scholarly journals Tiakina Kia Ora: Protecting Our Freshwater Mussels

2021 ◽  
Author(s):  
◽  
Hannah Jane Rainforth
Keyword(s):  
Organic Matter ◽  
Clearance Rate ◽  
Filtration Rate ◽  
Rejection Rate ◽  
Ecological Knowledge ◽  
Management Framework ◽  
Sediment Loads ◽  
Suspended Sediment Concentrations ◽  
Local Species ◽  
Survival And Growth

<p>Matauranga (traditional ecological knowledge) built up by Whanganui iwi during their long association with the Whanganui River provides information on local biota and anthropological changes to the river. This matauranga records a decline in one local species, the kakahi (Echyridella menziesii (Gray, 1843)). Reasons suggested for this decline include alterations to flow and desiccation following a hydropower scheme, sedimentation, domestic and agricultural pollution, gravel extraction and channel modification. Decline was confirmed by a survey of historic kakahi beds: decline was evident at 16 (73%) of 22 sites. Of those 16 sites, there were 7 sites where decline was so severe that the population had been extirpated. Of the 15 historic beds where kakahi are still extant, four (27%) were remnant populations. Evidence of recruitment was found at only four (27%) of the 15 extant populations, or 18% of the total number of sites searched. Effect of suspended sediment concentrations ranging from 5.5 to 1212 mg.L-1 on ka kahi feeding behaviour and physiology was explored. Both filtration rate and rejection rate increased with increased sediment load (from 1.62 mg.h-1 to 190.88 mg.h-1 and from 0.62 to 201.53 mg.h-1 respectively) but clearance rate decreased with sediment increase (from 0.42 to 0.20 L.h-1). Behaviour was unaffected, with kakahi filtering on average 78% of the time. As particulate organic matter increased, clearance rate decreased and filtration rate increased. Filtration rate declined with increasing % organic matter. Kakahi can continue feeding under very high sediment loads for short periods. Much remains uncertain about kakahi, from their early biology to reasons for decline. Restoration options were explored using an adaptive management framework within which different hypotheses can be trialled in an experimental manner. This proved difficult due to confounding factors. However, given the established link between vegetation clearance and sedimentation, an initial restoration focus which evaluates catchment revegetation and its impact on kakahi survival and growth is suggested.</p>

scholarly journals Tiakina Kia Ora: Protecting Our Freshwater Mussels

2021 ◽  
Author(s):  
◽  
Hannah Jane Rainforth
Keyword(s):  
Organic Matter ◽  
Clearance Rate ◽  
Filtration Rate ◽  
Rejection Rate ◽  
Ecological Knowledge ◽  
Management Framework ◽  
Sediment Loads ◽  
Suspended Sediment Concentrations ◽  
Local Species ◽  
Survival And Growth

<p>Matauranga (traditional ecological knowledge) built up by Whanganui iwi during their long association with the Whanganui River provides information on local biota and anthropological changes to the river. This matauranga records a decline in one local species, the kakahi (Echyridella menziesii (Gray, 1843)). Reasons suggested for this decline include alterations to flow and desiccation following a hydropower scheme, sedimentation, domestic and agricultural pollution, gravel extraction and channel modification. Decline was confirmed by a survey of historic kakahi beds: decline was evident at 16 (73%) of 22 sites. Of those 16 sites, there were 7 sites where decline was so severe that the population had been extirpated. Of the 15 historic beds where kakahi are still extant, four (27%) were remnant populations. Evidence of recruitment was found at only four (27%) of the 15 extant populations, or 18% of the total number of sites searched. Effect of suspended sediment concentrations ranging from 5.5 to 1212 mg.L-1 on ka kahi feeding behaviour and physiology was explored. Both filtration rate and rejection rate increased with increased sediment load (from 1.62 mg.h-1 to 190.88 mg.h-1 and from 0.62 to 201.53 mg.h-1 respectively) but clearance rate decreased with sediment increase (from 0.42 to 0.20 L.h-1). Behaviour was unaffected, with kakahi filtering on average 78% of the time. As particulate organic matter increased, clearance rate decreased and filtration rate increased. Filtration rate declined with increasing % organic matter. Kakahi can continue feeding under very high sediment loads for short periods. Much remains uncertain about kakahi, from their early biology to reasons for decline. Restoration options were explored using an adaptive management framework within which different hypotheses can be trialled in an experimental manner. This proved difficult due to confounding factors. However, given the established link between vegetation clearance and sedimentation, an initial restoration focus which evaluates catchment revegetation and its impact on kakahi survival and growth is suggested.</p>

scholarly journals Curvas-chave de descargas de sedimentos em suspensão no Baixo São Francisco

2020 ◽  
Vol 13 (3) ◽  
pp. 1248 ◽  
Author(s):  
Solange Cavalcanti de Melo ◽  
José Coelho de Araújo Filho ◽  
Renata Maria Caminha Mendes de Oliveira Carvalho
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Gradual Reduction ◽  
Sao Francisco River ◽  
Sediment Loads ◽  
São Francisco River ◽  
Historical Series ◽  
Suspended Sediment Concentrations

RESUMOO conhecimento da análise quantitativa das concentrações de sedimentos em suspensão transportados pelo rio São Francisco bem como sua relação com as vazões é de muita importância, pois pode auxiliar na identificação dos efeitos da intervenção humana e ou ocasionados pelas condições naturais da região. As regiões a jusante dos barramentos no rio São Francisco apresentam como principal consequência a regularização das vazões e a diminuição das concentrações de sedimentos. O objetivo da pesquisa foi determinar as curvas-chave de sedimentos em suspensão (CCS) nas estações fluviométricas instaladas no Baixo São Francisco (BSF) após a barragem de Xingó. Para o estabelecimento dessas curvas foram utilizados dados de vazão e concentração de sedimentos em suspensão, obtidos do sistema Hidroweb no site da Agência Nacional da Água (ANA) no período de 1999 a 2018. Foram obtidas CCS para todo o trecho do BSF as quais apresentaram bons coeficientes de determinação. Na análise dos dados também foi possível perceber que nos últimos anos, desde 2013 houve redução gradativa das vazões disponibilizadas na barragem de Xingó. Consequentemente, houve também a redução gradativa das cargas de sedimentos em suspensão geradas nas estações de Piranhas, Traipu e Propriá, ou seja, os menores valores já registrados no BSF correspondendo as menores séries históricas tanto de vazão como de sedimentos em suspensão.  Keys curves of sediment discharges in suspension in the Lower São Francisco A B S T R A C TThe knowledge of the quantitative analysis of suspended sediment concentrations carried by the São Francisco River as well as its relation with the flows is of great importance, since it can help in the identification of the effects of human intervention and/or caused by the natural conditions of the region. In the downstream regions of the São Francisco riverbanks, the main consequence was the regularization of flow rates and the reduction of sediment concentrations. The objective of the research was to determine the key curves of suspended sediments (CCS) at the fluviometric stations installed in the lower São Francisco river after Xingó dam. For the evaluation, flow data and suspended sediment concentration were used. These data were obtained from the Hidroweb system on the website of the National Water Agency (ANA) from 1999 to 2018. CCS were plotted for all stretches and presented good coefficients of determination (R2). Based on the analysis of the data it was also possible to notice that in recent years, since 2013 there has been a gradual reduction of the flows available in the Xingó dam. Consequently, there was also a gradual reduction of suspended sediment loads generated at the Piranhas, Traipu and Propriá stations, that is, the lowest values already recorded in lower São Francisco, corresponding to the lower historical series of both discharge and suspended sediments.Keywords: dam, flow, sediments 

scholarly journals Filtration Conditions for the Removal of Organic Matter in Eutrophic Waters by Freshwater Mussels Using Response Surface Methodology

2018 ◽  
Author(s):  
Hwan-Seok Choi ◽  
Young-Hyo Kim ◽  
Hyuk Lee ◽  
David C. Aldridge ◽  
Baik-Ho Kim
Keyword(s):  
Organic Matter ◽  
Filtration Rate ◽  
Production Condition ◽  
Freshwater Mussels ◽  
Statistical Design ◽  
Water Current ◽  
Experimental Conditions ◽  
Condition Optimization ◽  
Proposed Model ◽  
Central Composite

In this study, we applied a central composite design to estimate independent variables and establish optimal conditions of filtration rate and feces production that enhance filtration of suspended organic matter by the freshwater mussels Sinanodonta woodiana. The results indicated that statistical design methodology offers an efficient and feasible approach for high filtration and low feces production condition optimization. The proposed model equation takes into account the quantitative effect of variables and also the influence of interactions among variables on mussel filtration rate. Under the optimal experimental conditions (mussel size, 13.0 &plusmn; 0.2 cm; water current, 17.5 L/h), the experimental filtration rate of 4.47 &plusmn; 1.82 L/mussel/h showed a degree of correspondence with the predicted value of 8.4 L/mussel/h, which verified the practicability of this optimum strategy.

Production de litières et apport de bioéléments de quatre espèces fruitières locales des hautes savanes guinéennes du Cameroun

2019 ◽  
Vol 42.1 ◽  
pp. 7162-7174
Author(s):  
BAYÉ-NIWAH Claudette ◽  
HAMAWA Yougouda ◽  
LOURA B. Benoît ◽  
FAWA Guidawa ◽  
MAPONGMETSEM Pierre Marie
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Dry Matter ◽  
Fruit Trees ◽  
Experimental Device ◽  
Soil Restoration ◽  
Parkia Biglobosa ◽  
Ximenia Americana ◽  
Local Species

1 RÉSUMÉ Dans la perspective de contribuer à la gestion saine des agrosystèmes des hautes savanes guinéennes de Ngaoundéré, les litières ont été collectées sous 4 espèces fruitières locales, puis certains bioéléments ont été dosés dans la litière foliaire. Le dispositif expérimental exploité était un bloc complet randomisé à 4 répétitions. Les traitements correspondent aux 4 essences et les répétitions aux quatre localités. L’unité expérimentale était constituée de 4 arbres. La litière totale produite est de ,5541kg/m²/an. La litière foliaire (0,3745kg/m²/an) est la plus importante source de matière organique du sol. Cette production de litière varie significativement suivant les espèces (P˂0,000). Les espèces sont riches en calcium, mais pauvres en phosphore. Ximenia americana est l’espèce la plus riche en bioéléments (2378,12mg/100g de MS). X. americana (665,82mg/100g de MS) et Parkia biglobosa (354,47mg/100g de MS) sont les espèces les plus riches en éléments fertilisants. Ces résultats montrent que ces espèces fruitières produisent une litière foliaire fertilisante. Leur intégration dans les agrosystèmes serait très bénéfique pour la restauration des sols. Néanmoins, il serait nécessaire de suivre la dynamique de ces bioéléments dans les sols. ABSTRACT In In order to contribute to the healthy management of agro systems of the high Guinean savannahs of Ngaoundere, the litter of four local species of fruits tree was collected and certain bio elements were measured. A complete block randomized experimental device of four replications was used. Four treatments were considered and corresponded to the four local species of fruits trees tested. Each locality was considered as a replication. In each locality, four trees of each species were considered. The total litter produced was 0.5541kg/a/year. The foliar litter was the most important source of soil organic matter with 0.3745kg/a/year and varied significantly according to the species (p<0.000). All the species tested were rich in calcium and pover in phosphorus. Ximenia americana was the richest species in bio elements with 2378.12mg/100g of dry matter. X. americana and Parkia biglobosa were the richest species in nutrient with 665.82mg/100g and 354.47mg/100g of dry matter respectively. These results shown that, these species of fruit trees produce a fertilizing foliar litter and their integration in agro systems could contribute to soil restoration. Nevertheless, it would be necessary to monitor the dynamics of these bio elements in soils.

The effects of dissolved organic matter from a native and an invasive plant species on juvenile Daphnia survival and growth

2020 ◽  
Vol 42 (4) ◽  
pp. 453-456
Author(s):  
Keiko W Wilkins ◽  
Erin Overholt ◽  
Craig Williamson
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Invasive Plant ◽  
Aquatic Organisms ◽  
Secondary Compounds ◽  
Red Maple ◽  
Negative Effects ◽  
Survival And Growth ◽  
Presence And Absence

Abstract Shifts in the composition of terrestrial plant communities could have significant effects on freshwater zooplankton due to changes in the quality of inputs of terrestrially derived dissolved organic matter (DOM). Leachate from native red maple (RM) and invasive Amur honeysuckle (AH) were used to explore the effects of DOM source on survival and growth of juvenile Daphnia ambigua. Prior research with both terrestrial and aquatic organisms indicates that AH-derived DOM has negative effects. Comparing bioassays in the presence and absence of algae with no additional DOM, RM- or AH-derived DOM, RM had stronger negative effects on both Daphnia survival and growth while AH only decreased growth. The negative effects seen in the presence and absence of algae provided evidence for both indirect and direct effects due to phytotoxicity and plant secondary compounds, respectively. DOM source may play a key role in regulating consumers in aquatic ecosystems.

scholarly journals Performance of Floating wetland to reduce the organic matter in river water

2019 ◽  
Vol 280 ◽  
pp. 05013
Author(s):  
Nopi Stiyati Prihatini ◽  
Andy Mizwar ◽  
Rony Riduan ◽  
Chairul Irawan ◽  
Yulian Firmana Arifin
Keyword(s):  
Organic Matter ◽  
River Water ◽  
Flow Rate ◽  
Organic Pollutant ◽  
Organic Content ◽  
Pollutant Removal ◽  
Initial Information ◽  
Local Species ◽  
Local Plants ◽  
Floating Wetlands

Floating wetlands are innovative systems that rarely used in South Kalimantan Indonesia so their performance using local species of plant are still scarcely known. To gain initial information on their performance and potential in removing pollutants, especially organic content, an experiment have been conducted in laboratory scale. This study used local plants (Echinodorus palaefolius and Limnocharis flava) with a plant height of approximately ±30 cm and ±15 cm, grown with a distance of 15 cm x 15 cm, which was floated into a plastic-coated plywood reactor with a size of 80 cm x 40 cm x 40 cm. Water samples are taken from Kerukan River (Banjarmasin, South Kalimantan Indonesia) which is flowed continuously to the reactor with a flow rate of 0.002 L/s. After 30 days, floating wetland planted with E. palaefolius can reduce organic material (BOD, COD) by 82.19%; 77.22% and floating wetland planted with L. flava can reduce BOD and COD respectively by 78.83% and 72.75%. This show that floating wetland very potential to use as an organic pollutant removal from river water.

The relationship between sediment and water quality, and riverine sediment loads in the wave-dominated estuaries of south-west Western Australia

2004 ◽  
Vol 55 (6) ◽  
pp. 581 ◽  
Author(s):  
L. C. Radke ◽  
I. P. Prosser ◽  
M. Robb ◽  
B. Brooke ◽  
D. Fredericks ◽  
...  
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Soil Erosion ◽  
Organic Carbon ◽  
Water Column ◽  
Nitrogen And Phosphorus ◽  
Weathering Index ◽  
Sediment Loads ◽  
The Impact ◽  
Column Total

We examine surface sediment and water column total nutrient and chlorophyll a concentrations for 12 estuaries with average water depths <4 m, and calculated sediment loads ranging from 0.2 to 10.8 kg m−2 year−1. Sediment total nitrogen, phosphorus and organic carbon concentrations vary inversely with sediment loads due to: (i) the influx of more mineral-rich sediment into the estuaries; and (ii) increasing sediment sulfidation. Sediment total organic carbon (TOC) : total sulfur (TS) and TS : Fe(II) ratios correlated to sediment loads because enhanced sedimentation increases burial, hence the importance of sulfate reduction in organic matter degradation. Curvilinear relationships were found between a weathering index and organic matter δ13C in sediment, and sediment load. The rising phase of the curve (increasing weathering, lighter isotopic values) at low to intermediate loads relates to soil erosion, whereas regolith or bedrock erosion probably explains the declining phase of the curve (decreasing weathering, heavier isotopic values) at higher sediment loads. The pattern of change for water column total nutrients (nitrogen and phosphorus) with sediment loads is similar to that of the weathering index. Most water quality problems occur in association with soil erosion, and at sediment loads that are intermediate for the estuaries studied. Limited evidence is presented that flushing can moderate the impact of sediment loads upon the estuaries.

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