Ice-ice is a disease condition of seaweed

Seaweed

Seaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...

. Ice-ice is caused when changes in salinity

Salinity

Salinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...

, ocean temperature

Sea surface temperature

Sea surface temperature is the water temperature close to the oceans surface. The exact meaning of surface varies according to the measurement method used, but it is between and below the sea surface. Air masses in the Earth's atmosphere are highly modified by sea surface temperatures within a...

, and light intensity

Light intensity

Several measures of light are commonly known as intensity. These are obtained by dividing either a power or a luminous flux by a solid angle, a planar area, or a combination of the two...

 cause stress to seaweeds, making them produce a "moist organic substance" that attracts bacteria in the water and induces the characteristic "whitening" and hardening of the seaweed's tissues. Bacteria involved include those in the Vibrio

Vibrio

Vibrio is a genus of Gram-negative bacteria possessing a curved rod shape, several species of which can cause foodborne infection, usually associated with eating undercooked seafood. Typically found in saltwater, Vibrio are facultative anaerobes that test positive for oxidase and do not form...

-Aeromonas

Aeromonas

Aeromonas is a gram-negative, facultative anaerobic rod that morphologically resembles members of the family Enterobacteriaceae. Fourteen species of Aeromonas have been described, most of which have been associated with human diseases. The most important pathogens are A. hydrophila, A. caviae, and...

and Cytophaga

Cytophaga

Cytophaga is a genus of Gram-negative, gliding, rod-shaped bacteria.-Species:The following are some species in Cytophaga:* Cytophaga columnaris — the cause of columnaris disease in salmonid fish, as associated with increased water temperature; it is characterized by white necrotic plaques...

-Flavobacteria

Flavobacteria

The class Flavobacteria is composed of a single order of environmental bacteria. Flavobacteria are a group of commensal bacteria and opportunistic pathogens. Flavobacterium psychrophilum causes the septicemic diseases rainbow trout fry syndrome and bacterial cold water disease...

complexes. The bacteria lyse

Lysis

Lysis refers to the breaking down of a cell, often by viral, enzymic, or osmotic mechanisms that compromise its integrity. A fluid containing the contents of lysed cells is called a "lysate"....

 epidermal cells and chloroplast

Chloroplast

Chloroplasts are organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis. Chloroplasts capture light energy to conserve free energy in the form of ATP and reduce NADP to NADPH through a complex set of processes called photosynthesis.Chloroplasts are green...

s, turning the seaweed tissue white. The disease is known from seaweeds including Kappaphycus alvarezii

Kappaphycus cottonii

Kappaphycus alvarezii is a species of red alga. It is one of the most important commercial sources of carrageenans, a family of gel-forming, viscosifying polysaccharides. Farming methods affect the character of the carrageenan that can be extracted from the seaweed.This alga grows to two meters...

and Eucheuma denticulatum, economically important sources of carrageenan

Carrageenan

Carrageenans or carrageenins are a family of linear sulfated polysaccharides that are extracted from red seaweeds. There are several varieties of carrageen used in cooking and baking. Kappa-carrageenan is used mostly in breading and batter due to its gelling nature...

. In countries where seaweed is harvested as a crop, ice-ice can wreak havoc on yields. Zamboanga

Zamboanga Peninsula

Zamboanga Peninsula / Western Mindanao is a peninsula and an administrative region in the Philippines. Designated as Region IX, the region consists of three provinces, namely, Zamboanga del Norte, Zamboanga del Sur, and Zamboanga Sibugay, its component cities of Dipolog, Dapitan, Pagadian, and...

, Philippines, had an outbreak of ice-ice in 2004, while Bali

Bali

Bali is an Indonesian island located in the westernmost end of the Lesser Sunda Islands, lying between Java to the west and Lombok to the east...

, Indonesia, is experiencing an outbreak in 2009. A rise in surface sea temperatures of 2-3 degrees Celsius cause stress to the seaweeds, making them vulnerable to disease.