Species That Fly at a Higher Game: Patterns of Deep–Water Emergence Along the Chilean Coast, Including a Global Review of the Phenomenon

Abstract

Deep-water emergence (DWE) is the phenomenon where marine species normally found at great depths (i.e., below 200 m), can be found locally occurring in significantly shallower depths (i.e., euphotic zone, usually shallower than 50 m). Although this phenomenon has been previously mentioned and deep-water emergent species have been described from the fjord regions of North America, Scandinavia, and New Zealand, local or global hypotheses to explain this phenomenon have rarely been tested. This publication includes the first literature review on DWE. Our knowledge of distribution patterns of Chilean marine invertebrates is still very scarce, especially from habitats below SCUBA diving depth. In our databases, we have been gathering occurrence data of more than 1000 invertebrate species along the Chilean coast, both from our research and from the literature. We also distributed a list of 50 common and easily in situ-identifiable species among biologically experienced sport divers along the Chilean coast and recorded their sighting reports. Among other findings, the analysis of the data revealed patterns from 28 species and six genera with similar longitudinal and bathymetric distribution along the entire Chilean coast: along the Chilean coast these species are typically restricted to deep water (>200 m) but only in some parts of Chilean Patagonia (>39°S–56°S), the same species are also common to locally abundant at diving depths (<30 m). We found 28 of these ‘deep’ species present in shallow-water of North Patagonia, 32 in Central Patagonia and 12 in South Patagonia. The species belong to the phyla Cnidaria (six species), Mollusca (four species), Arthropoda (two species) and Echinodermata (16 species). We ran several analyses comparing depth distribution between biogeographic regions (two-way ANOVA) and comparing abiotic parameters of shallow and deep sites to search for correlations of distribution with environmental variables (Generalized Linear Models). For the analyses, we used a total of 3328 presence points and 10635 absence points. The results of the statistical analysis of the parameters used, however, did not reveal conclusive results. We summarize cases from other fjord regions and discuss hypotheses of DWE from the literature for Chilean Patagonia.

Out of the depths: new records of the sea anemone Oulactis coliumensis (Riemann-Zürneck & Gallardo, 1990) in shallow waters from northern Chile and Peru

“…Riemann-Zürneck & Gallardo (1990) inferred that the marginal ruff may have an adaptive value in this sense, favouring gas exchange in time spans of oxygen deficiency. As these episodes – usually linked to the expansion of the oxygen minimum zone – become more intense and shallower in depth due to climate change (Bakun et al ., 2015; Valdés et al ., 2021), more and more individuals may likely disperse towards the coast (see Häussermann et al ., 2021); which, not only raises new questions about their potential impact on shallow-water ecosystems, but also presents O. coliumensis as a suitable bioindicator of eutrophicated sediments.…”

Biodiversity and distribution of corals in Chile

“…This trend is observed along the Chilean coasts, though it is reversed in the Patagonian region: the data analysed here show that the highest species diversity occurs in the Magellanic Province (i.e., Chilean Patagonia) rather than further north (see Figure 5). Häussermann et al (2021), who have led numerous SCUBA diving expeditions of this province over the past two decades, reported that Northern Patagonia harbours the highest diversity of shallow-water anthozoans, followed closely by Central Patagonia; by comparison, Southern Patagonia harbours a lower level of biodiversity (Häussermann et al 2021). It is worth mentioning that the results reported here may be mainly reflecting the asymmetrical sampling effort of past research expeditions of Chilean coastal and marine waters and not the real pattern of coral distribution and biodiversity in this vast area.…”

“…As highlighted by our study of coral species occurrence, the coastal and marine waters of Chile, a vast area comprised several biogeographic provinces and ecoregions, remain poorly explored. This area includes relevant endemic biodiversity hotspots and fragile habitats (see e.g., Häussermann et al 2021 for the continental shelf, slope, and fjord areas, and Wagner et al 2021 for the Nazca and Salas y Gómez ridges), for which biodiversity estimates are especially important. Our study also demonstrates that the largest efforts to inventory coral species of this region were made by the Challenger (1872-1876), the Lund University Chile (1948)(1949), and the Huinay Fjord (2005-2019) expeditions.…”

“…3) Provinces according to the biogeographic classification proposed by Häussermann (2006) and Häussermann et al (2021), which is based on Pickard's (1971) subdivision of Chilean Patagonia:…”

“…Similar species distribution patterns were obtained when considering the biogeographic regions proposed by Camus (2001), at both the province and the district level (Peruvian Province with 40 species; Intermediate Area with 43 species: Northern District (26), Mediterranean District (15), and Southern District (12); and Magellanic Province with 132 species: Austral District (91) and Subantarctic District ( 83)) (Figure 6a, b). For the biogeographic regions of the Magellanic Province proposed by Häussermann (2006) and Häussermann et al (2021), the highest species richness was found in Central Patagonia (74 species) followed by Southern (68 species) and Northern (53 species) Patagonia (Figure 6c).…”