Tennants Lake
| Tennants Lake | |
|---|---|
| Location | Chatham Island, New Zealand |
| Coordinates | 43°49′45″S 176°34′10″W / 43.8291°S 176.5694°W |
| Primary outflows | two streams |
| Surface area | 45–50 ha (110–120 acres) |
| Max. depth | 4–6 m (13–20 ft) |
| Surface elevation | 21 m (69 ft) |
| Location | |
Interactive map of Tennants Lake | |
Tennants Lake is a sandy dune lake on Chatham Island, in the Chatham Islands of New Zealand. One of the deeper and clearer lakes on the island, it has a sandy drainage basin, unlikely much of the peat-dominated terrain on the island.
Description
Tennants Lake is a sandy dune lake on Chatham Island, the main island of the Chatham Islands of New Zealand. It is situated at an altitude of 21 metres (69 ft) and has an area of about 45 to 50 hectares (110 to 120 acres).[1][2] One of the deepest lakes on the island, it reaches a maximum depth of 4 to 6 metres (13 to 20 ft).[1][3][4] Alongside nearby Lake Marakapia, it forms part of a small chain of dune lakes inland from the shore of Petre Bay. These sandy drainage basins are unusual on Chatham, where the ground is dominated by peat.[1] The surrounding land is mainly pastoral farmland, with livestock given access to the lake. Two outflow streams drain it.[5] A small unnamed peaty lake lies opposite to Tennants, separated by a nearby road.[3]
The lake has a greater visibility than most other lakes on Chatham, rated at 5 m (16 ft) in a 2004 study.[6][7] The water colour is clear to yellowish.[5] A mesotrophic lake (intermediate levels of algae and nutrients),[1][8] it has typical amounts of algae and slightly elevated amounts of nitrogen and phosphorus. Its levels of ammoniacal nitrogen appear to be improving, although its phosphorus and algae levels are likely degrading.[9] After briefly becoming eutrophic in 2020 and 2021, it is one of only a few Chatham lakes to remain in this condition, preventing a murky condition.[8]
Flora and fauna
Tennants Lake hosts the aquatic plants Myriophyllum triphyllum and Ruppia polycarpa. A 2004 survey found many of these plants left without leaves, likely due to caterpillar activity. New Zealand smelt are commonly found in the lake.[10] In 1949, smelt from the lake (alongside samples from nearby Lake Huro and Lake Marakapia) were described as a separate species from New Zealand smelt, R. chathamensis; this was later synonymised with Retropinna retropinna, New Zealand smelt. Smelt from Lake Marakpia show genetic ties to those found in Tennants Lake, although Lake Huro seems to have a genetically distinct population.[11]
References
- ^ a b c d "Tennants Lake". Land, Air, Water Aotearoa. Retrieved 4 March 2026.
- ^ Champion & Clayton 2004, p. 7.
- ^ a b Champion & Clayton 2004, p. 9.
- ^ Pearman et al. 2025.
- ^ a b Meredith & Croucher 2007, p. 10.
- ^ Champion & Clayton 2004, p. 8.
- ^ Meredith & Croucher 2007, p. 9.
- ^ a b Meredith, Stevens & Barbour 2024, p. 25.
- ^ "Tennants Lake off Port Hutt Road". Land, Air, Water Aotearoa. Retrieved 4 March 2026.
- ^ Champion & Clayton 2004, pp. 11, 14.
- ^ Ara 2023, pp. 53, 64.
Bibliography
- Ara, Motia Gulshan (2023). Evolutionary History and Effects of Landlocking on New Zealand Smelts (PhD thesis). University of Otago.
- Champion, Paul D.; Clayton, John S. (March 2004). "Aquatic Vegetation of Chatham Island (Rekohu)". Department of Conservation Science Internal Series (164). Department of Conservation. ISBN 0-478-22086-3. ISSN 1175-6519.
- Meredith, Adrian S.; Croucher, Robyn (2007). State of the Environment Monitoring: Water Quality and Ecosystem Health of the Lakes, Streams and Te Whanga, Chatham Island/Rekohu/Wharekauri (PDF) (Report). Chatham Islands Council. ISBN 978-0-9582920-1-6.
- Meredith, Adrian; Stevens, Sebastian; Barbour, Sian (2024). Chatham Islands Surface Water Summary 2022-23 (PDF) (Report). Chatham Islands Council.
- Pearman, John K.; Sissons, Jack; Kihika, Joseph Kanyi; Thomson-Laing, Georgia; Wood, Susanna A. (2025). "Microbial Biodiversity and Metabolic Functioning in Sediments of Coastal Dune Lakes on a Remote Island". Metabarcoding and Metagenetics. 9: 189–213. doi:10.3897/mbmg.9.144128.