TY - JOUR
T1 - Foraminifera and testate amoebae (thecamoebians) in an anchialine cave
T2 - Surface distributions from Aktun Ha (Carwash) cave system, Mexico
AU - Van Hengstum, Peter J.
AU - Reinhardt, Eduard G.
AU - Beddows, Patricia A.
AU - Schwarcz, Henry P.
AU - Gabriel, Jeremy J.
PY - 2009/1
Y1 - 2009/1
N2 - Surface sediment samples from Aktun Ha (Carwash) cave system, Mexico, were analyzed for microfossils, carbonate isotopes, and organic matter content. Saline water flooded the cave during the Sangamon Interglacial highstand (124-119 kyr), hosting a marine assemblage dominated by saline foraminifera Bolivina sp. (73%) and Elphidium sp. (11%) with a mean δ13C = -5.5‰ and a mean δ18O = -2.7‰. This assemblage was found distal to sinkholes (>75 m upstream, >150 m downstream) and in yellow-orange sediment (mean total organic carbon [TOC] = 3.6%). Late Pleistocene (95-15 kyr) sea level fall reestablished vadose conditions in the cave, allowing for localized speleothem (flowstone) to seal in the marine assemblage. Holocene sea level rise completely reflooded the cave with freshwater by 6.5 kyr, providing a suitable habitat for a freshwater assemblage of living testate amoebae Centropyxis aculeata (≈38%), Arcella vulgaris (≈10%), and the foraminifer Ammonia tépida var. juvenile (≈35%), with a mean δ13C = -10.8‰ and a mean δ18O = -4.9‰ on the ostracod Cytheridella ilosvayi. This assemblage was found proximal to sinkholes (<75 m upstream, <150 m downstream) and in black to brown sediment (mean TOC = 17.5%). Foraminifera and testate amoebae colonize aquatic cave environments, respond to physicochemical conditions in the cave similarly to other coastal settings, and thereby provide promise for the application of protists as proxies in flooded caves.
AB - Surface sediment samples from Aktun Ha (Carwash) cave system, Mexico, were analyzed for microfossils, carbonate isotopes, and organic matter content. Saline water flooded the cave during the Sangamon Interglacial highstand (124-119 kyr), hosting a marine assemblage dominated by saline foraminifera Bolivina sp. (73%) and Elphidium sp. (11%) with a mean δ13C = -5.5‰ and a mean δ18O = -2.7‰. This assemblage was found distal to sinkholes (>75 m upstream, >150 m downstream) and in yellow-orange sediment (mean total organic carbon [TOC] = 3.6%). Late Pleistocene (95-15 kyr) sea level fall reestablished vadose conditions in the cave, allowing for localized speleothem (flowstone) to seal in the marine assemblage. Holocene sea level rise completely reflooded the cave with freshwater by 6.5 kyr, providing a suitable habitat for a freshwater assemblage of living testate amoebae Centropyxis aculeata (≈38%), Arcella vulgaris (≈10%), and the foraminifer Ammonia tépida var. juvenile (≈35%), with a mean δ13C = -10.8‰ and a mean δ18O = -4.9‰ on the ostracod Cytheridella ilosvayi. This assemblage was found proximal to sinkholes (<75 m upstream, <150 m downstream) and in black to brown sediment (mean TOC = 17.5%). Foraminifera and testate amoebae colonize aquatic cave environments, respond to physicochemical conditions in the cave similarly to other coastal settings, and thereby provide promise for the application of protists as proxies in flooded caves.
UR - http://www.scopus.com/inward/record.url?scp=61649100745&partnerID=8YFLogxK
U2 - 10.4319/lo.2009.54.1.0391
DO - 10.4319/lo.2009.54.1.0391
M3 - Article
AN - SCOPUS:61649100745
SN - 0024-3590
VL - 54
SP - 391
EP - 396
JO - Limnology and Oceanography
JF - Limnology and Oceanography
IS - 1
ER -