User:KVesterg/glacialstream

In the summer, glacial streams experience high stream flow because of ice melt. The high flow is characterized by high turbidity and sediment transport, which reduces the biomass of the resident periphyton, or the organisms living on the aquatic plants. At the end of summer, ice melt is reduced and stream flow decreases, causing an increase in the periphyton population.

Human impacts

- Climate change


 * Climate change induced glacial recession may reduce the effect of the stream flow pulse, and impact the stream's sources.
 * Study done in southeastern Alaska suggests that glacial recession will influence physical and biogeochemical properties of coastal streams.

- Pollutants


 * Impacts of persistent organic pollutants (POPs)

Ecology


 * Potentially useful source?: Alpine streams can be kryal, krenal or rhithral (characterized by varying temperatures) and their ecological communities vary

Climate change induced glacial recession may reduce the effect of the seasonal stream flow, as well as impact the stream's sources of water. It is expected that with glacial recession, there will eventually be less surface water flow. This is because high alpine areas generally have almost no below ground water storage, and thus, have an absence of aquifers that could have provided the stream with a reliable alternative water source. This means that glacial streams could become intermittent in the future. Streams that have reliable water sources and do not dry up intermittently, will likely be warmer in temperature, which will allow organisms downstream to move to higher elevations and claim new territory. A study done in southeastern Alaska suggests that glacial recession will influence changes in the physical and chemical properties of coastal waters that are connected downstream from glacial streams. These changes could have serious consequences for salmon spawning, ecosystem productivity, and eutrophication.

Alpine areas are generally seen as pristine environments, far away from human influence. However, this is not the case. Airborne contaminants, such as some pesticides, can accumulate in alpine areas and pose health risks to aquatic organisms living in these environments. Contamination by persistent organic pollutants (POPs) mostly occurs from local emissions and transport. Glacial recession of older glacial ice containing contaminants deposited on the ice decades ago (eg. DDT), will enter the stream ecosystem, where it can have health implications for the organisms living in / downstream from the environment. With warmer temperatures, rapid snowmelt will lead to a greater concentration of contaminants entering the stream at once.

Macroinvertebrates are indicator species and are often examined to determine how humans affect the ecosystem. Unfortunately, insufficient research has been conducted for the environmental preferences of macroinvertebrates in alpine environments, making monitoring changes in glacial streams more difficult.

As glaciers recede, new sediments become exposed to the surface. These sediments can be eroded and transported downstream, where they could potentially bury sessile organisms.

These changes might cause periphyton populations to begin growing earlier in the spring and continue growing later into the fall.