North Atlantic Gateway: Test bed of deep‐sea macroecological patterns

Abstract

Aim: The deep waters around Iceland, known as the North Atlantic Gateway, constitute an ideal location to investigate deep-sea ecological hypotheses. We constructed a comprehensive deep-sea macroecological dataset of the North Atlantic Gateway region and investigated the controlling factors of large-scale, deep-sea species diversity patterns. Location: Sub-polar North Atlantic Ocean. Time period: Modern. Major taxa studied: Ostracoda (Crustacea). Methods: We investigated deep-sea biodiversity patterns and applied ecological modelling (multiple regression and model averaging) to test whether these patterns are governed by environmental factors such as temperature, surface primary productivity, and seasonality. Beta diversity analyses were applied to evaluate the effect of a geographical barrier (Greenland-Iceland-Faeroe Ridge) on deep-sea benthic faunal distributions. Results:We constructed a deep-sea macroecological dataset with 32 stations, 5,676 specimens, and >122 species. We confirmed a linear latitudinal diversity gradient with higher diversity in the North Atlantic proper than in the Nordic Seas. We report a unimodal depth diversity gradient south of the ridge, but a linear diversity-decline with depth north of the ridge. The turnover component of beta diversity increased towards the ridge. Main conclusions:We found both temperature and surface primary production are important for deep-sea biodiversity. For the first time, we report a significant diversity-temperature relationship in both macroecological (spatial; this study) and existing paleoecological (time-series) data for the same taxa. In addition to temperature and surface primary production, bathymetric features such as a shallow ridge acting as a barrier are an important factor for deep-sea biodiversity distribution. The low diversity of the Nordic Seas is likely due to a combination of low temperatures and bathymetric barriers. These results substantially expand our understanding of the | 2057 JÖST eT al.

Investigating the environmental drivers of deep‐seafloor biodiversity: A case study of peracarid crustacean assemblages in the Northwest Atlantic Ocean

“…A unimodal relationship between deep‐sea diversity and productivity, consistent with the “Intermediate Productivity Theory” (Grime, ), has been reported by other studies (Cosson‐Sarradin et al, ; Jöst et al, ; Leduc, Rowden, Bowden, et al, ; Tittensor et al, ) and may help to explain our contrasting observations of positive, negative, and unimodal relationships between peracarid biodiversity and food availability (Table ). If food availability in the study region is at a magnitude toward the peak of a theoretical unimodal curve, depending on the metric of food availability analyzed, our data may cover the incline, peak, or decline of this curve, giving observations of positive, unimodal, or negative productivity—diversity relationships.…”

“…Our finding that high seafloor temperature values have a negative impact on the biomass and possibly taxon diversity of peracarid assemblages is in agreement with the recognition of temperature as a fundamental controlling environmental factor in marine environments (Danovaro et al, ; Hunt, Cronin, & Roy, ; Jöst et al, ; Perry, Low, Ellis, & Reynolds, ; Poloczanska et al, ; Tittensor et al, ; Yasuhara & Danovaro, ), and with the potentially high sensitivity of deep‐sea organisms to temperature change (Howes et al, ; McCauley et al, ; Tewksbury et al, ; Yasuhara et al, ). Our finding of a negative relationship between temperature and peracarid biomass may reflect the narrow thermal niche of many deep‐sea species (Carney, ; Yasuhara & Danovaro, ).…”

“…For example, Lambshead, Tietjen, Ferrero, and Jensen (2000), Lambshead et al (2002) reported a positive F I G U R E 1 Conceptual model, specified by Levin et al (2001), indicating the direct and indirect links between various environmental parameters (orange) and the taxonomic richness of deep-sea communities (purple). Color of arrow represents form of relationship: blue = positive, red = negative, black = complex (e.g., "U"-shaped or uni/ multimodal) relationship between nematode species diversity and surface productivity in the North Atlantic and Pacific oceans at bathyal, abyssal, and hadal depths, while Tittensor, Rex, Stuart, McClain, and Smith (2011), Leduc, Rowden, Bowden, et al (2012), and Jöst et al (2019 reported a unimodal relationship between molluscan, nematode, and ostracod diversity, respectively, and food availability proxies at bathyal and abyssal depths. Levin et al (2001) specified a unimodal relationship between food availability and taxon richness whereby at low food availability, diversity is depressed as a result of insufficient resources to support viable populations of species, whereas at high food availability, diversity is depressed because of a combination of reduced environmental heterogeneity and increased species dominance, resulting in a diversity maxima at intermediate levels of food availability.…”

“…Temperature represents a fundamental factor shaping biological communities, with demonstrable influence over faunal diversity, distributions, recruitment, growth rate, and species interactions in the marine environment (Ashford, Davies, & Jones, 2014;Danovaro, Dell'Anno, & Pusceddu, 2004;Poloczanska et al, 2013;Tittensor et al, 2010;Woolley et al, 2016;Yasuhara & Danovaro, 2016;Yasuhara, Tittensor, Hillebrand, & Worm, 2017). In the deep sea, temperature has been shown to have a significant influence over the ecological characteristics of benthic assemblages, including species diversity, biomass, and assemblage composition (Barrio Froján, 2012;Jöst et al, 2019;Yasuhara, Cronin, Menocal, Okahashi, & Linsley, 2008;Yasuhara & Danovaro, 2016;Yasuhara, Okahashi, Cronin, Rasmussen, & Hunt, 2014).…”

Time Machine Biology: Cross-Timescale Integration of Ecology, Evolution, and Oceanography

“…The continuity and duration of marine sediment core data make it possible to assess the relative importance of abrupt versus gradual, secular changes in climate to species and communities, tied to a refined (and ever improving) understanding of past climate change. The importance of spatial and temporal scales in (macro)ecology and (macro)evolution is well known (Brown and Maurer, 1989;Benton, 2009;Blois et al, 2013), with the patterns and drivers differing across space (Chiu et al, 2019;Jöst et al, 2019;Kusumoto et al, 2020) and time (Huang et al, 2018;Yasuhara et al, , 2019b. Marine sediment cores permit interrogation of these dynamics at multiple temporal scales (Lewandowska et al, 2020).…”