Branched glycerol dialkyl glycerol tetraethers (brGDGTs) of purportedly terrestrial origin are frequently detected in marine sediments, even in remote ocean sites where no direct impact from land erosion via rivers takes place. At these places, the most likely explanation for the presence of brGDGTs is in situ production or eolian...
The seasonality of sea surface temperatures (SST) estimated from the alkenone-U[superscript K’]₃₇ index has been a debated issue since the development of the sediment trap time series data from 34 sampling locations, we show that the maximum alkenone flux in sediment traps varies markedly across the oceans, only on latitude...
Climate regime shifts force fish communities through rapid transitions between alternate species assemblages, but little is known about the role that biochemical ecology plays in these transitions. We document a biochemical effect of climate-induced community transitions in boreal oceans: opposite population trajectories of lipid-rich and lipid-poor fish species. We compared...
Analysis of suspended particulate material (SPM) collected from the Columbia River and its estuary in 2007–2008 revealed the ubiquitous presence of polycyclic aromatic hydrocarbons (PAHs) from several distinct sources. The two dominant ones were: (1) a suite of non-alkylated, three to five-ringed compounds derived from high temperature combustion and (2)...
The flow through the Bering Strait, the only Pacific-Arctic oceanic gateway, has dramatic local, regional, and global impacts. Advanced year-round moored technology quantifies challengingly large temporal (subdaily, seasonal, and interannual) and spatial variability in the ~85 km wide, two-channel strait. The typically northward flow, intensified seasonally in the ~10–20 km...
Summertime carbon, nitrogen, and biogenic silica export was examined using ²³⁴Th:²³⁸U disequilibria combined with free floating sediment traps and fine scale water column sampling with in situ pumps (ISP) within the Eastern Tropical North Pacific and the Gulf of California. Fine scale ISP sampling provides evidence that in this system,...
Di-nitrogen (N₂) fixation plays a well-recognized role in the enhancement of primary production
and arguably particle export in oligotrophic regions of the subtropical and tropical oceans.
However, recent evidence suggests that N₂ fixation may also be significant in regions of the
surface ocean proximate to or overlying zones of intense...
Plant wax lipids and lignin phenols are the two most common classes of molecular markers that are used to trace vascular plant-derived OM in the marine environment. However, their ¹³C and ¹⁴C compositions have not been directly compared, which can be used to constrain the flux and attenuation of terrestrial...
Two major types of glycerol dialkyl glycerol tetraethers (GDGTs) are commonly
used in paleoecological and paleoclimatological reconstructions: isoprenoidal and
branched GDGTs. In aquatic environments, it was originally assumed that isoprenoidal
GDGTs, especially crenarchaeol, derive mainly from aquatic Thaumarchaeota, whilst
branched GDGTs are an allochthonous input derived from soil Bacteria. Recently,...
The localized impact of blooms of the mixotrophic ciliate Myrionecta rubra in the Columbia River estuary during 2007-2010 was evaluated with biogeochemical, light microscopy, physiological, and molecular data. M. rubra affected surrounding estuarine nutrient cycles, as indicated by high and low concentrations of organic nutrients and inorganic nitrogen, respectively, associated...