Seaweed thatch roofs

Eelgrass becomes fully waterproof after about a year and has insulation properties comparable to those of mineral wool, a dense, fibrous material made from molten glass, stone or industrial waste. A roof can last hundreds of years – one of island’s remaining seaweed roofs dates more than 300 years – for comparison, a concrete tile roof typically lasts around 50./quote]

http://www.bbc.com/travel/story/20200805-denmarks-300-year-old-homes-of-the-future?referer=https%3A%2F%2Fwww.bbc.com%2F

"But, after a fungal disease wiped out much of the eelgrass in the 1920s, knowledge of the technique slowly vanished."

Does anyone know if this is a world-wide fungal disease and whether or not the eelgrass has overcome this problem?

ABSTRACT
Wasting disease of the 1930's
An attempt was made to correlate wasting disease of the 1930's with factors such as seawater temperature, salinity
and sunshine, in order to establish a possible link with mechanisms behind climatic cycles, such as the sunspot
cycle, and the related Russell cycle.
Europe. Salinity and seawater temperature fluctuations could not have contributed significantly to eelgrass stress,
but there is a good correlation with reduced sunshine and raised turbidity levels. This correlation was verified with
an existing computor simulation model for eelgrass growtb. In the Netherlands, the response of eelgrass to adverse
light conditions was probably much enhanced by the activities associated with the closure of the Zuyder Sea in
1932.
USA. Salinilies and temperatures were above average, but ccrtainty not uniquely or dramaticaüy so, while sunshine
was well above average. No possible causal link could be established between climatic factors and wasting disease
inidation. This lends support (o the suggestion by Short et al (1987) that the wasting disease epidemie was perhaps
caused by the emergence of a pathogenic strain oi Labyrinthula.