Coastal zones sustain extensive biodiversity, support key processes for ocean dynamics, and influence the balance of the global environment. They also provide resources and services to communities, determine their culture, and are the basis for their economic growth. Cartagena Bay in the Colombian Caribbean is the place of the establishment of one of the country’s main cities, which has a great historical and tourist attraction, and it is also the location of the main commercial port and a great variety of industries. Historically, it has been affected by several environmental impacts and intense pollution. This situation has gained the attention of different researchers, so herein is presented a literature review with a systematic approach using RStudio’s bibliometrix on the presence of pollutants and the impact on biodiversity in recent decades, providing a critical analysis of the state of Cartagena Bay and its future needs to ensure its recovery and conservation. In addition, the socioeconomic dynamics related to the environmental state of Cartagena Bay are presented from the framework drivers, pressures, status, impacts, and responses (DPSIR). The update and critical understanding of the sources, fate, and effects of pollution are important not only for the knowledge of the status of this singular ecosystem but also to encourage future research and entrench evidence to support decision makers’ actions. This review highlights that several pollutants that have been detected exceeding sediment quality guidelines, like As, Cd, Hg, and PAH, are also reported to bioaccumulate and cause damage throughout the trophic levels of the coastal environment. In addition, the potential use of sentinel species and biomarkers for their monitoring is discussed. Finally, the factors that cause pollution and threaten the state of the bay continue to exert pressure and impact; thus, there is a call for the further monitoring of this ecosystem and the strengthening of policies and regulations.

The Colombian Caribbean faces environmental challenges due to urbanization, industrialization, and maritime activities, which introduce pollutants such as heavy metals, hydrocarbons, and microplastics into aquatic ecosystems. Perna viridis (Asian green mussel), an invasive species that has been established in Cartagena Bay since 2009, exhibits potential bioaccumulation capacity, making it a promising biomonitor. This study assessed the concentrations of mercury (Hg), cadmium (Cd), lead (Pb), and selenium (Se) in P. viridis across two key sites—a port area at the Cartagena Bay (CB) and Virgen marsh (VM) in Colombia—from 2020 to 2023. Seasonal variations driven by La Niña and El Niño phenomena significantly influenced metal concentrations, with transitional periods modulating pollutant accumulation. The levels of trace metals in soft tissue of P. viridis (dry weight) ranged from 0.0003 to 0.0039 µg/g (Cd), 0.04 to 0.21 µg/g (Hg), 0.05 to 1.18 µg/g (Pb), and 0.0029 to 0.0103 µg/g (Se). In suspended particulate matter (SPM), Cd ranged from 0.07 to 0.33 µg/g; Pb ranged from 4.94 to 25.66 µg/g; and Hg ranged from 0.18 to 1.20 µg/g. Results revealed differences in metal concentrations between sites and seasons, highlighting the role of environmental and anthropogenic factors in pollutant distribution. The findings confirm P. viridis as an effective biomonitor of complex pollution scenarios in Cartagena Bay. However, its invasive status highlights ecological risks to be addressed, such as interaction with native bivalves and benthic community structures. These results emphasize the need for ongoing monitoring efforts to mitigate pollution and preserve marine biodiversity in the Colombian Caribbean.

This study evaluates the potential of the flat oyster Isognomon alatus as a biomonitor species for metal contamination, based on bioaccumulation patterns in adults and juveniles present in the Seaflower Biosphere Reserve on San Andrés Island (Colombia) in three seasons climatic. The analysis by Atomic Absorption Spectrometry of I. alatus specimens and water samples collected in SAI (2009 and 2010) allowed us to observe higher concentrations (Max: 2,235 μg/g dry weight) of Zn in seston, compared to Cd (Max: 0.078 μg/g dry weight) and Cu (Max: 0.069 μg/g dry weight). These concentrations varied seasonally in relation to the intensity of rainfall in the area. By means of a two-way ANOVA (p<0.05), statistically significant differences were determined between sampling sites and seasons for metal concentrations (Cd, Cu, Zn) in organisms and for the Bioconcentration Factor (BCF), which corresponds to the relationship between the metal concentration in oysters and seston. Regarding the effect of age/size, the Cd concentration obtained and evaluated by ranges in juveniles is significantly lower than that observed in adults during the dry season, like what was recorded in other oyster studies. A comparison of the results obtained with the available data for I. alatus indicated that SAI had been impacted by Zn contamination. The results confirm the bioavailability of Cd previously reported; and the bioaccumulation of metals, especially Cu and Zn, according to FBC estimates.

The majority of marine plastic waste is anthropogenic. Recently, several reports have documented negative impacts on tourist beaches in the Caribbean, especially on the fauna associated with marine coastal ecosystems. This study analyzes the characteristics and seasonal variation of plastic waste considering the most common sizes on two beaches (Spratt Bight and Los Charquitos) of San Andres Island in 2021. Nine hundred twenty-six plastic items were collected from three perpendicular transects established in three beach strips. The largest number of plastic debris (416 items) was found in the dry season (March), followed by the transition (August, 280 items) and rainy season (November, 230 items). Regarding relative abundance, microplastics are the most predominant size class, while fragments are the most common form of plastic debris on San Andres Island beaches.

The sand dollar Mellita quinquiesperforata (Leske, 1778) is a lunulate echinoderm inhabiting sandy substrates in the Caribbean Sea's shallow coastal waters. This species functions as an environmental engineer, altering substrate characteristics, yet few studies have examined its abundance, size distribution, or relationship with substrate features. This study examines the impact of climate seasons, months, and substrate features on the relative abundance and size of M. quinquiesperforata, based on monthly observations conducted at La Boquilla beach (northern Cartagena de Indias, Colombia) from January to September 2023. According to our observations, aggregations of M. quinquiesperforata were observed, with densities ranging from 5 to 87 ind per m2. Relative abundance varied significantly with climatic seasons (Kruskal-Wallis test chi-squared = 42.041, P-value = 7.427e-10), with the lowest densities recorded in July (transition season, 5-20 ind m-2) and the highest in April (dry season, 10-45 ind m-2). No individuals were observed during January and February. Aggregations were most prevalent 31-40 m from the low-tide line, where the highest densities were recorded. Size measurements ranged from 0.7 to 9 cm, with an average of 5.76 ± 0.67 cm (n = 2.526), while weights averaged 17.3 ± 5.6 g. Significant differences in size were observed between climatic seasons (chi-squared = 9.4294, P-value = 0.008962), months (chi-squared = 58.891, df = 5, P-value = 2.06e-11), and spatial distribution (distance from the low-tide line) (chi-squared = 13.899, P-value = 0.0009591). No significant differences were detected in weight. Most individuals collected were adults, suggesting limited recruitment during the study period. Abundance estimates for La Boquilla beach were lower than reported for other South American localities, highlighting potential site-specific differences in environmental or ecological factors affecting M. quinquiesperforata populations. These findings contribute to a better understanding of the population dynamics and habitat preferences of this key benthic species in the Caribbean region.