Once you have located a place to make your ecosphere (see Water bodies) the fun can begin! For collection, I would recommend bringing the following:
The first step is to add the sediment to your container, you can assemble your ecosphere in the field or at home, I personally prefer home assemblage as it tends to be less hassle. If going this route, fill 2 separate containers of sediment and water. Try to only take as much sediment as you need, excess sediment should be returned as it is full of animal life. To avoid this issue, you could fill your jar with sediment in the field and add water at home. You should only add roughly 4cm (1.5″) of sediment, use a little less for smaller jars and a little more for larger jars, it really depends on the shape of the jar, but you can usually tell by eye when it's at a good level, do be careful however to not use too much, that is a mistake that many beginners make!
The next step is to add your plants, you can use native plants like short water reeds which grow half immersed in both rivers and ponds. If you can’t find any native plants, you can buy them. I don’t recommend adding sticks or allowing for there to be an excess of leaves, as when they break down they will release a lot of nutrients, which can poison the organisms and cause a crash. When planting, most stem plants can be pushed into the wet sediment with tweezers, Floating plants should be added after adding the water. If using stem plant be sure to push them down to the bottom of the sediment as trying to push them back into the ground once submerged is a nightmare!
The final step is to add the water, be careful not to add it too quickly as it will cause the sediment to cloud up the container. I recommend slowly pouring the water down the side of the container or slowly siphoning in the water to avoid this issue. Fill the container almost to the top, leaving an air gap to allow for gas exchange. There is no set size for this air gap because every jar is different in shape, however for most containers you can usually make it a little over the length of your thumbprint.