A 5.25‐m sediment core SRM‐1 and 45 surface samples from mangrove forests at the Shark River Estuary in the Everglades National Park, Florida, were examined by using X‐ray fluorescence and carbon isotopic analyses to study the history of intense hurricane landfall during the Late‐Holocene. Significance testing of the surface samples in relation to storm deposits from Hurricane Wilma suggests that elemental concentration of Sr and Cl and the ratio of Cl/Br are the most sensitive indicators for major hurricane events in our study area. The geochemical data sets of core SRM‐1 identified five active periods of intense hurricane activities during the last 3,500 years at ~3,400–3,000, ~2,200–1,500, ~1,000–800, ~600–300, and ~150 calibrated years before present to present. This is the longest paleohurricane record to date from South Florida. Our results are consistent with the view that intense hurricane activities in South Florida were modulated by Intertropical Convergence Zone (ITCZ) movements, El Niño/Southern Oscillation (ENSO) activities, and North Atlantic Oscillation (NAO) strength. This study contributes to the methodological advancement in paleotempestological studies by demonstrating that geochemical signals, particularly signals of saltwater intrusions, can be preserved in the sediment profiles on millennial time‐scale and measured by X‐ray fluorescence techniques, thereby enabling more storm records to be produced from otherwise suboptimal sand‐limited coastal systems such as the Florida Everglades. More work needs to be done to explore the use of geochemical and stable isotopic analyses in detecting storm signals from sand‐limited coastal environments.

Hurricanes are one of the most devastating earth surface processes. In 2020 and 2021, Hurricanes Zeta and Ida pounded the Mississippi River Delta in two consecutive years, devastated South Louisiana, and raised tremendous concerns for scientists and stakeholders around the world. This study presents a high-resolution spatial-temporal analysis incorporating planialtimetric data acquired via LIDAR, drone, and satellite to investigate the shoreline dynamics near Port Fourchon, Louisiana, the eye of Ida at landfall, before and after the beach nourishment project and recent hurricane landfalls. The remote sensing analysis shows that the volume of the ~2 km studied beachfront was reduced by 240,858 m³ after consecutive landfalls of Hurricanes Zeta and Ida in 2020 and 2021, while 82,915 m³ of overwash fans were transported to the backbarrier areas. Overall, the studied beach front lost almost 40% of its volume in 2019, while the average dune crest height was reduced by over 1 m and the shoreline retreated ~60 m after the two hurricane strikes. Our spatial-temporal dataset suggests that the Louisiana Coastal Protection and Restoration Authority’s (CPRA’s) beach nourishment effort successfully stabilized the beach barrier at Port Fourchon during the hurricane-quiescent years but was not adequate to protect the shoreline at the Mississippi River Delta from intense hurricane landfalls. Our study supports the conclusion that, in the absence of further human intervention, Bay Champagne will likely disappear completely into the Gulf of Mexico within the next 40 years.

Although many studies have attempted to reconstruct millennial‐scale hurricane patterns using various proxy‐based methods, it is still unclear what the most effective proxies are to identify storm surge deposits in different environmental settings. This study quantitatively compares the application of grain‐size, loss‐on‐ignition, stable isotopes, X‐ray fluorescence, and palynological proxies in paleotempestology from an organic‐rich environment in the Florida Everglades. The nonparametric tests indicate that only 9 among the 27 parameters (mean diameter, %water, %organic, %carbonate, Ca, Sr, Ca/Ti, Cl/Br, and marine microfossils) exhibited significant differences between storm‐surge and in situ deposits. The principal component analysis shows that five marine indicators (Sr, Ca, Ca/Ti, %Carbonate, and Marine microfossils) have the closest association with the allochthonous samples, while Cl/Br and Mz are the most sensitive proxies in low‐ and high‐energy environments, respectively. Moreover, organic geochemical proxies (e.g., δ¹³C and δ¹⁵N of bulk sedimentary organic matter) are ineffective for identifying storm‐surge deposits in organic‐rich mangrove environments.

Sedimentary DNA (sedaDNA), pollen, and charcoal records from two sediment cores along the lower Negro River floodplain revealed complementary ecological and hydrological patterns throughout the Holocene in the main blackwater river located in central Amazonia. The sedaDNA record from the Lake Pacú sediment core (~9440–370 cal yr BP) provides unprecedented insight into microbial and planktonic communities across millennial-scale environmental changes. During the early Holocene (~9440–8852 cal yr BP), the presence of planktonic diatoms (Discostella nipponica, Melosira varians) and ciliates (Rimostrombidium sp., Strombidium sp.) indicate shallow, moderately productive waters with relatively low acidity compared with current Negro River conditions. A transition from ~8852 to 4520 cal yr BP is characterized by increased biological diversity compared to the early Holocene, with higher abundances and taxonomic richness of diatoms, ciliates, rotifers (Brachionus sp., Asplanchna brightwellii), and Chlorophyta (Pyramimonas tetrarhynchus). These assemblages suggest episodes of elevated nutrient input, temporary water column stratification and hydrological connectivity with surrounding floodplain environments. This interval reflects a dynamic limnological regime, with productivity fluctuating under seasonal flooding and broader hydroclimatic variability. The Late Holocene interval (~4520–370 cal yr BP) shows a pronounced ecological shift. Particularly around ~3000 cal yr BP, sedaDNA reveals the occurrence of mesotrophic diatoms, green algae, rotifers and ciliates, taxa not found under the acidic, humic waters of the Negro River. These conditions were likely driven by river connectivity, changes in water level and flow from tributaries such as the Branco River, whose chemical properties differ significantly from the Negro River. After this interval, these taxa decline toward the most recent samples, reflecting a return to more acidic, low productivity conditions similar to the river today. Complementarily, palynological data from the Apuaú River sediment core (~6450–3540 cal yr BP), a left bank tributary of the Negro River, document simultaneous expansion of Várzea type vegetation and the presence of mesotrophic diatoms (~13%), reinforcing a regional pattern of increased nutrient flux and hydrological heterogeneity during the mid- to late Holocene. Additionally, charcoal peaks dated to ~3320–2620 cal yr BP indicate intensified fire activity during the late Holocene, most likely associated with a regional dry phase rather than anthropogenic activity. Overall, our multi-proxy reconstruction of the lower Negro River provides a rare molecular record throughout the Holocene, revealing shifts in aquatic communities, vegetation and fire regimes in central Amazonia.

Sedimentary ancient DNA (sedaDNA) has emerged as a powerful proxy for reconstructing past biodiversity and environmental change in lacustrine and coastal systems, yet standardized field guidance remains limited, particularly for researchers working in tropical and coastal depositional environments. Here, we present a practical sampling framework covering the key field protocols of sedaDNA research, from field collection to laboratory subsampling, with emphasis on contamination control at each step. We review recent sedaDNA applications across multiple research fields, highlighting the growing interdisciplinary relevance of the technique. Particular attention is given to the challenges of DNA preservation in dynamic depositional environments, including coastal and semi-arid regions, where shallow, physically reworked sediments and recurring human disturbance amplify degradation and contamination risks. A Brazilian case study from Itapipoca, Ceará, illustrates how the absence of basic contamination precautions during excavation of Late Pleistocene megafaunal deposits produced metabarcoding results dominated by modern domesticated and synanthropic taxa, making the dataset uninterpretable for paleoecological reconstruction. Together, the guidelines and case study demonstrate that rigorous contamination control is not optional but essential to credible sedaDNA research, especially in tropical and coastal systems, environments that are scientifically underrepresented and increasingly threatened by anthropogenic change.