Black Sea Phytoplankton checklist

Attention! The site was discontinued in 2014. The site is not supported and is not updated. Information on the site may be out of date.
Внимание! Разработка сайта прекращена в 2014 году. Сайт не поддрживается и не обновляется. Информация на сайте может быть устаревшей.

From Black Sea Phytoplankton checklist

The largest plant community in the oceans are the free drifting microscopic Phytoplankton. These single celled organisms use solar energy by photosynthesis to survive. Though normally existing in solitary form, they may form large chains or spherical shaped colonies, some large enough to see with the naked eye. Despite their small individual size, Phytoplankton are of enormous importance in the aquatic food chain creating a food source for a variety of organisms, fish and shellfish which in turn provide a food source for larger animals. In addition, the phytoplankton provide most of the oxygen we breath and fossilised phytoplankton are associated with deposits of oil and benthic deposits (sapropell in the Black Sea). Microalgal cells can range in size from less than 1 mm to greater than 1 000 µm, and in some cases can multiply to more than one million cells per liter during a high peak bloom. The phytoplankton evolved into a diverse group of photosynthetic organisms that are divided into categories according to size:

• Microplankton- from 20-200 µm;
• nanoplankton - from 10-20 µm;
• ultraplankton - from 2-10 µm and
• picoplankton less than 2 µm in size.

Picoplankton and ultraplankton tend to be more common in the open ocean than the coastal waters, whereas the larger nanoplankton and microplankton, such as diatoms and dinoflagellates, tend to dominate coastal waters.

Phytoplankton are responsive to the physical and chemical conditions in the aquatic environment. Sometimes their rapid reproduction causes nuisance growths or blooms. Algal blooms have dramatic effects on water chemistry, most notably pH and dissolved oxygen (DO). When algae remove carbon dioxide during photosynthesis they raise the pH by increasing the level of hydroxide. The opposite reaction occurs during respiration when carbon dioxide is produced lowering hydroxide and lowering the pH. Therefore, high pH (> 8.0) can be an indicator of increased photosynthesis. Algal blooms produce large amounts of oxygen during photosynthesis that may lead to supersaturated levels of DO in the water column. Conversely, during respiration, algal blooms remove the DO from the water column which may lead to oxygen reduction (hypoxia) or oxygen depletion (anoxia) in the water column and the bottom. Supersaturation of DO (> 110% saturation) can also be an indicator of increased photosynthesis particularly during mid-to-late afternoon. Microscopic algae are a concern for the water quality and ecosystem health. They can cause taste and odor problems, water discoloration, or form large mats that can interfere with boating, swimming, and fishing. Some reasons why algae are important to studying the biodiversity on marine ecosystems are:

• much of our information on photosynthesis, nutritional requirements, roles of vitamins, and studies of protoplasm comes from studies of algal physiology;
• algae play an important role in the production of oxygen and other organic materials;
• they serve in the food chain as a food source for species such as protozoa, rotifers, copepods, cladocerans, euphausiids, clams, mussels and various fish such as herring, and even some whales;
• algae serve as the first step in the system of energy transfer through aquatic food webs. All aquatic animals in both fresh and salt water require these small plants to maintain their existence;
• there is a growing speculation that the occurrences and blooms of phytoplankton in coastal waters are increasing world wide, especially those that have negative effects;
• algae are more and more becoming a great biotic indicator of environmental changes, and/or human induced alterations.

The main objectives for phytoplankton examination: Analysis of phytoplankton species composition abundance and biomass is carried out for the following purposes:

• to describe temporal trends in phytoplankton species composition, their abundance, biomass and abundance of blooms;
• to describe spatial distribution of phytoplankton species, their abundance, biomass and blooms;
• to identify key phytoplankton species (e.g. dominating, harmful and indicator species).