Marine Habitat Monitoring / Biotope Mapping
Biotope maps serve as important tools to visualize the seabed resources by showing the location of different biological communities and their boundaries. Habitat maps focus on the existing plants and animals as well as the nature of the benthic substrata such sand, rock and mud. A habitat map is a readily available source of information for policy makers, engineers, scientists, and other interested groups to utilize the marine resources or to make informed decisions that would help to protect and conserve the fragile and sensitive marine habitats such as coral reefs, seagrass meadows, mangroves and seaweed beds.
Marine Ecotoxicology is the study of contaminants in the marine environment and their toxicity to the marine organisms. This study also covers the mechanisms of contaminant accumulation and its effects on the living organisms at all biological levels (from molecules to ecosystem). Complete characterization of the contamination of a marine ecosystem would require analysis of contaminants in seawater, sediments and organisms. All these components present the positive and largely the negative effects of contamination and the need for monitoring. Analysis of seawater and sediments would provide the actual concentrations in the environment and information on sources and fluxes of contaminants. However, analysis of seawater and sediments may not show the true effects of the contaminants to organisms in view of their low concentrations. Their bioavailability also cannot be measured correctly. Seawater concentrations are also subjected to fast temporal fluctuations raising questions on the true representative value of these analyses. In this background, living organisms are of significance as they present the advantages of bioconcentrating the contaminants that can be easily analyzed. The concentration levels serve as direct measures of the bioavailability as the biological organisms integrate the environmental concentrations over a longer period than seawater. At the same time, it is impossible to measure contaminants in all the organisms of an ecosystem although the levels may present wide variations in their response to the same contaminant. In view of this reason, monitoring programs make use of bioindicator organisms that are of help in quantifying the contaminants and their bioavailability. The main objectives of such programs are:
- to identify the nature of contamination, concentration of contaminants, their distribution and sources;
- to determine the dynamics of the contaminants: fate of contaminants in abiotic and biotic compartments of the ecosystem;
- to assess the effects of contaminants on individuals, populations, and communities and
- to evaluate the impact on human health and activities (food resources, commercial interests, nature preservation)
Phytoplankton and Zooplankton
Phytoplankton form the basis for all the marine organisms, their food chain and food web, which makes them an important group of organisms to study. In large areas of the world’s oceans, a distinct annual pattern in the composition of the phytoplankton community can be identified, driven mainly by the availability of light, nutrients, and temperature, although they can be sensitive to a host of additional abiotic environmental factors, such as salinity, dissolved oxygen, total suspended solids, pH, and environmental contaminants. Furthermore, they have very short generation times and quickly respond to changes in their environment. These make them ideal indicators of changes and therefore are included in the environmental impact assessment programs.
Zooplankton as the secondary producers occupy the next level in marine food web, as they feed on phytoplankton. Zooplankton themselves are an important food source for organisms in the higher trophic levels, such as fish which makes them relevant in fisheries research. In addition, some zooplankton, such as crab zoea, shrimp nauplii, and larval fishes, represent the early life history stages of species with high ecological and economical importance to fisheries.
In the CEW projects, phytoplankton are key parameters in all EIA works, as part of water quality assessment (chlorophyll, TSS and nutrients). Zooplankton studies help the fisheries group to explain changes in catches, due to variation in the zooplankton biomass as food source, as well as to identify important areas in Saudi waters of the Arabian Gulf that serve as nursery grounds for species that are important to fisheries.
Fisheries contribute to food security, employment and economic diversification. Currently the fisheries production in the Arabian Gulf and the Red Sea cover around 20% of Saudi seafood consumption. The Center has conducted an extensive 5-years study (2013-2017) of Saudi fisheries in the Arabian Gulf including the development of mathematical models and software for stock assessment, population dynamics and the life history of fish stocks, the essential habitats and ecological underpinnings of fishery productivity, the environmental impacts of current fishing techniques and the management framework for sustainable and productive fisheries. Our Center has established laboratories for conducting state-of-the-art research in fish aging and reproduction as well as obtaining expertise in marine surveys covering the pelagic and demersal realms. We are regional leaders in fisheries research with the highest number of publications in highly reputed scientific journals, thus contributing to the progress of knowledge and the sustainable exploitation of fishery resources.
Saudi Arabia has an important wealth in fish and invertebrates in its territorial waters, similar to other countries in the region. This wealth includes the valuable green tiger shrimp, the blue swimming crab, the sand lobster, the pharaoh cuttlefish and the sea cucumber among the invertebrates, and the narrow-barred Spanish mackerel, several groupers, emperors, and seabreams as well as pelagic fish. Fishing has been a traditional activity of coastal communities for thousands of years and has grown alongside the demographic development of Saudi Arabia in the last few decades. The successful exploitation of its productive potential and therefore its sustainable contribution to food security and economic diversification relies on management based on continued scientific research.
Coral Reef Biology
Coral reefs are some of the oldest and most diverse ecosystems on the planet. They are living museums that reflect thousands of years of biological history. Coral reefs are the habitat, breeding, nursery and feeding grounds for numerous marine organisms including fishes and shell fishes. They provide resources and services worth many billion dollars to human societies through tourism. Coral reefs serve as natural shoreline buffers against waves, storms, and floods preventing loss of life, property damage, and erosion. Plants and animals inhabiting the reefs are important sources of new medicines.
Seagrass and Marine Algal Ecology
Seagrass beds are often cited as some of the most productive ecosystems on earth, rivaling cultivated crops in annual net primary production. Marked spatial and temporal patterns exist in distribution, productivity, and seasonality of seagrasses. It must also be emphasized that the shallow marine environment of the Saudi Arabian portion of the Arabian Gulf is not a pristine environment.
Humans have substantially altered water flow patterns, harvested great quantities of animals, changed nutrient inputs to the marine waters, and dredged and filled previously existing seagrass beds. Although seagrasses in this portion of the Gulf are widespread, the state of the seagrasses in the region has already been influenced by humans.
The specific objectives of the study are the following:
- Mapping the spatial extent of seagrass and algae along the Saudi Arabian waters of the Arabian Gulf;
- Documenting species composition and net above-ground productivity of these floral beds;
- Studying the biodiversity of marine fauna associated with the seagrass and algal beds;
- Studying the nursery function of seagrass beds at selected locations;
- Determining the spatial and intra-annual patterns in these seagrass and algal beds;
- Determining changes in the spatial extent and species composition of seagrass and algal beds brought about by anthropogenic activities;
- Studying the recovery rates of seagrass and algal beds at recently dredged locations; and
- Studying the transplantation possibilities of seagrass and algae in some selected location in the Arabian Gulf.
Mangroves, also called as ‘coastal woodlands’, ‘tidal forests’ or ‘mangals’ are interesting plants with their characteristic traits to survive in the land-sea interface and are distributed in the tropical and subtropical regions of the world between approximately 30o N and 30o S latitude. The conditions under which mangroves thrive include fine substrata (muddy or sand), protection from wave, a suitable tidal range and favorable ocean currents. However, the mangrove plants can also thrive under the harsh environmental conditions such as high salinity, high temperature, extreme tides, high sedimentation and muddy anaerobic soils.
Mangrove ecosystem supports an incredible variety of terrestrial and aquatic fauna and that way represents a repository of biodiversity. They are one of the most productive and biologically important ecosystems of the world and provide important ecosystem services to human society and marine ecosystem. The stabilization of the shoreline is one of the important functions of mangrove forests, which has been proved in the recent tsunami and hurricane episodes. Mangrove ecosystems also serve as feeding, breeding and nursery grounds for shrimps and fishes. They provide food, medicine, fuel and building materials for the local communities. Another important role of mangroves is in the regulation of global climate change through sequestering a major proportion of fixed carbon in the biosphere. Mangroves, including associated soils, could sequester approximately 22.8 million metric tons of carbon each year, which accounts for 11% of the total input of terrestrial carbon into the ocean and 10% of the terrestrial dissolved organic carbon (DOC) exported to the ocean.
The mangroves in the Arabian Gulf are part of the northern latitudinal limit of the Indo-Pacific mangrove realm. Because of the harsh environmental conditions here (high salinity, extreme temperature and low precipitation), the mangroves are species poor. Black mangrove, Avicennia marina is the only recorded species from the western Arabian Gulf.
Although mangroves in this region were negatively impacted during the 1991 Oil Spill, recovery happened later. Currently the main factor causing mangrove depletion is extensive land reclamation for coastal infrastructure development. The other threats are from dumping of solid and liquid wastes, pollution due to oil and oil-dispersant mixtures and grazing by camels.
Oceanography is a scientific discipline concerned with all aspects of the world’s oceans and seas, including their physical and chemical properties, their origin and geologic framework, and the life forms that occur in the marine environment. Traditionally, oceanography has been divided into four separate but related branches such as physical oceanography, chemical oceanography, marine biology and marine geology.
In the physical oceanography, the properties of seawater (temperature, density, pressure, and so on), their distribution and movements (waves, currents, and tides), besides the air-sea interactions are covered. Physical oceanography also focuses on describing the evolving patterns of ocean circulation and fluid motion. The physical oceanography research also deals with studies on climate, coastal and estuarine processes, geophysical fluid dynamics, coastal oceanography, tropical oceanography, etc.
The Oceanography Studies Section, a major section in the Center for Environment & Water (CEW), is playing a major role in the operation of applied research projects in the Center. State-of-the-art oceanography instrumentation such as Conductivity Temperature Depth (CTD) profilers, Wave and Tide Recorders, Acoustic Doppler Current Profilers (ADCP), Remotely Operated Vehicle (ROV), etc. is being used here. These instruments are utilized for baseline oceanographic data collection, monitoring of marine ecosystem, and assessing man-made and natural impacts on the environment.
Water and Sediment Quality
Investigations on the water quality parameters constitute an important part of environmental monitoring. When water quality is poor, it affects not only aquatic life but the surrounding ecosystem as well. Sediments play an important role in elemental cycling in the aquatic environment. They are responsible for transporting a significant proportion of many nutrients and contaminants. They also mediate their uptake, storage, release and transfer between the environmental compartments.
CEW has been engaged in studies on the seawater and sediment quality for over 35 years in the Arabian Gulf and over 15 years in the Red Sea. Most of these studies are conducted as part of the client-funded projects, for example, Environmental Impact Assessment and Monitoring Programs for the client Saudi Aramco, the pride of this nation.
The major seawater quality parameters being studied include in situ parameters (temperature, salinity, dissolved oxygen, pH and turbidity), nutrients, suspended solids, phytoplankton, chlorophyll, and contaminants such as trace metals and petroleum hydrocarbons. Water samples are collected either using Niskin water sampler or CTD. The major sediment quality parameters studied include sediment grains size, trace metals and petroleum hydrocarbons. Sediment samples are collected using van Veen grab or Box corer.
Marine mammals represent an important component of the marine ecosystem. It deals with the highly endangered top predators, which are under the serious threat of extinction due to increasing anthropogenic pressures. To better protect these key species, it is highly important to conduct continuous and systematic monitoring surveys for collecting information on their diversity, distribution, density and abundance and also on their feeding ecology and interactions with the fishing methods. These surveys are being conducted through fishermen questionnaires, examination of cetacean sighting reports, boat-based surveys and biopsy-collection campaigns. In the Saudi waters of the Arabian Gulf, the diversity of marine mammals’ community is very high. Humpback dolphin (Sousa plumbea), bottlenose dolphin (Tursiops aduncus) and dugong (Dugong dugon) are the most common species. While the two dolphin species are widely distributed, occurring in both inshore and offshore waters, Dugong dugon occurs exclusively in the southern area, located between Saudi Arabia, Bahrain and Qatar, mainly in the Gulf of Salwah. Less common cetacean species include the Bryde’s whale (Balaenoptera edeni), killer whale (Orcinus orca) and long-beaked common dolphin (Delphinus capensis). Total abundance of bottlenose dolphin in the Saudi waters of the Arabian Gulf is close to 15 thousand and that of humpback dolphin around seven thousand.
Bioaccumulation and Biomarkers
A chemical analysis alone is not considered useful for interpreting the pollutant impact in the marine ecosystem since it does not illustrate the harmful effects and the fate of chemical compounds on the living organism through biotransformation. In many cases, the biotransformation may increase the toxic effect of xenobiotic substances on organism through production of reactive metabolite compounds that are more toxic than the original parent compounds. Contrary to chemical monitoring of organisms, which principally evaluates the presence of pollutants in tissues, biomonitoring methods evaluate not only their presence, but also more significantly the response of the organisms to these pollutants. In this respect use of biomarkers in the assessment is quite valuable. Using the biomarkers, the effects of contaminants can be evaluated at the molecular, cellular, organelle and organism levels. The use of these biomarkers in monitoring does not replace chemical monitoring or population studies, but it integrates them in determining the toxic effects of pollutants, also when they are present at low, sub-lethal concentrations. For these reasons, the classic chemical analysis should be combined with the biological approach. , The “biomarkers” used in the biological approach elucidate the biological responses of environmental pollution. Being sensitive biomarkers can provide more comprehensive and biologically more relevant information on the potential impact of pollutants on the health status of organism. Commonly used biomarkers are: Tissue levels of metallothioneins, inhibition of cholinesterase activity, peroxisomal proliferation, mixed function oxygenases and EROD activity.
The evaluation of impacts of pollution on the marine ecosystem is based on two types of scientific findings:
- Indicators of change in the composition and/or stress on the marine ecosystem;
- Trend in the levels of bioaccumulation of chemical contaminants in the elements which are considered as indirect indicators of impact on the ecosystem.
Marine Ecology is the scientific study of marine-life habitat, populations, communities and their interactions among themselves and with the surrounding environment (abiotic and biotic).