Other physical factors
that have an effect
on seagrass beds
include
light, temperature, and desiccation (drying out).
For example,
water depth and turbidity
(density of particles in the water)
together or separately
control
the amount of light
available to the plants and the depth
to which the seagrasses may extend.
Although marine botanist W.A.Setchell
suggested early
on the temperature
was critical
to the growth and reproduction of eelgrass,
it has since been shown
that this particularly widespread seagrass
grows and reproduces
at temperatures between 2 and 4 degrees Celsius
in the Arctic
and at temperatures up to 28 degrees Celsius
on the northeastern coast of the United States.
Still, extreme temperatures,
in combination with other factors,
may have
dramatic detrimental effects.
For example,
in areas of the cold North Atlantic,
ice may form
in winter.
Researchers Robertson and Mann note
that when the ice begins to break up,
the wind and tides may move the ice around,
scouring the bottom
and uprooting the eelgrass.
In contrast,
at the southern end of the eelgrass
Seagrass beds also decline
if they are subjected
to too much exposure to the air.
The effect of desiccation
is often difficult to separate
from the effect of temperature.
Most seagrass beds
seem tolerant of considerable changes
in salinity (salt levels)
and can be found
in brackish (somewhat salty) waters
as well as in full-strength seawater.
Other physical factors
that have an effect on seagrass beds
include light, temperature, and desiccation (drying out).
For example, water depth and turbidity (density of particles in the water)
together or separately
control the amount of light available
to the plants and the depth
to which the seagrasses may extend.
Although marine botanist W.A.Setchell suggested
early on the temperature was critical to the growth and reproduction of eelgrass,
it has since been shown
that this particularly widespread seagrass grows and reproduces
at temperatures between 2 and 4 degrees Celsius
in the Arctic and at temperatures up to 28 degrees Celsius
on the northeastern coast of the United States.
Still, extreme temperatures,
in combination with other factors,
may have dramatic detrimental effects.
For example, in areas of the cold North Atlantic,
ice may form in winter.
Researchers Robertson and Mann
note that when the ice begins to break up,
the wind and tides may move the ice around,
scouring the bottom and uprooting the eelgrass.
In contrast, at the southern end of the eelgrass
Seagrass beds also decline
if they are subjected to too much exposure to the air.
The effect of desiccation
is often difficult to separate
from the effect of temperature.
Most seagrass beds
seem tolerant of considerable changes
in salinity (salt levels)
and can be found
in brackish (somewhat salty) waters
as well as in full-strength seawater.
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