Surface and Intermediate Water hydrography, planktonic and benthic biota in the Caribbean Sea - Climate, Bio-, and Geosphere linkages
Final Report Abstract
The presented data compilation of physical and hydrochemical parameters of the ambient water masses of CWC sites with L. pertusa in the Atlantic and the Mediterranean has shed new light on the boundary conditions for pristine CWC growth and occurrences. This study extents existing data sets (Dullo et al., 2008, Flogel et al. 2014) regarding a potential density envelope. Furthermore, our new results of hydrochemical parameters reveal a distinct tipping point with respect to DIC. The results show that pristine CWC occurrences are limited to bottom waters with DIC values <2170 pmol/kg. According to our data this applies to coral sites of catgegory I and partly II. These can be found in Norwegian, Scottish, Irish, GoM, and NW African waters, . However, sites of category III are described by higher DIC values such as those in Mediterranean, the Gulf of Cadiz, Mauretania, and the investigated W-Atlantic sites. It was suggested that the carbon for calcification originates from DIC of the ambient sea water (pers. comm., Christina Mueller, NIOO). While CVVCs can increase their internal DIC concentration (McCulloch et al., 2012) it is possible that strongly elevated values cannot be regulated by metabolic/ calcification processes. This clearly needs more research towards the calcification process of scleractinian corals such as L. pertusa. Further, these results ask for the next step—finding a causal relationship between density envelopes and potential nutrient enrichment along isopycnals because corals require nutritious particles to grow and outpace sedimentation rates and to maintain a healthy framework.
