intertidal area
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Author(s):  
Chee Kong Yap ◽  
Wen Siang Tan ◽  
Mohamad Saupi Ismail ◽  
Noorhaidah Ariffin ◽  
Wan Hee Cheng ◽  
...  

Monitoring the level of metal pollution in a water body, especially in polluted areas, is crucial. Gastropod shells have been used as a biomonitor for metal pollution. The goal of this study was to evaluate the utilisation of the mudflat snails, Telescopium telescopium shells, as biomonitoring materials for nickel (Ni) pollution in the intertidal area. The snails and their habitat surface sediments were sampled from 17 sites in Peninsular Malaysia. Up to 21 individuals from each site were sampled and dissected. In addition to the shells, six parts of the soft tissues (cephalic tentacle, foot, gill, muscle, mantle, and remaining soft tissues) were analysed for Ni. The snail shell was found to be a potential biomonitoring material for Ni pollution based on four positive points: (i) higher value of shell/soft tissue ratios (> 1.00); (ii) categorisation as a ‘microconcentrator’ based on bioaccumulation factor; (iii) significant correlation coefficients (at least P < 0.05) and significant influential total Ni levels in the sediments to the shell Ni; and (iv) higher precision of Ni in the shells based on the lowest value of the coefficient of variation of Ni. The described results indicated that the shell of T. telescopium would be suitable for assessing Ni pollution in the intertidal areas.


2021 ◽  
Vol 8 ◽  
Author(s):  
Wenzhe Xu ◽  
Yongxin Dang ◽  
Siu Gin Cheung ◽  
Zhinan Zhang ◽  
Jun Sun ◽  
...  

Stable isotope tracer addition can enhance the isotopic differences of primary producers for a wider food-web resolution than the use of natural abundance stable isotopes (NASIs) alone, particularly in ecosystems where primary producers have similar NASI values. To investigate the food sources and the trophic status of benthic infauna in an intertidal area near a Halophila minor seagrass bed within inner Tai Tam Bay, Hong Kong, China, a 15N addition experiment was conducted, and the results were compared with those from NASI data. Only benthic microalgae (BMA) were labeled by applying 15N-enriched NH4Cl to the sediment daily for the first 7 days during a 21-day study. In contrast to the NASI results, Bayesian mixing models based on the isotope tracer experiment suggested a larger dietary contribution of BMA for nematode Daptonema sp. and copepods, whereas a higher reliance on phytoplankton and seagrass detritus was noted for polychaete Neanthes sp. However, both NASI and isotope tracer addition demonstrated that seagrass detritus was a major food source for nematode Spilophorella sp. The present isotope tracer experiment also revealed a contrasting result of the relatively lower contribution of meiofauna in the diets of carnivores/omnivores as compared to the results of NASIs. This finding suggested that the isotope values in these consumers may have not reached an equilibrium with the added isotope in the study period. Thus, there is a need for applying NASI coupled with isotope tracer addition in the investigation of ecosystems in which primary producers have similar isotope values, especially in ecosystems with lower tissue turnover rates, in order for a more accurate determination of dietary contribution and trophic status of consumers in the food-web study.


2021 ◽  
Vol 24 (3) ◽  
pp. 333-342
Author(s):  
WD. Syarni Tala ◽  
Kusrini Kusrini ◽  
Jumiati Jumiati

Echinoderms are one of organisms that inhabit intertidal areas which have important ecological roles in marine ecosystems, also have high economic values. The community structure and distribution pattern of Echinoderms in the intertidal area can provide an overview of the condition of the Echinoderm community. This research aims to determine the community structure of Echinoderms in various habitat types in the intertidal areas of Lakeba Beach, Baubau Town. The community structure of Echinoderms were observed using quadratic transec method. Echinoderms found were 777 individuals consisting of 18 species from 5 classes. Echinoderms were distributed in four habitat types, i. e. sandy, sand covered with seagrass, rocky, and rock covered with algae habitats. The highest abundance of Echinoderm was Ophiocoma scolopendrina (Ophiuroidea) and the lowest were Maretia planulata, Arachnoides placenta (Echinoidea), Holothuria scabra, H. leucospilota, Stichopus horrens (Holothuroidea), and Isocrinidae (Crinoidea). The species diversity of Echinoderms was categorized as moderate (H’ = 1,42180), species evenness was moderate (E = 0,49191), and no dominant species of Echinoderm community (D = 0,36601). Echinoderm community living in the intertidal area was influenced by antropogenic factors.  Echinodermata merupakan salah satu organisme yang mendiami daerah intertidal yang memiliki peran ekologis penting bagi ekosistem laut, juga memiliki nilai ekonomis yang tinggi. Struktur komunitas dan pola distribusi Echinodermata pada daerah intertidal dapat memberikan gambaran mengenai kondisi komunitas Echinodermata. Penelitian ini bertujuan untuk mengetahui struktur komunitas dan pola distribusi Echinodermata di daerah intertidal Pantai Lakeba, Kota Baubau. Struktur komunitas dan pola distribusi Echinodermata diamati menggunakan metode transek kuadrat. Echinodermata yang ditemukan berjumlah 777 individu yang terdiri atas 18 jenis dari 5 kelas. Echinodermata terdistribusi pada empat tipe habitat yaitu habitat pasir, pasir yang ditutupi lamun, batu, dan batu yang ditutupi alga. Echinodermata yang memiliki kelimpahan tertinggi adalah Ophiocoma scolopendrina (Ophiuroidea) dan kelimpahan terendah adalah Maretia planulata, Arachnoides placenta (Echinoidea), Holothuria scabra, H. leucospilota, Stichopus horrens (Holothuroidea), dan Isocrinidae (Crinoidea). Keanekaragaman jenis Echinodermata dikategorikan sedang (H’ = 1,42180), kemerataan jenis sedang (E = 0,49191) dan tidak ada jenis yang dominan dalam komunitas Echinodermata (D = 0,36601). Komunitas Echinodermata yang hidup di daerah intertidal pantai dipengaruhi oleh faktor antropogenik.


2021 ◽  
Author(s):  
Nisfa Hanim ◽  
Achmad Farajallah ◽  
Vinna Putri

The report of genus Emerita from Indonesia has only contained one species, namely Emerita emeritus. They were found on the west coast of Sumatera and the south coast of Java. Although Indonesia is the number two country in the world that has long beaches and is dominated by sandy beaches, as the preferred habitat for sand crabs, reports regarding these biotas in Indonesia are still limited. The previous studies have expected about the occurrence of the other species which was related to Emerita emeritus in Southern Java. We reported the new species of Emerita which was found in Pangandaran beach, West Java. We found it in an intertidal area, near Citonjong Estuary. Here, we described and illustrated the species.


2021 ◽  
pp. 101954
Author(s):  
Zahid Nazeer ◽  
Ajmal Khan S. ◽  
Karuppasamy Manikandan ◽  
Seerangan Manokaran ◽  
Hua Hsun Hsu ◽  
...  

2021 ◽  
Vol 13 (2) ◽  
pp. 320
Author(s):  
José P. Granadeiro ◽  
João Belo ◽  
Mohamed Henriques ◽  
João Catalão ◽  
Teresa Catry

Intertidal areas provide key ecosystem services but are declining worldwide. Digital elevation models (DEMs) are important tools to monitor the evolution of such areas. In this study, we aim at (i) estimating the intertidal topography based on an established pixel-wise algorithm, from Sentinel-2 MultiSpectral Instrument scenes, (ii) implementing a set of procedures to improve the quality of such estimation, and (iii) estimating the exposure period of the intertidal area of the Bijagós Archipelago, Guinea-Bissau. We first propose a four-parameter logistic regression to estimate intertidal topography. Afterwards, we develop a novel method to estimate tide-stage lags in the area covered by a Sentinel-2 scene to correct for geographical bias in topographic estimation resulting from differences in water height within each image. Our method searches for the minimum differences in height estimates obtained from rising and ebbing tides separately, enabling the estimation of cotidal lines. Tidal-stage differences estimated closely matched those published by official authorities. We re-estimated pixel heights from which we produced a model of intertidal exposure period. We obtained a high correlation between predicted and in-situ measurements of exposure period. We highlight the importance of remote sensing to deliver large-scale intertidal DEM and tide-stage data, with relevance for coastal safety, ecology and biodiversity conservation.


2020 ◽  
Vol 647 ◽  
pp. 33-48 ◽  
Author(s):  
S Mangan ◽  
KR Bryan ◽  
SF Thrush ◽  
RV Gladstone-Gallagher ◽  
AM Lohrer ◽  
...  

Coastal intertidal soft-sediment habitats provide ecosystem services to millions of people worldwide, yet are under intense pressure from land-use change and sea-level rise (SLR). Both pressures interact to reduce light reaching the seafloor, thereby disrupting benthic primary producers and the ecosystem functions and services they provide. This study considers the implications of altered light climate on microphytobenthic (MPB) production in shallow estuaries. Continuous measurements of seafloor photosynthetically active radiation (PAR) were made over 9 mo on intertidal sandflats in 14 New Zealand estuaries spanning a turbidity gradient. A literature summary of benthic photosynthesis-irradiance curves was used to predict PAR limitation at sampling sites. Estimates of the proportion of time MPB would be light limited during emersion ranged from a median of 32-64% compared to a median of 55-100% during immersion. For estuaries close to 100% PAR limitation during immersion, emerged intertidal areas represent a refuge for MPB production which is vulnerable to SLR. Based on hypsometric curves (a representation of estuary bathymetry), the intertidal area of our study estuaries is predicted to decrease by 27-94% in response to SLR of 1.4 m. The combination of high PAR limitation during immersion and large losses of intertidal area will increase vulnerability to the loss of MPB production and the associated ecosystem services, which will push these ecosystems towards tipping points. The research highlights how the interplay between local and global scale stressors may ultimately trigger ecological collapse under future global change.


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