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Abstract/Summary
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<jats:p>Abstract. Internal tides are known to be an important source of mixing in the oceans, especially in the bottom boundary layer. The depth of internal-tide generation therefore seems important for benthic life and the formation of cold-water coral mounds, but internal-tide conversion is generally investigated in a depth-integrated sense. Using both idealized and realistic simulations on continental slopes, we found that the depth of internal-tide generation increases with increasing slope steepness and decreases with intensified shallow stratification. The depth of internal-tide generation also shows a typical latitudinal dependency related to Coriolis effects. Using a global database of cold-water corals, we found that, especially in Northern Hemisphere autumn and winter, the global depth pattern of internal-tide generation correlates (rautumn = 0.70, rwinter = 0.65, p < 0.01) with that of cold-water corals: shallowest near the poles and deepest around the Equator, with a decrease in depth around 25° S and N, and shallower north of the Equator than south. We further found that cold-water corals are situated significantly more often on topography that is steeper than the internal-tide beam (i.e. where supercritical reflection of internal tides occurs) than would be expected from a random distribution: in our study, in 66.9 % of all cases, cold-water corals occurred on a topography that is supercritical to the M2 tide whereas globally only 9.4 % of all topography is supercritical. Our findings underline internal-tide generation and the occurrence of supercritical reflection of internal tides as globally important for cold-water coral growth. The energetic dynamics associated with internal-tide generation and the supercritical reflection of internal tides likely increase the food supply towards the reefs in food-limited winter months. With climate change, stratification is expected to increase. Based on our results, this would decrease the depth of internal-tide generation, possibly creating new suitable habitat for cold-water corals shallower on continental slopes.
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1000
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Hinweis
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DeepGreen-ID: 8b91c26b80a0408abb8fd652aa55b1be ; metadata provieded by: DeepGreen (https://www.oa-deepgreen.de/api/v1/), LIVIVO search scope life sciences (http://z3950.zbmed.de:6210/livivo), Crossref Unified Resource API (https://api.crossref.org/swagger-ui/index.html), to.science.api (https://frl.publisso.de/), ZDB JSON-API (beta) (https://zeitschriftendatenbank.de/api/), lobid - Dateninfrastruktur für Bibliotheken (https://lobid.org/resources/search)
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