Matt Wilson
SE Alaska shoreline at low tide.
Photo: Matt Wilson
Juneau, Alaska tidal region and zonation observations
There is a very clear zonation of the shore between high and low tide. At the high water mark (HWM), little rockweed is clearly the most abundant algae, and remains so to the low water mark (LWM). As you get closer to the LWM broad-leaved kelp become more prevalent, although still outnumbered by little rockweed. Moving from high to low tide, mussels’ maximum size increases the closer to the LWM one gets. The same it true for barnacles as they grew from as small as .5cm in height (max) at the HWM to over 5cm at the LWM. Barnacles also become more prevalent compared to mussels as one gets closer to the HWM. Rock near the LWM seemed to be clearly dominated by either barnacles or mussels; very rarely were the numbers close to even, and the proportions reversed frequently along the shore. It would be intriguing to see the makeup of these same tide pools during more energetically favorable conditions. (Natural History journal excerpt, Matt Wilson, 14 Jan 2008)
Khao Sok, Thailand rain forest early morning auditory journaling
Photo: Matt Wilson
Prior to sunrise and ability to see into the forest there is a clear succession of sounds
From 5:20am to 6:00 gibbons were the most dominant sounds with very few birds heard. Then from 6:00 to 6:20 a smaller [sounding] monkey species took the place of gibbons as dominant sound, and then died off by 6:20; frogs followed and took over chorus very loudly and drowned out nearly every other sound in the forest. Birds also started calling at this time. At 6:25 insects became louder and frogs became less prevalent, but still present. A new species of frog started sounding at 6:30 and became the dominant sound at 6:40. Also at 6:40 a heron was seen flying overhead. At 6:45 gibbons returned and became dominant sound again and more herons were seen overhead flying in same direction as first – SE of location/bungalows. (Natural History journal excerpt, Matt Wilson, 1 Feb 2008)
I chose to present these two excerpts from my Natural History journal because of the recurring theme that they present. Both exemplify a theme of zonation in vastly differing biomes. I have pointed this out because this pattern also illustrates the specificity of the ecological niches that everything occupies, from the physical (location in the AK tidal region) to the behavioral (the succession and specificity of calls in Khao Sok) and the shades of gray in between the two. And as a result of this specificity, our changing climate can have quite the domino effect upon these ecosystems, and throw them into chaos. If a slight rise in ocean temperature (i.e. global warming) has enough of an impact to eliminate little rockweed from the tidal zone, is there a photosynthesizer adaptable enough to fill its niche with relative speed? If not, that is a very large energy source that has suddenly vanished. Or if a new species is able to fulfill this role, it quite possible could out-complete and exclude other kelp species from the tidal zone near the LWM, a result that very well could alter the ecosystem irrevocably - and most likely for the worse. Quite simply, it is a lose-lose situation when we interfere with nature.
Matt Wilson
wilsonmj at my.hiram.edu
last updated 27 September 2008
Banner Photo by Mathew J. Wilson