User:Cashi049/Trichodesmium

Sociality
Trichodesmium are able to transfer between living as a single filament and as a colony. These different morphologies impact the way that the Trichodesmium interact with the environment. Switching between morphologies shows that there are different benefits and costs of existing in each form, and helps scientists understand why transferring from one form to another is necessary. Trichomes, or free-floating single filaments, have higher rates of nitrogen fixation as opposed to colonies. When iron and phosphorus are limiting in the environment, the filamentous Trichodesmium are stimulated to aggregate together to form colonies. Colonies can outcompete trichomes when environmental factors such as predation and rate of respiration for nutrient fixing are at play. The size of the colonies are also linked with the environmental oxygen content, due to the influence of oxygen in the process of photosynthesis. Trichodesmium colonies are microbially diverse and are considered to be a holobiont, where multiple epibiont bacteria form a singular colony. In these holobionts, Trichodesmium is the core host, but the microbial diversity of the holobiont colony is an essential part of its ecological interactions. Some examples of the Trichodesmium microbiome’s epibiont bacteria include diazotrophs and several cyanobacteria species such as Richelia. Trichodesmium and the epibiont bacteria within the holobiont colonies may perform mutualistic interactions where limiting nutrients such as iron can be elucidated from dust. Other interactions with organisms arise when trichomes start to accumulate together. When colonies of Trichodesmium aggregate in large numbers, it is possible for them to produce a phycotoxin that can affect the growth other microorganisms in the local space of the ocean.