火山の影響で天然の温湧水が常時流入し、現在もなおヨシが越冬と繁殖を続けている琵琶湖において、冬季のヨシの生残と水温、気温の関係を調査した
冬期間に琵琶湖で湧き出た温水は8℃であった
最低気温が0℃のときに最低水温が6℃が保たれており、ここではヨシが越冬できた
冬季の最低水温が7℃以上を維持する場所では温湧水でも温排水でも熱帯産のヨシは越冬できるものと考えられる
ヨシの越冬には冬季に最低水温6℃以上が必要である。そして、温排水及び温湧水などがあれば、この条件を満たしヨシは越冬できる
In Lake Biwa where natural hot spring water flows constantly under the influence of the volcano, still today common reed continues to breed and wintering, we investigated the relationship between water temperature, air temperature and survival of common reed in winter.
The hot water springs in Lake Biwa in the winter period was 8 ℃
It has been kept 6 ℃ at minimum of water temperature when minimum air temperature was 0 ℃, and it is the reason why common reed could be wintering here
It is believed that common reed of tropical origin can be wintering with hot spring water or hot discharge water because the minimum water temperature is kept at 7℃ in the winter.
Reed requires water temperature at least 6 ℃ in winter to be wintering. And, if there is hot spring water or hot discharge water, it meets the requirement.
