Groups
In PVIK, algae are organized into groups at the genus level. Small genera may form a single group, while larger genera are split into subgroups to speed and simplify identification. Below is the list of the phytoplankton genera currently included in PVIK. Read more about the groups under the list. PVIK concentrates on European waters, because that is where the author has gathered her knowledge. But if you want to have a non-European group in PVIK, please take contact and we will see where we get.
Here is the list of the phytoplankton groups on PVIK. Five groups are visible in the open version. The groups are available to subscribers are marked with *.
- Aulacoseira – common European planktic species *
- Closterium – parallel in the middle, width less than 25 µm
- Closterium – with a beak *
- Dolichospermum – coiled
- Dolichospermum – straight *
- Lepocinclis – < 60 µm
- Lepocinclis – > 60 µm
- Phacus – roundish, with a short tail
- Trachelomonas – roundish *
The division is based on easily observed features such as shape or size – for example, roundish Phacus or Lepocinclis < 60 µm.
Where do you draw the line? How round does a Phacus have to be to count as “roundish”? Quite round. There is no absolute cut-off. If a Phacus looks roundish to you, use the key and then check the final candidates against the literature.
Some species may also span two subgroups. For example, a Lepocinclis measuring 40–80 µm is included in both the < 60 µm and > 60 µm groups. This means you are less likely to miss a species simply because it sits across a boundary.
Each genus page provides detail: why the genus was selected and how it is divided. It lists the species in each group and the key literature used to develop the group.
Here is the list of the phytoplankton groups on PVIK. Currently five groups are visible in the open version. Three additional groups are available to subscribers (marked with *). Seven groups are under construction.
Feel free to give feedback on PVIK, your opinion is valuable!