Last time I posted this blog, I was yearning to paddle my favorite stretch of the Hudson River. And so I did. For about 10 minutes. I'd no sooner dipped my paddle ten times when thunder started rumbling and dark clouds rolled across the sky, pushed in my direction by rising winds. By the time I returned to the take-out spot, torrents were sheeting down, filling my canoe and drenching me from top to bottom. Oh well. Summer's hideous heat and lack of bank-lapping water for six weeks had really fried all the riverbank wildflowers, so there wasn't much to see, anyway. But that was not the case at all, when my friend Sue Pierce and I returned this past week to one of our favorite ponds, Archer Vly, in northern Saratoga County.
There were no threatening clouds in sight, although there was a brisk wind riffling the pond when we first arrived. But by the time we'd reached the mid-point of the pond, it was all calm water, its reflective sheen decorated by acres of Water Shield leaves.
One reason we were eager to visit this pond was to see how the flora was recovering from the devastating flood that drowned most of the shoreline plants four years ago, caused by extra-heavy rains that year and a beaver-dam-clogged culvert. Although all of the waterside conifers have died (you can see the needle-free remains of them beyond where Sue is paddling, below), most of the herbaceous wildflowers and swamp-dwelling shrubs are returning to health. Not all of them in the numbers that thrived pre-flood, but definitely reclaiming their habitat.
For us wildflower fanatics, the most devastating loss was the entire disappearance of Narrow-leaved Gentians (Gentiana linearis) that once lined the shore of this pond in numbers too high to count. The first year past-flood, I found just one! But I'm happy to report that every year since then, the numbers have multiplied. They have not yet reached the abundance they once achieved, but we were encouraged to see plenty of them gracing the shore with their radiant blue blooms.
Many other shoreline wildflowers, especially those that prefer to grow with their roots in the water, were doing just fine as well. A little bee was exploring the bright-white blooms of Common Arrowhead (Sagittaria latifolia).
A generous clump of tiny-flowered Northern Bugleweed (Lycopus uniflorus) was nestled within some pondside boulders, sharing its damp spot with some small Sensitive Ferns (Onoclea sensibilis).
This handsome patch of Pickerelweed (Pontederia cordata) cares not a whit that its roots are underwater.
Common Pipewort (Eriocaulon aquaticum) is so happy to be wet, it even continues blooming if the water should rise to inundate even the flowerheads. This day, though, masses of them were raising their tiny white button-shaped blooms well above the water's surface.
We were once again delighted by hordes of Swamp Spreadwing Damselflies (Lestes vigilax) flitting and fluttering among the emergent Bur Reed leaves, the sunlight glittering off their transparent faceted wings, which they held half-open even while they perched. Shoreline vegetation like this is this damselfly's typical habitat, where they mate and lay their eggs.
This Swamp Spreadwing Damselfly stopped its constant fluttering to rest on my paddle, allowing me to observe the blue eyes, iridescent green thorax, and pale-blue band at the end of the bronzy-green abdomen that are distinctive for this species.
Here's another beautiful critter we found, this Monarch Butterfly caterpillar (Danaus plexippus) apparently preparing to pupate, as it assumed the typical curled-up posture prior to forming its chrysalis.
Of course, we were delighted to observe the flora and fauna mentioned above, but what really astounded us on this paddle were the incredible size and abundance of the colonial "moss animal" (Bryozoan) formations -- Pectinatella magnifica -- we observed in shallow water, in numbers we had never observed here before. Both Sue and I had noticed how warm the pondwater was now, much warmer than in other summers. I wonder if the warmer water contributed to the size and abundance of this organism's colonies.
Most of the Pectinatella colonies were too big and heavy to hoist out of the water, but this little one wasn't. I could bring it close enough to be able to discern each individual filter-feeding creature.
A beam of sunlight happened to ignite this colony, making it appear as if it were glowing from within!
Due to their key filter feeding abilities and removal of specific organisms within the water they form in, Bryozoans are seen as a beneficial aspect of a pond’s ecosystem. Their ability to filter out bacteria, algae, and protozoa can help prevent eutrophic blooms of these organisms.
And here was another fascinating organism we saw, a green-tinted, transparent gelatinous mass suspended underwater. I have found these masses of transparent greenish jelly in another lake I paddle, but I cannot recall ever finding them here on Archer Vly. They are formed by the colonial microscopic single-celled protozoa called Ophrydium versatile. Inhabitants of fresh water lakes and ponds all over the world, the individual cells line up side-by-side in the "blob"and attach themselves to a jelly-like substance they secrete. They are symbiotic with microscopic Chlorella algae that live inside the Ophrydium cells and give the blob its green color. While the algae contribute significantly to the colony's energy needs through photosynthesis, Ophrydium also filter feeds on bacteria and other small organisms for additional nutrients. Again, I am wondering if the warmer water temperature this year has contributed to the growth and abundance of this colonial organism.
And here was one more fascinating underwater find. Looks like some kind of water plant, doesn't it? But it's really an animal! Or, to be more exact, a colony of animals called Freshwater Sponge (Spongilla lacustris). Despite its green color and seaweed-like appearance, a lake sponge is composed of simple filter-feeding animals, possessing many cells but lacking a mouth or a brain or muscles or heart or any ability to move, once it becomes attached to a submerged rock or fallen limb. It somewhat resembles a green plant because (again!) of the green algae that inhabit it in a symbiotic relationship. The algae help the sponge utilize nutrients via photosynthesis, while the sponge supplies the algae with a place to live. But the sponge also acquires nutrients by filter feeding. Inside the sponge, specialized cells filter out small floating organic particles, such as bacterioplankton and other microbes from the water, thus contributing to the health of the water body it inhabits.
I do detect a consistent theme that unites all three of these filter-feeding colonial organisms: they all contribute to the health and cleanliness of the lakes and ponds they reside in. Archer Vly is fortunate that all three thrive within its waters. I wonder if the increase in water temperature this hot summer has contributed to an increase in harmful organisms like certain algae or bacteria? And this increase in harmful organisms has contributed to the increase in these filter feeders' size and abundance as they gobble up the bad organisms? It doesn't seem all that unlikely, does it?
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