Related by context. Frequent words. (Click for all words.) 60 rivers 58 deltas 56 river valleys 54 river basins 54 Coral reefs 54 glacial lakes 53 coral reefs 53 estuaries 53 lakes 53 freshwater ecosystems 52 coastal ecosystems 52 mud flats 52 freshwater lakes 52 glaciers 52 lowlands 52 flood plains 52 glacial melt 51 freshwater 51 flyways 51 coastlines 51 inundations 51 mountain glaciers 51 ecosystems 51 oceans 50 frequent droughts 50 floodplains 50 mangrove forests 50 tributaries 50 glacier melt 50 intertidal 50 landmass 50 fertile plains 50 freshwater mussels 49 reefs 49 coastal wetlands 49 freshwater wetlands 49 waterways 49 ecologies 49 croplands 49 Severe drought 49 biodiversity hotspots 49 seashores 49 drylands 49 subtropical regions 49 seamounts 48 arid regions 48 seagrasses 48 floods droughts 48 Droughts 48 salinity 48 biologically diverse 48 shorelines 48 Yangtze river 48 sea 48 wetland habitat 48 seagrass beds 48 Volcanic eruptions 48 coral atolls 48 archipelagos 47 melting glaciers 47 Mekong river 47 landmasses 47 floods 47 aquatic ecosystems 47 monsoon floods 47 mangroves 47 wetlands 47 marshes 47 habitats 47 subduction zones 47 freshwater fish 47 tidal surges 47 Tibetan Plateau 47 rivers lakes 47 inland 46 storm surges 46 terrestrial ecosystems 46 temperate zones 46 tsunamis 46 riverbanks 46 canals 46 mangrove swamps 46 marine ecosystems 46 biodiverse 46 salt marshes 46 mountain ranges 46 coral reef ecosystems 46 riverbeds 46 headwater 46 tropics 46 headwaters 46 coastal waters 46 fertile soils 46 marine biodiversity 46 semi arid 46 biota 46 savannas 46 sandbars 46 megacities 46 river 46 tropical forests