Foraminifera and testate amoebae (thecamoebians) in an anchialine cave: Surface distributions from Aktun Ha (Carwash) cave system, Mexico

Abstract

Abstract-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 d 13 C 5 25.5% and a mean d 18 O 5 22.7%. This assemblage was found distal to sinkholes (.75 m upstream, .150 m downstream) and in yellow-orange sediment (mean total organic carbon [TOC] 5 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 tepida var. juvenile (<35%), with a mean d 13 C 5 210.8% and a mean d 18 O 5 24.9% 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 5 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.

Reconstructing water level in Hoyo Negro, Quintana Roo, Mexico, implications for early Paleoamerican and faunal access

“…OM enters the cave via transport from terrestrial sources or through primary productivity in sunlit cenote water bodies while calcite rafts form on surface waters in cenotes or in air domes in the cave (Collins et al, a, b;van Hengstum et al, 2010;Taylor and Chafetz, 2004; van Hengstum et al, 2015). Gabriel et al (2009) was the first to examine how water level affected cenote development in the Yucatan while van Hengstum used microfossils (foraminifera and testate amoebae) and cave sediment records to reconstruct groundwater salinity over the past 4.5 Ka (van Hengstum et al, 2009b;van Hengstum et al, 2008;van Hengstum et al, 2010). Subsequent work in Bermuda and Bahamas used similar techniques (van Hengstum et al, 2011;van Hengstum et al, 2009a;van Hengstum et al, 2013).…”

“…Gabriel et al (2009) was the first to examine how water level affected cenote development in the Yucatan while van Hengstum used microfossils (foraminifera and testate amoebae) and cave sediment records to reconstruct groundwater salinity over the past 4.5 Ka (van Hengstum et al, 2009b;van Hengstum et al, 2008;van Hengstum et al, 2010). Subsequent work in Bermuda and Bahamas used similar techniques (van Hengstum et al, 2011;van Hengstum et al, 2009a;van Hengstum et al, 2013). However, many of the previous ideas relating cave sedimentation to sea-level were inferred from limited background data (e.g.…”

“…However, many of the previous ideas relating cave sedimentation to sea-level were inferred from limited background data (e.g. Bermuda; van Hengstum et al, 2011; also van Hengstum et al, 2009a;Bahamas;van Hengstum et al, 2013). Subsequent research by Collins et al (2015a,b) was conducted to enhance this body of research documenting sources and controls of sedimentation in Yax Chen (part of the nearby Ox Bel Ha Cave System) and its relationship with an extensive mangrove system and with a recent hurricane (Ingrid Sept 2013; Collins et al, 2015a,b).…”

Free-living amoebae in sediments from the Lascaux Cave in France

“…(Khan, 2006). However, amoebae have been scarcely investigated in caves (Coppellotti & Guidolin, 2003;Mulec, 2008;van Hengstum et al, 2009;Walochnik & Mulec, 2009;Mazei et al, 2012). Caves harbour pools, lakes and subterranean rivers, and the sediments and rock walls are constantly wet due to a relative humidity near saturation and water condensation.…”

Anthropogenic infilling of a Bermudian sinkhole and its impact on sedimentation and benthic foraminifera in the adjacent anchialine cave environment

“…Cave sediment can also preserve microfossils that are useful proxies of long-term aquatic environmental change, such as bivalves (Kitamura et al, 2007), gastropods (Moolenbeek et al, 1989;Kase & Hayami, 1992;Kano & Kase, 2008), ostracodes (Maddocks & Iliffe, 1986;Kornicker et al, 1998), benthic foraminifera (Javaux & Scott, 2003;van Hengstum & Scott, 2011, 2012, and testate amoeba (van Hengstum et al, 2009a). Given their statistically significant and diverse populations in small sediment samples, benthic foraminifera are particularly useful microfossils for environmental monitoring in coastal environments (Gooday et al, 1992;Gupta & Machain-Castillo, 1993;Murray, 2001).…”