Source, distribution, and transformation of dissolved and particulate organic matters in Qinzhou Bay, Northern Beibu Gulf

Frontiers in Marine Science, Год журнала: 2023, Номер 10

Опубликована: Апрель 18, 2023

Both dissolved and particulate organic matters (DOM POM) provide a reduced carbon pool of considerable size in coastal ecosystems, the two are closely linked. Currently, however, integrated study DOM POM remains limited, precluding more in-depth understanding their interaction regions. In April 2021, 13 surface water samples were collected from Qinzhou Bay, northern Beibu Gulf. The characterized using (DOC) analysis UV-visible fluorescence spectroscopy techniques. We determined for nitrogen (POC PN) also isotopic composition (δ C δ 15 N). weak to negligible relationships found between DOC, colored fluorescent DOM, salinity, chlorophyll together suggested that DOM’s distribution Bay is concurrently shaped by various processes, namely, hydrological situ biological processes. A high C/N ratio ~17, POC/chlorophyll (253 ± 112), depleted (−25.7 1.6‰) confirmed highly degraded originates mainly allochthonous input, which terrigenous matter freshwater phytoplankton each contributes 35%. total (TOC = DOC + POC) was positively correlated with humic-like peak M, revealing transformation labile into recalcitrant components. production efficiency M waters one order magnitude greater than inland or open oceans, indicating not only temperature but activity substrate key factor controlling Bay. High levels TOC suggest mass coexistence differing its reactivity, highlighting large potential photochemical as well microbial degradation future.

Язык: Английский

---

Stable isotopic and stomach content analyses reveal changes in the trophic level and feeding habit of large-head hairtail (Trichiurus lepturus) in the northern South China Sea

The Science of The Total Environment, Год журнала: 2023, Номер 896, С. 165313 - 165313

Опубликована: Июль 4, 2023

Язык: Английский

---

Crucial Role of Tributary Bays in the Carbon Burial of Three Gorges Reservoir

ACS ES&T Water, Год журнала: 2024, Номер 4(4), С. 1315 - 1324

Опубликована: Фев. 5, 2024

Tributary bays, which are formed in river tributaries for reservoir construction with a relatively lentic environment, have been estimated to hold unique biogeochemical processes and be involved ecological issues (e.g., algal bloom). Nevertheless, the role of tributary bays carbon cycling is unclear, precluding an accurate assessment budgets reservoirs. To fill this knowledge gap, we take Three Gorges Reservoir (TGR) as example assess budget typical bay (Xiangxi River, XXR) TGR. With laboratory experiments numerical models, demonstrate that XXR may important sink. This study exhibits primary productivity enhancement bloom) plays critical CO2 sequestration contributes significantly burial. Moreover, organic burial flux TGR equivalent (22 ± 9) % mainstream, demonstrating crucial Considering scientific debate on whether sink or source, suggest overlooking might lead significant error assessing budget.

Язык: Английский

---

Particle composition-specific approach to estimate the particulate organic carbon concentration off the coastal areas of Guangdong and eastern Hainan Island

Optics Express, Год журнала: 2024, Номер 32(15), С. 25644 - 25644

Опубликована: Июнь 19, 2024

High optical complexity caused by the variability of marine particles poses a major challenge to development bio-optical algorithms for particulate organic carbon (POC) concentration retrievals from measurements in coastal waters. Here, we developed particle composition-specific approach estimate POC off areas Guangdong and eastern Hainan Island, China. The ratio phytoplankton absorption detritus coefficient aph(443)/ad(443) was used optically discriminate water types. samples with ≤ 4.9 showed significant correlation between line height at 676 nm aLH(676) (R2 = 0.75, n 70, p < 0.01). In contrast, aph-dominant > had high covariance scattering 675 bp(675) 0.85, 37, Validation an independent dataset yielded small positive bias 0.81, APD 23.10%, RMSE 29.01 mg m

Язык: Английский

---

The Seasonal Effect of Coastal Current and Upwelling on the Dynamics of Dissolved Organic Matter in the Northwestern South China Sea

Journal of Geophysical Research Oceans, Год журнала: 2024, Номер 129(7)

Опубликована: Июнь 27, 2024

Abstract Previous studies have primarily focused on the impact of human activities coastal dissolved organic matter (DOM) cycles, while neglecting role dynamic processes. This limits our comprehensive understanding processes DOM, particularly in waters affected by multiple In this study, dynamics DOM northwestern South China Sea (SCS) were investigated using DOM‐related parameters and a three end‐member mixing model, which accounted for effects currents upwelling during spring, summer, winter seasons. Our results demonstrated that net addition was predominantly observed nearshore all seasons, owing to strong induced phytoplankton production particle desorption. However, weaker spring winter, removal decomposition western offshore area. observation can be attributed abundance microorganisms increased vertical water winter. Conversely, stronger provided more bio‐refractory limiting its decomposition, whereas stimulated productivity desorption, resulting period. eastern area, primary mechanism eliminating weak or absent upwelling. study revealed is widespread regions SCS facilitate DOM.

Язык: Английский

---