Oder River

• Category: Inland Aquatic Biomes.
• Geographic Location: Europe.
• Summary: The Oder River is an international waterway in east-central Europe that has received close monitoring of pollution to maintain and improve its ecosystems.

The Oder River is located in the east-central part of Europe and divides Poland from Germany. It originates in the Hruby Jesenik Mountains within the Czech Republic, and is fed by Warthe and Lausitzer Neibet River tributaries. Its width varies from 1 to 6 miles (1.5 to 10 kilometers). The endpoint of the Oder River is at the Baltic Sea, after it flows through the Szczecin Lagoon, close to Szczecin, the largest seaport in Poland.

The Oder flows for about 530 miles (850 kilometers); its watershed drains approximately 46,000 square miles (118,860 kilometers). Sometimes during the autumn and summer, the Oder River can become very low, yet during spring it can flood heavily, due to melting snow or heavy rains.

Called Odra in Poland, it is the second-longest river in that country. During the reign of the Roman Empire, it was part of the Amber Road; Germanic tribes used it as an important trade route. Water wheels and dams were already being constructed in the 13th century, diverting the flow for agricultural and power needs.

An international waterway, because it allows sea access to several nations, the Oder links to the Vistula River in Poland via the Warta River. Many other canals off the Oder link as far away as parts of Russia and Ukraine. While designed for human transport, these channels also have permitted the migration of hosts of exotic flora and fauna.

The Oder River begins as a freshwater river and then turns into brackish water as it travels through the Szczecin Lagoon, until it is a fully saline habitat at the Pomeranian Bay on the Baltic Sea. Nutrient loads are found to be generally heavier in the upstream waters. Mountains-and-valley terrain is the rule in the upper and middle segments; lakes and lowlands are found in the lower section. Some side tributaries are used in mining alluvial sands.

Biodiversity

The Oder River was recently a very heavily polluted waterway, however under new European Union guidelines it could potentially begin to recover and become a thriving ecosystem. The basin is a fairly good area for fish because of many different habitats. There are fertile, well-drained river meadows, at least 42 distinct wetland areas, and 15 varieties of forest community.

The lower Oder Valley has flora and fauna that are unique only to this area, or endemic. This area was originally settled for agricultural purposes, which did not work out well, due to the low level of land and extensive drainage problems. Eventually, it returned to a more natural state, and had the benefits of natural floods. There are now a peat bog, reeds, thickets, and swaths of alder trees. These habitats support a great variety of fish life: Eel, bream, dace, catfish, carp, and trench are a few types found here.

Bird species of the Oder include black redstart, icterine warbler, golden oriole, red-backed shrike, hawfinch, crested tit, both nightingale and thrush nightingale, hooded crow, serin, crested lark, red kite, hobby, marsh warbler, penduline tit, and white spotted bluethroat. Near Szczecin, the breeding crane population thrives. The lesser spotted eagle and white-tailed eagle can also be found here.

Beavers and otters are among some of the mammals increasing in numbers here. Others found in the region include: boar, roe deer, velvet shrew, bats, forest mice, migratory rats, and weasels. Amphibians include comb newt, grass frogs, water toad, and grey toad. There are also grass snakes.

Human Impact

Sewage, industrial waste, and farm runoff have polluted the Oder River for centuries. Early on in the 18th and 19th centuries, the Oder was shortened twice to improve it for the purpose of navigation. As a result of the building of 23 dams, fish suffered not only from pollution but also from the lack of fish ladders built to allow them to return upstream to their spawning grounds.

After 1945, the need for the river for transportation was not as great, so some of the river was able to return to its natural ecological state, including wet meadows, meanders, and alluvial forests. Fauna and flora have increased in number and variety, helped by such developments as the founding of the Lower Oder Valley International Park, a reserve shared by Germany and Poland.

In 1999, the International Commission for the Protection of the Oder (ICPO) was established between Poland, Germany, and the Czech Republic. Some of the ICPO’s goals were: to reduce pollution and prevent further pollution of the Oder and the Baltic Sea by contaminants; to achieve the most natural aquatic and littoral ecosystems possible with corresponding species diversity; to permit utilization of the Oder, in particular the production of drinking water from bank filtrate and the use of its water and sediments in agriculture; and to provide for precautions against the risk of flood damage.

In 2000, oxygen levels tested in the whole Oder River area were better than levels recorded in 1992. Organic pollution, total nitrogen, and phosphorous have become lower, but still need to be reduced. Bacterial pollution needs to continue to be lowered as well. As a result of programs implemented, scientists are returning sturgeon to the Oder River, to encourage the ecosystem to flourish.

Climate change scenarios predict an increased risk of extreme weather events globally. Ongoing sea-level rise and a sinking coast, as well as changes in precipitation in the Oder River watershed, will increase the flooding risk in the river basin and at the coast.

Along the Baltic Sea coast, an increased risk of storms and storm surges will have immediate negative effects on coastal erosion, protection measures, and tourism infrastructure. Climate change will affect not only the coast, but also the river basin itself; integrated coastal and river basin flood protection will be needed.

Warming waters have created a new problem with algae blooms in the Oder River. High salinity, sunlight, high water temperatures, and low water levels combined to overwhelm the natural resilience of the ecosystem and create conditions that allowed the brackish algae Prymnesium parvum to thrive. The algae produce prymnesins (toxins) that can destroy the gill tissue of fish and shellfish. In August 2022, the river experienced a major fish die-off as a result of these toxins. Continued monitoring of the waters shows temperatures are still high, though not at the levels they were that created the dire circumstances in 2022. With temperatures rising globally, scientists fear the occurence of similar incidents in the future.

Bibliography

Bethge, Philip. “Bringing the Sturgeon Back to Germany.” Spiegel, October 31, 2006.

Marszelewski, Wlodzimierz, and Adam Piasecki. "Changes in Water and Sewage Management After Communism: Examples of the Oder River Basin (Central Europe)." Scientific Reports, vol. 10, no. 1, 2020. DOI: 10.1038/s41598-020-62957-1. Accessed 18 Nov. 2024.

“The Oder River Under Stress.” Umwelt Bundesamt, 19 Jul. 2024, www.umweltbundesamt.de/en/topics/water/rivers/the-river-under-stress#the-oder-a-central-european-river. Accessed 18 Nov. 2024.

Perkins, Sid. “River Stats Trickle In.” Science News 164, no. 11 (September 2003).

Schnalitz, G. and A. Behrendt. Heavy Metal and Contaminant Loading in the Oder River Floodplains and Consequences for Livestock. Paulinenaue, Germany: Center for Agricultural Landscapes and Land Use Research, 1999.

Tittman, Angelina. "The Sturgeon Returns to the Elbe and the Oder: Whether It Remains Is Also a Question of Politics." Liebniz Institute of Freshwater Ecology and Inland Fisheries, 21 Oct. 2021, www.igb-berlin.de/en/news/sturgeon-returns. Accessed 18 Nov. 2024.

Torsi, Agnieska and Arkadusz Nedzarek. “Oceanological and Hydrobiological Studies.” International Journal of Oceanography and Hydrobiology 39, no. 3 (2010).