coral reef health

The Hydrogeology of Curaçao: an electrical resistivity study

Abstract

Worldwide, coral reef health is declining rapidly due to both global stressors (climate change) and local stressors (pollution). Reef maintenance on Curaçao focusses on reducing local stressors including terrestrial pollution. One f low path for terrestrial pollution is via submarine groundwater discharge (SGD). Yet, on the island of Curaçao these hotspots of submarine groundwater discharge have not yet been located, let stand quantified. With this research we aimed to increase our understanding of groundwater flow on the island. This will serve as a foothold for future SGD research. To do so, we have conducted 9 electrical resistivity tomography (ERT) measurements to understand (1) the heterogeneity of the lava formation, the main aquifer, (2) the saltwater-fresh water interface at the coast, and (3) the groundwater flow at geological interfaces. To assist in the interpretation of the data we measured groundwater levels and the discharge of Hato spring, in addition to observing local geological outcrops. We discovered that the lava formation is a very heterogenous aquifer due to variety in degree of weathering of the pillow basalt. As a result of the heterogenous permeability, the extent of seawater intrusion in the coastal lava formation is strongly variable. Yet, the lava formation does form a better barrier for sea-fresh water mixing than the limestone terraces. The midden formation (sedimentary rock) forms a thin aquifer near the surface. And, at the interface of lava and midden formation, the groundwater flow is hampered. As a result, the groundwater is confined within the lava formation until the lava formations reservoir “overflows”. The same occurs at the interface of the lava formation and the diorite intrusion. The next step in SGD research is quantifying the seaward groundwater flux where the lava formation is in direct contact with the sea or limestone formation. Here seaward groundwater flow is not hampered by the midden formation or the intrusion and thus forms hotspots of Submarine (polluted) Groundwater Discharge.

Date
2022
Data type
Research report
Theme
Research and monitoring
Report number
MSc Thesis
Geographic location
Curacao

Extrapolated Reef Health Index parameters of Bonaire reefs

Extrapolated zones of the point-based Bonaire coral inventory by de Froe et al. (2017)

Original point data was captured at a 500 meter interval at 5 meter depth (shallow) and at 10 meter depth (deep). This GIS polygon layer contains:

  • percentage of sand
  • percentage of cyano bacteria
  • number of fish species observed
  • weight of carniverous fish
  • weight of herbivorous fish
  • weight of omnivorous fish
  • rugosity
  • coral height
  • percentage of living coral cover
  • number of coral species
  • reef builders
  • rogosity
  • Reef Health Index value 
  • Reef Health Index name (interpretation from the value) 
  • percentage of turf and macro algae
Date
2020
Data type
Maps and Charts
Theme
Research and monitoring
Geographic location
Bonaire
Author
Image

AGRRA - Atlantic & Gulf Rapid Reef Assessment

The Atlantic and Gulf Rapid Reef Assessment (AGRRA) Program champions coral reef conservation and empowers those who protect these diverse ecosystems. We are an international collaboration of scientists, managers, and supporters aimed at improving the regional condition of reefs in the Western Atlantic and Gulf of Mexico. For 20 years, AGRRA has used an innovative regional approach to examine the condition of reef-building corals, algae and fishes and support the conservation of coral reef ecosystems. We curate and distribute data, research and educational materials that support this mission.

The AGRRA program began in 1997 by Dr. Robert N. Ginsburg – the guiding visionary force and mentor behind AGRRA’s efforts for 20 years. Collaborating with numerous colleagues, advisors and students, AGRRA has become a leading advocate for coral reef science and conservation. Dr. Ginsburg has led and supported AGRRA, through his foundation The Ocean Research and Education Foundation (ORE), inspiring new generations of ocean scientists, educators and conservationists.

AGRRA’s initial goals were to provide a standardized assessment of key structural and functional indicators that could be applied to reveal spatial and temporal patterns of regional reef condition. Priority was placed on conducting baseline assessments of remote reefs such as in Cuba, The Bahamas, Panama and Los Roques and on creating educational materials and leading training workshops for in-country partners around the Caribbean.

Since that time, we have collaborated with teams of scientific professionals and partners to fill many gaps, collectively conducted over 2,300 surveys, built one of the largest open-access public databases of coral reef condition, and contributed to numerous peer-reviewed publications and management plans.

A cornerstone of our program has been providing open-access to scientific data collected through our partner network. Over 2,300 surveys and 10,000’s of data scientific metrics of corals, fish, and key invertebrates have been collected throughout reefs in the Caribbean. The AGRRA data portal greatly improves the efficiency, transparency and reliability of data compilation and analysis. AGRRA has become a key source of scientific data used to inform reef policies, legislation, management and conservation.

AGRRA has developed a comprehensive set of visual training tools to help partners learn identification of key reef organisms, their role in reef health, and how to scientifically monitor, track and understand these systems. We strive to promote a learning platform through trainings, exchanges and education materials and to catalyze conservation impact through creative effective communication to wider audiences.

Our goals at AGRRA are to:

  • 1. Conduct scientifically sound, comparable regional surveys of the health of coral reefs using a standardized method
  • 2. Promote a collaborative learning platform through trainings, exchanges and open-access education materials
  • 3. Advance our scientific understanding of coral reefs, analyze data results and provide easy data access with the AGRRA data platform and on-line data entry tools
  • 4. Catalyze conservation impact through partnerships and creative effective communication to wider audiences.
Date
2016
Data type
Portal
Theme
Research and monitoring
Geographic location
Bonaire
Curacao
Saba
Saba bank
St. Eustatius
St. Maarten
Image
AGRRA - Atlantic & Gulf Rapid Reef Assessment