Temporal Niches in the Aquatic Ecosystem at Lake Runnemede

I've been formulating a new perspective of the aquatic ecosystem here, divided into temporal niches. Rather than constant competition for light, nutrients and other resources, different species of plants, algae and cyanobacteria appear to have formed distinct temporal (time-related) niches that form cooperative associations rather than competitive (for the most part). It appears to work something like this for the primary producers in the ecosystem:
 

1. During winter die-off, nearly all nutrients either precipitate to the substrate or are returned to the water column.
2. After ice-out (and sometimes during winters if open water or thin ice persist over winter), filamentous green algae are the first to return to the Lake and take up nutrients from the water column.
3. Rooted macrophytes return as early as they can, especially ones that grow out vegetatively from winter buds or rhizomes. Some of them take up nutrients from the water column, but primarily they get what they need from substrate via their roots.Their life cycles seem to be fast-tracked here, and flower and fruit quite a bit earlier than expected for our area
4. As the water warms, CB populations begin to increase and form colonies. The cold water green algae tendo to become aerated and form floating mats.
5. By midsummer the slower growing Water Lily populations begin to form dense aphotic glades which kill off other photosynthetic growth beneath them.
6. Non-rooted macrophytes (Ceratophyllum demersum and Utricularia spp.) also grow slowly but begin to dominate the deeper waters by mid-July, shading off low-growth rooted macrophytes and dominating nutrient uptake from the water column. It is during this growth phase that CB and other allelopathic species may release some cyanotoxins into the water column as available nutrients in the water column become scarce. However, the Ceratophyllum almost certainly reduces the populations of CB and probably prevent blooms during mid and late summer. I do not observe Microcystis colonies much after early July.
7. After the Ceratophyllum growth phase is over (by mid-July), the primary producers coexist in relative harmony for the rest of the summer.

Lake Runnemede pretty unique though, since it has no feeder streams and such high Ceratophyllum density. However, I expect that there are other plants found in the area that compete with CB and algae for nutrients in the water column, especially the dreaded Myriophyllum spicatum (Eurasian milfoil). So, aesthetics aside, the milfoil may have a role in preventing CB blooms in certain bodies of water! (just a guess on my part - no research that I know of to support that idea). At any rate, I also believe that the competition between macrophytes, algae and CB may cause the release of cyanotoxins during non-bloom conditions (again, my idea, not proven) that may cause rashes or other illnesses if water is swallowed. I also think that this ongoing competition may be the reason why TP readings in Runnemede are so variable from week to week.

Of course, other phytoplankton, zooplankton, vertebrates and non-vertebrate life forms, water chemistry and temperatures all fit into the overall picture as well, but the environment is largely structured by the plants and microorganisms listed.

Publicado el 17 de enero de 2024 a las 10:12 PM por anachronist