Flow controls on lowland river macrophytes: A review

We review the current status of knowledge regarding the role that flow parameters play in controlling the macrophyte communities of temperate lowland rivers. We consider both direct and indirect effects and the interaction with other factors known to control macrophyte communities. Knowledge gaps are identified and implications for the management of river systems considered. The main factors and processes controlling the status of macrophytes in lowland rivers are velocity (hence also discharge), light, substrate, competition, nutrient status and river management practices. We suggest that whilst the characteristics of any particular macrophyte community reflect the integral effects of a combination of the factors, fundamental importance can be attributed to the role of discharge and velocity in controlling instream macrophyte colonisation, establishment and persistence. Velocity and discharge also appear to control the relative influence of some of the other controlling factors. Despite the apparent importance of velocity in determining the status of macrophyte communities in lowland rivers, relatively little is understood about the nature of the processes controlling this relationship. Quantitative knowledge is particularly lacking. Consequently, the ability to predict macrophyte abundance and distribution in rivers is still limited. This is further complicated by the likely existence of feedback effects between the growth of macrophytes and velocity. Demand for water resources increases the pressure on lowland aquatic ecosystems. Despite growing recognition of the need to allocate water for the needs of instream biota, the inability to assess the flow requirements of macrophyte communities limits the scope to achieve this. This increases the likelihood of overexploitation of the water resource as other users, whose demands are quantifiable, are prioritised. (C) 2008 Elsevier B.V. All rights reserved.

Aquatic macrophyte distribution in relation to water and sediment conditions in the Itaipu Reservoir, Brazil

Aquatic macrophyte community distribution along the eastern shoreline of the Itaipu Reservoir (one of the South America's largest impoundments) is described in relation to limnological and sedimentological factors. The central body of the reservoir is mesotrophic, while the arms (flooded influent river valleys) along the eastern shore may be oligo-mesotrophic to eutrophic, depending on time of year and sub-catchment characteristics. Macrophyte community composition and species cover were surveyed at 30 sites in four arms, in relation to sediment total P and organic matter; underwater light regime; and water total P and Kjeldahl N concentration, alkalinity, conductivity, depth and pH. Seventeen euhydrophyte and six emergent macrophyte species were recorded. Large stands of Egeria najas dominated the euhydrophyte vegetation, together with free-floating weed species (Pistia stratiotes Linn., Salvinia auriculata Aublet and Eichhornia crassipes (Mart.) Solms.). Canonical Correspondence Analysis of the data showed that two sets of variables were important predictors of aquatic macrophyte community structure. Floating macrophyte assemblage was closely related to concentration of nutrients in both water and sediment, while light penetration was the strongest predictor of submerged species occurrence. Although a large number of potential nuisance species were present, dense growths were restricted to shallower areas of the Itaipu Reservoir, causing localised problems. The possibility of increasing interference by these plants with fisheries, recreational use, transport and hydroelectricity generation suggests a need for continued monitoring of weed distribution and abundance, and investigation of appropriate management measures.

Submerged macrophytes height estimation by echosounder data sample

Traditional methods of submerged aquatic vegetation (SAV) survey last long and then, they are high cost. Optical remote sensing is an alternative, but it has some limitations in the aquatic environment. The use of echosounder techniques is efficient to detect submerged targets. Therefore, the aim of this study is to evaluate different kinds of interpolation approach applied on SAV sample data collected by echosounder. This study case was performed in a region of Uberaba River - Brazil. The interpolation methods evaluated in this work follow: Nearest Neighbor, Weighted Average, Triangular Irregular Network (TIN) and ordinary kriging. Better results were carried out with kriging interpolation. Thus, it is recommend the use of geostatistics for spatial inference of SAV from sample data surveyed with echosounder techniques. © 2012 IEEE.

Water quality and communities associated with macrophytes in a shallow water-supply reservoir on an aquaculture farm

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A comparative study of Odonata (Insecta) in aquatic ecosystems with distinct characteristics

The objective of this study was to compare the richness and density of Odonata larvae in four distinct environments: lotic with large pollutant loads, lotic with small pollutant loads, lentic disconnected from a river and lentic connected to a river, as well as to record the physical and chemical parameters of the water in the four environments. We identified a total of 1,302 Odonata larvae in the four habitats. The environmental variables measured were: dissolved oxygen, pH, conductivity, suspended matter, air and water temperature, precipitation, depth, and the biomass of the macrophytes. The lentic habitats exhibited a greater Odonata larvae density in relation to the lotic habitats, except during April and December of 2006. The Guareí River, however, presented an elevated conductivity, possibly because of a greater quantity of pollutants it received during the period between June and September of 2006, and it showed a higher density of Odonata larvae in comparison to the Paranapanema River. The temperature and the dissolved oxygen on the water surface were, respectively, greater and smaller in the lakes in comparison to the rivers. In spite of the Odonata density being higher in the lentic ecosystems in comparison to the lotic, the richness was not altered during the period studied. Nevertheless, the genera composition was distinct, showing that some taxa show a certain preference for certain types of ecosystems like Calopterygidae and Neogomphus, which were shown exclusively in the Paranapanema River.

Remediation of feedlot effluents using aquatic plants

Feedlots have increased in several regions of Argentina, particularly in the Pampas. The absence of adequate treatments of the effluents produced in these establishments creates serious problems to the society. Phytoremediation can be defined as inexpensive and environmentally sustainable strategy used to remove pollutants by plants. The aim of this study was to evaluate the remediation potential of two macrophyte species (Eichhornia crassipes and Hydrocotyle ranunculoides) on a feedlot effluent. This effluent was treated with these species for 31 days. Control and macrophyte treatments decreased dissolved inorganic nitrogen (DIN), Kjeldahl nitrogen (Kj N), biological oxygen demand (BOD), chemical oxygen demand (COD), total dissolved salts (TDS), total phosphorus (TP), Pb, Zn and Cr levels. At macrophyte treatments, relatively constant pH levels were kept and decreased EC and TDS values were obtained compared to control, mitigating the release of contaminants and potential greenhouse gases to the atmosphere. Moreover, significant increases in biomass were obtained, being higher in E. crassipes. The results allow concluding that the presence of aquatic plants increases the removal rates of nutrients, organic matter and heavy metals from wastewater in approximately 10-17 days for a feedlot effluent with high organic load.

Zoocoenological state of microhabitats and its seasonal dynamics in an aquatic macroinvertebrate assembly (Hydrobiological case studies on lake Balaton, No. 1.)

In the years 2002, 2003 and 2004 we collected samples of macroinvertebrates on a total of 36 occasions in Badacsony bay, in areas of open water (in the years 2003 and 2004 reed-grassy) as well as populated by reed (Phragmites australis) and cattail (Typha angustifolia). Samples were taken using a stiff hand net. The sampling site includes three microhabitats differentiated only by the aquatic plants inhabiting these areas. Our data was gathered from processing 208 individual samples. The quantity of macroinvertebrates is represented by biovolume value based on volume estimates. We can identify taxa in abundant numbers found in all water types and ooze; as well as groups associated with individual microhabitats with various aquatic plants. We can observe a notable difference between the years in the volume of invertebrate macrofauna caused by the drop of water level, and the multiplication of submerged macrophytes. There are smaller differences between the samples taken in reeds and cattail stands. In the second half of 2003 – which was a year of drought – the Najas marina appeared in open waters and allowed to support larger quantities of macroinvertebrates. In 2004 with higher water levels, the Potamogeton perfoliatus occurring in the same area has had an even more significant effect. This type of reed-grass may support the most macroinvertebrates during the summer. From the aspect of diversity relations we may suspect different characteristics. The reeds sampling site proved to be the richest, while the cattail microhabitat is close behind, open water (with submerged macrophytes) is the least diverse microhabitat.

Assessing the Legacy of Red Mud Pollution in a Shallow Freshwater Lake: Arsenic Accumulation and Speciation in Macrophytes

Little is known about long-term ecological responses in lakes following red mud pollution. Among red mud contaminants, arsenic (As) is of considerable concern. Determination of the species of As accumulated in aquatic organisms provides important information about the biogeochemical cycling of the element and transfer through the aquatic food-web to higher organisms. We used coupled ion chromatography and inductively coupled plasma mass spectrometry (ICP-MS) to assess As speciation in tissues of five macrophyte taxa in Kinghorn Loch, UK, 30 years following the diversion of red mud pollution from the lake. Toxic inorganic As was the dominant species in the studied macrophytes, with As species concentrations varying with macrophyte taxon and tissue type. The highest As content measured in roots of Persicaria amphibia (L.) Gray (87.2 mg kg-1) greatly exceeded the 3 - 10 mg kg-1 range suggested as a potential phytotoxic level. Accumulation of toxic As species by plants suggested toxicological risk to higher organisms known to utilise macrophytes as a food source.

The red swamp crayfish Procambarus clarkii in Europe: Impacts on aquatic ecosystems and human well-being

Procambarus clarkii is currently recorded from 16 European territories. On top of being a vector of crayfish plague, which is responsible for large-scale disappearance of native crayfish species, it causes severe impacts on diverse aquatic ecosystems, due to its rapid life cycle, dispersal capacities, burrowing activities and high population densities. The species has even been recently discovered in caves. This invasive crayfish is a polytrophic keystone species that can exert multiple pressures on ecosystems. Most studies deal with the decline of macrophytes and predation on several species (amphibians, molluscs, and macroinvertebrates), highlighting how this biodiversity loss leads to unbalanced food chains. At a management level, the species is considered as (a) a devastating digger of the water drainage systems in southern and central Europe, (b) an agricultural pest in Mediterranean territories, consuming, for example, young rice plants, and (c) a threat to the restoration of water bodies in north-western Europe. Indeed, among the high-risk species, P. clarkii consistently attained the highest risk rating. Its negative impacts on ecosystem services were evaluated. These may include the loss of provisioning services such as reductions in valued edible native species of regulatory and supporting services, inducing wide changes in ecological communities and increased costs to agriculture and water management. Finally, cultural services may be lost. The species fulfils the criteria of the Article 4(3) of Regulation (EU) No 1143/2014 of the European Parliament (species widely spread in Europe and impossible to eradicate in a cost-effective manner) and has been included in the “Union List”. Particularly, awareness of the ornamental trade through the internet must be reinforced within the European Community and import and trade regulations should be imposed to reduce the availability of this high-risk species.

Networked aquatic microbial observing systems: An overview

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Assessing genetic diversity in cultured aquatic species : the Sydney Rock Oyster (Saccostrea glomerata) stock improvement program as a model

Genetic variation is the resource animal breeders exploit in stock improvement programs. Both the process of selection and husbandry practices employed in aquaculture will erode genetic variation levels overtime, hence the critical resource can be lost and this may compromise future genetic gains in breeding programs. The amount of genetic variation in five lines of Sydney Rock Oyster (SRO) that had been selected for QX (Queensland unknown) disease resistance were examined and compared with that in a wild reference population using seven specific SRO microsatellite loci. The five selected lines had significantly lower levels of genetic diversity than did the wild reference population with allelic diversity declining approximately 80%, but impacts on heterozygosity per locus were less severe. Significant deficiencies in heterozygotes were detected at six of the seven loci in both mass selected lines and the wild reference population. Against this trend however, a significant excess of heterozygotes was recorded at three loci Sgo9, Sgo14 and Sgo21 in three QX disease resistant lines (#2, #5 and #13). All populations were significantly genetic differentiated from each other based on pairwise FST values. A neighbour joining tree based on DA genetic distances showed a clear separation between all culture and wild populations. Results of this study show clearly, that the impacts of the stock improvement program for SRO has significantly eroded natural levels of genetic variation in the culture lines. This could compromise long-term genetic gains and affect sustainability of the SRO breeding program over the long-term.

Neutrophilic, microaerophilic Fe(II)-oxidizing bacteria are ubiquitous in aquatic habitats of a subtropical Australian coastal catchment (ubiquitous FeOB in catchment aquatic habitats)

We examined the abundance and distribution of neutrophilic, microaerophilic Fe(II)-oxidizing bacteria (FeOB) in aquatic habitats of a highly weathered, subtropical coastal catchment where Fe biogeochemistry is of environmental significance. Laboratory cultivation and microscopy indicated that stalked Gallionella and sheathed Leptothrix-like FeOB were present in microbial mats associated with a circumneutral-pH, groundwater seep and streambank surface sediment,whereas unicellular FeOB werewidespread in surface and subsurface waters, including a seep, shallow stream and estuary-adjacent groundwater. Direct Gallionella-specificPCR detected dominant bacterial members related to Sideroxydans paludicola (95% sequence identity, SI) and Gallionella capsiferriformans (96% SI) in the seep microbialmat. TGGE analysis indicated that themost common FeOB in water enrichment cultures were related to S. lithotrophicus (96% SI). The ubiquity of FeOB in Poona catchment aquatic habitats suggests bacterial Fe(II) oxidation is integral to catchment Fe biogeochemistry.

Exploring the effect of aquatic exercise on behaviour and psychological wellbeing in people with moderate to severe dementia : a pilot study of the Watermemories Swimming Club

Aim To explore the effects of a dementia-specific, aquatic exercise intervention on behavioural and psychological symptoms in people with dementia (BPSD). Method Residents from two aged care facilities in Queensland, Australia, received a 12-week intervention consisting of aquatic exercises for strength, agility, flexibility, balance and relaxation. The Psychological Well-Being in Cognitively Impaired Persons Scale (PW-BCIP) and the Revised Memory and Behaviour Problems Checklist (RMBPC) were completed by registered nurses at baseline, week 6, week 9 and post intervention. Results Ten women and one man (median age = 88.4 years, interquartile range = 12.3) participated. Statistically significant declines in the RMBPC and PW-BCIP were observed over the study period. Conclusion Preliminary evidence suggests that a dementia-specific, aquatic exercise intervention reduces BPSD and improves psychological well-being in people with moderate to severe dementia. With further testing, this innovative intervention may prove effective in addressing some of the most challenging aspects of dementia care.

Physical and functional implications of aquatic exercise for nursing home residents with dementia

Exercise has reported benefits for those with dementia. In the current study we investigated the feasibility of delivery and the physical and functional benefits of an innovative aquatic exercise program for adults with moderate to severe dementia living in a nursing home aged care facility. Ten adults (88.4 years, inter quartile range 12.3) participated twice weekly for 12 weeks. Anthropometric and grip strength data, and measures of physical function and balance were collected at baseline and post-intervention. Feasibility was assessed by attendance, participation, enjoyment and recruitment. Following exercise, participant's left hand grip strength had improved significantly (p = .017). Small to moderate effect sizes were observed for other measures. A number of delivery challenges emerged, but participant enjoyment, benefits and attendance suggest feasibility. Aquatic exercise shows promise as an intervention among those with dementia who live in a nursing home aged care facility. Greater program investigation is warranted.

The optimal frequency of aquatic physiotherapy for individuals with chronic musculoskeletal pain: a randomised controlled trial

Purpose: To establish whether there was a difference in health-related quality of life (HRQoL) in people with chronic musculoskeletal disorders (PwCMSKD) after participating in a multimodal physiotherapy program (MPP) either two or three sessions a week. Methods: Total of 114 PwCMSKD participated in this prospective randomised controlled trial. An individualised MPP, consisting of exercises for mobility, motor-control, muscle strengthening, cardiovascular training, and health education, was implemented either twice a week (G2: n = 58) or three times a week) (G3: n = 56) for 1 year. Outcomes: HRQoL physical and mental health state (PHS/MHS), Roland Morris disability Questionnaire (RMQ), Neck-Disability-Index (NDI) and Western Ontario and McMaster Universities’ Arthritis Index (WOMAC) were used to measure outcomes of MPP for people with chronic low back pain, chronic neck pain and osteoarthritis, respectively. Measures were taken at baseline, 8 weeks (8 w), 6 months (6 m), and 1 year (1 y) after starting the programme. Results: No statistically significant differences were found between the two groups (G2 and G3), except in NDI at 8 w (−3.34, (CI 95%: −6.94/0.84, p = 0.025 (scale 0–50)). All variables showed improvement reaching the following values (from baseline to 1 y) G2: PHS: 57.72 (baseline: 41.17; (improvement: 16.55%), MHS: 74.51 (baseline: 47.46, 27.05%), HRQoL 0.90 (baseline: 0.72, 18%)), HRQoL-VAS 84.29 (baseline: 58.04, 26.25%), RMQ 4.15 (baseline: 7.85, 15.42%), NDI 3.96 (baseline: 21.87, 35.82%), WOMAC 7.17 (baseline: 25.51, 19.10%). G3: PHS: 58.64 (baseline: 39.75, 18.89%), MHS: 75.50 (baseline: 45.45, (30.05%), HRQoL 0.67 (baseline: 0.88, 21%), HRQoL-VAS 86.91 (baseline: 52.64, 34.27%), RMQ 4.83 (baseline: 8.93, 17.08%), NDI 4.91 (baseline: 23.82, 37.82%), WOMAC 6.35 (baseline: 15.30, 9.32%). Conclusions: No significant differences between the two groups were found in the outcomes of a MPP except in the NDI at 8 weeks, but both groups improved in all variables during the course of 1 year under study.