Pollen analysis
Encyclopedia
Analysis of the distribution of pollen
grains of various species contained in surface layer
deposits, especially peat bogs and lake sediment
s, from which a record of past climate
may be inferred. Because the lake sediments accumulate over time, a core of the mud will show that the mud at the bottom will be the oldest and the mud at the top will be the newest. By separating the samples of the core, we can get a record of how the vegetation
around that site has changed. This has shown us that the area around the Great Lakes
was tundra
11,000 years ago.
For more details, please see the Palynology
entry.
when he presented a paper on fossil pollen grains in Swedish
bogs to the 1916 Scandinavian Scientist Conference
in Oslo
. The paper was repeated in the same year in Stockholm
but was not fully published until 1918. Antecedents of this work can be traced in the writings of scientists such as Früh (1885), who enumerated most of the common tree pollen types, together with a considerable number of spore
s and herb
pollen grains. In a study of bottom samples from Swedish lakes by Trybom (1888), Pinus (Pine) and Picea (Spruce) pollen was found in such profusion that he considered them to be serviceable as "index fossils". Georg F.L. Sarauw
studies fossil pollen of middle Pleistocene age (Cromerian) from the harbour of Copenhagen
. Lagerheim (in Witte 1905) and C.A.Weber (in H.A.Weber 1918) appear to be among the first to undertake percentage frequency calculations.
Pollen analysis was refined and developed by Johannes Iversen
and Knut Fægri
in their now classical textbook on the subject.
Pollen analysis enjoyed a popular period during the latter half of the 20th Century as the dominant method for investigations into the development of vegetation and climate during the Quaternary
period. It was perfected into a refined instrument of research, highly versatile and giving surprisingly intimate insights into conditions of the recent past.
Pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...
grains of various species contained in surface layer
Surface layer
The surface layer is the layer of a turbulent fluid most affected by interaction with a solid surface or the surface separating a gas and a liquid where the characteristics of the turbulence depend on distance from the interface...
deposits, especially peat bogs and lake sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
s, from which a record of past climate
Paleoclimatology
Paleoclimatology is the study of changes in climate taken on the scale of the entire history of Earth. It uses a variety of proxy methods from the Earth and life sciences to obtain data previously preserved within rocks, sediments, ice sheets, tree rings, corals, shells and microfossils; it then...
may be inferred. Because the lake sediments accumulate over time, a core of the mud will show that the mud at the bottom will be the oldest and the mud at the top will be the newest. By separating the samples of the core, we can get a record of how the vegetation
Vegetation
Vegetation is a general term for the plant life of a region; it refers to the ground cover provided by plants. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic characteristics. It is broader...
around that site has changed. This has shown us that the area around the Great Lakes
Great Lakes
The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...
was tundra
Tundra
In physical geography, tundra is a biome where the tree growth is hindered by low temperatures and short growing seasons. The term tundra comes through Russian тундра from the Kildin Sami word tūndâr "uplands," "treeless mountain tract." There are three types of tundra: Arctic tundra, alpine...
11,000 years ago.
For more details, please see the Palynology
Palynology
Palynology is the science that studies contemporary and fossil palynomorphs, including pollen, spores, orbicules, dinoflagellate cysts, acritarchs, chitinozoans and scolecodonts, together with particulate organic matter and kerogen found in sedimentary rocks and sediments...
entry.
History
Modern pollen analysis dates back to Lennart von PostLennart von Post
Ernst Jakob Lennart von Post was a Swedish naturalist and geologist. He was the first to publish quantitative analysis of pollen and is counted as one of the founders of palynology. He was a professor at Stockholm University 1929-1950.-Early life:Lennart von Post was born in Johannesberg, near...
when he presented a paper on fossil pollen grains in Swedish
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
bogs to the 1916 Scandinavian Scientist Conference
Scandinavian Scientist Conference
The Scandinavian Scientist Conferences was a series of meetings 1839-1936 for scientist and physicists from Denmark, Norway and Sweden, later also Finland and Iceland, in the era Scandinavism...
in Oslo
Oslo
Oslo is a municipality, as well as the capital and most populous city in Norway. As a municipality , it was established on 1 January 1838. Founded around 1048 by King Harald III of Norway, the city was largely destroyed by fire in 1624. The city was moved under the reign of Denmark–Norway's King...
. The paper was repeated in the same year in Stockholm
Stockholm
Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...
but was not fully published until 1918. Antecedents of this work can be traced in the writings of scientists such as Früh (1885), who enumerated most of the common tree pollen types, together with a considerable number of spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...
s and herb
Herb
Except in botanical usage, an herb is "any plant with leaves, seeds, or flowers used for flavoring, food, medicine, or perfume" or "a part of such a plant as used in cooking"...
pollen grains. In a study of bottom samples from Swedish lakes by Trybom (1888), Pinus (Pine) and Picea (Spruce) pollen was found in such profusion that he considered them to be serviceable as "index fossils". Georg F.L. Sarauw
Georg F.L. Sarauw
Georg Frederik Ludvig Sarauw was a Danish-Swedish botanist and archaeologist. He discovered the Maglemosian culture and was among the first to study fossil pollen.- Early life :...
studies fossil pollen of middle Pleistocene age (Cromerian) from the harbour of Copenhagen
Copenhagen
Copenhagen is the capital and largest city of Denmark, with an urban population of 1,199,224 and a metropolitan population of 1,930,260 . With the completion of the transnational Øresund Bridge in 2000, Copenhagen has become the centre of the increasingly integrating Øresund Region...
. Lagerheim (in Witte 1905) and C.A.Weber (in H.A.Weber 1918) appear to be among the first to undertake percentage frequency calculations.
Pollen analysis was refined and developed by Johannes Iversen
Johannes Iversen
Johannes Iversen was a Danish palaeoecologist and plant ecologist. He was born in Sønderborg and began studies in botany at the University of Copenhagen in 1923 under professor C.H. Ostenfeld, and with considerable inspiration from prof.em. Christen Raunkiær. At first he worked with macrophyte...
and Knut Fægri
Knut Fægri
Knut Fægri was a Norwegian botanist and palaeoecologist.- Academic career :Fægri was born in Bergen, and took the dr.philos. degree in 1934 with the thesis Über die Längenvariationen einiger Gletscher des Jostedalsbre und die dadurch bedingten Pflanzensukzessionen. He was hired as a research...
in their now classical textbook on the subject.
Pollen analysis enjoyed a popular period during the latter half of the 20th Century as the dominant method for investigations into the development of vegetation and climate during the Quaternary
Quaternary
The Quaternary Period is the most recent of the three periods of the Cenozoic Era in the geologic time scale of the ICS. It follows the Neogene Period, spanning 2.588 ± 0.005 million years ago to the present...
period. It was perfected into a refined instrument of research, highly versatile and giving surprisingly intimate insights into conditions of the recent past.