What the divers found<\/h2>\n\n\n\n
\u201cYou could see crayfish, small fish, pike,\u201d diver Luk\u00e1\u0161 Jus\u010d\u00edk said, translated from Slovak. His account describes a varied underwater landscape where wildlife lives among submerged features that visitors on the bank rarely get to see.<\/p>\n\n\n\n
The animal trap caught another diver\u2019s attention. \u201cIt\u2019s very old,\u201d he said, also translated from Slovak, although the account provides no date or explanation of how it arrived.<\/p>\n\n\n\n
The boat and drone add further questions about the lake\u2019s human history. Their presence is documented, but the circumstances behind their arrival remain unclear, and the written account does not say whether the objects were recovered.<\/p>\n\n\n\n
A lake shaped by landslides<\/h2>\n\n\n\n
Morsk\u00e9 Oko lies in the Vihorlat Mountains of eastern Slovakia, a densely forested region with a volcanic past. A major landslide blocked a stream valley, allowing water to collect behind the natural barrier and form the lake.<\/p>\n\n\n\n
Today, it covers roughly 34 acres, and <\/a>regional tourism information<\/a> puts its deepest water at about 82 feet. Those dimensions help explain how much of this landscape remains beyond the view of someone standing on the bank.<\/p>\n\n\n\n Its present shape also reflects <\/a>human intervention<\/a> long before the lost drone arrived. The <\/a>conservation authority<\/a> says a dam raised the water level by approximately 16 feet, expanding a lake that originally covered about 17 acres.<\/p>\n\n\n Why leave a fallen tree in the water? In a lake, <\/a>trunks and branches<\/a> create shelter and feeding areas, turning what looks like untidy debris into useful space for aquatic animals.<\/p>\n\n\n The <\/a>Wisconsin Department of Natural Resources<\/a> describes this role in its own lake conservation work. Its \u201cFish Sticks\u201d projects place woody structures near shorelines to restore habitat, showing why submerged wood deserves consideration when people manage a lake.<\/p>\n\n\n\n That ecological context helps explain the importance of the trees described at Morsk\u00e9 Oko. A blanket effort to clear the bottom could remove shelter along with unwanted objects, so identifying what actually supports wildlife matters before any cleanup begins.<\/p>\n\n\n\n The divers initially encountered reduced visibility that the report attributed to cyanobacteria. As they descended, the water became clearer, allowing more of the underwater landscape to come into view.<\/p>\n\n\n\n Often called blue-green algae, cyanobacteria are bacteria that use sunlight for energy. Some can produce toxins, according to the <\/a>U.S. Environmental Protection Agency<\/a>, but the presence of a bloom does not automatically establish that toxins are present. Water testing is needed to answer that question.<\/p>\n\n\n\n That distinction matters here because the account provides no laboratory results identifying toxins or measuring nutrient concentrations. Better visibility deeper down tells us what the divers could see, while questions about <\/a>water quality<\/a> require measurements that a visual inspection alone cannot supply.<\/p>\n\n\n\n The divers also faced a sharp temperature change underwater, although the written account gives no measured temperatures. That observation is consistent with thermal stratification, the layering that develops when warmer water sits above colder, denser water.<\/p>\n\n\n\n Researchers at the <\/a>International Institute for Sustainable Development\u2019s Experimental Lakes Area<\/a> explain that sunlight heats surface water more quickly than deeper water. Between warmer and colder layers, a zone of rapid temperature change can create the sudden chill that swimmers sometimes notice around their feet. The strongest temperature change occurs at the \u201cthermocline.\u201d<\/p>\n\n\n\n This layering matters beyond comfort. It can limit mixing between surface and deep water, affecting <\/a>how oxygen reaches the bottom<\/a>, although the dive account does not establish whether oxygen was low at Morsk\u00e9 Oko.<\/p>\n\n\n\n Morsk\u00e9 Oko is part of the Vihorlatsk\u00fd prales reserve, and its calm appearance does not mean few people visit. An October 7 update from the conservation authority recorded 21,105 visitors around the lake between June 15 and September 15, 2026, including 19,819 walkers and 1,286 cyclists.<\/p>\n\n\n\n That total was about 18 percent lower than the previous summer, but it still represents substantial foot and bicycle traffic. The authority stresses that these figures cover the lake locality, mainly arrivals from Remetsk\u00e9 H\u00e1mre, rather than the entire reserve.<\/p>\n\n\n\n For visitors, regional tourism guidance lists swimming, boating and fishing as prohibited, leaving the shoreline as the place to appreciate the lake. The official visitor update was published on <\/a>CHKO Vihorlat\u2019s website<\/a>.<\/p>\n\n\n Photo: Archive of the CHKO Vihorlat Administration<\/p>\n","protected":false},"excerpt":{"rendered":" Divers exploring Slovakia\u2019s Morsk\u00e9 Oko encountered crayfish, pike and fallen trees beneath its quiet surface, along with some unexpected human … <\/p>\n![\"Black-and-white](\"https:\/\/www.ecoticias.com\/en\/wp-content\/uploads\/2026\/10\/morske-oko-1977.jpg\")
Fallen trees have a job<\/h2>\n\n\n\n
![\"A](\"https:\/\/www.ecoticias.com\/en\/wp-content\/uploads\/2026\/10\/fallen-log-shore.jpg\")
What cloudy water can tell us<\/h2>\n\n\n\n
The sudden chill below<\/h2>\n\n\n\n
A busy shoreline to protect<\/h2>\n\n\n\n