Pelagic sediments primarily consist of material from what source?

Pelagic sediments are primarily composed of the remains of dead marine organisms and plankton. This organic material accumulates on the ocean floor, contributing to the sedimentary composition found in the deep-sea environment. The process involves the continuous sinking of microscopic life forms such as phytoplankton and zooplankton, which die and settle after their lifecycle. This organic contribution is substantial, especially in areas where these organisms thrive, like the photic zone, and drives the biological productivity of oceanic regions.

Land erosion and river transport play a significant role in sediment distribution within coastal regions and continental margins, but they do not primarily account for the composition of deep-sea pelagic sediments. Similarly, glacial and ice melt runoff can introduce various materials into the ocean, but this is more relevant to sedimentation in polar regions rather than the broad pelagic environment. Ocean water and diffuse nutrients, while crucial for the survival of pelagic organisms, do not directly contribute to the solid sediment material that characterizes pelagic sediments.