Small creek in Demerara basin, between Georgetown and Linden, Guyana

59th place in Biotope Aquarium Design Contest 2017

 Belgium. Jeroen Vanhooren

Volume: 100 L
Dimensions: 70x33x50 cm
List of fishes: Nannacara anomala, Nannostomus beckfordi and Pristella maxillaris
List of plants: N/A
Description of decorations: Predominately fine white sand, with a little clay added. There are some smaller greyish rocks. Twigs andbranches dominate this scenery, leaves at different stages of decomposition to complete.
Description of equipment: Internal sump, Juwel Eccoflow 300 lph, LED lights 28W 6800 K, automatic waterchange system with dripping technology.
Water parameters: Temperature is 26°C, pH is 6, kH is 0

Description of the area surrounding the biotope: Guyana has a not well defined shoreline with swampy and marshy areas. Demerara river basin lays in the eastern part of Guyana and divides the regions of Essequibo islands – West Demerara at the west bank and Demerara – Mahaica on the east bank. It flows north – originating at the northern slopes of the Makari Mountain. It starts with numerous rapids in the upper part of the river. After that the river flows through a huge area of the hilly sand and clay belt, mainly covered by forest. The last part of the river lies in the flat alluvial coastal plain, with the most economic activities (mostly sugar) and highly populated. This part has a completely man made water managment system, engineered by the Dutch to control the water in the low lying regions. It flows for 346 km until it reaches the Atlantic Ocean in Georgetown. The river is of huge economic importance. Large vessels can reach to Linden, more than 100 km upstream from the mouth.

Description of the underwater landscape of the biotope: This specific biotope is a small creek in the east bank Demerara – Mahaica region, between Georgetown and Linden at the borders of the hilly sand and clay belt. It substrate consists predominantly of fine white sand, with some clay and organic matter. Few smaller rocks occur. This aquarium is dedicated to the densely forested area, hence many branches andtwigs dominate this scenery.

Description of the parameters of the habitat: Water of this biotope is tea coloured and quite clear. The average temperature is 26°C, with only little variation due to the tropical climate and the overhanging forest. Water is typically soft and acidic. TDS 10-15 mg/l.

List of fishes: Nannacara anomala, several Nannostomus sp., Pristella maxillaris, Apistogramma steindachneri, Rineloricaria fallax, Crenuchus spilurus, Carnegiella strigata, Hemigrammus rodwayi, Hyphessobrycon eques, Crenicichla sp., Cleithracara maroni and many others.

List of plants: In this specific biotope no plants occur, due to the dense forest. In the broader region: Nymphaea sp., Nymphoides indica, Cabomba aquatica, Salvinia auriculata, Ludwigia sp., Utricularia, Eleocharis sp., Pistia stratoites, Elodea sp., Mayaca sp.

Threats to the ecology: The water quality of the lower Demerara is really poor and influenced by multiple pressures like untreated household effluents, agricultural activities and mining activities (bauxite, gold and diamonds). Luckily enough the more upstream part of the river is inbetter quality. The smaller affluents in the forested region of the basin are in good quality. The water management system (drainage and irrigation) of the East Demerara River Water Conservancy need to be restored to prevent severe coastal floodings in the region which already occured recently. Effects of the climate change is very unpredicatable but will be severe.
In the areas where mining activities occur, erosion is making the waterway virtually unnavigable. Bad environmental planning leading to huge economic costs.

Sources of information:

• The Freshwater fishes of British Guyana (Eigenmann)
• https://guyaneseonline.files.wordpress.com/2013/12/the-wonderful-demerara-river.pdf
• http://botany.si.edu/bdg/pdf/vegetation240.pdf
• http://botany.si.edu (information of the aquatic vegetation)
• Gbif.org
• http://www.pnuma.org/deat1/pdf/2010%20-%20GEO-Georgetown.pdf
• http://www.guyana.org/Handbook/physfea.html
• http://guyanachronicle.com/2017/01/09/sandbanks-rendering-upper-demerara–river-virtually-unnavigable
• http://www.guyana.org/Handbook/physfea.html
• http://countrystudies.us/guyana/19.htm
• https://library.wur.nl/isric/fulltext/isricu_i00002253_001.pdf
• https://www.britannica.com/place/Guyana#toc26771