scholarly journals Benefit of the Potential Future Hyperspectral Satellite Sensor (BIODIVERSITY) for Improving the Determination of Water Column and Seabed Features in Coastal Zones

2021 ◽  
Vol 14 ◽  
pp. 1222-1232
Author(s):  
Audrey Minghelli ◽  
Sayoob Vadakke-Chanat ◽  
Malik Chami ◽  
Mireille Guillaume ◽  
Marion Peirache
Keyword(s):  
Water Column ◽  
Coastal Zones ◽  
Satellite Sensor

Determination of methane yield of cellulose using different experimental setups

2014 ◽  
Vol 70 (4) ◽  
pp. 599-604 ◽  
Author(s):  
Bing Wang ◽  
Ivo Achu Nges ◽  
Mihaela Nistor ◽  
Jing Liu
Keyword(s):  
Water Column ◽  
Test System ◽  
Methane Yield ◽  
Biochemical Methane Potential ◽  
Methane Potential ◽  
Bmp Test ◽  
Potential Test

In this work, biochemical methane potential (BMP) tests with cellulose as a model substrate were performed with the aid of three manually operated or conventional experimental setups (based on manometer, water column and gas bag) and one automated apparatus specially designed for analysis of BMP. The methane yields were 340 ± 18, 354 ± 13, 345 ± 15 and 366 ± 5 ml CH4/g VS obtained from experimental setups with manometer, water column, gas bag, and automatic methane potential test system, which corresponded to a biodegradability of 82, 85, 83 and 88% respectively. The results demonstrated that the methane yields of cellulose obtained from conventional and automatic experimental setups were comparable; however, the methane yield obtained from the automated apparatus showed greater precision. Moreover, conventional setups for the BMP test were more time- and labour-intensive compared with the automated apparatus.

scholarly journals Dynamics of microalgal communities in the water-column/sediment interface of the inner shelf off Parana State, Southern Brazil

2004 ◽  
Vol 52 (3-4) ◽  
pp. 183-194 ◽  
Author(s):  
Ricardo Luiz Queiroz ◽  
Frederico Pereira Brandini ◽  
Franciane Maria Pellizzari
Keyword(s):  
Water Column ◽  
Cyanobacterial Bloom ◽  
Interface Layer ◽  
Benthic Diatoms ◽  
Southern Brazil ◽  
Planktonic Diatoms ◽  
Cell Densities ◽  
Sediment Interface ◽  
Microalgal Community

The composition and biomass of the microalgal community at the water-column/sediment interface on the continental shelf off Parana State (Brazil) were studied every 2 months during 1999. Samples for cell identification and determination of chlorophyll a were taken from the interface layer and at discrete depths up to 4 m above the sediment. Results showed a community mainly formed by benthic and planktonic diatoms >30 µm, benthic diatoms <30 µm and cyanobacteria. Cell densities were generally higher at the interface layer. Resuspension and sedimentation events seemed to be a paramount factor regulating the composition and biomass of these communities, and affected differently cells of different size classes. Cells >30 µm, which accounted for most of the pigment biomass, were resuspended from the interface after turbulent periods, and may take advantage of calm periods to stay and grow at the interface. Small benthic diatoms were more susceptible to wind-induced turbulence occurring in higher densities in the water column just above the water-sediment interface. A cyanobacterial bloom (Trichodesmiun) was observed at these bottom layers in the spring-summer periods.

scholarly journals ESTIMATION OF PHOSPHORUS AND NITROGEN RELEASED BY THE BREEDING OF OREOCHROMIS NILOTICUS IN CAGES IN THE TOHO AND TODOUGBA LAGOONS(SOUTHER BENIN) BETWEEN 2017 AND 2020

2021 ◽  
Vol 9 (11) ◽  
pp. 422-430
Author(s):  
Achoh Mardochee Ephraim ◽  
◽  
Agadjihouede Hyppolite ◽  
Gangbe Luc ◽  
Aizonou Romaric ◽  
...  
Keyword(s):  
Organic Matter ◽  
Water Column ◽  
Oreochromis Niloticus ◽  
Nutrient Release ◽  
Laboratory Analysis ◽  
The Other ◽  
Production Data ◽  
Nitrogen Concentrations ◽  
High Production

The present study aim to estimate the ratio of aquaculture in the phosphorus and nitrogen concentrations determined in the Toho - Todougba lagoons. For this purpose, the two lagoons were subdivided into 7 stations for the determination of phosphorus and nitrogen concentrations in the water column. Production data from 2017 to 2019 were collected from the Direction of the Ficheries Production and from the literature. Data for 2020 were collected directly from fish farmers. Annual tilapia production was estimated by year and the amounts of phosphorus and nitrogen released from aquaculture are deduced based on the ratio of Montanhini Neto & Ostrensky (2013). The concentration of each of these nutrients was estimated by station and compared to the concentration determined by laboratory analysis of the water. This methodology shows that the amount of phosphorus and nitrogen released to the environment varies from 0.49 mg/L to 0.18 mg/L for phosphorus and from 1.53 mg/L to 0.58 mg/L for nitrogen. The lowest values are obtained in 2020 and differ significantly from the other years (p <0.05). The quantity of phosphorus discharged is higher at the high production stations (Tonon 0.20 mg/L and Lokohoue 0.11 mg/L). Some of this is stored in the sediment. The nitrogen generated by aquaculture is significantly lower than the average determined in water (p <0.05). However, the concentration determined is still related to the amount of organic matter released due to aquaculture. Although aquaculture is not the only source of nutrient release to water, strategies for aquaculture with less nutrient release should be determined.

scholarly journals 210Po/210Pb Disequilibria in the Eastern Tropical North Pacific

2021 ◽  
Vol 8 ◽  
Author(s):  
Qiang Ma ◽  
Yusheng Qiu ◽  
Run Zhang ◽  
E Lv ◽  
Yipu Huang ◽  
...  
Keyword(s):  
Water Column ◽  
North Pacific ◽  
Biological Activities ◽  
Small Scale ◽  
Horizontal Transport ◽  
Activity Ratios ◽  
Scale Particle ◽  
Seawater Samples ◽  
Scale Variation

The 210Po/210Pb disequilibrium was attempted to reveal the small-scale particle dynamics in the eastern tropical North Pacific. Seawater samples in the full water column were collected from three sites in the Tehuantepec bowl near the East Pacific Ridge for determination of dissolved and particulate 210Po and 210Pb. Our results show that TPo/TPb activity ratios in the full water column at the three sites are less than 1, with an average of 0.56, indicating that the total 210Po in the oligotrophic sea is significantly deficient. The activity ratios of DPo/DPb in the dissolved phase are less than 1, while those in the particulate phase are greater than 1 (except for the bottom 300 m), indicating fractionation between 210Po and 210Pb in the scavenging process. A negative linear relationship between 210Po deficit and silicate proves that biological activities are responsible for 210Po deficiency in the upper 200 m. However, the deficit of 210Po in the bottom 300 m may be caused by the horizontal transport of the hydrothermal plume. After correcting the horizontal contribution, the removal rates of 210Po for the 200–1,500 m and the bottom 300 m layers increased by 7.5–21 and 26.1–29.5%, respectively. Correspondingly, the variation range of the residence time of a total 210Po became smaller. Our calculations suggest that horizontal transport is acting as a stabilizer for small-scale variation in the 210Po deficit in the eastern tropical North Pacific. Our study highlights the need to pay more attention to the small-scale variation of 210Po deficit when applying 210Po/210Pb disequilibria to trace biogeochemical processes, and the mechanism responsible for this variation deserves further study.

Tracking the spatiotemporal variability of the oxic–anoxic interface in the Baltic Sea with broadband acoustics

2020 ◽  
Author(s):  
Elizabeth Weidner ◽  
Christian Stranne ◽  
Jonas Hentati Sundberg ◽  
Thomas C Weber ◽  
Larry Mayer ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Baltic Sea ◽  
Water Column ◽  
Acoustic Scattering ◽  
Spatiotemporal Variability ◽  
Coastal Zones ◽  
Anoxic Zone ◽  
The Baltic Sea ◽  
Impedance Contrast ◽  
The Baltic

Abstract Anoxic zones, regions of the water column completely devoid of dissolved oxygen, occur in open oceans and coastal zones worldwide. The Baltic Sea is characterized by strong salinity-driven stratification, maintained by occasional water inflows from the Danish Straights and freshwater input from rivers. Between inflow events, the stratification interface between surface and deep waters hinders mixing and ventilation of deep water; consequently, the bottom waters of large regions of the Baltic are anoxic. The onset of the anoxic zone is closely coincident with the depth of the halocline and, as a result, the interface between oxic and anoxic waters corresponds to a strong impedance contrast. Here, we track acoustic scattering from the impedance contrast utilizing a broadband split-beam echosounder in the Western Gotland Basin and link it to a dissolved oxygen level of 2 ml/l using ground truth stations. The broadband acoustic dataset provides the means to remotely observe the spatiotemporal variations in the oxic–anoxic interface, map out the extent of the anoxic zone with high resolution, and identify several mechanisms influencing the vertical distribution of oxygen in the water column. The method described here can be used to study other systems with applications in ongoing oceanographic monitoring programs.

scholarly journals Pengujian dan Penentuan Spesies Gastropoda sebagai Bioindikator di Kawasan Reboisasi Mangrove Kepulauan Seribu, Indonesia

2020 ◽  
Vol 3 (1) ◽  
pp. 30
Author(s):  
Syahrial Rial ◽  
Muhammad Fauzan Isma ◽  
Ahmad Ryadi ◽  
M. Ilham Fajriansyah
Keyword(s):  
Principal Component ◽  
Mangrove Ecosystem ◽  
Coastal Zones ◽  
Bioindicator Species ◽  
Gastropod Species ◽  
The World ◽  
Small Plot ◽  
Line Transects ◽  
Mangrove Reforestation

The development of coastal zones throughout the world has resulted in changes in the order of the mangrove ecosystem, therefore, planting activities are carried out in various regions. The study of the testing and determination of gastropod species as bioindicators in the mangrove reforestation area was carried out in the Seribu Islands. This research aims to determine how suitable the gastropod species are used as bioindicators in assessing the success of mangrove reforestation, especially in the Seribu Islands. Collection of gastropod species is done by making line transects and plots drawn from the reference point (outermost mangrove stands) and perpendicular to the coastline to the mainland. Line transects are made of plots of size 10 x 10 m and in the size of 10 x 10 m a small plot of 1 x 1 m is made. Furthermore, testing is carried out with several criteria and analyzed using multivariate Principal Component Analysis (PCA) statistics. The results of the study show that the species Littoraria scabra has met all the specified testing criteria. Then L. scabra also has the highest eigenvalue compared to the other species, making it suitable to be used as a bioindicator species in assessing the success of the Seribu Islands mangrove reforestation.

Reproductive biology of Sabellaria wilsoni (Sabellariidae: Polychaeta), an important ecosystem engineer on the Amazon coast

2016 ◽  
Vol 98 (4) ◽  
pp. 743-754 ◽  
Author(s):  
D. Aviz ◽  
A.J.A. Pinto ◽  
M.A.P. Ferreira ◽  
R.M. Rocha ◽  
J.S. Rosa Filho
Keyword(s):  
Reproductive Biology ◽  
Ecosystem Engineer ◽  
Coastal Zones ◽  
Initial Development ◽  
Biological Communities ◽  
Gonadal Maturity ◽  
Biased Sex Ratio ◽  
Males And Females

The sabellariid worms are important ecosystem engineers in coastal zones, due to their ability to construct sand reefs, modify environments and structure biological communities. This article describes the reproductive biology of Sabellaria wilsoni on a beach of the Amazon coast. Each month between May 2008 and April 2009, specimens were collected for morphometric and histological analyses for sexing and determination of gonadal maturity. In females, the number and diameter of the oocytes at different stages of vitellogenesis were also recorded. The results showed that the species is dioecious, with sexual reproduction, females larger than males, and a female-biased sex ratio (overall, 1.6♀: 1♂). Four distinct stages of gonadal maturation were identified in the males and females – (i) initial development, (ii) maturing, (iii) mature and (iv) spawning. Sexual maturity is attained rapidly, and reproduction is continuous, with two breeding peaks, one in the dry season, related to the increased intensity of hydrodynamic conditions and reef erosion; and the other in the rainy season, when the availability of space and nutrients increases. The reproductive strategy of the species reinforces the classification of the sabellariids as r-strategists, adapted to colonize habitats with unstable environmental conditions.

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