It is definitely getting a bit cooler! According to my dive watch during my snorkel at Beaumaris today, the water today was still 19 degrees. I just bought tight-fitting long sleeve Frogskin top with a hood to go under my 5.5mm semi-dry wetsuit. From now until mid-August the temperature is going to drop about a degree every fortnight. It should still be nice for a month or so though. Usually at this time of year the weather is calming and the water clearer but last week’s heavy rains have made it a bit soupy.
When the clarity is poor there is only one thing to do. Look up close and concentrate on the little critters.
Temperate Coral Reef
At least when the water is full of sediment, everything is out feeding. Including the corals. Our temperature coral reefs are quite spectacular in places.
Tunicates
Among the seagrass I came across this colonial tunicate. These animals have fascinating life histories. They produce a free-swimming embryo almost identical to a human embryo. In fact we come from the same animal Phylum, so presumably share an ancestor. Both of our species starts life with a notochord. Ours turns into a spine. For the tunicate it buries into the sediment and metamorphoses into something like this.
Feather-duster worms
More animals out feeding in the planktonA soup of micro-organisms. Usually refers to all the zooplankton and algae in the ocean but can also be used to describe tiny insects in the atmosphere (see aerial plankton). More included these feather duster worms which are like our versions of tropical Christmas Tree Worms. If you touch them they suck back into their holes. On the sand were Purple-tipped Anemones, ready to grab fish and shrimp that pass. While Hermit Crabs tidy away anything they can consume. The Right-hand Hermit Crab pictured is sitting on top of a piece of encrusting coral.
Amazing sea urchins
And finally, I took this picture to show a hole dug out of the rock by a sea urchin. Urchins, relatives of the sea stars (like the close up of the biscuit star, pictured below) are long-lived. Some move around and others are sedentary. It’s possible that the animal that occupied this hole could have been 50 years old. You can see the gnaw marks where it continued to grow its home in the rock. In the foreground is the coral that depended on it for keeping competition at bay. Urchins are incredibly important for our ecosystemsHow ecosystems function An ecosystem is a community of lifeforms that interact in such an optimal way that how ecosystems function best, is when all components (including humans and other animals) can persist and live alongside each other for the longest time possible. Ecosystems are fuelled by the energy created by plants (primary producers) that convert the Sun's heat energy More, which is hardly surprising when you take a close look at their biology. They are very sophisticated sensory organisms that serve a function(Of an ecosystem). A subset of ecosystem processes and structures, where the ecosystem does something that provides an ecosystem service of value to people. More we hardly understand.
Annual temperature graph
Those winter dips can be icy and you might only be in for 30-40 minutes but if you choose a sunny day it can be worth it. Here’s the temperature graph from last year showing how it is likely to change in the coming weeks. You can find access to all these resources from my snorkelling page here.
