Publication Date:
2016-09-24
Description:
The brown algae Desmarestia menziesii and D. anceps form dense underwater forests
at the Western Antarctic Peninsula (WAP) in the upper to mid subtidal and play an important
role in this coastal ecosystem. Seawater temperatures at the WAP increased by about 2 °C
in the last 50 years and probably will rise further in future due to global warming. This may
have consequences for the physiological performance and community interactions of these
cold water adapted algae. In laboratory experiments with culture material we investigated the
influence of increased temperatures on the photosynthetic response, growth and interspecific
competition of both species. Increased temperature (5 °C) induced a higher growth rate of
D. anceps and a higher optimum quantum yield of photosynthesis in both species compared to
0 °C. Neither interspecific competition nor interactions between competition and temperature
were detected. The photosynthetic performance (rETRmax, α and Ek) of D. menziesii was significantly
more often affected by temperature increases than of D. anceps. It was shown that a
temperature increase from 0 °C to 5 °C was not harmful for both Desmarestia species in this
set-up. Generally, growth of D. menziesii was very low possibly reflecting a dormancy state
under continuous long-day conditions and thereby may have masked the influence of temperature
on growth. In order to determine realistic survival thresholds of these key species of
the Antarctic coastal ecosystem under global change scenarios, further multifactorial experiments
are of great importance, including field material, different algal life stages and reproductive
processes.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
,
info:eu-repo/semantics/article
Permalink
