Into the Benthos and Back: What have Infauna Taught Us

ABSTRACT ID 685153 Because of death and gravity, the bottom of the sea is the memory of the ecosystem, where a record of all past events can be found as you move into deeper layers of sediment. Thus, benthos are primary indicators for environmental assessments. As hydrocarbon exploration and production moved to deeper waters, so did environmental studies. But there were only a few Gulf-wide surveys in the deepest parts of the Gulf of Mexico, and our understanding of deep-sea processes was based primarily on other regions of the world. The intensive focus on deep-sea response during and after the Deepwater Horizon (DWH) accident increased our knowledge dramatically. We learned that the deep sea is dynamic, fragile, and will take a long time to recover. There was a 50% loss of biodiversity within 9 km diameter around the DWH site, and a 10% within a 17 km of the site. But there is still much to learn. The deep-sea is a reservoir of biodiversity on Earth, but about 60% of Gulf of Mexico taxa are still unknown, which is a major hinderance to understanding the effects of oil spills. The northern Gulf of Mexico is dominated by Mississippi River outflow, but exactly how it drives deep-sea dynamics needs better resolution. Two outcomes of the last decade of research is that we know benthos diversity is a sensitive indicator of environmental change and damage, the surface sediments are the biologically active zones, and the natural process of sinking particles will eventually cover the damaged sediment leading to natural recovery. This “restoration in place” strategy must be confirmed by future monitoring and assessment studies.

Ecosystem composition and environmental factors as drivers of pH on Barrier Reefs

<p>Tropical coral reefs are both biologically diverse and economically important ecosystems, yet are under threat globally, facing a multitude of stressors including global warming, ocean acidification, nutrient loading, over-fishing and sedimentation. Reef building corals precipitate an aragonite skeleton (CaCO<sub>3</sub>), which forms the base of the coral reef ecosystem, but it is this skeleton, which makes them sensitive to changes in ocean pH. To precipitate their skeletons, corals raise their internal pH, as seawater pH decreases this increases the energy demands needed to facilitate calcification. Furthermore, reductions in coral calcification has significant implications for reef health, potentially altering community structure with reef-wide consequences. Global ocean pH is decreasing due to rising atmospheric concentrations of CO<sub>2</sub>, however, dynamic ecosystems, alongside carbon and freshwater input from land, may result in coastal ocean pH being lower than is predicted by open ocean models. While it is predicted than ocean pH will decrease by 0.3 units by 2100 if emissions are not curbed, coral reefs, particularly those near major river outflow, may already be experiencing pH values similar to that of future scenarios.</p><p>Our aim was to determine the factors which influence pH in coastal reef systems and thus potentially mitigate or exacerbate atmospheric CO<sub>2</sub> mediated ocean acidification. This was achieved by contrasting reefs in distinct environmental settings and collecting data over a sufficient temporal resolution to permit the identification of pertinent drivers. To accomplish this we deployed fixed point observatories in the distinct reefs of Belize (fore and back reef sites), Fiji and Dominica. These custom-built platforms were equipped with a spectrophotometric pH sensor and a conductivity, temperature and dissolved oxygen (CT-DO) sensor from which data was logged at 30-120 minute intervals.</p><p>A strong diel cycle in pH, O<sub>2</sub> and temperature was observed at all reef sites in response to the changing balance of respiration and photosynthesis. However, the range of these changes varied between the different sites - Belize fore reef (pH 7.849­ – 8.000), Belize back reef (pH 7.897 – 8.039), Fiji (pH 7.951 – 8.0950) and Dominica (pH 7.843 – 8.144). Meteorological conditions, such as wind direction, affected the amplitude of diurnal pH variability and its relationship with other parameters, likely by influencing mixing and the spatial distribution of seawater and freshwater endmembers. The relationship between pH and O<sub>2</sub> varied between sites reflecting differences in ecosystem processes (e.g. calcification and primary production) and ecosystem composition (e.g. hard coral and algae cover, proximity to seagrass). Our data confirms that different reef sites are subject to varying degrees of ocean acidification and that controls on pH vary between environments. Furthermore, it highlights the need for widespread high-resolution monitoring to identify, and where possible enact protective measures, in vulnerable reef regions. As coral reefs continue to experience ocean acidification our data also serves to document baseline conditions against which future changes can be assessed.</p><p> </p>

Formation and In Situ Treatment of High Fluoride Concentrations in Shallow Groundwater of a Semi-Arid Region: Jiaolai Basin, China

Fluorine is an essential nutrient, and excessive or deficient fluoride contents in water can be harmful to human health. The shallow groundwater of the Jiaolai Basin, China has a high fluoride content. This study aimed to (1) investigate the processes responsible for the formation of shallow high-fluoride groundwater (SHFGW); (2) identify appropriate methods for in situ treatment of SHFGW. A field investigation into the formation of SHFGW was conducted, and the results of experiments using soils from high-fluoride areas were examined to investigate the leaching and migration of fluoride. The results showed that the formation of SHFGW in the Jiaolai Basin is due to long-term geological and evaporation processes in the region. Stratums around and inside the basin act as the source of fluoride whereas the terrain promotes groundwater convergence. The hydrodynamic and hydrochemical conditions resulting from slow groundwater flow along with high evaporation and low rainfall all contribute to the enrichment of fluoride in groundwater. In situ treatment of SHFGW may be an effective approach to manage high SHFGW in the Jiaolai Basin. Since soil fluoride in high-fluoride areas can leach into groundwater and migrate with runoff, the construction of ditches can shorten the runoff of shallow groundwater and accelerate groundwater loss, resulting in the loss of SHFGW from high-fluoride areas through river outflow. The groundwater level will be reduced, thereby lowering the influence of evaporation on fluoride enrichment in shallow groundwater. The results of this study can act a reference for further research on in situ treatment for high-fluoride groundwater.

THE NETWORK AND THE STRUCTURE OF COMPLEX, GEOLOGICAL AND HYDROLOGICAL MONUMENTS OF NON-LIVING NATURE OF LVIV OBLAST, UKRAINE

This article presents the current list and designed maps of monuments of non-living nature of Lviv region in Ukraine as well as some recommendations and suggestions for its improvement. The list of monuments of non-living nature is the most numerous category in the structure of the nature reserve fund of Ukraine in general and Lviv region in particular. There are 199 monuments of non-living nature in the Lviv region up to 2019: 2 objects of national importance and 197 of local importance. Depending on the object of protection, the monuments of non-living nature of Lviv region can be divided into botanical (122), hydrological (34), complex (20), geological (19) and forest (4). The majority of complex nature monuments cover specific forms of relief (individual hills, rocks, caves) with the complex nature conservation value and often historical and cultural importance. The large number of complex monuments of non-living nature is located in Skole and Zolochiv raions, a few in Brody and Yavoriv raions, and just a monument in each of Staryi Sambir, Turka, Drohobych, Kamianka-Buzka, Stryi and Mykolaiv raions. Geological monuments of non-living nature are organized for the preserve caves, rocks, geological outcrops, erosion deposits, and glacial formations. These natural monuments are distributed in ten administrative raions and in Lviv, generally related to the mountains in Lviv region, the Precarpathian plain and the Podolian upland. Hydrologic monuments of non-living nature include 29 springs and wells, 3 waterfalls, the peatland and the river outflow. The springs and wells of the mineral waters of the resorts of Morshyn (7), Truskavets (4), Schklo (6), Rozluch (4) and Velykyi Liubin (1) have a special reserved status. A majority of hydrological monuments are located in Stryi (7), Drohobych (6), Yavoriv (6) and Turka (5) raions. It is proposed to add the following geological monuments of non-living nature such as complex of rocks with caves in Mykolaiv raion, the butte of Chervona Gora in the Zhovkva raion and the complex of rocks in Skole raion to the list of monuments of non-living nature. Further research in the region should include the following objects such as abandoned mining objects, wells and springs of Skhidnytsia resort, drainage of the river Styr. Key words: monuments of non-living nature; geological monuments; hydrological monuments; Lviv oblast.

STRUCTURE OF THE SHAKHE RIVER OUTFLOW IN THE BLACK SEA ACCORDING TO REMOTE, PYROMETRIC AND CONTACT MEASUREMENTS

The results of studies of hydrophysical and bio-optical structure of the outflow of the Shakhe River, conducted during the IO RAS expedition “Black Sea-2018” at the marine site near Golovinka on the RV “Ashamba” on 1–2 June 2018, are presented. Information synchronously obtained, both with the help of remote sensing satellites (radar and optical sensors), infrared portable pyrometer, and onboard the RV (CTD probe as part of a shipboard flow system), was used. At the same time, seawater samples were taken from the sea surface layer, followed by laboratory analysis of their bio-optic and geochemical characteristics. Hydrophysical characteristics and submesoscale structure of the Shakhe River outflow at the test site studied both remotely and contactly, gave identical results. This makes it possible to further efficiently use these instruments on board of RVs to study the river outflows in the Black Sea. At the same time, portable infrared pyrometers make it possible to obtain significantly better spatial resolution in terms of temperature compared with satellite instruments, while satellite images can detect river outflows in the sea, their boundaries and structure.

The DeepWater Horizon Oil Slick: Simulations of River Front Effects and Oil Droplet Size Distribution

The effect of river fronts on oil slick transport has been shown using high resolution forcing models and a fully fledged oil drift model, OpenOil. The model was used to simulate two periods of the 2010 DeepWater Horizon oil spill. Metocean forcing data were taken from the data-assimilative GoM-HYCOM 1/50 ∘ ocean model with realistic daily river input and global forecast products of wind and wave parameters from ECMWF. The simulations were initialized from satellite observations of the surface oil patch. The effect of using a newly developed parameterization for oil droplet size distribution was studied and compared to a traditional algorithm. Although the algorithms provide different distributions for a single wave breaking event, it was found that the net difference after long simulations is negligible, indicating that the outcome is robust regarding the choice of parameterization. The effect of removing the river outflow was investigated to showcase effects of river induced fronts on oil spreading. A consistent effect on the amount and location of stranded oil and a considerable impact on the location of the surface oil patch were found. During a period with large river outflow (20–27 May 2010), the total amount of stranded oil is reduced by about 50% in the simulation with no river input. The results compare well with satellite observations of the surface oil patch after simulating the surface oil patch drift for 7–8 days.

The DeepWater Horizon Oil Slick: High Resolution Model Simulations of River Front Effects, Initialized and Verified by Satellite Observations

The effect of river fronts on oil slick transport has been demonstrated using high resolution forcing models and a fully fledged oil drift model, OpenOil. The model system is used to simulate the 2010 DeepWater Horizon oil spill. Metocean forcing data are taken from the GoM-HYCOM 1/50° ocean model with realistic river input and ECMWF global forecast products of wind and wave parameters with 1/8° resolution. The simulations are initialized from satellite observations of the surface oil patch. OpenOil includes most of the relevant processes, such as emulsification, evaporation, wave entrainment, stranding and droplet formation. The model takes account of the actual oil type and properties, using the ADIOS oil weathering database of NOAA. The effect of using a newly developed parameterization for oil droplet size distribution is studied and compared to a traditional algorithm. Although the algorithms provide different distributions for a single wave breaking event, it is found that the net difference after long simulations is negligible, indicating that the outcome is robust regarding the choice of parameterization. That indicates that the wave entrainment, vertical mixing and re-surfacing mechanisms that are part of OpenOil are more important for determining the final droplet size spectrum than the spectrum prescribed for individual wave breaking events. In both cases, the size of the droplets controls how much oil is present at the surface and hence are subject to wind and Stokes drift. The effect of removing river outflow in the ocean model is investigated in order to showcase effects of river induced fronts on oil spreading. A consistent effect on the amount and location of stranded oil is found, and considerable impact of river induced fronts is seen on the location of the surface oil patch. During a case with large river outflow (May 20-27, 2010), the total amount of stranded oil is reduced by about 50% in the simulation with no river input. The results compares well with satellite observations of the surface oil patch.