Phosphorous and Red Tide

Japanese Experience Decades Ago

Lake Biwa in Shiga Prefecture, Japan, is the largest inland lake in Japan. In the 1960s the lake was sufficiently contaminated by agricultural chemical run off for the Prefecture to enact the “Direction for Safe Use of Agricultural Chemicals”. The lake region was designated as an “agricultural chemical use prohibition area”, extending six kilometers from the lake. The Japanese Government subsequently incorporated these provisions in an Agricultural Chemicals Regulation Law.

In the 1970s, as the Japanese standard of living after WW II increased in line with industrialized growth, it became necessary to control industrial pollution of Lake Biwa. First, the Prefecture enacted a Pollution Control Ordinance in 1969, to be followed by The Water Pollution Control Law enacted by the Japanese Government in 1971. These stringent regulations helped to restore and keep the waters clear. Until, on October 16^th, 1977, in a pristine west shore area in the north of the lake, freshwater “red tide” appeared unexpectedly. The source was traced to phosphorous content of the synthetic detergents eagerly taken up for use by Japanese households. In October, 1979, growing local public outcry resulted in the passing of an “Ordinance Relating to the Prevention of Eutrophication in Lake Biwa” (referred to as the Lake Biwa Ordinance).

The Japanese Constitution enshrined “freedom of business” clauses, nevertheless, in spite of a vigorous campaign by the Detergent Industry Association against it, the prohibition of sale, exchange, or gifting synthetic detergent containing phosphorous was enforced. It is to be noted that the Biwa Lake Ordinance not only addressed the phosphorous issue, but instituted controls against eutrophication as well. Moreover, Shiga Prefecture counts only 1% of the national population of Japan and yet the detergents containing Phosphorous have disappeared from stores throughout the entire country. Several lessons can be learned from these events. The voice of a motivated local populace is potent. Look ahead to embrace the whole problem; avoid piecemeal legislation.

Cause of Red Tide

The positive correlation between red tide and phosphorous was established three decades ago. Algae spores are everywhere (e.g. Karenia brevis – a dinoflagellate is in the Gulf) awaiting sunshine and nutrientsAny food, chemical element or compound an organism requires to live, grow, or reproduce. to propagate explosively. The events at Lake Biwa illustrate a progression: first, the consequence of using more fertilizer than can be absorbed by crops is wasteful folly, second, allow these excess (phosphorous) nutrients to leach into water (even flowing into the oceans), third, fail to control sources of nutrients and sooner than later algae spores will reveal themselves – even as a toxicPoisonous, a substance that reacts with specific cellular components to kill cells. “red tide”. As these algal blooms die back, depleting supplies of vital dissolved oxygenMeasures the amount of gaseous oxygen dissolved in an aqueous solution. Oxygen gets into water by diffusion from the surrounding air, by aeration (rapid movement), and as a waste product of photosynthesis. as they decay, massive fish kills become commonplace, and mammalsGroup of warm blooded vertebrate animals. Common characteristics found in these organisms include: hair, milk secretion, diaphragm for respiration, lower jaw composed of a single pair of bones, middle ear containing three bones, and presence of only a left systemic arch. and humans can die from the inherent toxicity of the algal speciesA taxonomic category subordinate to a genus (or subgenus) and superior to a subspecies or variety, composed of individuals possessing common characters distinguishing them from other categories of individuals of the same taxonomic level. In taxonomic nomenclature, species are designated by the genus name followed by a Latin or Latinized adjective or noun. involved.

Recently, eighty eight manatees succumbed to a Florida “red tide”. (The misnomer “red tide”, given to an explosive algal reproduction, originates when surface mats viewed from a lee shore are moved by wind and wave and appear to possess tidalRelating to or affected by tides. properties). Although much is known about tracking and possible treatment of “red tide events”, the dinoflagellates involved are basic to the food chainA linked feeding series; in an ecosystem, the sequence of organisms through which energy and materials are transferred, in the form of food, from one trophic level to another..

However, the beauty of BIWA is its simplicity; an enclosed fresh waterWater that is relatively free of salts. body, like a big petrie dish. Florida “red tide” events are more complex.

Stages of Red Tide

Four stages are discussed in the scientific literature.

First, “Introduction”, posits dormant dinoflagellates in off-shore sediment. How they come to be there is unknown but is thought to be associated in some way with the phosphorous cycle's natural sedimentation phase before consolidation into rock forms.

Second, is a “Growth” phase, where concentrations of a thousand Karenia brevis cells per liter, quickly reproduce (bloomA rapid growth of microscopic algae or cyanobacteria in water often resulting in a coloured scum on the surface.) to double that amount, when it exhibits its toxicity. Each cell is between 20–45 microns across and 10–15 microns deep, a single cell alga. During this phase dissolved oxygenMeasures the amount of gaseous oxygen dissolved in an aqueous solution. Oxygen gets into water by diffusion from the surrounding air, by aeration (rapid movement), and as a waste product of photosynthesis. in the water is depleted by its own growth and by decaying fish kills.

Third, is termed the “Maintenance” phase. Waters become discoloured and wind and water move the blooms towards shore. The warmer temperatures encountered, sunshine, increased supplies of nutrientsAny food, chemical element or compound an organism requires to live, grow, or reproduce. excite further growth. Lethal toxins released become airborne by wave and wind action to be taken in by surfacing manatee, dolphin, turtles, and aquatic birds. Filter feeders such as sponges, zoo planktonMinute plant (phytoplankton) and animal organisms (zooplankton) that are found in aquatic ecosystems. and mollusksinvertebrate animals, including a variety of marine, fresh water and terrestrial snails; clams, oysters, mussels, scallops; squids, octopus, pearly nautilus, as well as the many extinct varieties. take in Karenia brevis killing speciesA taxonomic category subordinate to a genus (or subgenus) and superior to a subspecies or variety, composed of individuals possessing common characters distinguishing them from other categories of individuals of the same taxonomic level. In taxonomic nomenclature, species are designated by the genus name followed by a Latin or Latinized adjective or noun. higher in the food chainA linked feeding series; in an ecosystem, the sequence of organisms through which energy and materials are transferred, in the form of food, from one trophic level to another.. In turn infected preyOrganism that is consumed by a predator. kill their predatorsConsumer organism who feeds on prey. The process of consumption involves the killing of the prey.. Fish take in the poison across their gills and again their predators die. Humans are affected by eating contaminated shell fish and exhibit NSP (neurotoxic shell fish poisoning) which can cause paralysis and death. In addition, humans suffer breathing disorders even ashore by inhalation of the toxins on the wind.

The fourth “Dissipation” phase, follows as water temperatures fall and nutrient levels and salinityConcentration of dissolved salts found in a sample of water. Measured as the total amount of dissolved salts in parts per thousand. Seawater has an average salinity of about 34 parts per thousand (ppt), alternatively, measured as Specific Conductance or Specific Conductivity expressed in microSiemens per centimeter (µS/cm) normalized to a temperature of 25 degrees Celsius. Pure water is reckoned to be 0 µS/cm, and ocean seawater at 50,000 µS/cm. reduce. This phase is probably induced by intrusion of new water mass due to currents or fresh waterWater that is relatively free of salts. storm run off.

Manatee deaths per annum from exposure to “red tide”are reported to approach 150, and deaths of dolphins approach 110. Costs of incidental losses, for example, lost tourism have been reported at $20–25 million a year. Immeasurable other costs accrue cleaning fish kills from beaches, medical and veterinary costs, research and tracking of blooms, and safety warnings.

Control of Red Tide Events

Phosphorous is consumed by both growing aquatic plants and algae, and is described in the literature as the limiting nutrient for species of dynoflagelates and cyanobacteriaBacteria that have the ability to photosynthesize..

New technologies must be explored to control limiting nutrientsAny food, chemical element or compound an organism requires to live, grow, or reproduce., particularly with respect to control of red tide and other harmful algal bloomsExplosive reproduction of algae causing harm by release of toxins, both of which classes are reported to be Phosphorous limited. Recent tests of equipment witnessed in local tidalRelating to or affected by tides. waters, gave impressive results in the control of phosphatesA salt or ester of a phosphoric acid,
an organic compound of phosphoric acid in which the acid group is bound to nitrogen or a carboxyl group in a way that permits useful energy to be released (as in metabolism),
a nutrient used in fertilizers., although more tests are required to assess replication of these priliminary results.

In estuarineThe region of a tidal mouth of a river waters of Crystal River today, phosphorous concentrations over time have been rising sharply, even though measurements taken at spring sources of those waters do not show comparable increases. This could be attributed to the different mix of submerged aquatic plants and, or, reduced biomassThe total mass of living matter within a given unit of environmental area. from various causes, consuming less phosphorous in the river run. These increased estuarine levels are significantly impacting sea grasses, fish and shell fish habitatThe place or set of environmental conditions in which a particular organism lives., and in due time could trigger local “red tide” events.

It is noteworthy that although phosphorous in laundry detergents have been banned, those in dishwasher detergents have not. The label of encapsulated Cascade dishwasher fluid proudly announces “No more than 8% Phosphorous as Phosphate”!

Think about the consequences to the manatees on their annual migrationThe moving of one species or a group of species from one area to another. to find grazing in the Gulf. This past month the Japan Times has printed a center spread with photographs of dead Florida manatee showing oozed blood on their faces. We are not alone in this. The phosphorous problem is already being fought in the Canning River, Western Australia, with red tide phenomena offshore, and most probably elsewhere also. Recent studies ascribe phosphorous as the limiting nutrient to cyanobacteriaBacteria that have the ability to photosynthesize. algae blooms. Is it not time to curb the amounts of phosphorous entering our water resources by law, and explore the application of new technologies to control phosphorous once it has entered our water resources?

Since Biwa, as Florida officials have attested in a BBC programme, Planet –1 interview, and the Scripps Institute corroborates, increased population of coastal regions, destruction of wetlandsNatural land-use type that is covered by salt water or fresh water for some time period. This land type can be identified by the presence of particular plant species or characteristic conditions., forests and fields to make way, has wrought pollution of waterways with more nutrientsAny food, chemical element or compound an organism requires to live, grow, or reproduce. than required for crop growth, such that toxicPoisonous, a substance that reacts with specific cellular components to kill cells. “red tide” and dead zones can now be measured among all the continents, many inland water bodies and oceans of the world, sometimes in excess of a thousand square kilometers in area.

The following was published Monday, December 25, 2006, in the Ledger Newspaper

Courage is needed now to enact an ordinance locally, which legally controls phosphorous in all products, and obligates all parties concerned, in the preparation and execution of an overall and systematic plan to restore and conserve water qualityA term used to describe the chemical, physical, and biological characteristics of water, usually in respect to its suitability for a particular purpose. in (at least) Crystal River / Kings Bay.