Explanation Of Marine Lake Formation At Misool Raja Ampat West Papua, Indonesia

Marine lake in a karst landscape is one of the macro karst forms known as doline and is only found in some locations in the world. Moreover, the theory of marine doline formation is always associated with global sea-level rise which differs from one place to another due to several factors. This research was conducted to understand the formation process of marine lakes in Misool and how the water fills the basins formed especially at Holocene time. This was achieved by obtaining information on the longest underwater terrace which is also the longest standing water position recorded on the sea wall. The marine terraces were measured by sounding profiles to the sea bordering the seven marine lakes including Lenmakana, Balbullol, Lenkafal, Keramat, Karawapop, Keramat-2, and Keramat-3 as well as Harapan Jaya Sea. A total of 24 profiles were measured and stable isotopes δ18O and δD of water samples were used to determine the origin of water in the lakes. The results showed the longest terrace was at the depth of ˗33 and ˗3 m while the references from the area closest to Misool showed the same water level positions at 10,500 BP and 6,985 BP. Furthermore, the composition of δ18O and δD from lake water indicated the water samples were a mixture of groundwater and seawater with the seawater having the more dominant concentration and this allows it to fill the lake first through a previously formed cavity system.

Occurrence and Distribution of Technology-critical Elements (TCE) in Recent Freshwater and Marine Pristine Lake Sediments in Croatia: a Case Study

The appearance and vertical distribution of technology-critical elements (TCE) such as Li, Nb, Sc, Ga, Y, La, Sb, Ge, Te, and W were investigated in sediment cores taken in pristine freshwater and marine lakes located within protected areas of Croatia (Plitvice Lakes, Visovac Lake, and Mir Lake). These lake systems are isolated from the direct impact of human activities, and accordingly, the geochemical research in such environments may help to assess temporal trends in historical deposition of anthropogenic TCE. The analytical method of choice in determining the concentration of TCEs was High resolution inductively coupled plasma - mass spectrometry (HR ICP-MS). The results obtained have shown that the measured TCE spanned with wide ranges of concentrations, as a result of the different input of terrigenous material into the investigated lake systems which is further diluted by the formation of authigenic and biogenic carbonates. Evaluation of the anthropogenic impact on TCE levels showed low enrichment of Sb and Te in the upper sediment layers of the Mir Lake and the Plitvice Lakes. Despite that, concentrations of investigated TCE were low, compared to results described in the literature, indicating that the investigated remote lakes can be considered uncontaminated with these elements.

Water Temperature Increasing Caused Mastigias Papua Disappeared in Marine Lake Lenmakana Misool Raja Ampat Regency, West Papua

Mastigias papua is a jellyfish that is trademark of marine lakes. Ongeim’l Tketau Lake in Palau, Hang Du I Lake in Vietnam, Kakaban Lake in Kalimantan, and Lenmakana Lake in Raja Ampat Papua are exotic tourist destinations because of presence of these biota in the lake. Water temperature is very influential on the life of a jellyfish because of its mutual symbiosis with brown algae zooxanthellae. Mastigias has totally disappeared in several places due to water temperature increasing, including Lenmakana Lake in the West Monsoon 2017/2018 and 2018/2019. The absence of Mastigias in this lake will be explained by recorded logger data installed in the lake and at sea. Secondary data from NOAA and BMKG will be used to explain the condition of absence of jellyfish. Water lake temperature data showed an increase to 2.5oC when the Mastigias disappeared. Temperature increasing occur due to seasonal cycle patterns of lake water temperatures and weather cycles which change in time, the dry season occurs faster and the rainy season occurs slower. Conversely, in the West Monsoon 2019/2020, Mastigias still found in the lake. The rainy season which is 20 days faster than normal condition helps reduce the heat in West Monsoon.

A new genus and two new species of sea stars (Family Asterinidae) from Indonesian marine lakes, with notes on habitat and feeding ecology

A new genus of asterinid asteroid, Limnasterias gen. nov. and two new species, Limnasterias oinops sp. nov. and L. estradivariae sp. nov. are described from two East Kalimantan marine lakes, Indonesia. Limnasterias is differentiated from other asterinid genera by a combination of features: high aspect body with thick tissue covering; extensive papulate area; numerous single papulae in up to five rows at ray sides; boot-shaped inferomarginal plates; appressed superactinal plates and absence of superambulacral plates. The ecology and conservation of these species and their unique habitat are discussed.

Microbes and macro-invertebrates show parallel β-diversity but contrasting α-diversity patterns in a marine natural experiment

Documenting ecological patterns across spatially, temporally and taxonomically diverse ecological communities is necessary for a general understanding of the processes shaping biodiversity. A major gap in our understanding remains the comparison of diversity patterns across a broad spectrum of evolutionarily and functionally diverse organisms, particularly in the marine realm. Here, we aim to narrow this gap by comparing the diversity patterns of free-living microbes and macro-invertebrates across a natural experiment provided by the marine lakes of Palau: geographically discrete and environmentally heterogeneous bodies of seawater with comparable geological and climatic history, and a similar regional species pool. We find contrasting patterns of α-diversity but remarkably similar patterns of β-diversity between microbial and macro-invertebrate communities among lakes. Pairwise dissimilarities in community composition among lakes are positively correlated between microbes and macro-invertebrates, and influenced to a similar degree by marked gradients in oxygen concentration and salinity. Our findings indicate that a shared spatio-temporal and environmental context may result in parallel patterns of β-diversity in microbes and macro-invertebrates, in spite of key trait differences between these organisms. This raises the possibility that parallel processes also influence transitions among regional biota across the tree of life, at least in the marine realm.