biogenic sediments

Ode to copepods and fecal pellets

"Copepods are probably the most abundant multicellular organisms on earth. They outnumber the insects although insects are more diverse having more species than copepods. Humes (1994) estimated that there are some 11,500 species of copepods divided into approximately 200 families and 1650 genera."

Cyanobacteria

- Cell wall generally includes an outer layer of mucaceous material -Colonies may form large 'algae mats"

Biogenic Sediments: Organisms

- Cyanobacteria (aka "blue/green" algae): Bateria that obtain their energy through photosynthesis -Use water, Carbon Dioxide and light to manufacture their food - Bacteria are PROKARYOTIC cells -Algae are EUKARYOTIC cells (therefore, the term "blue/green algae" is no longer used to describe cyanpbacteria)

Biogenic Sediments: Organisms

- Microbes and other organisms form calcium carbonate - Cyanobacteria trap and bind thin layers of calcium carbonate - Phototactic calls then grow upward, through that layer - Sequential laminations accrete over time, resulting in the banded pattern common to stromatolites

OOIDS

-Concentric lamellae formed by abiotic chemical precipitation of CaCO3 in marine environments supersaturated with respect to calcium carbonate

Where will limestones form?

-Environments conducive to those organisms that produce calcium carbonate -Warm sub tropical to tropical marine waters -Environments characterized by low influx of clastic sediment..... areas far removed from influx of clastic sediment (silt, clay)

chemical precipitates

-Ooids -Speleothems -Calcareous Tufa -Salt pan / salt flat -Sabkha

Multi-cellular animals

-Sponges: opaline silica (PORIFERA) -Numerous Animal Groups: calcium carbonate (COLENTERATA, BRYOZOA, ECHINODERMATA, BRACHIOPODA, MOLLUSCA, ANTHROPODA)

Multi-cellular plants

-Various algal groups: clacium carbonate -Vascular plants: organic matter

Protist

A protist is a eukaryote that is either: - unicellular - multicellular without specialized tissues

Prokaryote versus Eukaryote

Prokaryote: single celled organism that lacks a membrane-bound nucleus or any membrane-bound organelles (such as mitochondria)(bacteria) Eukaryote: any organism having cells that contain a membrane bound nucleus and other membrane bound structures (organelles)

Organisms

Protists: +diatoms - plant- opaline silica +radiolarians - animal - calcium carbonate +coccolithophores - plant - calcium carbonate +foraminifera - animal - clacium carbonate

Biogenic Sediments: Minerals

Silica (SiO2) - opaline silica (SiO2 x H2O) Calcium Carbonate (CaCO3) - aragonite (orthorhombic) - calcite (trigonal = rhombohedral)

Large areas of the sea floor are covered with oozes of _________, _________, __________, _________ ..... and were in the geologic past

radiolaria, diatoms, foraminifera, coccoliths