A University of Otago marine scientist will be leading a small army of school pupils in a new study of how Port Otago's deepening project will affect marine life along the shoreline.
The university marine sciences department and the New Zealand Marine Studies Centre in Portobello are co-leading the "community monitoring initiative''.
It will look at how marine plant and animal life close to the shoreline are responding to the project to deepen the shipping channel that began last year.
Five schools had already signed on to the project, and more were welcome to join, marine studies centre programme director Sally Carson said.
Participating pupils and community members will head out and count the number of animals and plants they find in the intertidal zone, monitoring how the numbers change over time.
The zone was home to a diverse range of organisms, including snails, crabs, seaweed, barnacles, and "lots of encrusting animals that don't move'', Ms Carson said.
Otago marine sciences PhD candidate Matthew Desmond said the idea for the research project had come from the community, who had questions about how deepening the port might affect marine organisms.
Port Otago chief executive Geoff Plunket did not want to comment on how the study was conceived, or any concerns community members might have.
But he did say the deepening project had been through a long consultation process "with which the community has had a lot of involvement''.
If community members had questions, he said, "they had a significant opportunity to participate''.
Still, Mr Desmond said some people did have "concerns'' about the impact of the deepening.
And, he said, there were a couple of different ways it could be affecting marine life.
Although the harbour had been dredged since 1868, the deepening was a much bigger undertaking than the "maintenance'' dredging that preceded it, Mr Desmond said.
"The effect of doing that is disturbing a huge amount of sediment that's been there for a long time. There are a couple of concerns; one could be that things within those sediments could be chemicals or pollutants ... that then are disturbed.''
The disturbed sediment could also make the water cloudier, which might get in the way of photosynthesising organisms, such as plants and algae.
And the sediment might settle on rocky surfaces, obliterating the natural habitat of organisms that live exclusively on rock.
"Depending on which of these occur, it can have flow-on effects all the way up the food chain,'' he said.
"If these areas become less productive or are wiped out completely, you lose a huge amount of diversity and a huge amount of productivity within the harbour as well.''
Another concern was that it was impossible to know whether the deepening was having any of these effects until the study was done.
And if it was having a negative impact, Mr Desmond said, it might already be too late to do anything about it.
"Once it's happened, it can be too late,'' he said.
"These communities are really vulnerable; once they're gone, they're gone, they don't often come back.''
Nonetheless, Mr Desmond withheld judgement on whether the intertidal zone was suffering as a result of the deepening.
"I can't comment on whether we think there will be an effect or not - that's what we're going to find out, I guess.''
And, although Port Otago had to carry out extensive monitoring to retain resource consent for the 15m, 20-year deepening project, Mr Plunket said he would be open to looking at the results of the study once it was completed.
"We can't prejudge what they're going to find - they'll go out and do their study, and we'll take great interest in reading the final report,'' he said.
"If there are things in the final report that we think are worthy of further study, we'll study them.''
