Mapping Sensitive Habitats and Environmental Conditions in the Mediterranean

Offshore oil and gas projects in the Mediterranean are subject to an increasing level of regulation that stipulates Environmental Baseline Surveys (EBS) and Environmental Impact Assessment (EIA) must be carried out prior to any works in the marine environment.  Fugro’s wide range of offshore survey capabilities include capacity to undertake a variety of environmental surveys for the purposes of satisfying the aforementioned regulatory requirements, resource allocation and informing sound management of Marine Protected Areas (MPAs).

Fugro’s principal environmental services are based on Environmental Baseline Surveys and Habitat Investigations.  EBS are required and routinely executed in the Egyptian Mediterranean and Red Sea to describe the physical and chemical features of the seabed, prior to developmental works such as oil and gas projects, seabed pipeline installations and submarine telecommunications infrastructure.  The aim of these surveys is to provide a ‘snapshot’ of the pre-development character of the sediments and waters in the survey area, so that during the implementation and operation of the project and, ultimately, following its decommissioning, the environmental impact can be quantified, qualified and, if necessary, remediated.  Fugro’s field scientists are equipped to devise comprehensive seabed sampling campaigns that will capture the full range of sediment types, depths and benthic features.  In this way, the historic or potential effects ‘footprint’ of an installation may be qualified or predicted.  Using a variety of physical and chemical metrics, pre-existing contamination may be described and attributed using chemical and biological signals in the data.

Of principal concern is the degree of contamination in marine sediments by trace and heavy metals and hydrocarbons as indicators of anthropogenic (man-made) or natural impacts in marine environmental systems.  Large river systems such as the Nile originate well inland on the African continent and will pass through several thousand of kilometres of varied land and vegetation types including agricultural land, desert, industrial and residential areas, flood plains and wadis before draining into the Mediterranean basin.  This brings a significant source of nutrients, contaminants and plant matter to the Mediterranean Sea, and consequently, establishing the ‘normal’ baseline conditions and the origin of the substances present is crucial.  It is therefore of paramount importance that we are able to differentiate contaminants and pollutants that may arrive at the development site from those that arrive there as part of the natural cycling of marine detritus and riverine input.  This is possible as Fugro has a specialist hydrocarbons laboratory specialising in analysis of marine sediments in general and aliphatic fingerprinting in particular. Using specialist wet extraction techniques specifically designed for marine sediments, followed by ICP-MS and gas chromatography, Fugro are able to speciate hydrocarbon alkanes and forensically identify the source of contaminants and therefore derive whether they are naturally occurring or of anthropogenic origin.

Fugro’s in-house services also include Environmental Consulting specialists and analytical laboratories providing experts in permitting, EIA and formulation of mitigation strategies and chemical analytics, geotechnical analyses and experienced professional taxonomists for macrofaunal identification and enumeration.  Incorporating these services allows the streamlining and integration of the entire marine environmental survey process, enabling every stage of the field survey, analytical and reporting processes to be delivered from within Fugro.

Fugro’s second principal service comprises Habitat Investigations, required for to establish the presence of sensitive biological communities.  Using geophysical data acquired for the project, Fugro’s experienced marine biologists can interpret the acoustic data and categorise the seabed into sediment types and identify regions or features that warrant further investigation through sediment sampling and seabed photography. This involves the careful deployment of high-spec camera and video systems to the seabed in surveillance of rare, sensitive or endangered species such as coral reefs, seagrass beds, biogenic reefs, fish spawning grounds and carbonate structures, formed from the escape of leaking gases.  For contractors, it is vitally important to fully understand the ‘quality’ and extent of sensitive habitats so that they may plan and develop in a way that limits, or entirely avoids, environmentally damage. 

Deploying the high-resolution camera system using taglines and A-frame at stern of survey vessel
Deploying the high-resolution camera system using ‘taglines’ and A-frame at stern of survey vessel

The variety of equipment required for environmental surveys of this type is vast and requires rigorous prior preparation and planning; this means that equipment is maintained to a high standard and field scientists can gain training in-house on the exact equipment they will be expected to use at sea, combined with a comprehensive project briefing.  The combination of these factors means that Fugro’s field teams can always deliver high-quality data in challenging circumstances; field scientists are highly qualified and equipped to respond in-field to all manner of challenges encountered during survey operations.  Excessive water depths, seabed currents and adverse weather conditions are difficult to assess prior to arriving on site, and mental agility, health and safety awareness and good decision-making ability are pre-requisites.  The equipment required for a comprehensive baseline survey and habitat investigation comprises a diverse blend of sediment sampling gear including Day grabs and dual van Veen grabs for sandy/silty sediments up to moderate depths, Hamon grabs for coarse sediments and gravels, and Box corers for water depths exceeding 300 metres and mixed, consolidated sediments and clays.  Characterising the properties of the water column is achieved using multi-parameter probes that can capture continuous data of all the physical and chemical properties in a single deployment, rendering a ‘depth profile’ of the water, supplemented by discrete water sampling using remotely-triggered devices. 

Investigating seabed habitats is achieved by deployment of a custom-built frame-mounted camera system comprising high-resolution stills/video capture, lamps and strobe flash with positioning beacon and altimeter.  Using this, photographic data describing the seabed habitats can be accurately positioned to inform clients as to the exact location of sensitive seabed natural resources.  The systems are deployed via a lift wire, and can be fed into existing multi-core winch cables on the vessel allowing the teams to operate from any industry standard geophysical survey vessel.

Fugro routinely work in the waters surrounding Egypt, both in the Mediterranean and Red Sea.  Numerous projects have been undertaken offshore Egypt in recent years and the diversity of conditions observed belies the Mediterranean Sea’s relative size.  The Nile Delta provides a significant source of freshwater to the Mediterranean, that brings with it both nutrients and contaminants and sculpts a varied geomorphology that presents a range of sediment types and complex bathymetry; a fascinating setting for a complex, large scale Environmental Baseline Survey, supplemented with a detailed Habitat Mapping campaign. 

Recent surveys carried out in the Mediterranean have unveiled bathymetric features of astonishing size and complexity that were previously unknown to science, which in turn provide a variety of biological niches that may be exploited by different organisms.  Recent surveys have encountered giant submarine mud volcanoes, channel systems and relict landslides radiating out into deep waters from the west Nile delta. These were shown to be populated a variety of sensitive seabed habitats such extensive Maerl beds, a species of coralline red algae that forms solid, lattice-like calcareous substrates at particular depths on the seabed.  Historically dredged and ground for fertilizer in the UK and abroad, its use is now questionable in a world where sustainable development is paramount and alternatives are readily available.  Consequently, it is listed in Annex V of the EC Habitats Directive.  Maerl beds are the calcified structures of rhodophytic algae, and their complex, three-dimensional structures provide breeding and nursery grounds, food and shelter to a host of other marine life.

Also observed in the Egyptian Mediterranean are the carbonate structures formed when methane, escaping from the gas pockets beneath the seabed, reacts with seawater to form uncanny structures known as Methane-Derived Authigenic Carbonates (MDAC).  These structures accrete in soft, silty sediments where there is no consolidated footing for any marine life to colonise and grow.  Forming solid pillars, plates or mounds on the seabed, they play host to a variety of marine life in an otherwise desert-like marine environment. 

Commonly, these mounds are observed encrusted with an array of hydrozoans and bryozoans, minute colonial organisms related to corals that form dense structures that take on the appearance of feathers.   Data acquired by Fugro field teams have led to the postulation that the Mediterranean benthic habitats may contain infaunal species that are entirely new to science.  Marine habitats such as these, if not managed sensitively, will lose their ability to harbour higher life forms such as crustaceans (crabs and lobsters), echinoderms (sea stars and sea cucumbers) and fish.  This, of course, has implications for fishing industries and consequently people’s livelihoods, emphasising the importance of collecting high-quality data to facilitate sound decision-making and adherence to regulatory frameworks.

Collecting and interpreting data of this type is critical to future management of ecological and environmental systems.  In an environmental such as the Nile delta, geological processes have led to the accretion of substantial mineral reserves that co-occur with a complex and under-studied marine environment.  Understanding environmental linkages through comprehensive monitoring surveys provides us with the data required to make the crucial decisions that will affect the millions of people who live and work on the shores of the Western Nile delta, and the wider Mediterranean environment.  Data acquired can be utilised to formulate prevention and mitigation strategies for oil spills and contamination events, of which the socio-economic consequences, that may include contamination of drinking water, habitat destruction and disruption of feeding regimes of marine animals, would be utterly catastrophic. 

A: MDAC pillars encrusted with hydroids and bryozoans, sepulid worm colony in right of picture
B: Bearded Fireworms, bryozoans and biofilm mats off shore Egypt
C: Living Maerl beds give sediments a purple appearance
D: Seagrasses and Hydroid colonies in mixed, unconsolidated sediments

Oil and gas projects enacted in the Mediterranean region have the revenue-generating ability to support the re-building of economies during difficult times.  It is vital then that the environmental considerations of such projects keep pace and are scrutinised through rigorous research, surveying and monitoring, and impacts identified and thoroughly mitigated.  Fugro offers a turn-key solution for every exploration and development project all the way from initial permitting and licensing through to final decommissioning and ensuring the seabed is returned to its pre-development state.

By Fugro


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