751 articles
Permeameter
A permeameter is an apparatus that applies a known hydraulic gradient to water flowing through a soil sample, allowing its hydraulic conductivity to be determined.
Philippe Cousteau
Philippe Cousteau, also known as Philippe Pierre Cousteau, is an American ocean advocate and television producer born in 1980, son of Philippe Cousteau Sr. and grandson of Jacques-Yves Cousteau, who co-founded EarthEcho International.
Phoslock
Phoslock is a lanthanum-modified bentonite clay, about 95% bentonite and 5% lanthanum, that binds phosphorus in lakes and reservoirs to control eutrophication and cyanobacterial blooms.
Phosphorus limitation
Phosphorus limitation is the control of biological production by phosphorus supply, the principle that phosphorus, not nitrogen or carbon, governs algal blooms and eutrophication in lakes.
Phosphorus loading
Phosphorus loading is the quantity of phosphorus delivered to a water body per unit time, either from the watershed and atmosphere or released from lake sediments.
Phosphorus sorption
Phosphorus sorption is the attachment of dissolved phosphate to sediment and soil particle surfaces, a process that buffers phosphorus concentrations in streams, lakes, and estuaries and drives eutrophication.
Piezometer
A piezometer is an instrument or well that measures groundwater pressure at a specific point in the subsurface, commonly used to monitor seepage in dams.
Piri Reis
Piri Reis, born Ahmed Muhiddin Piri, was an Ottoman admiral and cartographer of the 1500s, best known for his 1513 world map and his sailing guide, the Kitab-ı Bahriye.
Plankton net
A plankton net is a cone- or cylinder-shaped device of fine mesh towed through water to filter and concentrate plankton, which collect in a bucket at the cod end.
Plymouth Marine Laboratory
Plymouth Marine Laboratory (PML) is an independent marine research charity in Plymouth, England, formed in 1988 by NERC, known for ocean acidification research and long-term ocean monitoring since 1903.
Polish Hydrobiological Society
The Polish Hydrobiological Society (Polskie Towarzystwo Hydrobiologiczne, PTH) is a Polish scientific association founded in 1959 that supports research in hydrobiology, the study of aquatic organisms.
Polynya (полынья)
A polynya (полынья), from Russian, is an opening of persistent or recurring open water within sea ice; coastal polynyas produce about 10% of Antarctic sea ice.
Poroelastic model
A poroelastic model is a continuum-mechanics description coupling fluid flow in a deformable porous solid to elastic stress and strain, based on Biot's 1941 consolidation theory.
Pororoca
Pororoca: the tidal bore of the Amazon River, waves up to 4 m traveling 800 km upstream during spring tides, February-March; famous for river surfing, the 37-minute record ride, and preventing an Amazon delta.
Porous media model
A porous media model is a continuum approach representing fluid flow and solute transport through soils and rocks using averaged parameters like porosity and permeability.
Potential evapotranspiration
Potential evapotranspiration (PET) is the maximum quantity of water a well-watered vegetation cover can lose as vapor in a given climate, combining soil evaporation and plant transpiration.
Preferential flow
Preferential flow is the movement of water and solutes through a small fraction of the pore network, such as roots, burrows, and cracks, bypassing most of the soil matrix.
Pressure ridge (ice)
A pressure ridge is a wall of broken sea ice pushed up and down when ice floes compress, with a sail above water and a much larger keel below.
Probable maximum flood
The probable maximum flood (PMF) is the flood resulting from the most severe meteorological and hydrologic conditions reasonably possible for a drainage basin, used as the upper-limit design flood for high-hazard dams.
Probable maximum precipitation
Probable maximum precipitation (PMP) is the greatest rainfall depth meteorologically possible at a location, the design basis for extreme floods at dams and nuclear plants.
Project Azorian
Project Azorian, also known as Project Jennifer, was a secret CIA operation during the Cold War to raise the sunken Soviet submarine K-129, lost with all hands in 1968.
Project Mohole
Project Mohole (1957–1966) was an American scientific program led by the American Miscellaneous Society that attempted to drill through the oceanic crust to the Mohorovičić discontinuity.
Pumping test
A pumping test pumps a well at a regulated rate while measuring water levels in observation wells to estimate aquifer properties such as transmissivity and storativity.
Pycnocline
A pycnocline is the ocean layer where water density changes most rapidly with depth, typically caused by temperature or salinity gradients, which restricts vertical mixing and stabilizes the water column.
Quicksand
Quicksand, also known as sinking sand, is sand saturated with water so that it flows like a liquid; people sink only to about the waist.
QuikSCAT
QuikSCAT (Quick Scatterometer) was a NASA satellite carrying the SeaWinds scatterometer, which measured ocean surface winds from its launch in 1999 until an antenna failure in 2009.
R/V Falkor
R/V Falkor was an 82.9-meter oceanographic research vessel operated by the Schmidt Ocean Institute from 2012 to 2022, converted from a German fisheries protection vessel and donated to Italy in 2022.
R/V Kaimei
R/V Kaimei (かいめい) is a Japanese seafloor wide-area research vessel built in 2016 and operated by JAMSTEC for broad, integrated surveys of the seafloor and strata beneath it.
R/V Meteor
R/V Meteor is a German multidisciplinary ocean research vessel, the third of three ships named Meteor, built in 1986 and owned by the Federal Republic of Germany.
R/V Mirai
R/V Mirai (みらい, "future") was a Japanese oceanographic research vessel of JAMSTEC, converted from the nuclear ship Mutsu, which completed 268 voyages from 1997 until retirement in 2025.