamation on tidal flats in different states (prograding or retreating) was investigated. We show that both enclosure and enrockment can induce accretion despite the varying wave climate and sediment supply, with the mean accretion rate raised by 1.8 cm/year and 1.2 cm/year, respectively. However, the resulting profiles are different in shape, especially on retreating flats. Finally, we point out that tidal range and sediment supply are the potential reasons affecting the choice of reclamation types in practices.


2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Thi Lan PHAM ◽  
Si Son TONG ◽  
Thi Thu Ha LE ◽  
Thi Le LE ◽  
Huu Duc HOANG

Tidal flat plays a crucial role in socio-economic development and ecological environment.Tidal flats in Ha Long-Cam Pha in Vietnam are impacted by human activities, especially coal miningactivities. Using remote sensing data is able to detect, extract, and monitor the changes of tidal flats andexploited coal mine area with multi-temporal, in various scales, and for a large coverage. This studyaims to investigate the impact of coal mining activities on the changes of tidal flats using remote sensingin Cam Pha, Ha Long, one of the biggest coal basins in Vietnam. Digital Elevation Models (DEMs) oftidal flats constructed by Landsat satellite images acquired in years 1989, 2001, and 2014 are comparedto determine the volume changes. Besides, coal mining activities including coal production, waste rockdump area, and the expansion of open coal mine during the period 1989-2014 are investigated usingcorrespondent Landsat images and the reports from the coal mine companies in the study area. Sedimentsamples in tidal flats are analyzed to determine the origin of the sediments. As the results, organic matterin the tidal flats is dominant with the concentration of 459 g/kg to 607 g/kg, which is evidence for theimpact of coal exploitation on the coastal environment. In addition, the relationship between coal mineactivities and tidal flat variation is well observed in this study.


Sign in / Sign up

Export Citation Format

Share Document