https://nypost.com/2019/08/13/algae-bloom-that-killed-three-dogs-is-the-same-bacteria-found-in-nj-lakes/

Algae: An Introduction

Phycology or algology is the study of algae. The word ‘Phycology’ is derived from the Greek word ‘Phykos’ meaning seaweed.

The algae are thallophytes (plants lacking roots, stems and leaves) that have chlorophyll as their primary photosynthetic pigment and lack a sterile covering of cells around their reproductive cells or organs.

General Characteristics

Nature, Habit and Habitat

Algae are cosmopolitan in distribution. They may grow in all kinds of habitats.
The group Algae is a heterogeneous group. So, thallus organization varies in a great range. For example:
-Motile unicellular: Chlamydomonas.
-Motile colonial: Volvox.
-Filamentous: Spirogyra.
-Heterotrichous: Fritschiella.
-Siphonaceous: Vaucheria.
Plant body is not divided into roots, stems and leaves.

Cellular characteristics

They may be prokaryotic or eukaryotic. Prokaryotic are included in Cyanobacteria.
They are autotrophs as they have chlorophyll.
Each cell is bounded by a typical cell wall, with a few exceptions like Euglena and Gymnodinium where a cytoplasmic membrane (made up of a protein layer supported by a substructure of microtubules), called pellicle is present.
Vascular bundle is absent.

Reproductive & Growth characteristics