The relative roles of coastal and oceanic processes in determining physical and chemical characteristics of an intensively sampled nearshore system

Abstract

We compared the extent to which offshore and remote-sensing measurements of sea surface temperature (SST), upwelling, and chlorophyll a (Chl a) were concordant with in situ measurements of temperature, Chl a, and water nutrients at Tatoosh Island, Washington for the past 8 yr. Offshore SSTs were significantly correlated with water temperatures at Tatoosh, though consistently 2uC to 3uC warmer. Sea-viewing wide field-of-view sensor Chl a estimates were poor predictors of Chl a at Tatoosh Island measured with an anchored fluorometer. Nitrate and phosphorus estimates at Tatoosh Island were positively correlated with an upwelling index and negatively correlated with SST, as would be expected from an upwelling source. In contrast, ammonium and nitrite were uncorrelated with the upwelling index or SST and showed elevated levels immediately adjacent to Tatoosh Island, suggesting strong local effects of marine invertebrates, birds, and mammals on nutrient dynamics and cycling in coastal ecosystems.

Exploring B/Ca as a pH proxy in bivalves: relationships between <I>Mytilus californianus</I> B/Ca and environmental data from the northeast Pacific

“…In this study, we take advantage of a 9-year instrumental record of ocean environmental variables including pH and temperature (Pfister et al, 2007;Wootton et al, 2008) and use it to address the difficulties of correlating sclerochronological data from an organism with an uncertain growth history, sampled at a different frequency than available environmental data. We measure B concentration by ion microprobe in the shell of the California mussel, Mytilus californianus, and compare the relationship between measured B/Ca and an instrumental record of pH and temperature at the mussel's growth site, Tatoosh Island, Washington (Pfister et al, 2007;Wootton et al, 2008).…”

“…We measure B concentration by ion microprobe in the shell of the California mussel, Mytilus californianus, and compare the relationship between measured B/Ca and an instrumental record of pH and temperature at the mussel's growth site, Tatoosh Island, Washington (Pfister et al, 2007;Wootton et al, 2008). We use growth rates and environmental data to determine the growth chronology of M. californianus and discuss the various controls on B incorporation into the shell.…”

Community context mediates the top‐down vs. bottom‐up effects of grazers on rocky shores

“…Not surprisingly, ammonium concentrations were higher in both grazer present and grazer barrier treatments than they were in no grazer treatments. The increase in ammonium concentrations associated with grazers in our experimental treatments was within the natural variability in ammonium concentrations at the site where we collected the seaweeds and grazers (see Materials and methods) and similar to consumer-mediated increases in other intertidal locations (Pfister et al 2007, Aquilino et al 2009. A similar level of local-scale nutrient recycling by consumers can enhance seaweed growth in the field, even on wave-swept rocky shores (Aquilino et al 2009).…”

Ammonium cycling in the rocky intertidal: Remineralization, removal, and retention

“…Besides this single perturbation, the pools have been left intact and contain a natural assemblage of macroalgae (especially the red macroalgae Prionitis sternbergii, and articulated and crustose coralline algae), microphytobenthos, macrofauna, and plants such as the surfgrasses Phyllospadix scouleri and P. serrulatus. The biological composition of the tidepools has been documented and includes limpets, anemones, and fishes; while mussels were the dominant animals in un-manipulated tidepools (Pfister 2007), with an average of 51.3% cover of mussels, ranging from 10% to 95% cover in tidepools with mussels. There was a strong distinction in species composition between tidepools with and without mussels, with the percent cover of mussels correlating strongly with multivariate statistical distinction of the tidepools (r 5 20.905, p , 0.001; Fig.…”

“…Prionitis sternbergii were sampled 2 weeks prior to the experiment for baseline natural abundance 15 N values and transplanted into the pools with Z-Spar Epoxy TM (Pfister 2007). On the day of the experiment, the red-alga Corallina vancouveriensis, from a single source patch, was also sampled for 15 N natural abundance, inserted into pieces of Styrofoam, and floated in each pool.…”