Over 400 California sea lions (Zalophus californianus) died and many others displayed signs of neurological dysfunction along the central California coast during May and June 1998. A bloom of Pseudo-nitzschia australis (diatom) was observed in the Monterey Bay region during the same period. This bloom was associated with production of domoic acid (DA), a neurotoxin that was also detected in planktivorous fish, including the northern anchovy (Engraulis mordax), and in sea lion body fluids. These and other concurrent observations demonstrate the trophic transfer of DA resulting in marine mammal mortality. In contrast to fish, blue mussels (Mytilus edulus) collected during the DA outbreak contained no DA or only trace amounts. Such findings reveal that monitoring of mussel toxicity alone does not necessarily provide adequate warning of DA entering the food web at levels sufficient to harm marine wildlife and perhaps humans.

Up and down go the cyanobacteria Plankton move together in strikingly coordinated daily patterns, sinking at night to avoid being eaten and rising to the surface in daylight to photosynthesize. Otteson et al. found similar activity patterns in even the smallest of planktonic organisms, such as photosynthetic bacteria (see the Perspective by Armbrust). Because it's hard to take regular samples in the open ocean, the authors built a robotic sampler and set it adrift for several days in the mid-Pacific. The captured bacteria showed immediate responses to changes in light, temperature, and salinity in ways that could affect the ocean's carbon and nitrogen cycles. Science , this issue p. 207 ; see also p. 134

The ecological patterns of many invertebrate larvae remain an ongoing mystery, in large part owing to the difficult task of detecting them in the water column. The development of nucleic-acid-based technology has the potential to resolve this issue by direct identification and monitoring of embryonic and larval forms in situ. We report herein on the successful development and application of nucleic-acid-based sandwich hybridization assays that detect barnacles using rRNA-targeted probes with both group-(order Thoracica) and species-(Balanus glandula) specificity. Primary results include the determination of target 18S rRNA sequences and the construction of "capture" probes for detection of larvae using hybridization techniques. In addition, we modified existing protocols for whole cell hybridization of invertebrate larvae as confirmation of the sandwich hybridization results. We used both hybridization techniques successfully in the laboratory on a plankton time series collected over 3 months, as well as a week-long in situ deployment of the technique in Monterey Bay, CA. The adaptability of this technology promises to be further applicable to various organisms and could be used to enhance our understanding of larval presence in the world's oceans.

Planktonic microbial activity and community structure is dynamic, and can change dramatically on time scales of hours to days. Yet for logistical reasons, this temporal scale is typically undersampled in the marine environment. In order to facilitate higher-resolution, long-term observation of microbial diversity and activity, we developed a protocol for automated collection and fixation of marine microbes using the Environmental Sample Processor (ESP) platform. The protocol applies a preservative (RNALater) to cells collected on filters, for long-term storage and preservation of total cellular RNA. Microbial samples preserved using this protocol yielded high-quality RNA after 30 days of storage at room temperature, or onboard the ESP at in situ temperatures. Pyrosequencing of complementary DNA libraries generated from ESP-collected and preserved samples yielded transcript abundance profiles nearly indistinguishable from those derived from conventionally treated replicate samples. To demonstrate the utility of the method, we used a moored ESP to remotely and autonomously collect Monterey Bay seawater for metatranscriptomic analysis. Community RNA was extracted and pyrosequenced from samples collected at four time points over the course of a single day. In all four samples, the oxygenic photoautotrophs were predominantly eukaryotic, while the bacterial community was dominated by Polaribacter-like Flavobacteria and a Rhodobacterales bacterium sharing high similarity with Rhodobacterales sp. HTCC2255. However, each time point was associated with distinct species abundance and gene transcript profiles. These laboratory and field tests confirmed that autonomous collection and preservation is a feasible and useful approach for characterizing the expressed genes and environmental responses of marine microbial communities.

In this contribution, we assess the application of methodology used in a novel in situ remote sampling platform, the environmental sample processor (ESP), for the identification and enumeration of a harmful algal species, the domoic acid-producing diatom Pseudo-nitzschia australis, using 2 molecular assays: a sandwich hybridization assay (SHA) and fluorescent in situ hybridization (FISH). Both the SHA and FISH assays were initially designed as laboratory-based methods that are now emulated in the ESP. Response of the SHA to a range of concentrations of P. australis using the laboratory (96-well plate) and ESP (DNA probe array) formats showed that the two were highly correlated. Enumeration of cells filtered and archived for FISH using a manifold designed for laboratory applications agreed well with counts of cells filtered and archived in the ESP at ≥2.5 × 10 4 cells L -1. At lower concentrations, it becomes statistically unlikely to derive a reliable abundance estimate, suggesting that FISH is better suited for qualitative analyses unless the target organism is very abundant. We also assessed the suitability of an oligonucleotide as synthetic target sequence to act as a SHA reagent quality control and internal standard for the plate assay. This was successful, but the probe and/or associated reagents were stable for onlỹ 60 days. Our results show that the ESP is capable of detecting P. australis in near real-time and also supports whole-cell archival samples, making it a potentially useful tool for future research and monitoring initiatives.