Rapid Effects of Marine Reserves via Larval Dispersal

Marine reserves have been advocated worldwide as conservation and fishery management tools. It is argued that they can protect ecosystems and also benefit fisheries via density-dependent spillover of adults and enhanced larval dispersal into fishing areas. However, while evidence has shown that marine reserves can meet conservation targets, their effects on fisheries are less understood. In particular, the basic question of if and over what temporal and spatial scales reserves can benefit fished populations via larval dispersal remains unanswered. We tested predictions of a larval transport model for a marine reserve network in the Gulf of California, Mexico, via field oceanography and repeated density counts of recently settled juvenile commercial mollusks before and after reserve establishment. We show that local retention of larvae within a reserve network can take place with enhanced, but spatially-explicit, recruitment to local fisheries. Enhancement occurred rapidly (2 yrs), with up to a three-fold increase in density of juveniles found in fished areas at the downstream edge of the reserve network, but other fishing areas within the network were unaffected. These findings were consistent with our model predictions. Our findings underscore the potential benefits of protecting larval sources and show that enhancement in recruitment can be manifested rapidly. However, benefits can be markedly variable within a local seascape. Hence, effects of marine reserve networks, positive or negative, may be overlooked when only focusing on overall responses and not considering finer spatially-explicit responses within a reserve network and its adjacent fishing grounds. Our results therefore call for future research on marine reserves that addresses this variability in order to help frame appropriate scenarios for the spatial management scales of interest

The Effects of Contaminated Sediments on Representative Estuarine Species and Developing Benthic Communities. Chapter 21

-Bioassay techniques developed to examine acute and sublethal effects of dredged sediments on marine life are described. Results are reported for laboratory tests conducted to determine sublethal and acute effects of Kepone-sorbed sediment and dredged spoil material from the James River and the Houston Ship Channel on the mysid shrimp, Mysidopsis bahia; oyster, Crassostrea virginica; and polychaete, Arenicola cristatahttp://gbic.tamug.edu/request.ht

Cycling of xenobiotics through marine and estuarine sediments

-The results of five broadly defined projects are reported. Cycling of xenobiotics was studied with a photobioassay system that used time-lapse photography to evaluate effects of Kepone and sodium pentachlorophenate on feeding activity of the lugworm, Arenicola cristata . Radio-labeled methyl parathion was used to demonstrate fate and effect in microcosms inhabited by lugworms. Uptake and depuration of chrysene by lugworms was evaluated in a flow-through system. A toxic sediment bioassay system was developed to provide a means to test effects of dredge spoil. Keponesorbed sediment and dredge spoil from James River and Houston Ship Channel were tested for 28 days. Long-term tests (100 days), with the same systems, were used to evaluate effects of a specific drilling mud from an an active exploratory platform. Predator-prey tests of sublethal effects of xenobiotics demonstrated effect in one-prey and two-prey systems. Evaluation of sublethal effects, such as avoidance of pollution gradients, was studied in a trough-type avoidance-response system. Tests with pinfish demonstrated that they will avoid chlorine-produced oxidants. Usefulness of small-scale microcosms was evaluated by developing methods to culture polychaetes and crustaceans. Various aspects of the biology of selected species were studiedhttp://gbic.tamug.edu/request.ht

The secret to successful deep-sea invasion: does low temperature hold the key?

There is a general consensus that today’s deep-sea biodiversity has largely resulted from recurrent invasions and speciations occurring through homogenous waters during periods of the Phanerozoic eon. Migrations likely continue today, primarily via isothermal water columns, such as those typical of Polar Regions, but the necessary ecological and physiological adaptations behind them are poorly understood. In an evolutionary context, understanding the adaptations, which allow for colonisation to high-pressure environments, may enable us to predict future events. In this investigation, we examine pressure tolerance during development, in the shallow-water neogastropod Buccinum undatum using thermally acclimated egg masses from temperate and sub-polar regions across the species range. Fossil records indicate neogastropods to have a deep-water origin, suggesting shallow-water species may be likely candidates for re-emergence into the deep sea. Our results show population level differences in physiological thresholds, which indicate low temperature acclimation to increase pressure tolerance. These findings imply this species is capable of deep-sea penetration through isothermal water columns prevailing at high latitudes. This study gives new insight into the fundamentals behind past and future colonisation events. Such knowledge is instrumental to understand better how changes in climate envelopes affect the distribution and radiation of species both along latitudinal as well as bathymetric temperature gradients

Interaction of self-trapped beams in high index glass RID B-7564-2011 RID B-2099-2008

We observe attraction, repulsion and energy exchange between two self-trapped beams in a heavy-metal-oxide glass exhibiting a Kerr-like response with multiphoton absorption. The coherent interaction between spatial solitons is controlled by their relative phase and modeled by a nonlinear dissipative Schrodinger equation. (C) 2009 Optical Society of Americ