Related by context. Frequent words. (Click for all words.) 57 terrestrial ecosystems 51 ecosystems 50 biota 49 marine sediments 49 hydrological cycle 48 marine ecosystems 48 mountain glaciers 48 aquatic ecosystems 47 Arctic 47 eutrophication 47 IPY 47 marine biodiversity 46 ecology 46 subtropical regions 46 polar bear habitat 46 atmospheric circulation 46 aquatic habitats 46 intertidal 46 boreal 46 biome 46 biomes 46 forest ecosystems 45 harmful algal blooms 45 coastal ecosystems 45 freshwater ecosystems 45 ecosystem 45 boreal forests 45 Arctic Ocean 45 polar caps 45 megafauna 45 biodiversity hotspots 45 species extinctions 45 landforms 44 anthropogenic 44 species 44 glacial melt 44 extinctions 44 permafrost 44 Holocene 44 glaciers 44 paleontological 44 sediment cores 44 shrinking glaciers 44 temperate regions 43 calving grounds 43 ecologies 43 biosphere 43 polar regions 43 geological formations 43 habitats 43 avian species 43 transboundary 43 Volcanic eruptions 43 ocean ecosystems 43 circumpolar 43 lake sediments 43 mid latitudes 43 Salish Sea 43 waterbirds 43 climatically 43 Pleistocene 43 biodiversity 43 diatoms 43 Little Ice Age 43 storminess 43 Serreze 42 melting permafrost 42 biologically diverse 42 habitat fragmentation 42 bioprospecting 42 caribou herd 42 latitudes 42 coral reef ecosystems 42 equatorial Pacific 42 oxygen depletion 42 Ecosystems 42 greenhouse warming 42 geologic formations 42 overhunting 42 boreal forest 42 ocean acidity 42 tectonics 42 ecologically 42 oceans 42 El Ninos 42 ecological 41 Pliocene 41 ocean acidification 41 aquatic ecosystem 41 gas hydrates 41 freshwater lakes 41 glaciation 41 landmasses 41 biosphere reserve 41 woodland caribou 41 Greenland 41 vertebrate species 41 Tibetan Plateau 41 speciation 41 icecap 41 decadal