The PO<inf>4</inf>, δ<sup>13</sup>C and Cd depth distributions measured in the N. Atlantic Ocean during recent GEOTRACES and CLIVAR cruises are a result of biological and circulation processes, with in-situ uptake and remineralization of organic matter dominating in the upper ~300m and mixing of water masses dominating in the thermocline and deep sea. The observed slopes of the NO<inf>3</inf>-PO<inf>4</inf>, preindustrial δ<sup>13</sup>C-PO<inf>4</inf> and (by analogy) Cd-PO<inf>4</inf> along isopycnals deviate significantly from that expected from Redfield in the thermocline and deep sea and in each case the observed slope is similar to the slopes of the end-member water masses being mixed. The depth increase in the Cd-PO<inf>4</inf> slope resulting from end-member mixing explains the observed kink at ~1μM PO<inf>4</inf> in the Cd-PO<inf>4</inf> relationship in the N. Atlantic. The observation that the PO<inf>4</inf>- preindustrial δ<sup>13</sup>C-Cd relationship in the modern N. Atlantic is heavily influenced by end-member mixing throughout most of the water column complicates the use of δ<sup>13</sup>C and Cd as proxies of the paleocean's nutrient distribution because changes in the PO<inf>4</inf>-δ<sup>13</sup>C-Cd composition of locally and remotely produced end-members water masses would change the PO<inf>4</inf>, δ<sup>13</sup>C and Cd depth distributions in the paleo N. Atlantic Ocean.
|Original language||English (US)|
|Number of pages||10|
|Journal||Deep-Sea Research Part II: Topical Studies in Oceanography|
|State||Published - Jun 1 2015|
- End-member mixing
- N. Atlantic Ocean
ASJC Scopus subject areas