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CrustalTrudger t1_j1hpehn wrote

As others have indicated, yes, fossils of deep sea organisms tend to be more rare, or at least are not as well represented as fossils in shallow marine or continental slope areas. The primary reasons for this is subduction of oceanic lithosphere and the general depositional history that characterizes these environments (e.g., Holland, 2016). As highlighted in this paper (and generally in many paleontology textbooks), the fossil record is relatively biased toward organisms that were deposited in environments that have a higher preservation potential (of which the deep sea, along with extremely erosive environments etc., is not one). An additional influence, depending on the geologic period and the type of fossil in question, that can influence preservation of deep sea fossils is the carbonate compensation depth, i.e., basically the depth below which carbonate begins to preferentially dissolve (there is a similar depth for aragonite). Given that the preserved part of many marine invertebrates are their calcite or aragonite hard parts, areas of the sea floor below the CCD are not conducive to preservation of their remains.