Hydrologists & Hydrogeologists take care of our drinking and recreational river-, reservoir/lake-, and ground-waters. They protect and manage aquifers and wetland ecosystems, and assess flooding risks; design and construct water wells, irrigation schemes, construction drainage schemes and deal with groundwater problems associated with mining and other industry. They help to harness geothermal energy through groundwater-based heat pumps and analyze the sources of, and remediate, water pollution.

Marine Geoscientists & Oceanographers monitor the chemical composition of the ocean water, study pollution, or help find naturally occurring resources on the seafloor; they assess the movements of the oceans, in the waves, currents, and tides that move the water itself. Their knowledge of seabed geology helps siting of offshore rigs, and the construction of wind farms and emerging technologies such as tidal power.

Geomorphologists, Sedimentologists & Glaciologists examine the shallow substrate beneath our feet; the 'critical zone' where rock, soil, water, air and living organisms interact. As well as delineating industrial mineral deposits (sand and gravel), they study weathering, coastal and river erosion, siltation, landslides, subsidence, sinkholes, deglaciation and the thawing of frozen ground (permafrost) due to climate and other environmental change, and work toward their remediation.

Environmental Geoscientists examine soil, rock, and the flow of groundwater to prevent contamination and to develop safe landfills and underground waste-disposal sites; they may plan the clean up from leaking pipes or chemical spills, the remediation of abandoned industrial sites, and restoration of polluted wetlands and coasts or undertake environmental impact assessments of construction projects.

Geological Engineers & Structural Geologists map and investigate the geological properties (e.g. strength, brittleness, and inherent stresses of rocks, slope stability, subsidence and earthquake potential), particularly at drill- and construction sites before any excavations, foundations, or earthworks are started for large civil engineering projects (roads, buildings, bridges, dams, mines, tunnels, pipelines, wind turbines, etc).

Mineral Exploration Geologists identify the industrial minerals (silica, salt, potash, limestone, gypsum, etc.), metals (copper, nickel, zinc, gold, rare earths), and precious stones (diamonds, emeralds, etc) in rocks and sediments, and assess the economic viability of extracting these resources. They may monitor sample collection, preparation, and analysis of samples and enhance the processing of minerals from ores.

Mine Geologists: The extraction of metal commodities, precious stones, coal and oil sands, and industrial minerals requires that mining geologists continually assess and analyze geological data relating to resource quality and its location in order to advise on safe short-term and long-term open pit, quarry, or underground mine production plans, and for waste remediation and management.

Petroleum Geologists: Despite the urgent need to reduce our dependence on fossil fuels, new reserves still will be needed for where transport and power generation by fossil fuels cannot be replaced, and for lubricants, pharmaceuticals, and (non-single-use) plastics. These geoscientists locate natural gas and oil deposits, and work toward environmentally responsible extraction of these resources, including carbon storage and geothermal energy extraction.

Geophysicists interpret the data of the earth's tectonic moments and assess risks for earthquake-prone areas and for other geohazards. Many geophysicists work alongside the geoscientists listed above in the exploration of petroleum and minerals, assist in the assessment of surface and groundwater flow, contaminant movements and substrate irregularities, or aid the development of carbon storage and geothermal energy.

Geochemists use physical and inorganic chemistry to investigate the amount and distribution of chemical elements and their isotopes in rocks and minerals; analyse the age, nature and components of rock, minerals, soil, and other environmental samples. Many geochemists work alongside the geoscientists listed above to guide oil and mineral exploration, improve water quality, and remediate toxic waste sites.

Biogeochemists & Biogeologists work with the geoscientists listed above to investigate the cycling through the global environment of chemical elements, from essential 'nutrients' such as carbon, nitrogen and phosphorus, to toxic metals; they study the paleoecological aspects of ancient life forms, history and evolution of life, and establish a relative time frame for past geological and climatic events.