Ecological patterns in anchialine caves

Abstract

Anchialine caves are characterized by high levels of endemism and extreme conditions. However, few ecological studies have been conducted in these ecosystems. This study integrates biotic and abiotic parameters of two sets of cave systems with contrasting high and low species richness. Seven ecological patterns are used to explain the expected species richness and density in an anchialine cave. In addition, the population size for conspicuous macrofauna was estimated. The high impact that single-events have on anchialine fauna are also reported. These findings reinforce the conclusions of previous studies of the high extinction risk of anchialine cave fauna, and substantiate the necessity of ad hoc conservation strategies for anchialine caves.

Habitat Partitioning in the Marine Sector of Karst Subterranean Estuaries and Bermuda's Marine Caves: Benthic Foraminiferal Evidence

“…In the Mediterranean, S. emaciatum has been recently described in benthic foraminiferal communities from a marine cave with carbonate sedimentation on the Murica coastal region in Spain (Cueva Gemelas: Bergamin et al, 2020), but not in marine caves on eastern Sardinia with siliciclastic sedimentation and evidence for the discharge of meteoric water (Romano et al, 2018(Romano et al, , 2020. On the island of Cozumel (Mexico) where Aerolito Cave is located (Mejía-Ortiz et al, 2007a,b;CalderóN-GutiéRrez et al, 2018), caves passages flooded with oxygenated saline groundwater and benthic carbonate sediment also host populations of S. emaciatum (van Hengstum, personal observation). Murray (2006) states that Spirillina and Patellina prefer hard substrates, so it remains possible that the cave walls/ceiling may be providing an ideal natural hard substrate for these taxa.…”

Distribution patterns, carbon sources and niche partitioning in cave shrimps (Atyidae: Typhlatya)

“…Groundwater in the anchialine systems of Yucatan is vertically stratified by the intrusion of marine water from the coast which inserts below the freshwater that constantly flows towards the coast 2 . This marked halocline, along with changes in temperature, dissolved oxygen, pH and redox potential has been considered a physicochemical barrier that separates freshwater and saline communities 5 , 6 . This stratification is expected in coastal systems, and as distance from the coast increases, the marine intrusion is found deeper and only a few deep cenotes inland may reach the saline layers 7 .…”

“…This work gathers evidence that suggests how three sympatric cave shrimp species that coexist in groundwater ecosystems have partitioned their niche to avoid competitive exclusion.Groundwater in the anchialine systems of Yucatan is vertically stratified by the intrusion of marine water from the coast which inserts below the freshwater that constantly flows towards the coast 2 . This marked halocline, along with changes in temperature, dissolved oxygen, pH and redox potential has been considered a physicochemical barrier that separates freshwater and saline communities 5,6 . This stratification is expected in coastal systems, and as distance from the coast increases, the marine intrusion is found deeper and only a few deep cenotes inland may reach the saline layers 7 .In terms of energy production and food webs, the sun-influenced cenote pools-cenote is a Mayan derived name for local sinkholes-are the only sites where photosynthesis can take place and allochthonous organic matter can enter the system.…”

Changes in Organic Matter Deposition Can Impact Benthic Marine Meiofauna in Karst Subterranean Estuaries

“…Downstream passages are well-mixed and resemble typical marine conditions, whereas the water column in the open pool of the sinkhole and the upstream passages is stratified. Here, a sharp mixing zone (halocline) between brackish (∼15 psu) and saline (∼37 psu) water masses occurs typically at ∼7 m water depth (Mejía-Ortíz et al, 2007;Calderón-Gutiérrez et al, 2018). Shifts in the depth and thickness of the mixing zone in response to high-intensity rain events have been documented in Aerolito (Calderón-Gutiérrez et al, 2018), similar to the mainland Yucatán Peninsula (Coutino et al, 2017;Brankovits et al, 2018).…”