Michel Loup / Four Pike (Esox lucius) and their reflections under the water surface, amongst Potamogeton sp pondweed in a mountain lake, Jura, France. Veolia Environnement Wildlife Photographer of the Year 2009 - W...

Michel Roggo / Pondweed (Potamogeton sp.) in channel of the Danube Delta, Romania, May 2015 . Photographed for The Freshwater Project

Kim Taylor / Raft spider (Dolomedes fimbriatus) female on leaf (Potamogeton sp) Surrey, England, September.

Chris Mattison / Broad-leaved pondweed (Potamogeton natans) growing among Sphagnum moss in a small pond in Woorgreens Nature Reserve, Gloucestershire, UK

Nick Upton / Broad-leaved pondweed (Potamogeton natans) flowering in a marshland pond, Devon, UK, June

Willem Kolvoort / Longleaf Pondweed (Potamogeton nodosus) River Ijesell, Holland. July.

Willem Kolvoort / Brook with Rigid Hornwort (Ceratophyllum demersum), Shining Pondweed (Potamogeton lucens) with Great Yellowcress (Rorippa amphibia) North Holland. June.

Wild Wonders of Europe / Lundgren / Current pulling weeds possibly Potamogeton sp, along riverbed, Danube Delta, Romania, June.

Wild Wonders of Europe / Lundgren / Aquatic plant, possibly Potamogeton sp, in river current, Danube Delta, Romania, June.

Adrian Davies / Leaves of Bog Pondweed {Potamageton polygonifolius} New Bridge Marsh, Dartmoor, Devon, England

Niall Benvie / Pondweed {Potamogeton sp} Tansley bog, Beinn Eighe NNR, W Ross, Scotland

Willem Kolvoort / Broad leaved pondweed (Potamogeton sp) underwater in brook, Holland

Willem Kolvoort / Great diving beetle male (Dytiscus marginalis) on Shining pondweed (Potamogeton Lucens), sand-winning Pit, Holland

Willem Kolvoort / Looking up at Shining pondweed (Potamogeton lucens) from bottom of sand winning pit, Holland

Willem Kolvoort / European edible frog developing tadpole (Rana esculenta) scraping algae from Shining pondweed (Potamogeton lucens) Holland

Willem Kolvoort / Marsh snail (Lymnaea palustris) on Perfoliate pondweed (Potamogeton perfoliatus), sand winning pit, Holland

Willem Kolvoort / Marsh snail (Lymnaea palustris) on Perfoliate pondweed (Potamogeton perfoliatus), sand winning pit, Holland

Willem Kolvoort / Marsh snail (Lymnaea palustris) on Perfoliate pondweed (Potamogeton perfoliatus), sand winning pit, Holland

Willem Kolvoort / Swan mussels (Anodonta cygnaea) and Perfoliate pondweed (Potamogeton perfoliatus) Czarna Hanca river, Poland

Willem Kolvoort / Semi-aquatic beetles (Macroplea appendiculata) on Shining pondweed (Potamogeton lucens) with Rotifer colonies (Sinantherina), sand-winning pit, Holland

Willem Kolvoort / Pondweed (Potamogeton sp) covered with colonies of Bellanimacules (Vorticella), in sand-winning pit, Holland

Willem Kolvoort / Underwater view of Perfoliate pondweed (Potamogeton perfoliatus) in Zuiderzee estuary, Ijsselmeer, Holland. On the bottom are fossil shells from the time the estuary was salt, but it has been closed...

Willem Kolvoort / Juvenile Pike (Esox lucius) amongst Pondweed (Potamogeton sp), stripes aid in camouflage, Lake Naarden, Holland

Jean E. Roche / Pondweed leaves floating on pond surface {Potamogeton sp} Camargue, France

Niall Benvie / Pondweed (Potamogeton sp). Scotland, UK, Europe

Heidi & Hans-Juergen Koch / Giant Fire-bellied Toad (Bombina maxima) emerging from pond weed, native to China

Konrad Wothe / Broad-leaved Pondweed (Potamogeton natans), Dolomites, Italy

Franco Banfi / Northern pike (Esox lucius) amongst Shining pondweed (Potamogeton lucens), Sion, Valais canton, southwestern Switzerland, Europe

Franco Banfi / Northern pike (Esox lucius) amongst Shining pondweed (Potamogeton lucens), Sion, Valais canton, southwestern Switzerland, Europe

Franco Banfi / Northern pike (Esox lucius) amongst Shining pondweed (Potamogeton lucens), Sion, Valais canton, southwestern Switzerland, Europe

Franco Banfi / Northern pike (Esox lucius) amongst Shining pondweed (Potamogeton lucens), Sion, Valais canton, southwestern Switzerland, Europe

Franco Banfi / Pondweed (Potamogeton lucens), Sion, Valais canton, southwestern Switzerland, Europe

Alex Hyde / Broad-leaved pondweed (Potamogeton natans) growing in moorland pool, with raindrops beading on the hydrophobic surface of the leaves. Peak District National Park, Derbyshire, UK. December.

Nick Upton / Broad-leaved pondweed (Potamogeton natans) in heathland pond. Dorset, England, UK. June.

Nick Upton / Common European toad toadlet (Bufo bufo) sitting on a Broad-leaved pondweed (Potamogeton natans) leaf in a pond, Dorset, UK, June.

Nick Upton / Pondweed leafhopper (Erotettix cyane) nymph resting on a leaf of Broad-leaved pondweed (Potamogeton natans), its sole host plant in a heathland pond, Dorset, UK, June. This tiny insect is one of the U...

Nick Upton / Pondweed leafhopper (Erotettix cyane) adult resting on a Broad-leaved pondweed (Potamogeton natans) leaf, its sole food plant, in a heathland pond, Dorset, UK, June. This tiny insect is one of the UK'...

Michel Roggo / Northern pike (Esox lucius) amongst Shining pondweed (Potamogeton lucens) on tbed of Lake Neuchatel, Switzerland, September. Photographed for The Freshwater Project.

Michel Roggo / Northern pike (Esox lucius) amongst Shining pondweed (Potamogeton lucens). Lake Neuchatel, Switzerland, September. Photographed for The Freshwater Project.

Willem Kolvoort / Common toad (Bufo bufo) tadpoles amongst Perfoliate pondweed (Potamogeton perfoliatus) in ditch. Netherlands. May.

Willem Kolvoort / Common newt (Lissotriton vulgaris) female amongst Shining pondweed (Potamogeton lucens) in garden pond. Netherlands. April.

Willem Kolvoort / Common toad (Bufo bufo) tadpoles eating algae on Floating pondweed (Potamogeton natans). Netherlands. May.

Will Watson / Reed Beetle (Donacia veriscolorea) on Broad-leaved Pondweed (Potamogeton natans), Shatsky National Natural Park, Volyn Oblast, Ukraine, May.

Will Watson / Fen raft spider (Dolomedes plantarius) and Reed beetle (Donacia veriscolorea) on Broad-leaved Pondweed (Potamogeton natans), River, Volyn Oblast, Ukraine, May.

Michel Roggo / Shining pondweed (Potamogeton lucens), beginning of autumn, Lake Bienne, La Neuveville, Canton of Berne, Switzerland, October. Photographed for The Freshwater Project.

Michel Roggo / Northern pike (Esox lucius) amongst Shining pondweed (Potamogeton lucens), Lake Neuchatel, near Boudry, Canton of Neuchatel, Switzerland. September. Photographed for The Freshwater Project.

Michel Roggo / Northern pike (Esox lucius) amongst Shining pondweed (Potamogeton lucens), Lake Neuchatel, near Boudry, Canton of Neuchatel, Switzerland. September. Photographed for The Freshwater Project.

Michel Roggo / Northern pike (Esox lucius) amongst Shining pondweed (Potamogeton lucens), Lake Neuchatel, near Boudry, Canton of Neuchatel, Switzerland. September. Photographed for The Freshwater Project.

Michel Roggo / Shining pondweed (Potamogeton lucens), Lake Neuchatel, near Boudry, Canton of Neuchatel, Switzerland. August. Photographed for The Freshwater Project.

Michel Roggo / Sago pondweed or Fennel pondweed, (Potamogeton pectinatus) Lake Neuchatel, close to Serrières, Canton of Neuchatel, Switzerland, July. Photographed for The Freshwater Project.

Michel Roggo / Sago pondweed or Fennel pondweed, (Potamogeton pectinatus) Lake Morat, close to Vallamand-Dessous, Canton of Fribourg, Switzerland, June. Photographed for The Freshwater Project.