Assessing coral health in South Water Caye Marine Reserve, Belize

This time series dataset includes weekly and bi-weekly discrete seawater samples of pH and total alkalinity, dissolved inorganic carbon, phosphates and profile measurements of temperature and salinity from 2009 to 2015. These are used to track the dynamics and controls on local carbon chemistry at the southwest part of Puerto Rico in support of the ocean acidification and water quality research in regional coastal and near-shore zones. Some of these environmental parameters have been monitored since 2009 when the National Oceanic and Atmospheric Administration (NOAA) Coral Health and Monitoring Program established the Atlantic Ocean Acidification Test-Bed (AOAT) at the Marine Reserve of La Parguera, Puerto Rico. As a key part of this project, a moored autonomous pCO2 system (MAPCO2) was deployed along the fore-reef of Enrique shelf reef and a discrete sampling at the Marine Reserve for data validation and calibration commenced. This monitoring effort supports the requirements of the recent implementation of La Parguera as a Class III climate and ecosystem monitoring station through the National Coral Reef Monitoring Program (NCRMP) in support of the NOAA Coral Reef Conservation Program (CRCP) and the Ocean Acidification Program (OAP).

Coral reefs are sensitive to environmental perturbations, and an unprecedented decline in corals has been reported globally as a result of increasing global and local stressors including excessive input of anthropogenic nutrients. This study investigated the effect of land-based sources of nutrients (N and P) associated with sewage, on ocean water quality and the health of corals in Mombasa Marine National Park and Reserve in Kenya to inform integrated coastal zone management and ocean governance. A year-long study was conducted to determine water quality according to protocols described in Grasshoff et al. (2007). Coral health status was also monitored using Underwater Visual Census (UVC) to record coral reef ecological parameters. The study area’s temperature, salinity, pH and dissolved oxygen were within the recommended standards for healthy coral reefs. The study indicated that land-based nutrients, Chlorophyll-a (Chl a) and total suspended solids (TSS), are the key factors affecting corals and could be the reason for the observed coral health, which ranged from fairly healthy to unhealthy. On average, nutrient concentrations were higher than recommended to maintain at least 50% coral coverage. Ammonia was the dominant form of nitrogen ranging from 0.105 to 0.4130 mg/l, while nitrate concentrations were 0.0348-0.0468 mg/l, indicating the possibility of blooming algal species in the area. Total suspended solids were above the recommended values, ranging between 33.5 and 79.3mg/l and Chl a 0.7114 and 1.58 μg/l. The study concluded that land-based nutrient load influenced coral reef health during the study period. It recommends that land-based pollution needs to be addressed as part of a holistic, integrated coastal zone management approach supporting practical, sustainable and legal management of nutrient discharge into the marine environment to preserve the water quality of Mombasa Marine National Park and Reserve.

Halos around coral reefs are landscape-scale patterns arising from multispecies interactions that collectively structure reefscapes over many thousands of square kilometers. First described in the 1960s, halos are known from a handful of locations and continue to captivate scientists. What remains unknown is how globally widespread, persistent, and dynamic halos are. We examined satellite imagery of reefs globally, coupled with in situ field observations, to show that halos are a globally ubiquitous, persistent, yet dynamic ecological phenomenon spanning vastly different systems. We further document the previously undescribed presence of halos outside the tropics surrounding seagrass "reefs" and highlight the temporal scales over which coral reef halos change, merge, and persist. Specifically, we show that halos can change in size over relatively short temporal scales of months, despite persisting over decades. In doing so, we document patterns suggesting that additional biophysical mechanisms than previously assumed may shape halos. Understanding the full suite of mechanisms governing halo formation and maintenance may enable us to use them as proxies for species interactions. Given the global extent of halos, their role in affecting sedimentary carbon storage, and their relationship with marine reserve existence and maturity, they may ultimately serve as globally relevant indicators of coral reef ecosystem functioning and health.

Bleaching of Oculina patagonica has been extensively studied in the Eastern Mediterranean Sea, although no studies have been carried out in the Western basin. In 1996 Vibrio mediterranei was reported as the causative agent of bleaching in O. patagonica but it has not been related to bleached or healthy corals since 2003, suggesting that it was no longer involved in bleaching of O. patagonica. In an attempt to clarify the relationship between Vibrio spp., seawater temperature and coral diseases, as well as to investigate the putative differences between Eastern and Western Mediterranean basins, we have analysed the seasonal patterns of the culturable Vibrio spp. assemblages associated with healthy and diseased O. patagonica colonies. Two sampling points located in the Spanish Mediterranean coast were chosen for this study: Alicante Harbour and the Marine Reserve of Tabarca. A complex and dynamic assemblage of Vibrio spp. was present in O. patagonica along the whole year and under different environmental conditions and coral health status. While some Vibrio spp. were detected all year around in corals, the known pathogens V. mediteranei and V. coralliilyticus were only present in diseased specimens. The pathogenic potential of these bacteria was studied by experimental infection under laboratory conditions. Both vibrios caused diseased signs from 24 °C, being higher and faster at 28 °C. Unexpectedly, the co-inoculation of these two Vibrio species seemed to have a synergistic pathogenic effect over O. patagonica, as disease signs were readily observed at temperatures at which bleaching is not normally observed.

The marine ecosystems of the Galapagos Marine Reserve (GMR) host unique biological communities, including some of the world’s most biodiverse coral reefs. However, global climate variability increasingly threatens these reefs, with the GMR experiencing similar degradation. Monitoring these vulnerable sites, especially during and after El Niño Southern Oscillation (ENSO) events, is essential for understanding how temperature shifts impact these ecosystems. Using DSLR cameras, overlapping images were captured across eight 10x10 m plots in key coral areas within the GMR, enabling the creation of photomosaic 3D models. Advanced techniques, such as Structure from Motion (SfM) for high-resolution 3D reef mapping and deep learning models for ecological analysis, segmentation, and plot registration, have been employed to facilitate temporal comparisons of coral health and coverage. This research offers an in-depth view of the GMR’s response to climate variability, underscoring the resilience and adaptability of its subtidal communities to environmental shifts. The findings provide the Galapagos National Park Directorate (GNPD) with critical insights to inform management strategies aimed at bolstering coral resilience against future climatic events.