The waters of the cold Benguela Current are tremendously productive. This is a consequence of the wind-driven upwelling that brings a continual supply of dissolved nutrients from deeper waters to the surface. 

Tiny organisms called phytoplankton absorb nutrients; near the surface, with exposure to sunlight and the process of photosynthesis, these organisms reproduce rapidly, supplying the ocean with an abundant primary base for marine food webs. These phytoplankton blooms cover vast areas of the ocean and are visible from space. Biological oceanographers try to describe and understand the largest ecological regime on earth.

 This regime, the home of marine ecosystems, is three-dimensional and, unlike terrestrial environments, has few boundaries across which the organisms cannot move or diffuse. In the development of sciences, there is commonly an initial descriptive phase followed by a period of analysis during which processes are understood and quantified. 

Eventually, an ability to predict is sought. A proper descriptive basis is fundamental to this development and in many geographical regions, this basis is yet to be developed. Elsewhere, the shift from description to analysis has accelerated during the last decade. 

However, research has tended to be focused on the level of organisms. More attention needs also to be given to the properties and functions of ecosystems. 

The relentless quickening in the impact of human activity on marine ecosystems demands that every attempt be made to accelerate the development of our predictive abilities. Proper management of ocean fisheries requires that biological productivity be sustained and stabilised, particularly in shelf areas. To this end, it is fundamental that we understand better how marine ecosystems function. Direct observations of oceanic organisms are often difficult and most sampling is, perforce, indirect. 

Each sampling technique has substantial limitations to the range of phenomena it can effectively discriminate. These sampling inadequacies limit the expansion of knowledge and need to be overcome through improvements in sampling strategies, the development of new sampling techniques, and efficient data collection and manipulation with better interaction of biological and environmental data. With all that is yet to be learned about life in the ocean, there are some areas where there appear to be special opportunities for significant progress during the next few decades. With regards to the food-web dynamics, during the last three decades understanding of planktonic primary production has advanced through the use of a standard, the technique shows discrepancies with other methods of assessment when nutrients are limiting, light is above saturation, and dissolved organic matter and bacteria are abundant. 

It appears to underestimate production, particularly in the lighted zones of permanently stratified subtropical or tropical regions. Aspects that particularly need investigation are the role of different size fractions among planktonic primary producers, particularly very small cells and cyanobacteria; the fluxes of dissolved organic matter to and from primary producers; the role of bacteria in the plankton; the role of incubation duration and chamber dimensions in producing artefacts during the measurement process; the contribution of non-planktonic primary producers to the organic carbon flux of the water column in coastal and estuarine regions. Once primary production is quantified as an elemental flux, questions arise about the quality of the product and its availability to the food web. 

The size structure of phytoplankton communities can determine the distribution of the organic matter to different parts of the food chain. The palatability of different phytoplankton species varies among grazers, whose ability to select, either mechanically by rejection of certain cells or behaviourally by moving elsewhere, needs examination. 

The dynamics of blooms, the patterns of succession in phytoplankton communities and the factors determining the species composition of the communities are basic to our understanding of the primary production function in ecosystems. 

Classical food-chain work has concentrated on the consumption of relatively large phytoplankton cells such as diatoms and dinoflagellates by ‘net zooplankton’, e.g. copepods. 

Now, evidence from a number of directions shows that very small primary producers (nanoplankton and picoplankton) are responsible for a significant portion of the organic flux and that they are grazed by small copepods, ciliates and mucus-net feeders such as salps. 

Questions concerning the vertical profile of productivity, the significance of patchiness, the dependence of the survival of planktonic larvae on minimum cell abundance in the water column, and the relationship of chlorophyll and cell maxima to the production maximum can be effectively answered only by using continuously profiling techniques. Techniques for continuous profiling of primary production and sensors capable of measuring nutrient concentrations would dramatically improve our capability to test hypotheses about the spatial relations of biological processes in the photic zone. 

The use of fluorometers and particle counters in undulating towed instruments has made it possible to test ideas on vertical and horizontal spatial organisation in the surface layers. Moored arrays with the same sensors will provide breakthroughs for work on the time changes that are important in the ocean on scales from minutes to years. 

The role of microorganisms (bacteria, yeasts, protozoa, and fungi) in the food web of both the shallow and deep pelagic zones and benthic environments in the production and degradation of particulate organic carbon and the utilisation of dissolved organic matter needs to be quantified, as it may be central to an understanding of the flux of organic carbon through marine ecosystems. 

Both dissolved and particulate carbon may have two major pools, one of relatively refractory material, which turns over slowly relative to the generation times of the biota, and another smaller pool, which cycles rapidly because it consists of compounds readily assimilated by bacteria and other heterotrophs. Consequently, a portion of primary production always cycles through microorganisms. 

The subsequent lack of oxygen in the water, even though short, can cause sea life to avoid the area and fish and other marine animals in the vicinity to die. These eruptions of hydrogen sulphide are characteristic along the central coast of Namibia, where the earliest observers recorded them in the late nineteenth century.

*Dr Moses Amweelo is a former minister of Works, Transport and Communication. He is currently a part-time lecturer at IUM and UNAM. He earned a doctorate in Technical Science, Industrial Engineering and Management from the International Transport Academy (St. Petersburg, Russia).