**6. Organisms**

Alonso *et al.* [7] determined Hg contents in sediments and fish (*Eugerres plumieri* mojarra and *Mugil curema* mullet) in the CGSM.

*E. plumieri* is a resident species in the CGSM, a secondary consumer, predominantly of the bivalve *Mytilopsis sallei* that forms banks on the bottom of the swamp, a filter-feeding species, while the mullet (*M. incilis*) is purely detritivorous. In the first, the contents were always about twice as high as in the second. The highest contents corresponded to the samples at the beginning of the year, corresponding to the end of the dry season and the beginning of the rainy season. As mentioned for the bay of Cartagena, the contents in the two species were 7.3 times lower than in BC (**Table 2**).

Campos [12] made the first determinations of Hg in the oyster Crassostrea rhizophorae, in samples collected in January 1987 at two stations located in the northern fringe, one on the western side at the mouth of the Clarín channel that transports and discharges water from of the Magdalena River and the second in the eastern part of the strip, near the mouth of the CGSM in the sea. The contents fluctuated between 0.04 and 0.18 μg Hg g−1 p.s., the latter corresponding to the samples from the Clarín channel.


*The mean value and standard error are given. LOD Limit of detection (7.4 μg Hg g−1 d.w.).*

#### **Table 2.**

*Total mercury content (μg Hg g−1 d.w.) in two species of fish from the CGSM collected between March and November 1996.*

*Mercury in the Colombian Caribbean: The Bay of Cartagena, A Model in Resilience DOI: http://dx.doi.org/10.5772/intechopen.107240*


#### **Table 3.**

*Total mercury content (μg kg−1 fresh weight) in fish species from the CGSM collected between January and December 2018.*

Pinzón-Bedoya *et al.* [13] determined the concentrations of Hg (μg/kg f.w, fresh weight) contained in the muscle of fish species usually consumed by inhabitants of the area (**Table 3**). The compilation of the data shows that the results presented by Alonso *et al.* [7] an increase in the concentrations of Hg has been presented, which could demonstrate that the contributions of this metal persist, whether due to anthropic or natural origin, to the ecosystem; Likewise, it is possible to affirm the existence of accumulative and magnifying processes of Hg from the sediments to fish and bivalves.

Alonso *et al.* [7] indicated that the concentrations of Hg measured in the ecosystem components of the Ciénaga Grande de Santa Marta could be attributed to atmospheric deposition processes since this area did not present a significant industrial development. However, Caballero-Gallardo *et al.* [14] warn that the CGSM receives contaminants from intensive agriculture, especially bananas and African palm. Regardless of the source, the truth is that in the results of Pinzón-Bedoya *et al.* [13] Hg concentrations were positively correlated with morphometric variables (weight and length), evidencing Hg bioaccumulation processes in the aquatic biota of this ecosystem.
