Wetlands Work connects farmers and agricultural landowners with wetland planners, restoration programs and sources of funding. It is a product of the Chesapeake Bay Program and its partners. Understanding Wetlands What is a Wetland?
Types of Wetlands Importance of Restoration. Clean Water Wildlife Economy. Contact Us. Pollutants find their way through river systems into seas, sometimes creating coastal ocean zones void of oxygen and aquatic life.
It is estimated that 80 percent of the waste we produce is dumped untreated into waters, polluting water supplies. Freshwater pollution is recognized as a growing global concern that is threatening access to safe drinking water for 1. Finding sustainable solutions for improved management and re-use of waste-water is urgent.
In this regard, wetlands play a significant role in pollution control and detoxification. The East Kolkata Wetlands in India treat urban waste from the city and the treated water is used for pisciculture and agriculture and thus providing livelihood directly for 50, people.
Wetlands are a cost effective and sustainable solution to be considered in integrated efforts to prevent, reduce and control freshwater and marine and coastal pollution and improve access to clean and safe water for all. Harmful substances may also be buried in wetland soil, where bacteria and other microorganisms break the substances down so they are no longer harmful.
So, let's say there are two farms, each one is next to a lake. On one of the farms, there is a wetland next to the lake. On the other farm, there is not. In the dry season, the dominant taxa in this sites were Sphaeriidae sph , Naucoridae nau , Caenidae ca , and Libellulidae lib. Figure 4. Redundancy analysis triplot of macroinvertebrate taxa, environmental variables, and sites during the wet and dry seasons see Supplementary Table S5 for full names of taxa codes and Supplementary Table S1 for the site codes.
The first axis grouped Boye sites into two, those sites before Joining the wetland B1, B2, B3, and B4 , being in one group and sites within the wetland B5, B6, and B7 and at the outlet point B8 being in the other group. Unlike the dry season, Simuliidae was abundant in Fisho sites highly abundant in F4 during the wet season. Potamonidae dominated the upstream F1 of Fisho wetland. Axis 1 The first axis separated Boye sites from others.
They were associated with low pH and EC. Figure 5. Redundancy analysis triplot of diatom taxa, environmental variables, and sites see Supplementary Table S6 for full names of taxa codes and Supplementary Table S1 for the site codes. During the wet season, TP, NO 3 , and NH 4 were identified as the set of important environmental variables determining the distribution of diatom taxa among sites Figure 5 , Wet season.
In Jimma, the natural riverine wetlands of the town receive streams which are considered as major carriers of the towns waste. During the dry season, water quality improvement was observed by the significant reduction in concentration of TN and DIN, and a considerably lower NH 4 after passing through the wetland. Concerning phosphorus, a retention of TP and PO 4 was revealed from lowered concentrations in sites within the wetland and after passing through the wetland.
These results are in line with a review done by Fisher and Acreman on the potential of natural wetlands to remove nutrients. Although there was a slight increase in the concentration of NO 3 in sites located within the wetlands, a significant reduction was observed in the effluent. Unlike the dry season, no clear gradient was observed during the wet season. The integrative response of biological indicators revealed the water purifying effect of the studied wetlands and their potential to support biodiversity.
The relative abundance of filter collectors is among the recommended indices to assess ecological status of wetlands in Ethiopia Mereta et al. It can be associated with the reduced load of nutrients and organic pollutants after joining the wetlands. Lougheed et al. In this study, the higher diatom taxa richness and lower percent pollution tolerant taxa in sites after joining the wetland indicated water quality improvement.
Similarly, our finding indicated a higher abundance and richness of diatoms during the wet season. On the other hand, diversity indices of macroinvertebrates were lower in the wet season. Gebrehiwot et al. This might be due to habitat instability, resulted from increased runoff, which in turn drift off macroinvertebrates. The percent change of nutrients and organic pollutants differ among wetlands.
This variation can be attributed to the difference in influent quality, and extent of catchment disturbance. Among wetlands, the concentration of nutrients and electrical conductivity were significantly higher in sites associated with Boye wetland than Fisho and Kitto wetland sites. The more polluted Boye wetland showed a higher TP reduction during the dry season. This can be due to the higher phosphorus input to Boye wetland from the streams flowing to it or anthropogenic pressure in the surrounding since its located in urban downstream.
The wetlands nutrient retaining effect was not observed in wet season, rather there was more leaching of nutrients than reduction. This might be due to instability of sediments and habitats. The biological indices reflect major ecological degradation in Boye wetland. High load of organic and inorganic pollutant makes the environment less favorable for sensitive taxa Eppink et al.
This can be attributed to the heavily degraded incoming water to Boye. Compared to Boye wetland the other two wetlands, located in urban upstream, still have the capacity to sustain their ecological quality. This was indicated by the higher diversity and richness of the assessed bioindicators. However, in this study, heavily polluted sites recorded a minimum of five. This discrepancy may be due to the difference in the type of pollution since the sites are located in a different land use type.
The presence of moderately tolerant macroinvertebrate taxa in Boye sites after passing through the wetland indicated a relatively improved water quality.
Most of Fisho and Kitto sites were dominated by moderately tolerant taxa. Highly tolerant taxa Lakew and Moog, such as Oligochete were among the dominant during the wet season. During the dry season, the upstream of Kitto K1 is characterized by a high level of DO and had a low level of organic pollution. This variation in macroinvertebrate communities among sites can be explained by the difference in habitat, and in the level of degradation. In general, the relation among macroinvertebrate community assemblage, environmental parameters, and sites, discriminate Boye wetland sites as the most degraded in both seasons.
A previous study Ambelu et al. Diatom taxa which are tolerant of high level of EC, e. Gomphonema parvulum is among the taxa which are potential indicators of eutrophication Bere and Mangadze, Less tolerant taxa, e.
There was a homogenized distribution of highly tolerant, and moderately tolerant taxa during the wet season. This could result from the drifting effect of runoff since it is the major factor governing the seasonal variation in tropical wetlands ecosystem Bellinger et al.
In indicating the water quality improvement and ecological quality, macroinvertebrates and diatoms, indicated a coherent response toward pollution gradient during the dry season. Similarly, a consistent response of these bioindicators was reported by Resende et al. Both bioindicators discriminated Boye site as the most ecologically degraded. In conclusion, this study proved the potential of natural riverine wetlands in Jimma, Ethiopia, to retain nutrients and organic pollutants.
The gradient of nutrients, BOD, and DO before and after joining the wetlands showed retention of pollutants within the wetlands.
Percent change of nutrients and organic pollutants varied among wetlands and between wet and dry seasons. During the wet season, a higher concentration of nutrients was observed within the wetland. However, the water quality was better diluted during the wet season. Macroinvertebrates and diatom metrics clearly indicated the water purifying effect of studied wetlands and their potential to support biodiversity. B1 and B3 of Boye were identified as severely degraded, whereas, K1 Kitto upstream was the only site with an intrinsic good ecological quality.
In general, the integrated response of biota and environmental parameters discriminate Boye wetland sites as the most ecologically degraded. Hence, we conclude that, when the incoming water is heavily degraded, the retention of pollutants seriously affects the ecological quality of the wetlands themselves.
Therefore, future integrated wetland management interventions should also target the incoming streams or rivers to reduce the nutrient and organic loading. Therefore, this study suggested that when the influents are marginally polluted the natural riverine wetlands can serve as natural treatment systems without affecting their ecological quality.
Simultaneous use of macroinvertebrates and diatoms along with environmental parameters is recommended to have a comprehensive information on water quality and ecological status of natural riverine wetlands. Future studies should include wetland macrophyte identification, and hydrological parameters, e. The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation, to any qualified researcher.
AS contributed in data collection, analysis, and manuscript writing. IS contributed in manuscript writing. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Abebe, S. Impact of disappearance of Lake Haramaya on the livelihood of the surrounding community: the case of Haramaya District in Oromia national regional state.
Ethiopia J. Google Scholar. Alakananda, B. Diatom-based pollution monitoring in urban wetlands. Soil Water Res. Ambelu, A. Physicochemical and biological characteristics of two ethiopian wetlands. Wetlands 33, — APHA Standard Methods for the Examination of Water and Wastewater.
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Shimelis Berlin: Springer. Bellinger, B. Benthic diatoms as indicators of eutrophication in tropical streams.
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