Fossil remains of dinoflagellates consist primarily of the nonmotile or cyst stage. Dinoflagellate cysts are common in most sediment samples from the Chesapeake Bay. They are useful in documenting temporal trends in Chesapeake
Fossil remains of dinoflagellates consist primarily of the nonmotile or cyst stage. Dinoflagellate cysts are common in most sediment samples from the Chesapeake Bay. They are useful in documenting temporal trends in Chesapeake phytoplankton during climatic changes in the Holocene, as well as during the postcolonial period of 19th century agricultural land clearance and 20th century fertilizer application and urbanization.
Dried sediment samples, weighing between 4.0 and 7.0 grams, were prepared for palynological analysis by decalcifying with dilute (i.e. 10%) hydrochloric acid and then neutralizing (to a pH of 7) with deionized water to remove carbonates. After neutralization, hydrofluoric acid (52% by volume) was added to each sample and the resulting mixture was allowed to rest at room temperature for ~48 hours. After resting, the samples were rinsed with deionized water into 50 milliliter (ml) centrifuge tubes. A 10 ml solution of acetic anhydride and sulfuric acid, in a ratio of 9:1, was added to each sample. Samples were heated in a water bath at 100°C for 10 minutes after which, 25 ml glacial acetic acid was added to each sample to arrest the reaction. The samples were then treated with 25 ml solution of 10% potassium hydroxide and heated to 70°C in a water bath.
The samples were then centrifuged with a Damer/IEC Model K centrifuge at 1500 rpm and washed until neutralized to a pH of 7. If the samples contained sand, heavy minerals, or organic material, they were centrifuged at 500 rpm for 20 minutes and then at 1500 rpm for 10 minutes with 3 ml zinc chloride, a heavy liquid with