On the hunt for marine microfossils
Posted on: 06/01/2022 By: Jane Earland
Research has begun on the Iceland Work Package palaeoecology and is being carried out by Jane Earland during the beginning stages of her PhD studentship funded by the SEACHANGE Project. The aim of this palaeoecological investigation is to determine if anthropogenic activity since the Viking settlement of Iceland in AD 870, such as 20th century industrial-scale fishing, has had an impact on marine ecology.
To start this research project, we are using sediment cores collected on the North Icelandic Shelf during an earlier project (EU FP7 project “MILLENNIUM”) in 2006. Based on published research of cores close to collection site of these cores, we suggest our two cores can provide a record of palaeoecological data spanning the last 1000 years and the last 3000 years. These cores therefore cover they key transitional period from the ‘pristine’ Icelandic marine environment prior to the Viking invasion in AD 870, through to the present.
Within the sediment cores, we are looking for marine microfossils. The microfossils we find may be the physical remains planktonic and benthic foraminifera, coccolithophores, ostracods, diatoms, dinoflagellate cysts, ichthyoliths, fish otoliths and molluscs. These fossilised remains can help us to build a picture of marine ecological diversity through time, and determine if there are correlations between species diversity and human activity.
To identify these microfossils, samples of sediment were taken from the two cores at regular intervals. The age of each sediment sample can be determined, meaning we can provide a continuous dated record of microfossils through time. Once sampled from the core, the sediment was then dried, and washed through a 63-micron sieve (these fossils really are tiny!) to remove most of the sediment and leave the fossils behind. Using a microscope, we are now looking at the samples and picking out any microfossils we can see. These can then be identified and show us what species are present in the sample.
Microfossils picked out from the sediment cores under the microscope
During the SEACHANGE research cruise, we are aiming to collect more sediment cores closer to the coast of Iceland. This should help us to determine where human impacts have had the largest impact. It should also help us determine if human impacts on the Icelandic marine system began at different points in time.
