Research into how caves form increasingly reveals the critical role of microbes in promoting chemical erosion through the production of acidic byproducts. The caves of Gunung Mulu National Park in Sarawak, Malaysia, offer a setting to explore a novel nitrogen-driven method of cave passage modification and enlargement. These caves include some of the world's largest and longest cave systems, including Clearwater Cave, which extends over 250 kilometers, and many of these caves feature unusual formations, such as massive ceiling scallops and corroded speleothems. We suggest that these distinctive features result from dissolution caused by microbial activity.

Microbial activity within the nitrogen-rich guano from birds and bats in the caves generates ammonia gas. This ammonia adheres to moisture on cave walls, where microbes recapture the ammonia and metabolize it, producing nitric acid as a byproduct and leading to the chemical dissolution of the rock. Using several analytical techniques, both in the field and in the lab, we propose that nitrogen-driven dissolution is a common process in tropical caves, and that this mechanism may play a significant role in enlarging cave passages after their initial formation.

Although sulphuric acid caves (SAS Caves) have been known of for over two centuries (Socquet described a SAS cave in Aix-les-Bains in 1801), these caves were considered as "geological oddities". They rank among the "hypogene" caves, and are important for the understanding of void formation not directly connected to present-day meteorology and surface morphology (e.g., hydrocarbon reservoirs, Mississippi valley type Pb-Zn ore deposits). Since the discovery of Lechuguilla Cave in New Mexico and Movile Cave in Romania (both in 1986) speleological and karstological research has intensified and many more SAS caves have been discovered and recognized.

Today over 90 SAS cave occurrences have been reported around the world, and their number is increasing steadily as cavers have started to recognize their typical morphologies and by-products. This talk, prepared in collaboration with Ilenia Maria D'Angeli, will show the distribution of SAS caves in the world, the different typologies, their unique morphology and by-products, their role in understanding landscape evolution, and their intriguing microbiology and biology.

In this talk, I will present data collected from Maaras Cave over the past seven years, focusing primarily on hydrogeology and geomorphology. The Maaras Cave system is located along the northwestern margin of the Aggitis River basin. It contains an active fluvial system fed by a closed karstic basin, the Kato Nevrokopi polje, to the northwest. The cave is formed within the marbles of the Rhodope Massif and exhibits a distinct morphological pattern. It lacks closed loops and follows a hierarchical structure, where lower-order tributaries merge into higher-order passages. The system consists of two main tributaries, an eastern and a western branch—that converge into a single conduit flowing toward the spring a typical branchwork cave following Palmer's classification.

If you want to know more about caves and fossil mammal remains from Mae Hong Son Province, in north-western Thailand, then join me for this talk where I am going to share everything from my most recent research fieldwork in Thailand, in January 2024.

One of the most interesting and important sites that I visited was Tham Lod rock shelter where I sampled teeth fron Eld's deer. Tham Lod is a magnificent and famous cave and a well-stratified archaeological site, where more than 100,000 archaeological items were unearthed during previous excavations. I and my NERC DTP PhD student Laura Hemmingham have had the opportunity to collect samples of over 200 fossil deer teeth, excavated from several Thailand caves and open sites.

Through the Eld's deer project we studied the diet of Pleistocene deer in relation to climate using the methods of dental wear analysis (DWA), mesowear and species distribution models. My research focuses on palaeoecology of the Quaternary and I am analysing tooth material to understand what these animals ate during the Ice Age and how they responded to environmental and ecological changes.

I started caving in 2002 and have participated in multiple caving expeditions with the Hellenic Speleological Society and with speleologists from Vienna University. I completed my undergraduate degree in Geology, and my Masters degree in Palaeontology, in Greece. My PhD in Palaeontology was from Royal Holloway University of London. I moved to London in 2010 and since September 2015 I have been working as a curator in the Natural History Museum (NHMUK). I am responsible for fossil mammals (over 350,000 specimens from around the world). During this talk I will be also presenting tales and projects that I had the opportunity to work on from other European and UK cave sites.

The natural world is full of tiny magnets: in the soil, in the water, and even in caves. These magnets have fascinating histories that can tell us about changes in the Earth's magnetic field, about rainfall and temperature, about soil microbes and even about industrial pollution. While scientists have been studying natural magnets for many years, it is only recently that magnetometers have become sensitive enough to measure the magnetism of cave deposits, like stalagmites and stalactites. This talk will introduce the wonderful world of cave magnetism, focusing particularly on our recent magnetic study of the flooding history of Waipuna Cave, New Zealand.

Abstract not available

The Raking Light team are working with the management at Kents Cavern, Torquay on a project to record and research the myriad inscriptions and other markings left behind by visitors to the cave. Early researchers such as Father John McEnery and William Pengelly noted many of the inscriptions they found but noted that some were already being lost to a covering of calcite. As part of the cave's conservation plan, the aim is to record and photograph the current state of the inscriptions as well as other marks throughout the cave made with chalk, candle smoke and pencil. The project is amassing a wealth of detail about early visitors to the cave and, working with genealogical and historic records, the team hopes to shine a light on the identity of some of these people.

In the late 19th century, inspired by rich paleontological and archaeological finds in temperate caves, scientists began to systematically explore the caves of peninsular Malaya and Borneo. Early speleologists were stymied by what they perceived as a general absence of artefacts, remains, and specialised animal species. Their conclusions led to a colonial perception of Malaya as a land where there is nothing old but nature. By 1900, scientific attention also turned to bat guano, on the cave floors, and how it might be commercially exploited as a phosphate fertiliser source for the growing plantation economy. In the writings of archaeologists, an antagonism developed towards these guano diggers whose excavations disturbed the stratigraphy of potential field sites. This talk will trace the work of subsequent cave archaeologists through the first half of the 20th century, centring on Batu Caves in Selangor, Gunung Pondok in Perak, and Niah Caves in Sarawak. Attempts to establish the prehistory of Malaya and Borneo coincided and interacted, in the 1950s and 60s, with the writing of a history of the new nation of Malaysia. I will conclude by considering the legacies of colonial speleology on research in the last several decades.