A pollen core is a

core sample A core sample is a cylindrical section of (usually) a naturally-occurring substance. Most core samples are obtained by drilling with special drills into the substance, such as sediment or rock, with a hollow steel tube, called a core drill. The h ...

of a medium containing a

stratigraphic Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostrati ...

sequence of

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...

. Analysis of the type and frequency of the pollen in each layer is used to study changes in climate or land use using regional vegetation as a proxy. This analysis is conceptually comparable to the study of

ice core An ice core is a core sample that is typically removed from an ice sheet or a high mountain glacier. Since the ice forms from the incremental buildup of annual layers of snow, lower layers are older than upper ones, and an ice core contains ic ...

Methods

Cores are obtained from deposits where pollen is likely to have been trapped. Cores are generally obtained from

lacustrine A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...

sediments and

peat Peat (), also known as turf (), is an accumulation of partially decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, moors, or muskegs. The peatland ecosystem covers and is the most efficien ...

bog A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and muskeg; a ...

s although soil sediments may also be obtained. Degradation of the pollen exine and

bioturbation Bioturbation is defined as the reworking of soils and sediments by animals or plants. It includes burrowing, ingestion, and defecation of sediment grains. Bioturbating activities have a profound effect on the environment and are thought to be a pr ...

may reduce the quality of the pollen grains and stratigraphy of the core so researchers frequently select locations where the sediments are under

anaerobic Anaerobic means "living, active, occurring, or existing in the absence of free oxygen", as opposed to aerobic which means "living, active, or occurring only in the presence of oxygen." Anaerobic may also refer to: * Anaerobic adhesive, a bonding a ...

conditions. The cores are then subjected to

pollen analysis Palynology is the "study of dust" (from grc-gre, παλύνω, palynō, "strew, sprinkle" and ''-logy'') or of "particles that are strewn". A classic palynologist analyses particulate samples collected from the air, from water, or from deposits ...

palynologist Palynology is the "study of dust" (from grc-gre, παλύνω, palynō, "strew, sprinkle" and ''-logy'') or of "particles that are strewn". A classic palynologist analyses particulate samples collected from the air, from water, or from deposits ...

s who are able to infer the proportions of major plant types from the concentrations of different pollen types found in the cores.

Coring Equipment

There are a number of tools used for coring, often with specialized uses:

Core Samplers

*Glew Corer: A gravity corer used for lake surface sediments to capture the water-sediment interface. Similar to the Kajak-Brinkhurst sampler. *Brown Corer: *Frozen Finger: A tube is placed into the sediment and then filled with

liquid nitrogen Liquid nitrogen—LN2—is nitrogen in a liquid state at low temperature. Liquid nitrogen has a boiling point of about . It is produced industrially by fractional distillation of liquid air. It is a colorless, low viscosity liquid that is wide ...

causing the sediment around the tube to freeze solid, preserving fine scale structure. *Livingstone Piston Corer: A long metal tube with a piston at the lower end. Once the core tube is at the desired depth the piston is released and the barrel can be pushed downwards into the sediment. Generally used for lake sediments. *Russian: A chamber corer used to sample

Grab Samplers

*Ekman Grab Sampler: *Petersen Grab: *Ponar Grab: {{DEFAULTSORT:Pollen Core Pollination Palynology