Global Journal of Science Frontier Research, H: Environment & Earth Science, Volume 22 Issue 5

remains a mystery, and any scientific effort to clarify that are welcome. It is with urgent necessity to spotlight this tragedy in this unique and sensitive reef habitat experiencing ongoing damaging effects that include socio-economic resources losses not yet evaluated and addressed. More than 2 years later now; here we show that the dimension of these impacts, how long they are expected to last, anticipated collateral damages, and then propose mitigation options and mechanisms to reduce the magnitude of any future spill. As the oil becomes less and less visible to the naked eye, and the world is ravaged by new disasters (e.g. COVID-19 pandemic), and it is easy to let the largest oil spill in the South Atlantic fall into oblivion, leaving it to nature and for local human communities to bear its consequences for the decades to come. Our paper deals with a specific site, the “Pirangi Reef area”, which was subjected to the oil spill In October 2019, and was previously studied in 2013 and 2014 by Eichler et al (2019) and Eichler and Moura (2020) with no spotting of oil patches in the sediment or in the water. After the oil spill, we sampled new sites to compare and discuss questions on the human-induced changes on the reef system and in the symbiont-bearing species (SBS) of foraminifera; therefore, water and surface sediments were recovered from areas of small reef patches near tourism boating sites. Here we also discuss impacts and evidence of the oil spill in this biodiverse area, which more than 2 years have passed and we still are uncertain about the type of oil or even culpability; and benthic communities are continuing to suffer consequences of these and other deleterious impacts now for decades. The release of hydrocarbons from oil spills into marine environments has immediate and acute effects on living organisms. In addition, chronic contamination has an effect over time as hydrogen sulphide, methane and ammonia are released in the environment acidifying even more the water-sediment interface. II. S ymbiont- B earing S pecies Numerous publications have shown that certain benthic foraminifera (in particular, species of Amphistegina ) that thrive in and around coral reef habitats are affected by global or local environmental stresses the same way hermatypic corals are. These species belong to several families––both porcelaneous and hyaline––but they all act as hosts to diverse algal endosymbionts comparable to the zooxanthellae of corals. “The potential advantages of algal symbiosis to foraminifers lie in at least three major areas: a) energy from photosynthesis; b) enhancement of calcification; and c) uptake of host metabolites by symbiotic algae” (Hallock, 1999). As with hermatypic corals, these symbiont-bearing foraminifera (SBF) prefer nutrient- poor, shallow, warm-water environments (e.g., Hallock, 2000) and they also have a zooxanthella. Most reef- building corals contain photosynthetic algae, called zooxanthellae, that live in their tissues. The corals and algae have a mutualistic relationship, the same with the foraminifera specimen. The coral/foraminifera shell provides the algae with a protected environment and compounds they need for photosynthesis. In return, the algae produce oxygen and help the coral/foraminifera to remove wastes. Most importantly, zooxanthellae supply the coral/foraminifera with glucose, glycerol, and amino acids, which are the products of photosynthesis. The coral/foraminifera use these products to make proteins, fats, and carbohydrates, and produce calcium carbonate. The relationship between the algae and coral polyp/foraminifera facilitates a tight recycling of nutrients in nutrient-poor tropical waters. In fact, 90% of the organic material photosynthetically produced by the zooxanthellae is transferred to the host coral/foraminifera tissue. This is the driving force behind the growth and productivity of calcium carbonate. Sometimes when corals become physically stressed, the polyps expel their algal cells and the colony takes on a stark white appearance. This is commonly described as “coral bleaching”. If the polyps go for too long without zooxanthellae, coral bleaching can result in the coral's death. The same occur with the larger foraminifera (SBS). Because of their intimate relationship with zooxanthellae, reef-building corals and foraminifera respond to the environment like plants. Reef corals and SBS require clear water so that sunlight can reach their algal cells for photosynthesis. For this reason they are generally found only in waters with small amounts of suspended material, or water of low turbidity and low productivity. This leads to an interesting paradox—coral reefs and SBS require clear, nutrient-poor water, but they are among the most productive and diverse marine environments. An investigation of historical trends in Brazil demonstrated the usefulness of this findings in tracking environmental changes related to ENSO events. III. S tudy A rea The study area is located located on the southern coast of Rio Grande do Norte (RN) state (5° 58'S - 35° 06'W), in Northeastern Brazil (Figure 1) in the coastal zone of the Estuary Pium and inner shelf adjacent to the reef area Pirangi. Reef formation is around 2 Km long and 500m wide, part of a discontinuous reef system extending over the coast of the RN. The reef area is about 1 km 2 and approximately 800m far from the shoreline. During low tides, depth in the vicinity of the reef does not exceed 2m. Water temperature is relatively constant throughout the year (28 to 29°C) and tidal range varies from 0.1 to 2.7 m. Presence of shallow, clear, warm water throughout the © 2022 Global Journals 1 Global Journal of Science Frontier Research Volume XXII Issue V Year 2022 50 ( H ) Version I Evidence of Sediment Sterility and Benthic Quality as Deleterious Consequences After the 2019 Oil Spill in Northeastern Brazil