> [!summary] Progressive Summary > Didn't read the chapter on crickets. Everything else was great. Lyrical prose. # Structured Notes ## Definitions bathyscope - bucket with a clear bottom for looking at riverbeds ## Chapter Summaries ### Mussel A single mussel can filter up to 50 L of water a day. > By bringing lucidity to its world, the mussel allows light to reach the bottom of the river, which in turn powers the lives of submerged aquatic plants. The mussels excrete their faeces on the riverbed, providing fertiliser for the plants and insect larvae. The plants provide food for shrimp, snails, minnows and scores of insects. Mussels have been an important food source for us. In South Africa, there is a mega midden called Mussel Point that measures 350m long and 200m wide. In Bulgaria, a terracotta figure dating back 5000 BCE was discovered near the village of Dolnoslav, and its eyes are made of mother-of-pearl. Mussels can live to over 100 years. We can tell their age by counting the rings in its shell. The Freshwater Pearl Mussel is the only freshwater creature known to form pearls. Pearls are "lustrous answers to the shock of being alive." They are formed when a particle enters the mussel, and it secretes a substance called nacre around it. Mussel populations across Europe have been decimated, declining by as much as 95 per cent in some places. During the spring and summer, male mussels release their sperm into the river. Some of the sperm find their way into female mussels, fertilising their eggs. On the same day, all the females release millions of larvae known as glochidia. The larvae attach themselves to the gills of juvenile trout and salmon, where they will grow for months. (The glochidia are irritants, and the trout and salmon form a cyst around them, in a process called encystment). The trout and salmon also help ferry them upstream, otherwise the mussels would be carried out to sea. All this complexity only happens when the river has the right conditions. Due to human impacts, these conditions no longer exist in a lot of places. Deforestation in uplands causes more silt to enter the rivers, changing the sedimentation load. Synthetic fertilisers and sewage discharge also alter the chemical composition of the river. An uprooting of being: > All around the country, mussels were being untenanted from their homelands, and it was an uprooting being experienced by other animals too, with a thousand terrible variations. > The disappearance of a species is always a plural event, because it involves the unravelling of an interconnected world. > The loss of one species is always a loss for others. # Quotes # References