Aerial algae , coloured golden yellow , etc ., when dry often becoming greenish grey ; more or less fragrant .Threads articulate , branched .

In the islands of the Archipelago , it is a favourite ingredient in ragouts , to which it imparts a red colour , besides rendering them of a thicker and richer consistence .The dried frond , like many other Algae when infused in water , exhales an odour resembling that of violets ; and Dr .Patrick Neill mentions that it communicates that flavour to vegetables with which it is mixed .

And , last of unsuspected places , may he mentioned the damp surface of naked soil , or swampy places in lawns , and on heaths or moors .The most usual , and one might say legitimate , habitats of fresh - water algae will be in the water , in sluggish or stagnant ditches , but by preference in ditches which are not stagnant , or at the least have no stagnant odour , slow - running streams , and lakes , moor - pools , ponds , canal - banks , attached to timber or stones , on twigs , sticks , and stems , which have for some time been immersed in water , and amongst bog moss in swamps , especially where there is a little depression and a miniature pool of clear water is extemporized .Swift rivers , torrents , etc .

There are other species which really change colour shortly after their removal from the water , as the various kinds of Sporochnoidece , which pass rapidly from a clear olive to a verdigris - green .But this is the effect of death and incipient decomposition , for with the colour they lose their crispness , become flaccid , and emit an offensive odour , and , as has been observed by botanists , possess the remarkable property of changing the colour of other small filiform Algae with which they may come in contact .No doubt this is owing to the development of some active chemical agent , ( perhaps Bromine ) .

Dark granules are found embedded in the endochrome or chlorophyll of the algae cells , sometimes single , sometimes in clumps .They become more abundant as the algae die , and , finally , they so completely fill the algae cells that the latter no longer appear green but black ; whilst , simultaneously with these changes , the algae become stinking and decomposed .This process ( which has been closely followed by Lanzi in his aquarium ) takes place on a large scale each year in the Roman Campagna .

121 Contact with and ( suspected ) exposure to harmful algae and algae toxins Contact with and ( suspected ) exposure to ( harmful ) algae bloom NOS Contact with and ( suspected ) exposure to blue - green algae bloom Contact 018 Contact with and ( suspected ) exposure to other hazardous metals Contact with and ( suspected ) exposure to chromium compounds Contact with and ( suspected ) exposure to nickel dust Z77 .02 Contact with and ( suspected ) exposure to hazardous aromatic compounds Z77 .020 Contact with and ( suspected ) exposure to aromatic amines Z77 .

This would be the case if the water could be kept free from algae and infusoria , but unfortunately these are favoured as much by light as the lower organisms are enfeebled .The minute algae which render the water green ( Scenedesmus , Closterium and others related to the Desmids , are specially active ) , also cause an unpleasant fishy odour and taste , which , though not poisonous , give rise to com - plaints from the consumers .Many attempts have been made to remedy this evil by fountains , circula - tion , and scouring , but the algae grow so rapidly when supplied with fresh water , that it has been found STORAGE .

The second was by Alphonse Fteley , the engineer who designed the Sudbury system of the Boston Water Works , telling of the growth of algae in the Sudbury reservoirs , particularly No .3 , and the filtration experiments which he had made with the hope of getting rid of the odors caused by the algae .These experiments brought no definite result .

Immediately before the flood , however , the water is green in colour and has a â    very objectionable smell , somewhat like that of decaying vegetation , becoming more marked after boiling or distillation .This green colour is due to the presence of chlorophyll - containing algae brought down in immense quantities from the White Nile , and the smell is probably derived from the putrefaction of the dead algae and the liberation of the essential oil which they contain .No detailed investigation of these algae has yet been made , but Kaufmann â    states that Synedra acus Grunov , variatio delicatissima \ A7iahoina variabilis ; and Aphanizomenon Kaufnianni were present in the green water of 1895 and 1896 .

Lanzi has found in the cells of microscopic algæ from the Roman marshes certain dark - green granules , which are most numerous when the plants are farthest gone in decomposition .At length these granules fill the cells , are black under the microscope , and the algae emit an offensive odor .In the Campagna marshes are formed in winter , which in spring develop algae abundantly .

Length 1 - 1600 " .Very abundant in stinking films floating on water containing decaying freshwater Algae .BtBL .

The two former substances are of feeble germiÂ ¬ cidal power and are of little practical value except as deodorants .Copper sulfate has won a deserved reputation for destroying the microscopic algae that sometimes impart offensive odors and tastes to public water - supplies .The death of the algae in large bodies of water may be effected by as great a dilution as 1 : 1 , 000 , 000 .

Substance , tender and flaccid , soon decomposing .This plant is said to smell like violets .Grows on the larger Algae .

The two former substances are of feeble germiÂ ¬ cidal power and are of little practical value except as deodorants .Copper sulfate has in recent years won a deserved reputation for destroying the microscopic algae that sometimes impart offensive odors and tastes to public water - supplies .The death of the algae in large bodies of water may be effected by as great a dilution as 1 : 1 , 000 , 000 .

35 .) In putrid water , partly floating on the surface , partly attached to Algae .The branching is here , just as with C .

During the summer months complaints were received in the Department of growth of algae on tidal land at Helenâ   s Bay .Investigations were carried out by one of the Port Public Health Inspectors at low tide and , while considerable patches of algae did exist there was no offensive odour and it was not necessary to report the matter to the Crown Estate Commissioners .Five tierces of hog casings , produce of the U .

During the early months of the year there was particular concern about the condition of the Carshalton Ponds .During a period of no natural flow there was an excessive growth of algae and weeds and an offensive odour from the ponds .Arrangements were made for the Sutton District Water Company to increase their pumping to the west pond and the Greater London Council undertook a programme of spraying and clearing the algae .

) Faint brownish tinge , ] fine particles of vege - table deLris present , but no algÂ £ 6 .Faint brownish tinge ; ] no smell ; no algae .Nitrites and Nitrates ] absent .

The presence of fish in a storage reservoir does no harm , and the larger water plants tend to purify the water by giving off oxygen under the influence of sunlight .Certain small water weeds , such as nostoc , and some minute unicel - lular algae , often evolve most offensive odours .It sometimes happens that these minute algae increase enormously in tanks , and later on , the conditions becoming unfavourable to them , they die off with equal rapid it } , and decompose and greatly pollute the water .

Surface and very filthy waters improve very much by storage , due to sedimentation , which , by the way , carries down many of the bacteria .Filtered water and deep well - waters deteriorate much by exposure in open reser - voirs , due to the growth of algae and various water bacteria , which , while not dangerous to health , give the water a peculiar and disagreeable odor .The proper storage of such waters demands covered reser - voirs , although a method of destroying algae has lately been discovered .