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Volume 27.1
January–April 2024
Full table of contents
ISSN: 1094-8074, web version;
1935-3952, print version
Recent Research Articles
See all articles in 27.1 January-April 2024
See all articles in 26.3 September-December 2023
See all articles in 26.2 May-August 2023
See all articles in 26.1 January-April 2023
Relative abundances calculated for each sample and core.
Part 1.
M77/2-59-1 | late Holocene | early Holocene | BA/ACR | Heinrich Stadial-1 | ||||||||||||||||
Species / Age (cal yr BP) |
3024 | 3413 | 3801 | 4178 | 4531 | 4877 | 8098 | 8596 | 9095 | 9594 | 10093 | 13112 | 13504 | 13867 | 14230 | 14569 | 15080 | 15643 | 16330 | 17065 |
Alabaminella weddellensis | 4.85 | 5.96 | 5.45 | 4.50 | 5.77 | 4.17 | 3.03 | 4.35 | 2.64 | 3.10 | 2.67 | 0.00 | 0.00 | 0.38 | 0.00 | 0.00 | 0.44 | 0.00 | 0.00 | 0.00 |
Anomalinoides minimus | 3.00 | 3.34 | 3.50 | 5.03 | 2.54 | 3.79 | 4.33 | 4.35 | 4.70 | 3.53 | 5.08 | 3.11 | 0.23 | 0.57 | 0.69 | 0.63 | 0.29 | 0.00 | 0.00 | 0.00 |
Bolivina interjuncta var. bicostata | 0.57 | 0.73 | 0.00 | 0.53 | 0.46 | 0.19 | 0.43 | 1.16 | 1.17 | 1.21 | 1.60 | 6.99 | 3.97 | 4.39 | 3.45 | 2.83 | 5.84 | 4.05 | 4.84 | 3.93 |
Bolivina pacifica | 0.00 | 0.00 | 0.39 | 0.00 | 0.23 | 0.19 | 0.43 | 0.00 | 0.15 | 0.52 | 0.40 | 0.78 | 2.10 | 4.77 | 5.86 | 5.03 | 1.61 | 2.02 | 3.96 | 5.36 |
Bolivina quadrata | 0.14 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.87 | 0.87 | 1.03 | 1.03 | 1.60 | 4.50 | 3.50 | 6.87 | 1.38 | 2.83 | 1.75 | 0.00 | 3.96 | 3.39 |
Bolivinita minuta | 21.83 | 21.80 | 29.57 | 22.49 | 20.09 | 13.64 | 12.12 | 16.81 | 16.74 | 19.83 | 20.32 | 18.94 | 9.11 | 5.92 | 2.76 | 0.63 | 10.80 | 3.85 | 1.32 | 0.36 |
Cassidulina carinata | 2.71 | 3.78 | 5.06 | 6.08 | 8.31 | 5.11 | 5.19 | 8.70 | 6.75 | 6.21 | 6.42 | 5.28 | 5.37 | 7.63 | 0.00 | 1.89 | 4.38 | 7.29 | 8.79 | 4.82 |
Cassidulina delicata | 9.70 | 11.92 | 11.28 | 12.17 | 9.93 | 12.88 | 13.42 | 8.41 | 11.89 | 12.33 | 8.16 | 2.80 | 7.01 | 3.63 | 4.14 | 3.77 | 7.74 | 15.59 | 7.69 | 10.00 |
Cassidulina minuta | 8.27 | 4.22 | 0.00 | 1.59 | 4.85 | 2.27 | 0.00 | 4.06 | 1.17 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.44 | 0.00 | 0.00 | 0.00 |
Epistominella afueraensis | 0.00 | 0.00 | 1.56 | 0.00 | 0.00 | 4.36 | 1.30 | 5.80 | 2.94 | 1.47 | 1.07 | 2.95 | 1.87 | 0.19 | 0.00 | 0.63 | 0.00 | 0.00 | 0.66 | 0.00 |
Epistominella exigua | 5.56 | 5.67 | 5.45 | 8.20 | 5.77 | 6.63 | 7.79 | 7.54 | 8.66 | 10.17 | 8.02 | 11.96 | 10.75 | 15.08 | 21.38 | 16.35 | 17.08 | 9.11 | 13.19 | 22.68 |
Epistominella obesa | 2.57 | 3.05 | 1.56 | 3.70 | 5.08 | 0.95 | 0.00 | 0.00 | 0.00 | 1.81 | 0.94 | 0.78 | 3.74 | 2.10 | 4.48 | 3.14 | 2.77 | 3.24 | 1.76 | 1.61 |
Epistominella pacifica | 0.71 | 1.45 | 0.39 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 1.17 | 0.95 | 2.67 | 0.00 | 2.57 | 6.30 | 5.52 | 0.00 | 2.19 | 2.02 | 1.76 | 0.89 |
Epistominella smithi | 0.00 | 0.00 | 0.00 | 0.00 | 0.23 | 0.19 | 0.00 | 0.29 | 0.00 | 0.00 | 0.00 | 4.97 | 5.84 | 0.00 | 0.00 | 4.40 | 3.50 | 2.83 | 5.71 | 5.00 |
Gyroidina rothwelli | 1.14 | 1.16 | 1.95 | 1.06 | 0.69 | 0.95 | 0.87 | 3.19 | 1.47 | 2.41 | 2.81 | 4.97 | 5.37 | 5.15 | 4.14 | 3.14 | 3.21 | 4.66 | 0.88 | 1.61 |
Uvigerina auberiana | 6.56 | 7.27 | 5.06 | 6.35 | 6.24 | 7.77 | 6.93 | 5.51 | 6.31 | 5.26 | 5.08 | 3.26 | 3.27 | 2.10 | 1.03 | 1.26 | 0.00 | 0.00 | 0.00 | 0.00 |
Uvigerina semiornata | 2.85 | 1.60 | 1.56 | 3.97 | 5.08 | 4.73 | 3.90 | 2.61 | 3.08 | 1.12 | 3.21 | 2.64 | 1.64 | 0.76 | 0.00 | 1.57 | 1.90 | 0.81 | 2.86 | 1.25 |
Virgulina spinosa | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.09 | 0.00 | 0.47 | 1.87 | 7.06 | 6.21 | 20.44 | 1.17 | 0.61 | 0.88 | 0.00 |
Miliolids | 0.14 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.15 | 0.09 | 0.27 | 0.16 | 0.00 | 0.00 | 0.00 | 0.00 | 0.29 | 0.00 | 0.66 | 0.18 |
Other calcareous | 29.24 | 28.05 | 27.24 | 24.34 | 24.48 | 32.20 | 39.39 | 26.38 | 29.96 | 28.88 | 29.68 | 25.47 | 31.78 | 27.10 | 38.97 | 31.45 | 34.60 | 43.93 | 41.10 | 38.93 |
Agglutinated | 0.14 | 0.00 | 0.00 | 0.00 | 0.23 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
Total number specimens | 701 | 688 | 257 | 378 | 433 | 528 | 231 | 345 | 681 | 1160 | 748 | 644 | 428 | 524 | 290 | 318 | 685 | 494 | 455 | 560 |
Total number species | 57 | 71 | 40 | 48 | 51 | 56 | 45 | 50 | 67 | 70 | 63 | 52 | 51 | 54 | 43 | 49 | 56 | 49 | 52 | 53 |
Part 2.
M77/2-52-2 | late Holocene | early Holocene | BA/ACR | Heinrich Stadial-1 | Last Glacial Max | ||||||||||||||||||||||
Species / Age (cal yr BP) | 3130 | 3845 | 4202 | 4559 | 4917 | 8097 | 8486 | 8839 | 9192 | 9546 | 9899 | 12714 | 13177 | 13641 | 14143 | 14465 | 15147 | 15469 | 16151 | 16653 | 17155 | 17657 | 20168 | 20670 | 21172 | 21674 | 22176 |
Bolivina costata | 27.12 | 33.88 | 25.50 | 33.81 | 23.13 | 42.46 | 22.96 | 20.85 | 18.98 | 23.13 | 17.32 | 4.35 | 1.15 | 1.00 | 5.23 | 2.34 | 0.88 | 1.35 | 0.90 | 2.24 | 0.74 | 1.38 | 4.15 | 4.60 | 4.56 | 3.66 | 6.04 |
Bolivina spissa | 4.24 | 4.47 | 6.19 | 3.57 | 3.06 | 6.36 | 4.14 | 3.64 | 4.92 | 6.22 | 5.08 | 4.35 | 3.93 | 2.99 | 3.35 | 2.05 | 4.84 | 2.12 | 4.30 | 2.52 | 1.98 | 2.75 | 0.98 | 1.02 | 1.45 | 0.37 | 0.15 |
Bolivinita minuta | 1.69 | 1.88 | 2.23 | 1.67 | 3.40 | 2.21 | 5.80 | 3.24 | 4.92 | 3.84 | 5.77 | 11.84 | 19.86 | 4.23 | 6.90 | 1.46 | 3.96 | 1.54 | 4.52 | 1.12 | 0.74 | 0.79 | 0.37 | 0.26 | 0.00 | 0.18 | 0.15 |
Bulimina pagoda | 0.00 | 0.71 | 0.99 | 1.43 | 0.68 | 0.41 | 0.59 | 0.81 | 0.00 | 0.00 | 0.00 | 1.21 | 0.69 | 1.00 | 1.05 | 0.88 | 1.10 | 0.19 | 0.00 | 0.84 | 0.50 | 0.79 | 5.73 | 3.32 | 6.01 | 3.84 | 6.50 |
Cassidulina carinata | 0.00 | 1.65 | 1.73 | 0.95 | 4.08 | 0.00 | 1.78 | 0.00 | 0.51 | 0.73 | 1.39 | 2.42 | 2.08 | 6.97 | 4.60 | 4.39 | 4.84 | 3.08 | 0.45 | 3.36 | 4.95 | 2.75 | 8.29 | 23.27 | 9.12 | 10.42 | 7.28 |
Cassidulina delicata | 7.63 | 5.88 | 7.18 | 7.38 | 8.84 | 8.44 | 15.50 | 10.53 | 12.03 | 11.83 | 20.55 | 12.80 | 8.78 | 15.17 | 12.13 | 9.94 | 7.47 | 6.92 | 6.33 | 9.52 | 6.93 | 13.75 | 8.41 | 5.63 | 8.29 | 5.67 | 14.86 |
Cassidulina laevigata | 0.85 | 0.00 | 0.00 | 0.48 | 0.00 | 0.28 | 0.00 | 0.81 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.25 | 0.00 | 0.00 | 0.00 | 0.38 | 1.36 | 0.00 | 0.00 | 2.36 | 0.98 | 0.00 | 3.11 | 6.95 | 14.09 |
Cibicides mckannai | 0.42 | 3.29 | 2.72 | 2.38 | 1.02 | 4.43 | 1.54 | 3.64 | 4.24 | 3.22 | 2.54 | 4.59 | 6.70 | 6.72 | 3.56 | 1.46 | 3.30 | 1.15 | 2.26 | 1.12 | 0.99 | 1.96 | 1.95 | 0.26 | 1.66 | 0.18 | 1.24 |
Epistominella exigua | 7.63 | 3.06 | 2.97 | 6.67 | 9.86 | 0.00 | 2.25 | 1.62 | 1.69 | 1.76 | 3.70 | 3.38 | 2.77 | 1.99 | 4.18 | 9.36 | 13.19 | 23.27 | 22.17 | 25.49 | 31.19 | 33.01 | 0.98 | 10.23 | 0.62 | 5.12 | 3.56 |
Epistominella pacifica | 1.69 | 4.47 | 0.00 | 0.00 | 3.40 | 1.38 | 6.51 | 6.28 | 7.29 | 6.95 | 2.54 | 4.11 | 5.08 | 8.21 | 2.51 | 0.88 | 3.52 | 6.35 | 3.62 | 2.24 | 1.98 | 1.96 | 0.00 | 0.00 | 0.21 | 1.10 | 2.17 |
Epistominella smithi | 3.39 | 4.24 | 7.43 | 6.67 | 3.06 | 2.35 | 0.00 | 0.00 | 0.00 | 0.93 | 2.77 | 6.28 | 8.08 | 1.74 | 8.58 | 11.40 | 6.81 | 4.62 | 3.85 | 4.48 | 6.44 | 1.77 | 10.12 | 5.88 | 4.97 | 4.02 | 2.32 |
Uvigerina auberiana | 7.63 | 9.88 | 10.64 | 8.57 | 9.18 | 5.67 | 5.44 | 5.87 | 4.58 | 4.67 | 5.77 | 6.04 | 5.54 | 5.47 | 4.81 | 6.14 | 2.42 | 2.69 | 2.71 | 3.08 | 0.50 | 2.75 | 7.68 | 5.63 | 7.25 | 5.85 | 5.88 |
Uvigerina bifurcata | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.62 | 0.00 | 0.00 | 1.15 | 0.00 | 1.26 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 4.63 | 3.07 | 8.91 | 0.00 | 0.00 |
Uvigerina peregrina | 0.00 | 0.94 | 0.00 | 0.00 | 0.00 | 0.00 | 1.18 | 1.21 | 1.19 | 0.83 | 0.00 | 0.00 | 0.92 | 0.00 | 1.26 | 0.88 | 0.66 | 0.58 | 2.04 | 0.28 | 0.00 | 0.00 | 2.32 | 4.09 | 5.60 | 10.05 | 5.73 |
Uvigerina semiornata | 8.05 | 6.82 | 8.42 | 8.10 | 6.12 | 5.39 | 5.56 | 8.91 | 10.85 | 4.67 | 3.46 | 7.00 | 5.54 | 11.44 | 4.60 | 7.60 | 10.55 | 4.23 | 6.11 | 8.68 | 5.69 | 6.29 | 17.20 | 5.88 | 6.53 | 3.66 | 6.04 |
Miliolids | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.14 | 0.00 | 0.00 | 0.34 | 0.00 | 0.23 | 0.00 | 0.46 | 0.00 | 0.42 | 0.29 | 0.22 | 0.00 | 0.23 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.31 | 0.37 | 0.00 |
Other calcareous | 28.39 | 16.94 | 21.78 | 16.19 | 22.11 | 19.92 | 25.80 | 31.78 | 27.80 | 30.08 | 28.41 | 30.92 | 25.87 | 32.84 | 35.15 | 40.35 | 35.82 | 40.96 | 38.69 | 34.17 | 37.38 | 26.92 | 26.10 | 26.85 | 31.40 | 38.57 | 23.84 |
Agglutinated species | 1.27 | 1.88 | 2.23 | 2.14 | 2.04 | 0.55 | 0.95 | 0.81 | 0.68 | 0.52 | 0.46 | 0.72 | 1.39 | 0.00 | 0.42 | 0.58 | 0.44 | 0.58 | 0.45 | 0.84 | 0.00 | 0.79 | 0.12 | 0.00 | 0.00 | 0.00 | 0.15 |
Total number specimens | 236 | 425 | 404 | 420 | 294 | 723 | 845 | 494 | 590 | 964 | 433 | 414 | 433 | 402 | 478 | 342 | 455 | 520 | 442 | 357 | 404 | 509 | 820 | 391 | 965 | 547 | 646 |
Total number species | 45 | 48 | 50 | 41 | 48 | 53 | 62 | 67 | 60 | 77 | 46 | 60 | 50 | 53 | 69 | 67 | 59 | 63 | 50 | 51 | 45 | 50 | 76 | 50 | 75 | 73 | 70 |
Part 3.
M77/2-50-4 | BA/ACR | Heinrich Stadial-1 | Last Glacial Max | |||||||||||||||||
Species / Age (cal yr BP) |
12873 | 13502 | 14131 | 14377 | 14622 | 14868 | 15359 | 15850 | 16341 | 16832 | 17215 | 17598 | 20095 | 20359 | 20623 | 20900 | 21178 | 21455 | 21733 | 22010 |
Bolivina costata | 39.30 | 28.85 | 43.63 | 44.31 | 32.44 | 25.06 | 30.97 | 26.58 | 12.08 | 5.85 | 11.38 | 6.52 | 17.22 | 7.60 | 11.18 | 9.43 | 9.13 | 8.30 | 10.14 | 10.71 |
Bolivina pacifica | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.76 | 0.00 | 0.21 | 0.67 | 0.00 | 5.33 | 4.67 | 0.37 | 0.58 | 0.63 | 2.20 | 0.48 | 0.53 | 0.62 | 0.74 |
Bolivina seminuda var. humilis | 1.08 | 3.13 | 4.54 | 4.19 | 2.89 | 4.79 | 5.51 | 5.91 | 6.26 | 4.68 | 5.57 | 3.12 | 3.30 | 5.85 | 3.80 | 6.72 | 5.77 | 3.36 | 2.96 | 2.98 |
Bolivinita minuta | 10.03 | 6.73 | 3.32 | 1.20 | 4.44 | 3.02 | 1.31 | 1.69 | 3.80 | 4.68 | 3.39 | 2.83 | 0.73 | 2.34 | 1.27 | 1.55 | 1.44 | 1.77 | 3.28 | 3.87 |
cf. Buccella peruviana | 0.00 | 0.00 | 2.09 | 1.80 | 0.00 | 0.50 | 0.52 | 1.05 | 0.00 | 0.00 | 0.00 | 2.69 | 0.37 | 0.00 | 2.11 | 3.88 | 1.92 | 1.59 | 1.56 | 5.36 |
Buliminella tenuata | 0.54 | 2.88 | 1.57 | 2.40 | 2.44 | 5.16 | 2.62 | 0.63 | 2.24 | 2.34 | 1.45 | 0.57 | 2.20 | 0.00 | 1.05 | 0.00 | 0.00 | 1.06 | 0.00 | 0.89 |
Cassidulina auka | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.76 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 5.13 | 1.75 | 2.32 | 3.23 | 5.77 | 4.59 | 1.40 | 1.04 |
Cassidulina carinata | 0.00 | 0.00 | 0.00 | 0.00 | 0.89 | 1.51 | 0.00 | 2.11 | 0.89 | 0.58 | 2.42 | 2.97 | 7.33 | 5.85 | 6.96 | 5.68 | 1.92 | 10.78 | 7.49 | 4.02 |
Cassidulina delicata | 8.40 | 8.65 | 4.01 | 2.99 | 5.11 | 4.66 | 6.82 | 3.59 | 11.19 | 8.77 | 7.02 | 6.09 | 6.59 | 5.26 | 9.49 | 7.75 | 13.94 | 8.30 | 7.49 | 7.74 |
Epistominella afueraensis | 7.05 | 1.20 | 2.09 | 2.40 | 0.00 | 6.30 | 0.79 | 1.48 | 4.25 | 4.09 | 2.91 | 1.42 | 2.20 | 1.17 | 0.63 | 1.03 | 1.44 | 2.47 | 0.16 | 0.45 |
Epistominella exigua | 2.44 | 2.64 | 1.75 | 4.19 | 3.78 | 2.52 | 0.00 | 3.16 | 5.59 | 7.02 | 6.78 | 14.16 | 1.83 | 8.77 | 4.43 | 9.82 | 1.44 | 7.77 | 12.17 | 8.18 |
Epistominella obesa | 0.00 | 1.92 | 3.14 | 6.59 | 6.44 | 6.17 | 7.35 | 6.96 | 18.34 | 7.02 | 12.11 | 8.50 | 12.45 | 14.62 | 10.13 | 10.59 | 10.58 | 8.13 | 2.50 | 9.08 |
Epistominella pacifica | 0.27 | 7.21 | 5.76 | 6.59 | 4.89 | 2.77 | 1.57 | 4.64 | 2.91 | 1.17 | 1.21 | 0.85 | 3.30 | 0.00 | 0.00 | 0.13 | 0.00 | 1.24 | 0.47 | 0.00 |
Epistominella smithi | 6.78 | 2.40 | 0.00 | 0.00 | 2.22 | 2.90 | 2.89 | 3.80 | 0.22 | 1.75 | 2.42 | 0.14 | 0.00 | 0.00 | 0.63 | 0.00 | 0.00 | 0.18 | 0.00 | 0.30 |
Fursenkoina fusiformis | 0.81 | 1.92 | 0.87 | 1.20 | 2.44 | 2.02 | 2.10 | 1.05 | 1.12 | 1.17 | 5.08 | 3.97 | 0.00 | 0.00 | 0.21 | 0.78 | 0.48 | 0.71 | 0.16 | 0.30 |
Pseudoparella subperuviana | 6.78 | 6.25 | 6.11 | 0.00 | 6.00 | 4.91 | 7.09 | 7.81 | 2.24 | 14.04 | 9.93 | 5.81 | 7.33 | 2.34 | 2.53 | 2.84 | 8.65 | 4.95 | 15.60 | 9.08 |
Pseudoparella sp. | 0.54 | 2.64 | 4.36 | 0.00 | 5.11 | 1.13 | 4.99 | 4.64 | 8.28 | 7.02 | 0.00 | 7.37 | 0.73 | 17.54 | 5.70 | 1.03 | 4.33 | 4.95 | 4.21 | 9.52 |
Uvigerina semiornata | 0.00 | 3.13 | 1.40 | 2.40 | 2.44 | 1.76 | 2.62 | 2.32 | 1.79 | 0.58 | 0.48 | 1.27 | 2.56 | 4.68 | 6.12 | 3.88 | 3.37 | 6.71 | 2.03 | 1.64 |
Virgulina cornuta | 0.00 | 0.00 | 0.70 | 2.40 | 1.11 | 1.89 | 1.84 | 0.84 | 0.89 | 1.75 | 5.57 | 5.38 | 2.20 | 1.17 | 1.69 | 0.39 | 0.48 | 1.24 | 0.62 | 0.74 |
Miliolids | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 1.17 | 0.24 | 0.14 | 1.10 | 1.17 | 0.63 | 0.78 | 0.96 | 0.53 | 0.31 | 0.30 |
Other calcareous | 15.99 | 20.43 | 14.66 | 17.37 | 17.33 | 21.41 | 21.00 | 21.52 | 17.23 | 26.32 | 16.71 | 21.39 | 22.71 | 19.30 | 28.48 | 28.16 | 27.88 | 20.85 | 26.83 | 22.92 |
Agglutinated species | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.14 | 0.37 | 0.00 | 0.00 | 0.13 | 0.00 | 0.00 | 0.00 | 0.15 |
Total number specimens | 236 | 425 | 404 | 420 | 294 | 723 | 845 | 494 | 590 | 964 | 433 | 414 | 433 | 402 | 478 | 342 | 455 | 520 | 442 | 357 |
Total number species | 45 | 48 | 50 | 41 | 48 | 53 | 62 | 67 | 60 | 77 | 46 | 60 | 50 | 53 | 69 | 67 | 59 | 63 | 50 | 51 |
Part 4.
M77/2-47-2 | BA/ACR | Heinrich Stadial-1 | Last Glacial Max | |||||||||
Species / Age (cal yr BP) |
13282 | 13717 | 14692 | 15388 | 16085 | 16782 | 17478 | 19568 | 20265 | 20961 | 21658 | 22354 |
Bolivina costata | 19.71 | 15.90 | 25.24 | 23.28 | 24.87 | 19.92 | 22.61 | 21.39 | 13.92 | 26.03 | 25.76 | 30.50 |
Bolivina seminuda var. humilis | 5.53 | 3.77 | 0.00 | 1.90 | 2.09 | 1.17 | 3.45 | 3.18 | 1.62 | 1.91 | 2.62 | 0.71 |
Bolivinita minuta | 2.88 | 3.35 | 4.11 | 5.94 | 3.14 | 2.73 | 1.53 | 2.60 | 1.94 | 2.50 | 0.87 | 2.13 |
Buccella peruviana | 4.81 | 8.37 | 4.50 | 3.80 | 2.88 | 4.69 | 1.92 | 4.62 | 3.88 | 5.00 | 3.49 | 4.61 |
Cassidulina delicata | 7.21 | 11.30 | 13.50 | 15.44 | 13.87 | 10.94 | 12.26 | 7.80 | 6.15 | 11.32 | 11.79 | 7.09 |
Cassidulina minuta | 3.13 | 0.00 | 4.11 | 0.00 | 2.62 | 3.13 | 5.36 | 8.96 | 2.91 | 2.21 | 6.11 | 0.00 |
Epistominella obesa | 9.86 | 14.85 | 3.52 | 2.38 | 11.26 | 14.84 | 15.33 | 15.90 | 15.53 | 9.12 | 6.55 | 7.45 |
Pseudoparella subperuviana | 8.65 | 11.51 | 9.98 | 13.54 | 7.85 | 8.20 | 7.28 | 3.18 | 13.59 | 10.74 | 4.37 | 3.90 |
Pseudoparella sp. | 9.13 | 5.02 | 4.31 | 6.18 | 8.90 | 7.81 | 4.21 | 11.85 | 10.36 | 6.76 | 5.24 | 13.83 |
Miliolids (Quinqueloculina sp.) | 0.00 | 0.00 | 0.20 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
Other calcareous | 29.09 | 25.94 | 30.72 | 27.55 | 22.51 | 26.56 | 26.05 | 20.52 | 30.10 | 24.41 | 33.19 | 29.79 |
Agglutinated species | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
Total number specimens | 416 | 478 | 511 | 421 | 382 | 256 | 261 | 346 | 309 | 680 | 229 | 282 |
Total number species | 40 | 37 | 39 | 36 | 33 | 34 | 32 | 33 | 38 | 45 | 33 | 37 |
Part 5.
M77/1-416 | Last Glacial Max | ||||||
Species / Age (cal yr BP) |
20176 | 20395 | 20505 | 20615 | 21073 | 21531 | 21983 |
Bolivina plicata | 0.90 | 0.39 | 0.93 | 2.99 | 5.19 | 5.59 | 3.44 |
Bolivina seminuda var. humilis | 3.62 | 6.25 | 6.48 | 12.69 | 1.48 | 13.13 | 22.14 |
Buliminella elegantissima | 0.00 | 0.78 | 21.30 | 0.75 | 20.74 | 0.28 | 0.00 |
Cassidulina auka | 38.01 | 16.80 | 21.30 | 14.93 | 6.67 | 5.03 | 1.91 |
Epistominella afueraensis | 0.90 | 27.34 | 0.00 | 9.70 | 0.00 | 6.70 | 9.54 |
Epistominella exigua | 6.33 | 2.34 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
Epistominella obesa | 0.00 | 0.00 | 1.85 | 0.00 | 8.89 | 0.84 | 5.73 |
Epistominella pacifica | 9.95 | 12.11 | 9.26 | 10.45 | 0.74 | 33.52 | 12.98 |
Gyroidina rothwelli | 13.12 | 10.94 | 2.78 | 14.93 | 1.48 | 2.23 | 7.63 |
Nonionella auris | 0.00 | 0.78 | 9.26 | 0.00 | 14.81 | 0.00 | 0.00 |
Planulina limbata | 7.24 | 2.34 | 3.70 | 2.24 | 0.74 | 1.40 | 3.44 |
Pseudoparella subperuviana | 0.00 | 0.00 | 4.63 | 0.00 | 17.04 | 0.84 | 2.29 |
Uvigerina peregrina | 0.00 | 1.95 | 0.00 | 1.49 | 0.00 | 5.59 | 5.73 |
Uvigerina striata | 0.90 | 0.78 | 0.00 | 0.00 | 0.74 | 2.23 | 5.34 |
Miliolids (Quinqueloculina sp.) | 0.45 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
Other calcareous | 19.00 | 17.19 | 18.52 | 29.85 | 21.48 | 22.63 | 19.85 |
Agglutinated species | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
Total number specimens | 221 | 256 | 108 | 134 | 135 | 358 | 262 |
Total number species | 26 | 28 | 21 | 28 | 22 | 33 | 26 |
Zeynep Erdem NIOZ Royal Netherlands Institute for Sea Research, Texel, The Netherlands. zeynep.erdem@nioz.nl
previously GEOMAR Helmholtz Centre of Ocean Research, Kiel, Germany
Dr. Zeynep Erdem received her B.Sc. and M.Sc. from the Istanbul Technical University (ITU), Istanbul, Turkey and Dr. rer. nat. from the University of Kiel in 2016. As a part of her PhD project, she worked in the Research Unit Paleoceanography of GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany as part of a multidisciplinary project focusing on oxygen limited marine environments. Currently, she is working in Marine Microbiology and Biogeochemistry Department at NIOZ Royal Netherlands Institute for Sea Research, Texel, The Netherlands as a postdoc researcher. Her research interests are paleoceanography, multi proxy (biogeochemical) applications on marine sediments and micropaleontology, specificly benthic foraminifera.
Joachim Schönfeld. GEOMAR Helmholtz Centre of Ocean Research, Kiel, Germany. jschoenfeld@geomar.de
Dr. Joachim Schönfeld obtained his Dr. rer. nat. from the University of Kiel in 1989 and continued research at the Federal Bureau of Geosciences and Natural Resources, Hannover, GEOMAR Research Centre for Marine Geosciences, Kiel at Department 5 – Geowissenschaften, Bremen University and with Tethys Geoconsulting, Ltd., Kiel, Germany. Doctor Schönfeld is currently a staff scientist from the Research Unit Paleoceanography of GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany. His scientific interests are benthic foraminifera, their taxonomy, ecology, Mesozoic and Cenozoic paleoceanography, stratigraphy and climate history.
FIGURE 1. A) Map of the research area showing the core locations. The dashed line shows the approximate position of the section in B) depth vs latitude section showing the dissolved oxygen concentrations and the core locations. Oxygen data were taken from a CTD compilation after Schönfeld et al. (2015). Contour lines indicate the dissolved oxygen concentration interval. Prepared by ODV Software (Schlitzer, 2010)
FIGURE 2. Schematic description of the focused time intervals and samples considered regarding to the benthic foraminifera study at each core.
FIGURE 3. Dominance and Fisher α diversity indices calculated for each sample and core. Note that the scale bars are different.
FIGURE 4. Downcore distributions of the most abundant species (>5% relative abundance) observed in the sediment cores. N.A.: in case of absence of the species. Note that the scale bars are different.
FIGURE 5. Downcore distributions of A. minimum, A. weddellensis, B. minuta, C. delicata, E. exigua and U. auberiana observed in core M77/1-59-1. Note that the scale bars are different.
FIGURE 6. Visual description of core M77/1-416 with magnetic susceptibility (SI) measurements and < 63 μm (weight %) information. Relative abundances of given species are potentially in relation with the downslope transported material.
FIGURE 7. Optical microscope images; scale bar equals 100 μm. 1. Epistominella pacifica umbilical view 47-2; 128 cm, 2. Epistominella exigua spiral view 52-2; 450 cm, 3. Epistominella exigua umbilical view 52-2; 450 cm, 4. Anomalinoides minimus spiral view 59-1; 523 cm, 5. Anomalinoides minimus umbilical view 59-1; 523 cm, 6. Epistominella obesa spiral view 50-4; 100 cm, 7. Epistominella obesa spiral view 50-4; 100 cm, 8. Epistominella obesa umbilical view 50-4; 100 cm, 9. cf. Buccella peruviana spiral view 50-4; 230 cm, 10. cf. Buccella peruviana umbilical view 47-2; 113 cm, 11. Cassidulina auka 416; 100 cm, 12. Alabaminella weddellensis spiral view 52-2; 270 cm, 13. Gyroidina subtenera spiral view 52-2; 270 cm, 14. Gyroidina subtenera umbilical view 52-2; 230 cm, 15. Cassidulina minuta 52-2; 120 cm, 16. Cassidulina carinata 50-4; 210 cm, 17. Cassidulina delicata 47-2; 128 cm.
FIGURE 8. SEM images; scale bar equals 100 μm. 1. Bolivina seminuda 416; 200 cm, 2. Bolivina cf. seminuda var. humilis 416; 200 cm, 3. Bolivina seminuda var. humilis 47-2; 113 cm, 4. Bolivina pacifica 52-2; 270 cm, 5. Bolivina interjuncta var. bicostata 52-2; 520 cm, 6. Bolivinita minuta 52-2; 270 cm, 7. Bolivina aff. tortuosa 59-1; 523 cm, 8. Bolivina costata 52-2; 270 cm, 9. Bolivina ordinaria 47-2; 128 cm, 10. Bulimina pagoda 52-2; 520 cm, 11. Fursenkoina fusiformis 50-4; 230 cm, 12. Virgulina spinosa 59-1; 963 cm, 13. Fursenkoina glabra 50-4; 230 cm, 14. Anomalinoides minimus spiral view 59-1; 523 cm, 15. cf. Buccella peruviana umbilical view 47-2; 113 cm, 16. cf. Buccella peruviana peripheral view 47-2; 113 cm, 17. cf. Buccella peruviana spiral view 50-4; 230 cm, 18. Epistominella exigua spiral view 52-2; 450 cm, 19. Epistominella exigua umbilical view 52-2; 450 cm, 20. Anomalinoides minimus umbilical view 59-1; 523 cm, 21. Epistominella afueraensis umbilical view 416; 200 cm, 22. Epistominella afueraensis peripheral view 416; 200 cm, 23. Epistominella afueraensis spiral view 416; 200 cm, 24. Alabaminella weddellensis spiral view 52-2; 270 cm.
FIGURE 9. Optical microscope images; scale bar equals 200 μm. 1. Planulina limbata umbilical view 416; 100 cm, 2. Epistominella pacifica 416; 200 cm, 3. Epistominella pacifica umbilical view 416; 200 cm, 4. Angulogerina angulosa 50-4; 100 cm, 5. Epistominella smithi spiral view 50-4; 210 cm, 6. Uvigerina striata 416; 200 cm, 7. Uvigerina hispida 52-2; 120 cm, 8. Epistominella afueraensis spiral view 416; 200 cm, 9. Epistominella afueraensis umbilical view 416; 200 cm, 10. Gyroidina rothwelli umbilical view 416; 100 cm, 11. Gyroidina rothwelli spiral view 416; 100 cm.
FIGURE 10. Optical microscope images; scale bar equals 200 μm. 1. Bolivina interjuncta 47-2; 168 cm, 2. Bolivina subadvena 47-2; 113 cm, 3. Bolivina plicata microspheric form 416; 200 cm, 4. Bolivina plicata macrospheric form 416; 100 cm, 5. Bolivina argentea 50-4; 350 cm, 6. Praeglobobulimina spinescens 47-2; 168 cm, 7. Bolivina spissa macrospheric form 52-2; 520 cm, 8. Bolivina spissa microspheric form 47-2; 128 cm, 9. Stainforthia complanata 50-4; 210 cm, 10. Bolivina alata 50-4; 110 cm, 11. Buliminella tenuata 50-4; 100 cm, 12. Globobulimina pacifica 52-2; 230 cm, 13. Uvigerina peregrina 416; 200 cm, 14 - 15. Bulimina exilis 50-4; 100 cm & 350 cm, 16. Buliminella curta var. basispinata 50-4; 350 cm, 17. Uvigerina auberiana 50-4; 350 cm, 18. Cassidulina crassa 52-2; 520 cm.
FIGURE 11. SEM images; scale bar equals 200 μm. 1. Bolivina interjuncta 47-2; 168 cm, 2. Bolivina plicata microspheric form 416; 200 cm, 3. Bolivina plicata macrospheric form 416; 100 cm, 4. Bolivina spissa 52-2; 520 cm, 5. Uvigerina peregrina 416; 200 cm (different specimen depicted in optical microscope and SEM image), 6. Praeglobobulimina spinescens 47-2; 168 cm, 7. Stainforthia complanata 50-4; 210 cm, 8. Uvigerina auberiana 50-4; 350 cm, 9. Uvigerina semiornata 52-2; 230 cm, 10. Bolivina alata 50-4; 110 cm, 11. Buliminella cf. curta 50-4; 100 cm, 12.-13 Bulimina exilis 50-4; 100 cm & 350 cm, 14. Uvigerina striata 416; 200 cm, 15. Hoeglundina elegans 52-2; 500 cm, 16. Globobulimina pacifica 52-2; 230 cm, 17. Cassidulina delicata 47-2; 128 cm, 18. Cassidulina crassa 52-2; 520 cm, 19. Cassidulina auka 416; 100 cm
FIGURE 12. Optical microscope images; scale bar equals 100 μm. 1. Bolivina costata 52-2; 270 cm 2. Bolivina ordinaria 47-2; 128 cm, 3. Bolivina cf. seminuda var. humilis 416; 200 cm, 4. Bolivina seminuda 416; 200 cm, 5-6. Bolivina interjuncta var. bicostata 52-2; 520 cm and 450 cm, 7. Bolivinita minuta 52-2; 270 cm, 8. Bolivina aff. tortuosa 59-1; 523 cm, 9. Bolivina seminuda var. humilis 47-2; 113 cm, 10. Bolivina pacifica 52-2; 270 cm, 11. Bolivina tongi var. filacostata 59-1; 523 cm, 12. Buliminella cf. curta 50-4; 100 cm, 13. S uggrunda eckisi 50-4; 110 cm, 14. Suggrunda porosa 47-2; 128 cm, 15. Fursenkoina fusiformis 50-4; 230 cm, 16. Fursenkoina glabra 50-4; 230 cm, 17. Buliminella elegantissima 416; 180 cm, 18. Bulimina mexicana 52-2; 520 cm, Bulimina pagoda 52-2; 520 cm.
FIGURE 13. SEM images; scale bar equals 200 μm. 1. Cibicidoides wuellerstorfi spiral view 52-2; 500 cm, 2. Cibicides mckannai umbilical view 52-2; 230 cm, 3. Epistominella smithi umbilical view 50-4; 210 cm, 4. Epistominella smithi spiral view 50-4; 210 cm, 5. Planulina limbata umbilical view 416; 100 cm, 6. Epistominella pacifica umbilical view 416; 200 cm, 7. Epistominella pacifica spiral view 416; 200 cm, 8. Epistominella pacifica peripheral view 416; 200 cm, 9. Gyroidina rothwelli spiral view 416; 100 cm, 10. Oridorsalis umbonatus umbilical view 52-2; 230 cm, 11. Gyroidina subtenera umbilical view 52-2; 230 cm, 12. Gyroidina subtenera spiral view 52-2; 270 cm, 13. Epistominella pacifica umbilical view 47-2; 128 cm, 14. Gyroidina rothwelli umbilical view 416; 100 cm, 15. Cassidulina carinata 50-4; 210 cm.
TABLE 1. The metadata of the sediment cores used in this study.
Cruise |
Core name |
Year |
Lat |
Long |
Water depth |
Reference; |
M77/2 | 059-PC1 | 2008 | 03°57.01' | 81°19.23' | 997 | Mollier-Vogel et al., 2013 |
M77/2 | 052-PC2 | 2008 | 05°29.01' | 81°27.00' | 1249 | Erdem et al., 2016 |
M77/2 | 047-PC2 | 2008 | 07°52.01' | 80°31.36' | 626 | Erdem et al., 2016 |
M77/2 | 050-PC4 | 2008 | 08°01.01' | 80°30.10' | 1013 | Erdem et al., 2016 |
M77/1 | 416-GC4 | 2008 | 17°28,13' | 71°52,62' | 505 | Erdem et al., 2016 |
TABLE 2. List of the most abundant species with >5 % relative abundance observed in each sediment core. The most abundant and common species are indicated bold. * species without image.
Species name |
Occurrence |
||||
59-1 |
52-2 |
50-4 |
47-2 |
416 |
|
Alabaminella weddellensis | 0-6 | absent | absent | ||
Anomalinoides minimus | 0-5 | absent | absent | ||
Bolivina costata | 1-43 | 5-45 | 16-26 | ||
Bolivina interjuncta var. bicostata | 0-7 | 0-5 | |||
Bolivina pacifica | 0-6 | 0-5 | 0-6 | ||
Bolivina plicata | absent | 0-6 | |||
Bolivina quadrata* | 0-7 | absent | absent | ||
Bolivina seminuda var. humilis | 1-7 | 0-6 | 1-23 | ||
Bolivina spissa | 0-5 | 0-7 | absent | ||
Bolivinita minuta | 0-30 | 0-20 | 0-10 | 0-6 | |
cf Buccella peruviana | 0-5 | 2-9 | |||
Bulimina exilis | 0-6 | ||||
Bulimina pagoda | 0-7 | absent | |||
Buliminella elegantissima | 0-22 | ||||
Cassidulina auka | absent | 0-6 | 0-6 | 2-38 | |
Cassidulina carinata | 0-9 | 0-24 | 0-11 | ||
Cassidulina delicata | 3-14 | 5-21 | 3-14 | 6-16 | |
Cassidulina laevigata* | 0-14 | absent | |||
Cassidulina minuta | 0-9 | 0-9 | absent | ||
Cibicides mckannai | 0-7 | absent | absent | ||
Epistominella afueraensis | 0-7 | 0-27 | |||
Epistominella exigua | 5-23 | 0-33 | 0-13 | 0-6 | |
Epistominella obesa* | 0-5 | 0-15 | 2-16 | ||
Epistominella pacifica | 0-6 | 0-8 | 0-8 | 0-34 | |
Epistominella smithi | 0-6 | 0-12 | 0-7 | absent | absent |
Fursenkoina fusiformis | 0-5 | 0-5 | |||
Gyroidina rothwelli | 0-5 | 2-14 | |||
Nonionella auris* | 0-15 | ||||
Planulina limbata | 0-7 | ||||
Pseudoparella sp. | 0-18 | 4-14 | absent | ||
Pseudoparella subperuviana* | 0-15 | 3-14 | 0-18 | ||
Uvigerina auberiana | 0-8 | 0-11 | absent | ||
Uvigerina bifurcata | absent | 0-9 | absent | absent | |
Uvigerina peregrina | 0-10 | 0-6 | |||
Uvigerina semiornata | 0-5 | 3-17 | 0-7 | ||
Uvigerina striata | 0-5 | ||||
Virgulina cornuta* | 0-6 | ||||
Virgulina spinosa | 0-21 | absent | absent | absent |
Pleistocene to Holocene benthic foraminiferal assemblages from the Peruvian continental margin
Plain Language Abstract
The majority of modern foraminifera pursue a benthic lifestyle, and they constitute an important group of organisms in benthic ecosystems with high levels of environmental adaptation, contributing significantly to biogeochemical cycling. Foraminiferal tests are readily preserved in the near-surface sediments after reproduction, thus providing a fossil record of environmental changes, such as bottom-water temperature, surface ocean productivity, or bottom and pore water ventilation. Foraminifera are therefore important tools for reconstructions of oceanographic conditions in the past. This study presents the benthic foraminiferal species inventory and assemblage composition observed in sediment cores that were recovered from offshore Peru. The sediment samples cover the last 22 thousand years including the transition from the last ice-age to the present warm period, thus, a major climatic event. Additionally, a documentation with incident light and scanning electron microscopic images of common species from the samples is presented, a timely contribution to our knowledge of Peruvian benthic foraminifera.
Resumen en Español
Asociaciones de foraminíferos bentónicos pleistocenos a holocenos del margen continental peruano
El inventario de foraminíferos bentónicos y la composición de sus asociaciones fueron documentados a lo largo de cinco testigos sedimentarios del margen peruano entre 3°S y 18°S a profundidades de agua de 500 a 1250 m, cubriendo el límite inferior de la Zona Mínima de Oxígeno (ZMO). El énfasis fue puesto en determinados intervalos temporales de los últimos 22 mil años cuando prevalecieron condiciones climáticas y oceanográficas distintas a las actuales. En total, tres especies aglutinadas y 186 calcáreas fueron reconocidas. Bolivina costata, Bolivinita minuta, Cassidulina delicata y Epistominella exigua fueron las más abundantes. Las distribuciones de foraminíferos revelaron un cambio marcado en la composición de las asociaciones particularmente en los testigos más profundos durante y luego de la deglaciación. La diversidad declinó y las especies de Bolivina se volvieron dominantes. Estos cambios tuvieron lugar gradualmente a lo largo de milenios y no se registraron fluctuaciones de alta frecuencia. Este patrón provee evidencia de condiciones ecológicas relativamente estables y cambios lentos en la circulación de las aguas de fondo durante la última deglaciación.
Resumen en lenguaje sencillo
La mayoría de los foraminíferos modernos tienen un estilo de vida bentónico y constituyen un grupo importante de organismos en los ecosistemas bentónicos, con altos niveles de adaptación ambiental, contribuyendo significativamente al ciclo biogeoquímico. Las tecas de los foraminíferos se preservan en la superficie o cerca de la superficie sedimentaria luego de la reproducción, proveyendo así un registro fósil de los cambios ambientales, tales como temperatura de agua, productividad oceánica superficial, o ventilación de aguas de fondo o porales. Los foraminíferos son, por ende, herramientas importantes para las reconstrucciones de condiciones oceanográficas del pasado. Este estudio presenta el inventario de especies de foraminíferos bentónicos y composición de asociaciones observado en testigos de sedimentos que fueron obtenidos en el offshore de Perú. Las muestras sedimentarias cubren los últimos 22 mil años, incluyendo la transición desde la última edad de hielo al presente período cálido, por ende, un importante evento climático. Adicionalmente, se presenta la documentación de imágenes con luz incidente y microscopio electrónico de barrido de especies comunes, una contribución oportuna a nuestro conocimiento de los foraminíferos bentónicos peruanos.
Palabras clave: foraminíferos bentónicos; taxonomía; Perú; Zona Mínima de Oxígeno; Holoceno; Deglaciación
Traducción: Diana Elizabeth Fernández
Résumé en Français
Assemblages de foraminifères benthiques de la marge continentale péruvienne du Pléistocène à l’Holocène
L’inventaire des foraminifères benthiques et la composition de leur assemblage ont été documentés dans cinq carottes de sédiments de la marge péruvienne entre 3°S et 18°S à des profondeurs d’eau de 500 m à 1250 m, couvrant la limité inférieure de la Zone de Minimum d’Oxygène (ZMO) actuelle. L’accent a été mis sur certains intervalles de temps pendant les derniers 22 milliers d’années quand des conditions océanographiques et climatiques différentes de celles d’aujourd’hui prévalaient. Un total de trois espèces à test agglutiné et 186 espèces à test calcaire ont été reconnues. Bolivina costata, Bolivinita minuta, Cassidulina delicata et Epistominella exigua étaient les plus abondantes. Les distributions des foraminifères ont révélé des changements marqués de la composition des assemblages, en particulier dans les carottes les plus profondes, pendant et après la déglaciation. La diversité a décliné et les espèces de Bolivinia sont devenues dominantes. Ces changements ont eu lieu graduellement sur plusieurs millénaires, et des fluctuations de haute fréquence n’ont pas été enregistrées. Le schéma observé indique des conditions écologiques relativement stables et des changements lents de la circulation des eaux de fond pendant la dernière déglaciation.
Mots-clés : foraminifères benthiques ; taxinomie ; Pérou ; Zone de Minimum d’Oxygène ; Holocène ; déglaciation
Translator: Antoine Souron
Deutsche Zusammenfassung
Der Artbestand und die Zusammensetzung benthischer
Foraminiferengemeinschaften wurde an fünf Sedimentkernen vom peruanischen Kontinentalhang dokumentiert, die aus Wassertiefen von 500 bis 1250 m zwischen 3°S und 18°S entlang der unteren Grenze der heutigen Sauerstoffminimumzone genommen worden sind. Der Schwerpunkt dieser Untersuchung wurde auf bestimmte Zeitintervalle während der letzten 22.000 Jahr gelegt, in denen andere klimatische und ozeanografische Bedingungen als heute vorgeherrscht haben. Insgesamt wurden drei agglutinierende und 186 kalkschalige Arten festgestellt. Bolivina costata, Bolivinita minuta, Cassidulina delicata und Epistominella exigua waren am häufigsten. Die Foraminiferenverteilungen entlang der Kerne zeigten einen markanten Wechsel in der Artenzusammensetzung während oder nach der letzten Abschmelzphase, was sich besonders in den tieferen Kernen zeigt. Die Diversität nahm ab und Arten der Gattung Bolivina dominierten. Diese Veränderungen erfolgten allmählich über einen Zeitraum von mehreren tausend Jahren. Kurzzeitige Fluktuationen wurden nicht registriert. Dieses Muster weist auf vergleichsweise stabile ökologische Bedingungen während des letzten Abschmelzphase und sehr langsame Änderungen in der Tiefwasserzirkulation nahe am Meeresboden hin.
Schlagwörter: benthische Foraminiferen; Taxonomie; Peru; Sauerstoffminimumzone; Holozän; Abschmelzphase
Translator: Authors
Arabic
Translator: Ashraf M.T. Elewa
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Review: The Princeton Field Guide to Mesozoic Sea Reptiles
The Princeton Field Guide to Mesozoic Sea Reptiles
Article number: 26.1.1R
April 2023