- Email: [email protected]
Towards a coastal condition assessment and monitoring of the Gulf of Mexico Large Marine Ecosystem (GoM LME): Terminos Lagoon pilot site
Environmental Development 7 (2013) 72–79
Contents lists available at SciVerse ScienceDirect
Environmental Development journal homepage: www.elsevier.com/locate/envdev
Towards a coastal condition assessment and monitoring of the Gulf of Mexico Large Marine Ecosystem (GoM LME): Terminos Lagoon pilot site Virginia García-Ríos a,n, Leticia Alpuche-Gual c, Jorge Herrera-Silveira b, Jorge Montero-Muñoz b, Sara Morales-Ojeda b, Daniel Pech d, María Fernanda Cepeda-González a, Omar Zapata-Pérez b, Gerardo Gold-Bouchot b a
Gulf of Mexico Large Marine Ecosystem Project, Apdo. Postal 73-Cordemex, Merida, Yucatan 97310, Mexico Departamento de Recursos del Mar, CINVESTAV-IPN, Unidad Merida, Apdo. Postal 73-Cordemex, Merida, Yucatan 97310, Mexico c Instituto EPOMEX, UAC, Av. Agustín Melgar s/n entre Juan de la Barrera y Calle 20, Colonia Buenavista, 24039 Campeche, Campeche, Mexico d Departamento de Ciencias de la Sustentabilidad, ECOSUR, Unidad Campeche, Av. Rancho Polígono 2-A, Col. Ciudad Industrial, 24500 Lerma, Campeche, Mexico b
a r t i c l e in f o
a b s t r a c t
Article history: Received 1 February 2013 Accepted 18 April 2013
The demonstration project on monitoring and environmental evaluation of the Gulf of Mexico Large Marine Ecosystem (GoM LME) aims to provide the basis for the joint monitoring of the Gulf of Mexico between the USA and Mexico. The project is roughly based on the National Coastal Condition (NCC) reported by the USEPA–NOAA–USGS and changes to the approach used in the USA have been adopted. It consists of five modules: Habitat degradation, water quality, sediment quality, fish, and benthic fauna. For each module different parameters are measured, and categorized as being in “good” (score of 5), “fair” (score of 3) or “poor” (score of 1) condition according to pre-determined criteria. The Coastal Condition Index is calculated as the mean of the scores for all modules. Results were presented to stakeholders and environmental managers as maps with color-coded “street lights” indicating the status of each sampling station and parameter. Terminos Lagoon in Mexico
Keywords: Monitoring Terminos Lagoon Coastal condition Ecosystem health Transboundry environmental problems Gulf of Mexico Large Marine Ecosystem
n
Corresponding autor. Tel.: +52 999 9429400. E-mail address: [email protected], [email protected] (g.-R. virginia).
2211-4645/$ - see front matter & 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.envdev.2013.04.007
V. García-Ríos et al. / Environmental Development 7 (2013) 72–79
73
was exclusively used as a site for the demonstration study. We discuss the importance of adopting a bilateral (Mexico-US) transboundary monitoring strategy to assess the coastal condition of the GoM LME. & 2013 Elsevier B.V. All rights reserved.
1. Introduction 1.1. Gulf of Mexico Large Marine Ecosystem (GoM LME) The Gulf of Mexico is a deep marginal sea located at the southeastern corner of North America. It is the ninth largest body of water in the world with a surface area of 1.51 106 km2 and a volume of 2.43 106 km3, representing 0.4% and 0.2% of the surface area and volume of the world's oceans, respectively. The Gulf is connected to the Caribbean Sea through the Yucatan channel and to the North Atlantic Ocean though the Straits of Florida. The basin is surrounded by three continental shelves: Florida, to the East; Texas-Louisiana, to the Northwest; and Campeche and Yucatan, to the South (Fig. 1). The GoM LME is an important center of marine and estuarine biodiversity, with the presence of cosmopolitan and endemic species. The ecosystem is considered as reserve of high micro- and macrobiologic diversity with mangroves, coral reefs and marine grasses, possess high species richness, marine food production as well as oil and gas production. 1.2. Transboundary environmental problems The Gulf of Mexico faces serious environmental problems. According to the Gulf of Mexico LME Transboundary Diagnostic Analysis (TDA), coastal degradation was identified as one of the main problems (Gulf of Mexico TDA, 2011) in the Gulf of Mexico. Coastal degradation is caused by natural variations which are part of the ecosystems, but could be magnified by human activities. Thus an efficient integrated monitoring and assessment program in the adjacent countries could be helpful in the development of mitigation strategies and fiscal and environmental accountability. Monitoring is an essential part of adaptive management; it allows for
Fig. 1. Gulf of Mexico, and demonstration project pilot site (Terminos Lagoon) (INEGI, 2008).
74
V. García-Ríos et al. / Environmental Development 7 (2013) 72–79
the incorporation of new information and follows the efficacy of management actions (GaertnerMazouni and De Witt, 2012). For that reason the aim of the present work was built upon the USA experience (EPA, NOAA and USGS) on coastal ecosystem health monitoring to initiate the monitoring in the Mexican portion of the GoM-LME. With this work it is expected to provide the basis for bilateral cooperation, establish a consistent design for LME-wide monitoring, establish a common set of indicators and sampling design, and allow both countries to determine the status and trends of the coastal environment to assess the efficacy of environmental management decisions. In the present paper we present the first results of the joint assessment and discuss the local strategies in the implementation of the monitoring pilot project protocols.
2. Material and methods The monitoring pilot project was part of the regional initiative supported through a combination of Global Environmental Facility (GEF) funding and with co-financing from the USA and Mexico. 2.1. Site of study The pilot project was developed in Terminos Lagoon, Mexico. It is a very complex system of estuaries, lagoons, wetlands and associated terrestrial ecosystems. It covers 2500 km2 in the southwestern Gulf of Mexico. It is in the watershed of the Usumacinta and Grijalva rivers. This has one of the highest biodiversity of Mexico. Although it represents only 4.7% of the land mass of the country, its ecosystems are habitat to 64% of national biodiversity. This basin provides 30% of the runoff from the rivers of Mexico (147 km3/year) and make this huge ecological hydrosystem the habitat to 67% of living species in the country and ranks first nationally in the number of higher plants (20,000 species), freshwater fish (150 species), amphibians (180 species) and birds (240 species) (Toledo, 2003). It is also home to 1468 wildlife species including terrestrial and aquatic vertebrates and 30 endemic species of amphibians, reptiles, birds and mammals. It is one of five areas of international importance for the Gulf of Mexico (Yáñez-Arancibia et al., 2013). Although a protected area, it harbors many endangered, threatened and protected species. Along with another protected area, Centla Marshlands, it receives the total discharge of the Grijalva– Usumacinta river systems into the sea. Also this runoff is the second most important in the Gulf of Mexico after the Mississippi river. The high freshwater flow creates a seasonal front in the continental shelf, blocking water circulation and mixing across the shelf and thus trapping nutrients, suspended matter and pollutants near shore. The lagoon has high primary productivity, and it is considered the most important breeding ground for several species of shrimp and finfish in the southern Gulf of Mexico. The largest commercial fishing fleet in the Mexican portion of the Gulf depends on these resources. High biological diversity and productivity of Terminos Lagoon is mainly threatened by the large agricultural areas surrounding it (mainly rice and sugar cane), population growth, oil extraction and transport activities. Roughly 87% of domestic oil production is extracted offshore which is very close to the lagoon. In terms of its importance from an ecosystem-perspective and the level of impact it receives, Terminos Lagoon constitutes an ideal site for this pilot project considering its biological and socioeconomic importance. The strong relationship between environmental health and important fisheries resources provides a unique opportunity to demonstrate the use of monitoring as an integral part of adaptive management, and both environmental and fiscal accountability. 2.2. Coastal condition index and adjusted indicators Based on the experience of the National Coastal Assessment Program in the United States a comprehensive approach (that includes water quality, sediment quality, contaminants in fish, benthic
V. García-Ríos et al. / Environmental Development 7 (2013) 72–79
75
community, and habitat degradation) was used. The approach gives a balanced assessment of environmental status, which if associated with probability based sampling design, provides a robust, cost effective and scientifically defensible basis for adaptive management and accountability. The coastal condition index approach includes a set of indicators for each module. For each module different parameters were measured and the result was further categorized as “good”, “fair” or “poor” according to pre-established criteria. The Coastal Condition Index was calculated as the mean of the scores for all modules. Overall condition for each region was calculated by summing the scores for the available indices and dividing by the number of available indices (i.e., equally weighted), where good¼ 5; fair ¼3; and poor¼1. Results were presented to stakeholders and environmental managers as maps with color-coded “street lights” indicating the status of each sampling station and parameter. Adequate indicators for the southern Gulf were added or modified from those used in the Northern Gulf. For example, fecal enterococci were added to the water quality module to observe the impact on human health. The impact of contaminants on fish physiology was measured by incorporating molecular biomarkers to the fish module. The complete list of indicators used in the United States, along with the additional indicators used in the present work is shown in Table 1. 2.3. Sampling design The sampling design for the monitoring pilot project was stratified and probability-based, using the zones determined from hydrology as a basis for stratification. This design provided a robust, unbiased and cost-effective way to get environmental results which are scientifically defensible. Fig. 2 shows the location of the 45 probabilistic sites in the stratification zones. The station locations, as well Table 1 Indicators regionally adjusted. Index
EPA indicator
New proposal
Water quality
Chlorophyll a Dissolved inorganic nitrogen
HAB's Nitrites Nitrates Ammonia % Oxygen saturation Total suspended solids Enterococci
Dissolved oxygen Water clarity Dissolved inorganic phosphorus Sediment quality
Contaminants PAH Metals Chlorides Sediment toxicity with Ampelisca abdita test Total organic carbon
Benthic Biotic integrity index based on community characteristics Benthic index based in the relative abundance of condition and biomass assessment of indicator species sensitive, tolerant and resistant species Coastal habitat
Fish tissue
Wetland loss rate
Sea grass Seagrass-seaweed relationship Covertures Biomass Density Species composition
Contaminants
Biomarkers CYP1A expression Vitelogenin expression Glutathione transferase Catalase
PAH Metals Chlorides
76
V. García-Ríos et al. / Environmental Development 7 (2013) 72–79
Fig. 2. Location of the 45 probabilistic sites in the stratification zones in Terminos Lagoon.
as a finalized list of indicators were determined in accordance with the experts in the area for each module. Samples and measurements of water, sediments and fish were taken during the baseline sampling in November, 2010. The historical loss rate of vegetation coverage was evaluated using six Landsat images (TM5 and ETM+), corresponding to the path/row 22–47 and 21–47 of the years 1991, 2001 and 2011. A composition of the false-color image (bands 4, 3, 2) was used and applied the method of unsupervised classification with the ISODATA algorithm. An important component of this project was to ensure the quality and comparability of the results. Thus, a regionally agreed quality control and assurance (QA/QC) component was included to ensure the validity and comparability of all field procedures and laboratory results.
3. Results The overall environmental condition of the Terminos Lagoon has been rated fair, with an overall score of 3 (Fig. 3). Water quality (Fig. 4A) and benthic index (Fig. 4C) are fair; the sediment contaminants index is good (Fig. 4B); the coastal habitat (Fig. 4D) and fish contaminans and biomarkers index (Fig. 4E) are poor. The biological significance of contaminant levels in sediments was evaluated using sediment quality guidelines (Buchman, 2008). These were ERL (effects range low) and ERM (effects range median). These criteria relate concentrations of contaminants in sediment with a low (ERL) and medium probability of toxicity (ERM) respectively. Index rated sediments as good, but in contrast fish tissue contaminants index was poor. In order to elucidate these results it is suggested to include an analysis of other pollutants, such as emerging contaminants in both, fishes and sediments, in futures studies.
4. Discussion The NCCR IV (2012) shows an overall condition score of 2.4 for the USA Gulf coast waters. The assessment was based primarily on the EPA's NCA data collected between 2003 and 2006. However, the score is very similar to the Terminos Lagoon score (3.0) based on data collected in 2010. While the general condition of water quality component was rated as fair, among the variables of this component the chlorophyll-a and phosphates were rated as fair, while dissolved oxygen,
V. García-Ríos et al. / Environmental Development 7 (2013) 72–79
77
Fig. 3. Overall condition of the Terminos Lagoon.
dissolved inorganic nitrogen and transparency were rated as good. The low residence time of the water according to the size of the lagoon (Smith et al., 1999) could be responsible for the condition recorded. The general condition of the benthic fauna was rated as fair probably due to changes in the physical characteristics of the habitat that might be linked to weather seasonality and/or anthropogenic modification of the habitat. The high freshwater input by rainfall or water discharges would drowns the entire lagoon, inducing a marked salinity gradient (Hernández-Guevara et al., 2008). In response, the benthic fauna could vary in relative dominance allowing the presence of tolerant species. Procurement of extra funds has helped to monitor two other sites, viz., Celestún and Sistema Arrecifal Veracruzano (Veracruz Reef System). The second site is important because it allows us to gain experience by replicating the approach in a reef ecosystem and also in the associated watershed. A similar approach was used in three oceanographic cruises on the continental shelf of the Yucatan Peninsula. The assessment helped to establish the environmental baseline of the region as a response to the Macondo oil well accident in the Northern Gulf. Future analysis of the data will allow us to determine whether sampling density can be decreased to reduce costs, to see if the added parameters allow us to distinguish the different sites, and finally if the parameters used are orthogonal (that is, if we are not measuring the same thing more than once). Based in this first multidisciplinary monitoring experience we expect to expand the scheme at different identified sites along the Mexican portion of the Gulf of Mexico. Results from current pilot project activities have had a very good response with academia and government promoting the joint assessment of health condition in the Gulf of Mexico.
5. Conclusions Overall score is consistent with those for similar ecosystems in the Northern Gulf of Mexico. The approach using the NCC scheme has proved to be useful for the conditions in Mexico, and particularly the modifications adopted for Mexico's conditions.
78
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Fig. 4. Environmental condition of the Terminos Lagoon, Mexico. (A) Water quality index. (B) Sediment contaminants index. (C) Benthic index. (D) Coastal habitat index (historical coverage loss between 1991 and 2011). (E) Fish tissue contaminants and biomarkers index.
This monitoring approach has been replicated in an offshore ecosystem (the continental shelf North of the Yucatan Peninsula) and two other coastal ecosystems in the Southern Gulf of Mexico: Celestun and the reef system in Veracruz, and is expected to be implemented in different inshore ecosystem of the Gulf of Mexico. Detection limits and species identification should be improved to enhance the comparability with measurements in the USA (NCCR IV, 2012).
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References Buchman, M.F., 2008. Screening Quick Reference Tables, NOAA OR&R Report 08-1. Office of Response and Restoration Division, National Oceanic and Atmospheric Administration, Seattle WA 34pp.. Gaertner-Mazouni, N., De Witt, R., 2012. Exploring new issues for coastal lagoons monitoring and management. Estuarine, Coastal and Shelf Science 114, 1–6. Gulf of Mexico TDA, 2011. Transboundary Diagnostic Analysis. Integrated Assessment and Management of the Gulf of Mexico Large Marine Ecosysem. 〈http://www.gulfofmexicoproject.org〉. Hernández-Guevara, NA., Pech, D., Ardisson-Herrera, P-L., 2008. Temporal trends in benthic macrofauna composition in response to seasonal variation in a tropical coastal lagoon, Celestun, Gulf of Mexico. Marine and Freshwater Research 59, 772–779. INEGI, 2008. División política Estatal. Comisión Nacional para el Conocimiento y Uso de la Biodiversidad. Versión 2. Escala 1:250000. Modificado de Conjunto de Datos vectoriales y toponimia de la carta topográfica. Serie IIIInstituto Nacional de Estadística Geografía e Informática (2003–2004). NCCR IV, 2012. National Coastal Condition Report. 〈http://www.epa.gov/nccr〉. Smith, S.V., Marshall Crossland, J.I., Crossland, C.J., 1999. Mexican and Central American Coastal Lagoon Systems: Carbon, Nitrogen and Phosphorus Fluxes (Regional Workshop II), LOICZ Reports & Studies No. 13. LOICZ IPO, Texel, The Netherlands ii+115pp. Toledo, Alejandro, 2003. Ríos, costas, mares. Hacia un análisis integrado de las regiones hidrológicas de México. Instituto Nacional de Ecología-SEMARNAT, Mexico. Yáñez-Arancibia, A., Day, J.W., Reyes, E., 2013. Understanding the ecosystem-based management approach in the Gulf of Mexico. Journal of Coastal Research 63, 243–261. (special issue).
Contents lists available at SciVerse ScienceDirect
Environmental Development journal homepage: www.elsevier.com/locate/envdev
Towards a coastal condition assessment and monitoring of the Gulf of Mexico Large Marine Ecosystem (GoM LME): Terminos Lagoon pilot site Virginia García-Ríos a,n, Leticia Alpuche-Gual c, Jorge Herrera-Silveira b, Jorge Montero-Muñoz b, Sara Morales-Ojeda b, Daniel Pech d, María Fernanda Cepeda-González a, Omar Zapata-Pérez b, Gerardo Gold-Bouchot b a
Gulf of Mexico Large Marine Ecosystem Project, Apdo. Postal 73-Cordemex, Merida, Yucatan 97310, Mexico Departamento de Recursos del Mar, CINVESTAV-IPN, Unidad Merida, Apdo. Postal 73-Cordemex, Merida, Yucatan 97310, Mexico c Instituto EPOMEX, UAC, Av. Agustín Melgar s/n entre Juan de la Barrera y Calle 20, Colonia Buenavista, 24039 Campeche, Campeche, Mexico d Departamento de Ciencias de la Sustentabilidad, ECOSUR, Unidad Campeche, Av. Rancho Polígono 2-A, Col. Ciudad Industrial, 24500 Lerma, Campeche, Mexico b
a r t i c l e in f o
a b s t r a c t
Article history: Received 1 February 2013 Accepted 18 April 2013
The demonstration project on monitoring and environmental evaluation of the Gulf of Mexico Large Marine Ecosystem (GoM LME) aims to provide the basis for the joint monitoring of the Gulf of Mexico between the USA and Mexico. The project is roughly based on the National Coastal Condition (NCC) reported by the USEPA–NOAA–USGS and changes to the approach used in the USA have been adopted. It consists of five modules: Habitat degradation, water quality, sediment quality, fish, and benthic fauna. For each module different parameters are measured, and categorized as being in “good” (score of 5), “fair” (score of 3) or “poor” (score of 1) condition according to pre-determined criteria. The Coastal Condition Index is calculated as the mean of the scores for all modules. Results were presented to stakeholders and environmental managers as maps with color-coded “street lights” indicating the status of each sampling station and parameter. Terminos Lagoon in Mexico
Keywords: Monitoring Terminos Lagoon Coastal condition Ecosystem health Transboundry environmental problems Gulf of Mexico Large Marine Ecosystem
n
Corresponding autor. Tel.: +52 999 9429400. E-mail address: [email protected], [email protected] (g.-R. virginia).
2211-4645/$ - see front matter & 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.envdev.2013.04.007
V. García-Ríos et al. / Environmental Development 7 (2013) 72–79
73
was exclusively used as a site for the demonstration study. We discuss the importance of adopting a bilateral (Mexico-US) transboundary monitoring strategy to assess the coastal condition of the GoM LME. & 2013 Elsevier B.V. All rights reserved.
1. Introduction 1.1. Gulf of Mexico Large Marine Ecosystem (GoM LME) The Gulf of Mexico is a deep marginal sea located at the southeastern corner of North America. It is the ninth largest body of water in the world with a surface area of 1.51 106 km2 and a volume of 2.43 106 km3, representing 0.4% and 0.2% of the surface area and volume of the world's oceans, respectively. The Gulf is connected to the Caribbean Sea through the Yucatan channel and to the North Atlantic Ocean though the Straits of Florida. The basin is surrounded by three continental shelves: Florida, to the East; Texas-Louisiana, to the Northwest; and Campeche and Yucatan, to the South (Fig. 1). The GoM LME is an important center of marine and estuarine biodiversity, with the presence of cosmopolitan and endemic species. The ecosystem is considered as reserve of high micro- and macrobiologic diversity with mangroves, coral reefs and marine grasses, possess high species richness, marine food production as well as oil and gas production. 1.2. Transboundary environmental problems The Gulf of Mexico faces serious environmental problems. According to the Gulf of Mexico LME Transboundary Diagnostic Analysis (TDA), coastal degradation was identified as one of the main problems (Gulf of Mexico TDA, 2011) in the Gulf of Mexico. Coastal degradation is caused by natural variations which are part of the ecosystems, but could be magnified by human activities. Thus an efficient integrated monitoring and assessment program in the adjacent countries could be helpful in the development of mitigation strategies and fiscal and environmental accountability. Monitoring is an essential part of adaptive management; it allows for
Fig. 1. Gulf of Mexico, and demonstration project pilot site (Terminos Lagoon) (INEGI, 2008).
74
V. García-Ríos et al. / Environmental Development 7 (2013) 72–79
the incorporation of new information and follows the efficacy of management actions (GaertnerMazouni and De Witt, 2012). For that reason the aim of the present work was built upon the USA experience (EPA, NOAA and USGS) on coastal ecosystem health monitoring to initiate the monitoring in the Mexican portion of the GoM-LME. With this work it is expected to provide the basis for bilateral cooperation, establish a consistent design for LME-wide monitoring, establish a common set of indicators and sampling design, and allow both countries to determine the status and trends of the coastal environment to assess the efficacy of environmental management decisions. In the present paper we present the first results of the joint assessment and discuss the local strategies in the implementation of the monitoring pilot project protocols.
2. Material and methods The monitoring pilot project was part of the regional initiative supported through a combination of Global Environmental Facility (GEF) funding and with co-financing from the USA and Mexico. 2.1. Site of study The pilot project was developed in Terminos Lagoon, Mexico. It is a very complex system of estuaries, lagoons, wetlands and associated terrestrial ecosystems. It covers 2500 km2 in the southwestern Gulf of Mexico. It is in the watershed of the Usumacinta and Grijalva rivers. This has one of the highest biodiversity of Mexico. Although it represents only 4.7% of the land mass of the country, its ecosystems are habitat to 64% of national biodiversity. This basin provides 30% of the runoff from the rivers of Mexico (147 km3/year) and make this huge ecological hydrosystem the habitat to 67% of living species in the country and ranks first nationally in the number of higher plants (20,000 species), freshwater fish (150 species), amphibians (180 species) and birds (240 species) (Toledo, 2003). It is also home to 1468 wildlife species including terrestrial and aquatic vertebrates and 30 endemic species of amphibians, reptiles, birds and mammals. It is one of five areas of international importance for the Gulf of Mexico (Yáñez-Arancibia et al., 2013). Although a protected area, it harbors many endangered, threatened and protected species. Along with another protected area, Centla Marshlands, it receives the total discharge of the Grijalva– Usumacinta river systems into the sea. Also this runoff is the second most important in the Gulf of Mexico after the Mississippi river. The high freshwater flow creates a seasonal front in the continental shelf, blocking water circulation and mixing across the shelf and thus trapping nutrients, suspended matter and pollutants near shore. The lagoon has high primary productivity, and it is considered the most important breeding ground for several species of shrimp and finfish in the southern Gulf of Mexico. The largest commercial fishing fleet in the Mexican portion of the Gulf depends on these resources. High biological diversity and productivity of Terminos Lagoon is mainly threatened by the large agricultural areas surrounding it (mainly rice and sugar cane), population growth, oil extraction and transport activities. Roughly 87% of domestic oil production is extracted offshore which is very close to the lagoon. In terms of its importance from an ecosystem-perspective and the level of impact it receives, Terminos Lagoon constitutes an ideal site for this pilot project considering its biological and socioeconomic importance. The strong relationship between environmental health and important fisheries resources provides a unique opportunity to demonstrate the use of monitoring as an integral part of adaptive management, and both environmental and fiscal accountability. 2.2. Coastal condition index and adjusted indicators Based on the experience of the National Coastal Assessment Program in the United States a comprehensive approach (that includes water quality, sediment quality, contaminants in fish, benthic
V. García-Ríos et al. / Environmental Development 7 (2013) 72–79
75
community, and habitat degradation) was used. The approach gives a balanced assessment of environmental status, which if associated with probability based sampling design, provides a robust, cost effective and scientifically defensible basis for adaptive management and accountability. The coastal condition index approach includes a set of indicators for each module. For each module different parameters were measured and the result was further categorized as “good”, “fair” or “poor” according to pre-established criteria. The Coastal Condition Index was calculated as the mean of the scores for all modules. Overall condition for each region was calculated by summing the scores for the available indices and dividing by the number of available indices (i.e., equally weighted), where good¼ 5; fair ¼3; and poor¼1. Results were presented to stakeholders and environmental managers as maps with color-coded “street lights” indicating the status of each sampling station and parameter. Adequate indicators for the southern Gulf were added or modified from those used in the Northern Gulf. For example, fecal enterococci were added to the water quality module to observe the impact on human health. The impact of contaminants on fish physiology was measured by incorporating molecular biomarkers to the fish module. The complete list of indicators used in the United States, along with the additional indicators used in the present work is shown in Table 1. 2.3. Sampling design The sampling design for the monitoring pilot project was stratified and probability-based, using the zones determined from hydrology as a basis for stratification. This design provided a robust, unbiased and cost-effective way to get environmental results which are scientifically defensible. Fig. 2 shows the location of the 45 probabilistic sites in the stratification zones. The station locations, as well Table 1 Indicators regionally adjusted. Index
EPA indicator
New proposal
Water quality
Chlorophyll a Dissolved inorganic nitrogen
HAB's Nitrites Nitrates Ammonia % Oxygen saturation Total suspended solids Enterococci
Dissolved oxygen Water clarity Dissolved inorganic phosphorus Sediment quality
Contaminants PAH Metals Chlorides Sediment toxicity with Ampelisca abdita test Total organic carbon
Benthic Biotic integrity index based on community characteristics Benthic index based in the relative abundance of condition and biomass assessment of indicator species sensitive, tolerant and resistant species Coastal habitat
Fish tissue
Wetland loss rate
Sea grass Seagrass-seaweed relationship Covertures Biomass Density Species composition
Contaminants
Biomarkers CYP1A expression Vitelogenin expression Glutathione transferase Catalase
PAH Metals Chlorides
76
V. García-Ríos et al. / Environmental Development 7 (2013) 72–79
Fig. 2. Location of the 45 probabilistic sites in the stratification zones in Terminos Lagoon.
as a finalized list of indicators were determined in accordance with the experts in the area for each module. Samples and measurements of water, sediments and fish were taken during the baseline sampling in November, 2010. The historical loss rate of vegetation coverage was evaluated using six Landsat images (TM5 and ETM+), corresponding to the path/row 22–47 and 21–47 of the years 1991, 2001 and 2011. A composition of the false-color image (bands 4, 3, 2) was used and applied the method of unsupervised classification with the ISODATA algorithm. An important component of this project was to ensure the quality and comparability of the results. Thus, a regionally agreed quality control and assurance (QA/QC) component was included to ensure the validity and comparability of all field procedures and laboratory results.
3. Results The overall environmental condition of the Terminos Lagoon has been rated fair, with an overall score of 3 (Fig. 3). Water quality (Fig. 4A) and benthic index (Fig. 4C) are fair; the sediment contaminants index is good (Fig. 4B); the coastal habitat (Fig. 4D) and fish contaminans and biomarkers index (Fig. 4E) are poor. The biological significance of contaminant levels in sediments was evaluated using sediment quality guidelines (Buchman, 2008). These were ERL (effects range low) and ERM (effects range median). These criteria relate concentrations of contaminants in sediment with a low (ERL) and medium probability of toxicity (ERM) respectively. Index rated sediments as good, but in contrast fish tissue contaminants index was poor. In order to elucidate these results it is suggested to include an analysis of other pollutants, such as emerging contaminants in both, fishes and sediments, in futures studies.
4. Discussion The NCCR IV (2012) shows an overall condition score of 2.4 for the USA Gulf coast waters. The assessment was based primarily on the EPA's NCA data collected between 2003 and 2006. However, the score is very similar to the Terminos Lagoon score (3.0) based on data collected in 2010. While the general condition of water quality component was rated as fair, among the variables of this component the chlorophyll-a and phosphates were rated as fair, while dissolved oxygen,
V. García-Ríos et al. / Environmental Development 7 (2013) 72–79
77
Fig. 3. Overall condition of the Terminos Lagoon.
dissolved inorganic nitrogen and transparency were rated as good. The low residence time of the water according to the size of the lagoon (Smith et al., 1999) could be responsible for the condition recorded. The general condition of the benthic fauna was rated as fair probably due to changes in the physical characteristics of the habitat that might be linked to weather seasonality and/or anthropogenic modification of the habitat. The high freshwater input by rainfall or water discharges would drowns the entire lagoon, inducing a marked salinity gradient (Hernández-Guevara et al., 2008). In response, the benthic fauna could vary in relative dominance allowing the presence of tolerant species. Procurement of extra funds has helped to monitor two other sites, viz., Celestún and Sistema Arrecifal Veracruzano (Veracruz Reef System). The second site is important because it allows us to gain experience by replicating the approach in a reef ecosystem and also in the associated watershed. A similar approach was used in three oceanographic cruises on the continental shelf of the Yucatan Peninsula. The assessment helped to establish the environmental baseline of the region as a response to the Macondo oil well accident in the Northern Gulf. Future analysis of the data will allow us to determine whether sampling density can be decreased to reduce costs, to see if the added parameters allow us to distinguish the different sites, and finally if the parameters used are orthogonal (that is, if we are not measuring the same thing more than once). Based in this first multidisciplinary monitoring experience we expect to expand the scheme at different identified sites along the Mexican portion of the Gulf of Mexico. Results from current pilot project activities have had a very good response with academia and government promoting the joint assessment of health condition in the Gulf of Mexico.
5. Conclusions Overall score is consistent with those for similar ecosystems in the Northern Gulf of Mexico. The approach using the NCC scheme has proved to be useful for the conditions in Mexico, and particularly the modifications adopted for Mexico's conditions.
78
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Fig. 4. Environmental condition of the Terminos Lagoon, Mexico. (A) Water quality index. (B) Sediment contaminants index. (C) Benthic index. (D) Coastal habitat index (historical coverage loss between 1991 and 2011). (E) Fish tissue contaminants and biomarkers index.
This monitoring approach has been replicated in an offshore ecosystem (the continental shelf North of the Yucatan Peninsula) and two other coastal ecosystems in the Southern Gulf of Mexico: Celestun and the reef system in Veracruz, and is expected to be implemented in different inshore ecosystem of the Gulf of Mexico. Detection limits and species identification should be improved to enhance the comparability with measurements in the USA (NCCR IV, 2012).
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