Posts Tagged ‘succession’

More early succession – bryozoans, barnacles and fishes

November 8, 2012

On Monday 29 October, D block marine scientists went down to the Pearson College dock and checked on the substrates that they had suspended in the water on 10 September 2012. There have been lots of observable changes…

 September – clean

October – diatoms

October – bryozoans

September – clean

 October – bryozoans

 September – a rusty can

October – still a rusty can but now with a barnacle!


 October –                 sailfin sculpin inside jar!

 October – shrimp in mesh outside jar

 October – it may look like just a concrete block with diatoms but there was a spiny lumpsucker on it when it was pulled up – the photographer was too slow to capture the fish!

And we had a few accidents over the almost two month period:

The box shown above now looks like this:

And there was a tangle of two substrates:

Early succession – diatoms, shrimp and fish

October 26, 2012

On 10 October 2012, B block marine scientists went down to the Pearson College dock and checked on the substrates that they had suspended in the water on 7 September 2012.

After a month there have been some changes:


A bleach bottle is now covered in benthic diatoms:


So is the piece of cinder block:


And a glass jar:




The “Kraken” bottle is covered in diatoms too:



And it is home to at least one dock shrimp:




The tire also housed several shrimp (the photos didn’t turn out though, sorry!)



And the substrate below…



…had a crescent gunnel living between the bottle and the mesh covering.


September 7, 2012

Ecological succession can be defined as ‘the orderly process of change over time in a community’ or ‘the sequence of appearance and disappearance of species in an ecosystem after a disturbance or following the creation of a new habitat’. It is a pattern of colonization and extinction.

At Pearson College a similar change occurs every year when a new cohort of students arrives in the fall.  The first week of classes is now over and this afternoon, first year Marine Science students set up a succession experiment that will be ongoing throughout their two year tenure at the College.

Each student in B block chose a substrate (from the Recycling Shed) to suspend from the Pearson College dock at about 0.5 m depth.  The substrates included: a small concrete block, a glass jar, a plastic plant pot, a piece of wood, a large tin can, a plastic bleach bottle and an old tire.

A mesh-wrapped bottle.

A coat hanger with plastic mesh attached.

Lily’s glass bottle (no mesh!).

The old tire came from a beach clean-up that Marine Science students did three years ago.

Today the substrates are uncolonized – students will track the process of ecological succession by pulling up their substrate every two months or so.  We’ll keep you posted…