Precipitation Patterns And Subsequent Delivery Of Freshwater

Published Date: 02 Nov 2017

Introduction

Wetlands are ecologically very important and among the most productive ecosystems on earth. It plays a role as a carbon sink to mitigate the effects of climate change by which storing and capturing carbon (Bridgham et al. 2006). Climate change impacts to the wetland ecosystems will be caused by the effects of rising of temperatures globally and increasing of Carbon Dioxide (CO2) concentrations in the atmosphere (Bates et al. 2008). This paper attempt to discuss the impact of climate change on coastal area and wetland whereby the physical and chemical factors such as increasing temperature, alteration in precipitation patterns and the phosphorus impact globally is considerably important scenarios to look into.

Increase in Temperature

The alteration or changes in climate impact nowadays is becoming a serious issue being voiced out in Environmental Protection Agency (EPA). The impact of climate changes can be broad and in a variety ways and one of the impacts is rising temperature of coastal area and wetlands. Loss of wetlands and estuaries, decreasing water quality and buffer zone are examples of effective parallel to increase in global temperature (Bates et al. 2008).

As the global temperature rise, the water in the ocean is becoming warm because heated by the sun resulting of increasing greenhouse gases which depleted the ozone layer. Ice cap and precipitation fall which suppose fall as snow also lead as the outcome of rise of temperature which also affected in coastal area and wetlands and not only in the ocean. All of this is resulting of sea level rises where half of meter of ocean level will increase in 2100 (Michener et al. 1997). The outcome from the rising temperature which leads to sea-level rise is lost of wetlands and estuaries. Wetlands are created mostly in lowland area which when the sea level rises, it will impact the habitat of wetland by submerged the habitat into deep water (Nicholls et al. 2007). It shows 1% of percentage every year will decline in habitat of wetlands area globally due to sea level rise (Nicholls&Hoozemanns 2000).

Rising of temperature also actually gives effect to the water quality in the lake itself through a fall in Oxygen concentration which actually released of phosphorus from sediments, increased the thermal stability and altered mixing pattern (Ccsp 2009). This case actually was seriously happening during summer season where it actually affects micro-organism and distribution species in the lake. The rising temperature will lead to the reproduction of plankton communities which will alter the water quality in the lake which will become more turbid and murky as a result of the present of blue-green algal bloom (Sommer&Lengfellner 2008). One of coastal wetland functions is to prevent flooding from nearby place or area and also as housing for the community’s fish species. The degradation of this habitat will create a problem which there is no flood’s buffer zone for impaction from these habitats (Nicholls et al. 1999).

Alteration in Precipitation Patterns and Subsequent Delivery of Freshwater

According to IPCC 2007 precipitation pattern is likely to increase globally whereby more precipitation and more intense storms occur in the mid to high latitudes in the northern hemisphere. However, a coastal ecosystems areas are susceptible to the major impact of climate change is changes in precipitation patterns and then delivery of fresh water. These impacts include changes in productivity, survival and / or distribution of estuarine of fish and other species, changes in salinity gradients and reduced lake levels (Shellenbarger et al. 2009)

Changes in precipitation pattern will also affect the coastal systems through changes in the measure, timing, strength, and quality of freshwater flow into the estuarine system. A quantity of fresh water flowed into the estuaries salinity gradient effect, which can have a profound effect on the distribution and survival of flora and fauna. The frequency of heavy rainfall can also lead to sedimentation eroding and vegetation during peak flow, sediment redistribution, and increased pollution which affects water quality (such as, more frequent sewer overflows cause pollution to coastal aquatic systems) (Gutierrez et al. 2011; Scavia et al. 2002).

The adaptation and mitigation measures for coastal area or estuaries ecosystem are to help the aquatic and terrestrial ecosystems cope with the effects of climate change. The adaptations and mitigation measures mentioned as follows; a) to make sure the habitat maintained to support the aquatic life and terrestrial ecosystem function by identifying and mapping of high priority area for conservation using information on species distribution (current and projected), habitat classification, land cover, and geophysical settings (including changing area); b) to identify, especially groundwater, flow and discharge sites, and areas that become point sources of sediment to the coastal ecosystem process; c) to assess the potential for migration of coastal habitats and species and priority areas of highest potential migration, to make sure ecosystem functioning of the existing physical barriers and in the future; d) to slow and reduce damage to ecosystems from anthropogenic point sources implemented through land use planning, water resource planning, pollution reduction, and the best management practices implemented; e) to cooperate with water resource managers to find, upgrade, or remove outdated sewer and storm water, infrastructure to reduce water pollution; f) to enhance the rehabilitation, improvement, and conservation of riparian and buffer zones in agricultural and rural areas to reduce non-point source pollution; g) to reduce the impact of impervious surface and storm water runoff in urban areas to improve water quality, groundwater flow, and hydrologic function (IPCC 2007).

Climate Change Effects on Phosphorus Loading in Wetland Areas

Climate change do affects the weather where frequent and severe heat waves caused drought and unseasonal rainfall. By 2050, there will be a decrease in freshwater availability in Central, South, East and Southeast Asia as it is related to the amount and timing off runoff and precipitation. Therefore, due to increases of heavy precipitation events would produce flood risks. In the meantime, droughts will also are likely to become more widespread (Easterling et al. 2007; Kundzewicz et al. 2007).

Eutrophication is one of the main problems in wetland ecosystems. It caused from the abundance of nutrients such as phosphorus and nitrate in water bodies (Conley et al. 2009). The climate change may have profound effects on phosphorus transport in stream and caused eutrophication. It caused the changes of rainfall, flooding, drought and the more frequent and severe heat waves (Jeppesen et al. 2009). In a study of drying and rewetting small scale pond and marsh, conducted by Song et al. (2007), the result was a high concentration of phosphate in outflow. It also showed all extracellular enzyme activities in soil were much higher in the drying period compared to normal weather (Song et al. 2007).

Phosphorus can be found naturally in water, soil and sediment. Phosphorus is an essential element and a macronutrient which required by plants in large amount. In a phosphorus cycle, it is taken up by plants from soil, and then utilized by animals that consume plants and through decay process, phosphorus is returned to the soil. During drought or dry season, there will be increase in the enzyme activities indicates the increase of decomposition rates in the soil (Kang&Freeman 2000).

Increasing in various anthropogenic activities and problem with global climate change will caused drought and rewetting of wetland area to occur more frequently. High runoff, direct drainage to wetlands and development with low infiltration can modify the hydrological regime (Dunne&Leopold 1978; Paul et al. 2001). Meanwhile, global climate change may result the modification of drought and rewetting cycle in wetland areas. Thus, these changes will lead to substantial release of phosphate to water bodies in wetlands and could induce serious environmental problems (Dugan 1994; Song et al. 2007).

Conclusion

Tropical wetlands such as peatlands and mangroves are important in global carbon cycling. The impacts of climate change will eventually change the carbon cycle and ecosystem as a whole. Moreover, it caused an increase of global temperature which affected the wetlands water table, alteration in precipitation patterns and eutrophication in wetland areas. The result of climate change in hydrological cycle (freshwater flow) as well as a heavy rainfall intensity will cause flash flood and will increased freshwater delivery, increased erosion of shores and coastal habitats, salinization of groundwater and estuaries, changes in sedimentation, nutrient loadings and other coastal habitats. Physical buffer zone such as mangroves and floodplains play an important role to reduce the impact on climate change (Scavia et al., 2002)