scholarly journals Transfer of mercury from benthic invertebrates to fishes in lakes with contrasting fish community structures

1997 ◽  
Vol 54 (6) ◽  
pp. 1320-1330 ◽  
Author(s):  
Allan HK Wong ◽  
Donald J McQueen ◽  
D Dudley Williams ◽  
Eric Demers

We examined the flow of mercury (Hg) from benthic invertebrates to fishes in lakes with contrasting fish community structure. The study was carried out in two whole lakes in southcentral Ontario in 1992. Both were remote from direct sources of contamination and were chosen because of their physical and chemical similarities. Although the fish communities in the two lakes were qualitatively similar, the total number of fishes in Ranger Lake was an order of magnitude smaller than that in Mouse Lake. As a result of the lower net predation from benthivorous fishes, documented in earlier studies, Ranger Lake benthic invertebrate populations were significantly higher. However, benthic invertebrate taxa in Mouse Lake were generally larger and had higher Hg concentrations. This was partly attributed to the stunted growth of Mouse Lake fishes, which did not allow them to prey on larger benthos as a result of gape limitations. Despite the lower Hg concentrations in Ranger Lake benthos, total benthic invertebrate Hg pools were higher in this lake as a result of its higher total benthic invertebrate biomass. However, the transfer of total Hg from benthic invertebrates to fishes was higher in Mouse Lake due to the higher consumption rates of benthivorous fishes.

2020 ◽  
Vol 14 (1) ◽  
pp. 49-58
Author(s):  
Hodri Msp Ubb

Air Remuding River is  a river which located in Pangkal Niur Lama Hamlet, Riau Silip District, Bangka Regency. Air Remuding River is ± 1 km from Pangkal Niur Lama Hamlet. This study aims to analyze the structure of the fish community in the Air Remuding River and to analyze the relationship between the physical and chemical factors of the waters to the species composition of the fish in the Air Remuding River. This research  conducted in the month of January 2020 in the waters of the Air Remuding River, Pangkal Niur Lama Hamlet, Riau Silip District, Bangka Belitung Islands Province. The results of this study indicate that the most common fish caught in the Air Remuding river we're 2501 fishes (Rasbora bankanensis). Diversity Index (H '), Air Remuding River fish with a range of 0.66-0.72. included in the criteria of moderate diversity, while the Uniformity Index (E), Air Remuding River fish were high uniformity and the Dominance Index ranged from 0.19 to 0.23. The composition of fish species in the Air Remuding River correlates with DO, depth, current velocity and nitrate.


2018 ◽  
Vol 26 (8) ◽  
pp. 230-239
Author(s):  
Feryal A. M. Al-Ameen

    The present study was conducted to determine the structure of benthic invertebrates community, as well as a study of some factors associated with water quality in Shatt Al-Kufa. The study was included a choice of three sites located along the Shatt Al-Kufa River, water samples and benthic invertebrates were collected during the period from February 2014 to January 2015.     The abiotic study included measurements of chlorophyll a, salinity, total dissolved solids, biochemical oxygen demand, total hardness, nitrate, and sulfate. The biotic study included the determination the composition of the benthic invertebrates community through the study of the mean population density, the relative abundance index of these organisms and the Jaccard Coefficient was calculated to identify the value of similarity between the studied sites. In the present study, 28 taxa of benthic invertebrates were recorded belong to 4 main groups which are: 8 taxa belonged to Annelida, 7 belonged to Insecta, 10 belonged to Mollusca, 3 belonged to Nematoda. Annelida recorded the highest percentage 40.8% of the total number of benthic invertebrates, Insecta with 30.3%, Mollusca and Nematoda with 28.4 %, 0.5% respectively. Benthic invertebrate has shown positive and negative relationships with the studied physical and chemical characteristics.


2019 ◽  
Vol 609 ◽  
pp. 33-48 ◽  
Author(s):  
RP Lyon ◽  
DB Eggleston ◽  
DR Bohnenstiehl ◽  
CA Layman ◽  
SW Ricci ◽  
...  

2020 ◽  
Vol 637 ◽  
pp. 159-180
Author(s):  
ND Gallo ◽  
M Beckwith ◽  
CL Wei ◽  
LA Levin ◽  
L Kuhnz ◽  
...  

Natural gradient systems can be used to examine the vulnerability of deep-sea communities to climate change. The Gulf of California presents an ideal system for examining relationships between faunal patterns and environmental conditions of deep-sea communities because deep-sea conditions change from warm and oxygen-rich in the north to cold and severely hypoxic in the south. The Monterey Bay Aquarium Research Institute (MBARI) remotely operated vehicle (ROV) ‘Doc Ricketts’ was used to conduct seafloor video transects at depths of ~200-1400 m in the northern, central, and southern Gulf. The community composition, density, and diversity of demersal fish assemblages were compared to environmental conditions. We tested the hypothesis that climate-relevant variables (temperature, oxygen, and primary production) have more explanatory power than static variables (latitude, depth, and benthic substrate) in explaining variation in fish community structure. Temperature best explained variance in density, while oxygen best explained variance in diversity and community composition. Both density and diversity declined with decreasing oxygen, but diversity declined at a higher oxygen threshold (~7 µmol kg-1). Remarkably, high-density fish communities were observed living under suboxic conditions (<5 µmol kg-1). Using an Earth systems global climate model forced under an RCP8.5 scenario, we found that by 2081-2100, the entire Gulf of California seafloor is expected to experience a mean temperature increase of 1.08 ± 1.07°C and modest deoxygenation. The projected changes in temperature and oxygen are expected to be accompanied by reduced diversity and related changes in deep-sea demersal fish communities.


2013 ◽  
Vol 1 (2) ◽  
pp. 117
Author(s):  
Fakhrizal Setiawan ◽  
Janny D Kusen ◽  
Georis JF Kaligis

In order to look at changes in coral and reef fish communities during the period of 2006 to 2013, this research was carried out at Bunaken National Park (BNP) with 26 observation sites. The existing data and information of reef fish communities in the park generally could not be used as representative for describing the whole region. Percentage of coral cover and fish abundance during the study period shows that Bunaken Island is more similar to other locations. Reef fish community structure as seen from ecological index (H' at all sites being categorized, E category labile and low category C) shows the condition of the reef fish community is still good. Changes in the structure of reef fish communities showed declining conditions compared to 2006, and coral cover continued to decrease compared to 1998 and 2007. Good overall reef fish and coral cover have decreased; it is thought to be related to the pressure in BNP. Some of the pressures in the region were (i) increasing numbers of domestic as well as foreign visitors, (ii) increasing number of residents in the region, as well as the burden of waste and trash from the Bay of Manado. Penelitian dilakukan di Taman Nasional Bunaken (Utara dan Selatan)   pada 26 lokasi  pengamatan untuk menganalisis perubahan struktur komunitas ikan karang melalui kajian dari suatu time series data dari beberapa penelitian sebelumnya. Data primer mengenai ikan-ikan karang diperoleh melalui visual sensus bawah air yang bersamaan dengan observasi terumbu karang menggunakan point intercept transect. Nilai persentase tutupan karang dan kelimpahan ikan menunjukkan bahwa pada lokasi pengamatan Pulau Bunaken paling baik dibandingan lokasi lainnya. Struktur komunitas ikan karang yang dianalisis dengan indeks ekologi menunjukkan indeks keanekaragaman (H’) di semua site masuk kategori sedang, indeks kesamaan (E) kategori labil dan indeks Dominansi (C) kategori rendah. Hasil penelitian ini menunjukkan bahwa kondisi komunitas ikan karang masih baik, sekalipun  perubahan struktur komunitas ikan karang menunjukkan kondisi yang menurun dibandingkan tahun 2006, begitu juga tutupan karang yang terus turun dibandingkan tahun 1998 dan 2007. Secara keseluruhan baik ikan karang maupun tutupan karang mengalami penurunan, hal ini diduga terkait dengan tekanan yang dialami kawasan TN. Bunaken. Salah satu tekanan terhadap kawasan adalah jumlah turis dari dalam maupun luar negeri yang semakin meningkat tiap tahunnya, penambahan jumlah penduduk di dalam kawasan, serta beban limbah dan sampah dari Teluk Manado.


2018 ◽  
Vol 25 (2) ◽  
pp. 229
Author(s):  
Zhongyi LI ◽  
Qiang WU ◽  
Xiujuan SHAN ◽  
Tao YANG ◽  
Fangqun DAI ◽  
...  

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