Fouling communities and degradation of archeological metals in the coastal sea of the Southwestern Gulf of Mexico

Abstract

Corrosion and biofouling phenomena of cast iron and brass were evaluated under natural conditions to determine the degradation process of archeological artifacts. Field exposure studies of experimental materials were conducted over 15 months at an offshore position in the sea of Campeche in the Gulf of Mexico. Corrosion was determined by gravimetric measurements. The community structure of the benthic assemblage inhabiting the surfaces of both materials was evaluated. A total of 53 species was identified. The community in both cases was composed of a small number of species. Encrusting, attached and erect life forms were dominant on iron. Attached life forms were dominant on brass. Biofouling produced a decrease in the weight loss measurements of cast iron samples. Biofouling provided a beneficial factor for in situ preservation of iron archeological artifacts in wreck sites.

Non-destructive electrochemical evaluation of corrosion protection systems subjected to accelerated ageing tests: a strategy for the conservation of colonial Mexican metal alloys

“…In this study, representative cast-iron and brass coupons were manufactured considering the typical composition that these alloys had during the colonial period [43]. Table 1 shows the chemical composition (wt.…”

Agent-based modelling for the study of shipwreck site formation processes: A theoretical framework and conceptual model.

“…Colonisers fell into five categories: 1) organisms with vertical growth, including filamentous macroalgae and bryozoans; 2) encrusting organisms such as sponges, particularly abundant on the iron surface; 3) calcareous tube-forming organisms such as polychaetes; 4) bivalves such as oysters; 5) conical exoskeleton organisms, such as barnacles. 50 The ABM includes only one type of agent that represents colonising organisms. We collectively named these "corals" and their initial-size is 0.0005.…”

“…Thus, data about the movement of marine currents were reported by the seasons of the year i.e., quarterly, 56 while studies on wood and metal degradation, as well as on the growth of colonising organisms, reported data at intervals of six months or one year. 50,57,58 Based on this, we decided that the unit of time that would represent each moment of Execution in the ABM would be one month.…”

“…As we did for wood degradation, for metal elements we also developed linear regression equations for estimating the monthly corrosion of iron and brass pieces based on experimental data reported by López Garrido et al 50 A detailed explanation of the development of the following equations can be found in Ref. 70.…”

“…We based growth rates for both metals on experimental data reported by two studies carried out in the Gulf of Mexico. 50,67 The detailed rationale for determining such growth conditions can be found in Ref. 70.…”