The estuary of the Danshuei River, a hypoxic subtropical estuary, receives a high rate of untreated sewage effluent. The Ecopath with Ecosim software system was used to construct a mass-balanced trophic model for the estuary, and network analysis was used to characterize the structure and matter flow in the food web. The estuary model was comprised of 16 compartments, and the trophic levels varied from 1.0 for primary producers and detritus to 3.0 for carnivorous and piscivorous fishes. The large organic nutrient loading from the upper reaches has resulted in detritivory being more important than herbivory in the food web. The food-chain length of the estuary was relatively short when compared with other tropical/subtropical coastal systems. The shortness of food-chain length in the estuary could be attributed to the low biomass of the top predators. Consequently, the trophic efficiencies declined sharply for higher trophic levels due to low fractions of flows to the top predators and then high fractions to detritus. The low biomass of the top predators in the estuary was likely subject to over-exploitation and/or hypoxic water. Summation of individual rate measurements for primary production and respiration yielded an estimate of -1791 g WW m(-2) year(-1), or -95 g C m(-2) year(-1), suggesting a heterotrophic ecosystem, which implies that more organic matter was consumed than was produced in the estuary.
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http://dx.doi.org/10.1016/j.marpolbul.2007.07.008 | DOI Listing |
Killer whales () have been documented to prey on white sharks (), in some cases causing localised shark displacement and triggering ecological cascades. Notably, a series of such predation events have been reported from South Africa over the last decade, with killer whales specifically targeting sharks' liver. However, observations of these interactions are rare, and knowledge of their frequency across the world's oceans remains limited.
View Article and Find Full Text PDFEcology
January 2025
Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, California, USA.
Understanding how foundation species recover from disturbances is key for predicting the future of ecosystems in the Anthropocene. Coral reefs are dynamic ecosystems that can undergo rapid declines in coral abundance following disturbances. Understanding why some reefs recover quickly from these disturbances whereas others recover slowly (or not at all) gives insight into the drivers of community resilience.
View Article and Find Full Text PDFUnlabelled: Top predators have oversized impacts on food webs and ecosystem dynamics, and introducing a novel predator to a naive environment can have dramatic consequences for endemic biodiversity. Lake Tanganyika is unique among African lakes in the diversity of the pelagic top predators in the genus , where four species are endemic to the lake. Using a combination of reduced-representation and whole genome resequencing data, and pairing these with phylogenetic and demographic modeling approaches, we find that colonization of Lake Tanganyika was much more recent (∼1-2 Mya) than other major and diverse clades within the lake.
View Article and Find Full Text PDFNutrients
January 2025
Laboratory of Nutritional Biochemistry, Department of Clinical Nutrition, Medical University of Gdansk, 80-211 Gdansk, Poland.
As an endurance multi-sport race, triathlon places significant energy demands on athletes during performance and training. Insufficient energy intake from food can lead to low energy availability (LEA) and Relative Energy Deficiency in Sport (RED-S). We aimed to measure symptoms related to LEA, examine the risk of RED-S, and find how diet relates to the risk of RED-S in highly trained female amateur triathletes.
View Article and Find Full Text PDFIntest Res
January 2025
Department of Gastroenterology and Hepatology, Kyorin University School of Medicine, Mitaka, Japan.
Background/aims: Crohn's disease (CD) leads to bowel damage and disability if suboptimally treated. We investigated firstyear treatment decisions and real-world use of biologics in patients with CD in Japan.
Methods: In this retrospective observational study (2010-2021) from the JMDC claims database, patients with a new diagnosis of CD (no CD claims record within 12 months before index) who received ≥ 1 pre-defined treatment were grouped by use of biologics and systemic corticosteroids (SCS) within the first year of diagnosis.
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