Id Identification Type Name Description Distinguishing Features Tags
57 Algae Algae
137 Algae Algal organic matter Generally amorphous, yellowish or brown or greenish brown, and typically embedding diatom frustules, carbonate minerals, fragmentary organic debris, diagenetic Fe-bearing minerals (sulfides and oxides), and other sediment components in a pigmented matrix.
100 Algae Charophyte Multicellular charophyte algae such as _Chara_ form calcium carbonate (calcite) encrustations on their surfaces. Transparent colorless to murky or stained with black. Nonpleochroic. High birefringence (small irregular calcite crystals). Irregular shapes include tubes and nodules. Moderate relief. _Chara_ is typically found in calcium-bicarbonate waters; other genera are found in fresher water. bumpy
128 Algae Chlorophyte
122 Algae Chrysophyte
63 Algae Coccolithophore
93 Algae Cyanobacteria When preserved, cyanobacterial remains have a characteristic blue-green pigment. Filaments may or may not be visible. Occur in zones of rapid deposition and anoxia, sometimes associated with diagenetic minerals also formed in reducing environments. Likeliest to be found in very recent sediments, as oxidation of pigments occurs rapidly. Blue-green
129 Algae Desmids
79 Algae Diatom Transparent colorless to slightly brown or red tinted. Nonpleochroic. Isotropic. Many different shapes; in two-dimensional view these may appear as circles, rectangles of varying aspect ratios, canoe-shapes, banana-shapes, etc. moderate relief. Occur in essentially all lakes and rivers, but may not be preserved in sediments due to high- or low-pH conditions or silica undersaturation of bottom waters. Isotropic
94 Algae Phacotus Transparent colorless spheres show white and occasionally pastel birefringence colors. A dark ragged "X" across the sphere (also described as a pinwheel, baseball seams) rotates as the stage is rotated. Phacotus is a lacustrine green alga with a calcite lorica, and can be abundant in temperate hardwater lakes. Lorica with two slightly different appearances in cross-polarized light (one sometimes with a red ring near the perimeter) may be views of the outside and inside of loricae, as they commonly separate after death. Circular
66 Algae Silicoflagellate

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