Temperate and tropical brown macroalgae thrive, despite decalcification, along natural CO2 gradients.

نویسندگان

  • Vivienne R Johnson
  • Bayden D Russell
  • Katharina E Fabricius
  • Colin Brownlee
  • Jason M Hall-Spencer
چکیده

Predicting the impacts of ocean acidification on coastal ecosystems requires an understanding of the effects on macroalgae and their grazers, as these underpin the ecology of rocky shores. Whilst calcified coralline algae (Rhodophyta) appear to be especially vulnerable to ocean acidification, there is a lack of information concerning calcified brown algae (Phaeophyta), which are not obligate calcifiers but are still important producers of calcium carbonate and organic matter in shallow coastal waters. Here, we compare ecological shifts in subtidal rocky shore systems along CO2 gradients created by volcanic seeps in the Mediterranean and Papua New Guinea, focussing on abundant macroalgae and grazing sea urchins. In both the temperate and tropical systems the abundances of grazing sea urchins declined dramatically along CO2 gradients. Temperate and tropical species of the calcifying macroalgal genus Padina (Dictyoaceae, Phaeophyta) showed reductions in CaCO3 content with CO2 enrichment. In contrast to other studies of calcified macroalgae, however, we observed an increase in the abundance of Padina spp. in acidified conditions. Reduced sea urchin grazing pressure and significant increases in photosynthetic rates may explain the unexpected success of decalcified Padina spp. at elevated levels of CO2 . This is the first study to provide a comparison of ecological changes along CO2 gradients between temperate and tropical rocky shores. The similarities we found in the responses of Padina spp. and sea urchin abundance at several vent systems increases confidence in predictions of the ecological impacts of ocean acidification over a large geographical range.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Brown macroalgae flora on the coastline of Bushehr province counties

Marine brown macroalgae are an important part of the tidal coaste flora in Bushehr province with rocky, coral and sandstone beds. Brown seaweeds need a solid and stable support (natural or artificial) to be attached algae holdfasts to the them, ensuring their establishment for growth, multiplication and development against violent waves. Because of this, most macroalgae are not able to grow on ...

متن کامل

UV-susceptibility of photosynthesis of adult sporophytes of four brown Antarctic macroalgae (Phaeophyceae)

The Antarctic ozone hole is reported to develop annually in Austral spring since the late 1970s and results in increasing irradiances of solar UV-B radiation on the earth’s surface and in the aquatic environment (Farman et al. 1985, Häder et al. 1998). Exposure of organisms to enhanced UV-B radiation results in multiple damage, e.g. dimerisation of DNA molecules, formation of reactive oxygen sp...

متن کامل

Feedbacks and responses of coral calcification on the Bermuda reef system to seasonal changes in biological processes and ocean acidification

Despite the potential impact of ocean acidification on ecosystems such as coral reefs, surprisingly, there is very limited field data on the relationships between calcification and seawater carbonate chemistry. In this study, contemporaneous in situ datasets of seawater carbonate chemistry and calcification rates from the high-latitude coral reef of Bermuda over annual timescales provide a fram...

متن کامل

Climatic zonation drives latitudinal variation in speciation mechanisms.

Many groups of organisms show greater species richness in the tropics than in the temperate zone, particularly in tropical montane regions. Forty years ago, Janzen suggested that more limited temperature seasonality in the tropics leads to greater climatic zonation and more climatic barriers to organismal dispersal along elevational gradients in the tropics relative to temperate regions. These ...

متن کامل

Oecologia (Berl

Breeding birds were censused along four elevational gradients in the Adirondack Mountains, New York, and the Green Mountains, Vermont. The bird communities of the four gradients were basically similar in species composition, richness and amplitude patterns. Three measures of species diversity decreased with increasing elevation. Low-elevation communities contained higher proportions of rare spe...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Global change biology

دوره 18 9  شماره 

صفحات  -

تاریخ انتشار 2012